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Space Studies Board Annual Report 1998 (1999)

Chapter: 3. Summaries of Major Reports

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Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3 Summaries of Major Reports

3.1 Report of the Workshop on Biology-based Technology to Enhance Human Well-being and Function in Extended Space Exploration

A Report of the Steering Group for the Workshop on Biology-based Technology for Enhanced Space Exploration1

EXECUTIVE SUMMARY

Biological systems are regenerative, energy and size efficient, and adaptable to changing environments. As humans venture further into space and spend longer periods of time there, these attributes may provide the basis for technologies that can sustain life in deep space and on other planets.

This concept was explored at the Workshop on Biology-based Technology to Enhance the Human Presence in Extended Space Exploration, held on October 21-22, 1997, by the Space Studies Board (SSB) of the National Research Council at the Center for Advanced Space Studies in Houston, Texas. The objective was to identify areas in biology-based technology research that appear to hold special promise for carrying biological science into technology directly applicable to space exploration.

Workshop participants sought to identify how biological concepts and principles might contribute to enabling technologies for long-duration missions involving the actual presence of humans (as opposed to robots only) at exploration sites on other planets, such as Mars (see Chapter 1). In the 2010 to 2020 time frame and beyond, NASA proposes to carry out international human missions to planetary bodies such as Mars (a mission of at least 600 days) with no crew rotation or resupply available. Such a mission is beyond today's technical capabilities. Advances are needed in a variety of technical areas to reduce risk, equipment weight, power requirements, and costs as well as to increase reliability.

The workshop's two discussion sessions focused on biology-based research areas with a potential for (1) enhancing human well-being in space exploration and (2) enhancing human presence and function in space exploration. Because the workshop was intended as an initial effort and not a detailed scientific investigation, participants dealt with the discussion topics in a somewhat conceptual manner and did not attempt to assess their merits.

Based on discussions in the two sessions and on their quantitative judgments, participants identified six topics that seem promising enough in the near term to warrant further examination in follow-on workshops: closed-loop

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“Executive Summary” reprinted from Report of the Workshop on Biology-based Technology to Enhance Human Well-being and Function in Extended Space Exploration, National Academy Press, Washington, D.C., 1998, pp. 1-6.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

aquaculture systems as a model for advanced life support (ALS) water processing and waste management systems; biosensors for detecting pollutants and pathogens in air and water; biomaterials for spacecraft and habitats; space suit design incorporating biological concepts; use of magnetoencephalography to monitor astronauts' cognitive states; and synergistic human-robot systems. Also identified in each session were additional areas in which R&D advances by NASA or others may benefit the space program either in the near term or over the longer term.

The concepts discussed in sessions 1 and 2 are described in Chapters 2 and 3, respectively. Chapter 4 touches briefly on workshop participants' observations regarding points for considerations in any follow-on activities—including the importance of defining specific technical requirements for long-duration human exploration of space and the usefulness of tracking developments in fields other than aeronautics and space science that may contribute to the application of biology-based systems and principles in Human Exploration and Development of Space (HEDS) Enterprise missions.

OPPORTUNITIES FOR APPLYING BIOLOGICAL CONCEPTS AND PRINCIPLES
Enhancing Human Well-Being

Session 1 participants sought to identify biological concepts and principles that might be further explored to address needs related to regenerative advanced life support (ALS) systems, spacecraft and habitats, and the health of humans and useful biological organisms. A central theme was the value of reducing, reusing, recycling, and recovering materials so as to reduce size, mass, and power requirements (and thus cost) as well as increase reliability for long-term human exploration of space. Session 1 participants identified three topics that seem promising for exploration in follow-on workshops, as well as two research areas that might offer NASA short-term payoffs and two that might offer longer-term payoffs.

Topics for Follow-on Workshops

Closed-loop Aquaculture Systems as a Model for ALS Water Processing and Waste Management Systems. Provision of clean water is a basic requirement for extended space exploration missions. A workshop on current technologies in the maturing field of closed-loop aquaculture and innovative fermentation processes used in waste treatment might assist in the development of highly efficient closed-loop regenerative ALS systems for extended space missions.

Biosensors for Detecting Pollutants and Pathogens in Air and Water. To maintain human health and comfort as well as functioning plant and microbial populations, rapid and reliable detection and monitoring systems are needed to ensure that air and water in spacecraft and in habitats do not contain disease-causing pathogens or discomfort-causing levels of pollutants. Potential applications of biosensors could be explored in a workshop that would also have to define the research required to identify which microorganisms and pollutants should be detected on spacecraft and habitats and to establish sensitivity requirements relevant to NASA's needs. The use of biosensors in the skin of planetary habitats that could alert the crew to radiation levels and/or level of radiation-induced damage could also be addressed as part of this follow-on workshop.

Biomaterials for Spacecraft and Habitats. Biomaterials and biologically inspired materials might incorporate capabilities ranging from self-diagnosis and self-repair of certain system components to protection of astronauts and other biological organisms from the effects of radiation. Furthermore, such materials could also help make missions to other planets possible by virtue of their being lightweight and renewable, offering opportunities to reduce transportation cost and mass. These and other potential attributes as well as trade-offs in labor, space, and energy should be examined in a focused workshop before specific biomaterials are used in space applications.

Research Areas Offering Short-Term Payoffs

Cultivation of Algae as Food. Algae and cyanobacteria are used as nutritional supplements on Earth and might be cultivated for that purpose on spacecraft, as well as for waste treatment, CO2 recycling, and O2 generation. In addition to identifying edible species that could be grown in the space environment, it may also be worth exploring

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

the genetic engineering of algae and/or cyanobacteria to enhance their value and palatability as food, or the development of suitable food processing methods to either remove or degrade undesirable components (such as nucleic acids). Because cyanobacteria are more easily cultured and genetically engineered than eukaryotic algae or higher plants, they may hold greater promise in the short run for use in air recycling, wastewater treatment, and food production. The significant base of information on algae and cyanobacteria needs to be reexamined to identify their potential for use in such applications.

Development of Plants with Enhanced Disease Resistance. The types of diseases likely to occur in space horticulture must be identified so that plants resistant to specific diseases can be developed. Research is also needed to enable identification and management of the relevant disease-causing organisms.

Enzymatic Catalysts for Housekeeping. Humidity control is probably key to preventing overgrowth of microorganisms, which can also become resistant to the biocides used to wipe down bulkheads. When cleaning is necessary, enzymes (e.g., proteases, lipases) can be used as alternatives to chemical cleaning agents, an approach that has emerged for industrial cleaning applications. Enzymes, which are naturally occurring proteins, can be designed to target the compounds that enable microorganisms to adhere to surfaces. Furthermore, enzymes are highly suitable for spaceflight because they are lightweight, biodegradable, and have a long shelf life. However, some enzymes may cause allergies. Research is needed to examine the feasibility of using enzymes for housekeeping in spacecraft and planetary habitats, and to evaluate risks of exposing crew members to these potentially potent allergens.

Research Areas Offering Long-Term Payoffs

Genetic Engineering of Plants. Plants, a fundamental biological system, will be essential to human well-being in long-duration space exploration. Plants can be used not only as food but also as sources of useful materials and chemicals and for the recycling of carbon dioxide and other inorganic and organic wastes. To meet defined requirements for spaceflight, plants might be engineered, for example, to produce miniature roots or leaves, grow under low-light conditions, exhibit increased resistance to disease or radiation, and produce structural materials such as biodegradable plastics or specific nutrients needed by humans.

Radiation Protection and Monitoring. Certain plants and microorganisms have effective DNA-repair mechanisms that confer some measure of radiation resistance or tolerance. Research aimed at understanding such mechanisms might provide a basis for transferring these capabilities to plants and organisms cultivated on spacecraft. It may also be possible to design a biological dosimeter for radiation monitoring through the use of specific microorganisms or designed DNA integrated into biochips for monitoring purposes. The applicability of advanced biological dosimeters for space exploration could be addressed as part of the workshop on biosensors suggested above.

Enhancing Human Presence and Function

Session 2 participants sought to identify biological concepts and principles that might enhance human function in four areas: perception, manipulation and locomotion, cognition, and systems and computation. The group discussions reflected a number of themes, including similarities between deep space and the deep ocean that suggest a potential for transferring diving technologies and concepts to the space program; the merits of biological concepts as models for processes that are inherently simple and evolutionary, as opposed to complex and excessively mechanical; and the need to strike an appropriate balance between the tasks assigned to machines versus those assigned to humans. The group identified three topics that seem promising enough in the short term to be addressed at follow-on workshops.

Topics for Follow-on Workshops

Space Suit Design Incorporating Biological Concepts. As part of the effort to design lightweight space suits suitable for use on Mars, biological concepts and principles could be applied to enhance astronauts' comfort and function. A future workshop could explore, for example, the application of biomechanical concepts such as 40-degree-angle wrist settings to provide maximum dexterity and grip, biomolecular materials modeled on strong yet dexterous sharkskin, technologies such as actuators and microelectrical mechanical systems (MEMS) that could

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

assist with movement or self-repair, external sensors that produce haptic and other sensory feedback to the astronaut, and galvanic stimulation to provide cues about spatial orientation in microgravity.

Use of Magnetoencephalography to Monitor Astronauts' Cognitive States. Physiological monitoring of brain waves could provide confidential biofeedback on astronauts' cognitive states for the purpose of enhancing functional effectiveness and promoting relaxation. Magnetoencephalography, which is based on the use of superconducting quantum interference devices (SQUIDs) to detect very small magnetic fields, offers a number of advantages, including rapid response and ease of use. A SQUID cryogenic cap or helmet for recording brain waves may be particularly appropriate in the space environment, where temperatures are theoretically cold enough to make the SQUIDs superconducting. A future workshop could explore the benefits and feasibility of designing such a system.

Synergistic Human-Robot Systems. A future workshop could explore the design of synergistic human-robot systems that would meet needs for system reliability and configurability, effective human-machine collaboration, improved situational awareness, and optimal decision making. Three biology-based concepts seem particularly promising: (1) collaborative multirobot systems modeled on the task sharing of the insect kingdom. Advantages include rapid adaptation to the loss of individual robots, robust communication among all robotic or biological elements, system reconfigurability, and the capability to deploy specialized individuals. (2) Robotics systems that exhibit emergent system behavior mediated by emotion and anxiety, as well as a learning process augmented by emotion. Such systems would “think” more like humans, whose decision-making and problem-solving abilities are improved by access to their emotions. (3) Interfaces that enable human comprehension of system data without information overload, and the communication of human affect and intentions to robots.

Research Areas Offering Short-Term Payoffs

Artificial Vision Systems. Technologies being actively investigated in many sectors offer the possibility of enhancing human vision and providing new modalities, such as over-the-horizon sight. However, existing devices tend to be bulky, primitive, and, in most cases, far less sensitive, precise, or adaptive than their biological counterparts. The state of the art needs to be improved. Of particular interest is using very large-scale integration (VLSI) and MEMS technology to integrate sensing, processing, and possibly display elements into small, light-weight, low-power units. Biological principles and biology-inspired designs could provide critical guidance in such efforts. For instance, visual computational sensors or artificial retinas that provide spatio-temporal processing at the place of sensing could enable task-oriented, rapidly adaptable processing of visual information.

Exercise Based on Biological Concepts. As an alternative or supplement to the treadmill currently used for exercise during spaceflight, it might be useful to explore an exercise concept that mimics the activities of an embryo during its time in the womb. A “bungee suit” with elastic properties might be designed that would enable gymnastics regimens that could maintain or restore an astronaut's physical state.

Research Areas Offering Long-Term Payoffs

Adaptation to Different Gravitational States. Astronauts' adaptation to microgravity and subsequent readaptation to Earth's gravity might be accelerated by understanding and manipulating the fragile transition between the two states. Evidence from everyday life and biomedical research—including a rapid increase in understanding of the central nervous system and its plasticity—points to an inherent biological capability for dual adaptation. A combination of pharmacological intervention and appropriate training and exercise might effectively prepare astronauts for adaptation to alternating gravitational states.

Software for Emotion-Mediated Learning. In humans, emotional states mediate decision making and learning. Software for robotics systems could be designed to exhibit emergent system behavior mediated by emotion and anxiety, and a learning process augmented by emotion. Such systems might meet needs for software reliability and configurability, effective human-machine collaboration, improved situational awareness, and optimal decision making.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

“Principal Investigator (PI) in a Box.” Given the complexity and new challenges associated with long-term human exploration of space, astronauts might benefit from having instant access to a database of the accumulated experience of previous astronauts. The database could support dynamic mission planning and execution strategies and improved problem solving and could be self-organizing to respond to immediate needs. Biology-based concepts could also be applied to the presentation of data. For example, algorithms based on the survival instinct might present data on the most life-threatening situation first.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

3.2 The Exploration of Near-Earth Objects

A Report of the Committee on Planetary and Lunar Exploration1

EXECUTIVE SUMMARY

Near-Earth objects (NEOs) are asteroids and comets with orbits that intersect or pass near that of our planet. About 400 NEOs are currently known, but the entire population contains perhaps 3000 objects with diameters larger than 1 km. These objects, thought to be similar in many ways to the ancient planetesimal swarms that accreted to form the planets, are interesting and highly accessible targets for scientific research. They carry records of the solar system's birth and the geologic evolution of small bodies in the interplanetary region. Because collisions of NEOs with Earth pose a finite hazard to life, the exploration of these objects is particularly urgent. Devising appropriate risk-avoidance strategies requires quantitative characterization of NEOs. They may also serve as resources for use by future human exploration missions. The scientific goals of a focused NEO exploration program are to determine their orbital distribution, physical characteristics, composition, and origin.

Physical characteristics, such as size, shape, and spin properties, have been measured for approximately 80 NEOs using observations at infrared, radar, and visible wavelengths. Mineralogical compositions of a comparable number of NEOs have been inferred from visible and near-infrared spectroscopy. The formation and geologic histories of NEOs and related main-belt asteroids are currently inferred from studies of meteorites and from Galileo and Near-Earth Asteroid Rendezvous spacecraft flybys of three main-belt asteroids. Some progress has also been made in associating specific types of meteorites with main-belt asteroids, which probably are the parent bodies of most NEOs. The levels of discovery of NEOs in the future will certainly increase because of the application of new detection systems. The rate of discovery may increase by an order of magnitude, allowing the majority of Earth-crossing asteroids and comets with diameters greater than 1 km to be discovered in the next decade.

A small fraction of NEOs are particularly accessible for exploration by spacecraft. To identify the exploration targets of highest scientific interest, the orbits and classification of a large number of NEOs should be determined by telescopic observations. Desired characterization would also include measurements of size, mass, shape, surface composition and heterogeneity, gas and dust emission, and rotation. Laboratory studies of meteorites can focus NEO exploration objectives and quantify the information obtained from telescopes. Once high-priority targets have been identified, various kinds of spacecraft missions (flyby, rendezvous, and sample return) can be designed. Some currently operational (Near-Earth Asteroid Rendezvous [NEAR]) or planned (Deep Space 1) U.S. missions are of the first two types, and other planned U.S. (Stardust) and Japanese (Muses-C) spacecraft missions will return samples. Rendezvous missions with sample return are particularly desirable from a scientific perspective because of the very great differences in the analytical capabilities that can be brought to bear in orbit and in the laboratory setting.

Although it would be difficult to justify human exploration of NEOs on the basis of cost-benefit analysis of scientific results alone, a strong case can be made for starting with NEOs if the decision to carry out human exploration beyond low Earth orbit is made for other reasons. Some NEOs are especially attractive targets for astronaut missions because of their orbital accessibility and short flight duration. Because they represent deepspace exploration at an intermediate level of technical challenge, these missions would also serve as stepping stones for human missions to Mars. Human exploration of NEOs would provide significant advances in observational and sampling capabilities.

The Committee on Planetary and Lunar Exploration (COMPLEX) has considered appropriate baseline research efforts, as well as a number of augmentations to existing programs for the discovery and characterization of NEOs. With respect to ground-based telescopic studies, the recommended baseline is that NASA and other appropriate agencies support research programs for interpreting the spectra of near-Earth objects (NEOs), continue and coordinate currently supported surveys to discover and determine the orbits of NEOs, and develop policies for the public disclosure of results relating to potential hazards. Augmentations to this baseline program include, in priority order, that relevant organizations do the following:

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“Executive Summary” reprinted from The Exploration of Near-Earth Objects, National Academy Press, Washington, D.C., 1998, pp. 1-2.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  1. Provide routine or priority access to existing ground-based optical and infrared telescopes and radar facilities for characterization of NEOs during favorable encounters, or

  2. Provide expanded, dedicated telescope access for characterization of NEOs.

The baseline recommendation with respect to laboratory studies and instrumentation is that NASA and other appropriate agencies should support continued research on extraterrestrial materials to understand the controls on spectra of NEOs and the physical processes that alter asteroid and comet surface materials. An appropriate augmentation to this baseline is to support the acquisition and development of new analytical instruments needed for further studies of extraterrestrial materials and for characterization of returned NEO samples.

Spacecraft missions and the development of the associated technology and instrumentation are essential components of any program for the study of NEOs. The baseline recommendation in this area is to support NEO flyby and rendezvous missions. Appropriate augmentations include, in priority order, that relevant organizations do the following:

  1. Develop technological advances in spacecraft capabilities, including nonchemical propulsion and autonomous navigation systems, low-power and low-mass analytical instrumentation for remote and in situ studies, and multiple penetrators and other sampling and sample-handling systems to allow low-cost rendezvous and sample-return missions.

  2. Study technical requirements for human expeditions to NEOs.

Although studies evaluating the risk of asteroid collisions with Earth and the means of averting them are desirable, they are beyond the scope of this report.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

3.3 Exploring the Trans-Neptunian Solar System

A Report of the Committee on Planetary and Lunar Exploration*

EXECUTIVE SUMMARY

A profound question for scientists, philosophers and, indeed, all humans concerns how the solar system originated and subsequently evolved. To understand the solar system's formation, it is necessary to document fully the chemical and physical makeup of its components today, particularly those parts thought to retain clues about primordial conditions and processes.1

In the past decade, our knowledge of the outermost, or trans-neptunian, region of the solar system has been transformed as a result of Earth-based observations of the Pluto-Charon system, Voyager 2's encounter with Neptune and its satellite Triton, and recent discoveries of dozens of bodies near to or beyond the orbit of Neptune. As a class, these newly detected objects, along with Pluto, Charon, and Triton, occupy the inner region of a hitherto unexplored component of the solar system, the Kuiper Belt. The Kuiper Belt is believed to be a reservoir of primordial objects of the type that formed in the solar nebula and eventually accreted to form the major planets. The Kuiper Belt is also thought to be the source of short-period comets and a population of icy bodies, the Centaurs, with orbits among the giant planets. Additional components of the distant outer solar system, such as dust and the Oort comet cloud, as well as the planet Neptune itself, are not discussed in this report.

Our increasing knowledge of the trans-neptunian solar system has been matched by a corresponding increase in our capabilities for remote and in situ observation of these distant regions. Over the next 10 to 15 years, a new generation of ground- and space-based instruments, including the Keck and Gemini telescopes and the Space Infrared Telescope Facility, will greatly expand our ability to search for and conduct physical and chemical studies on these distant bodies. Over the same time span, a new generation of lightweight spacecraft should become available and enable the first missions designed specifically to explore the icy bodies that orbit 30 astronomical units (AU) or more from the Sun. The combination of new knowledge, plus the technological capability to greatly expand this knowledge over the next decade or so, makes this a particularly opportune time to review current understanding of the trans-neptunian solar system and to begin planning for the future exploration of this distant realm.

Based on current knowledge, studies of trans-neptunian objects are important for a variety of reasons that can be summarized under five themes:

  1. Exploration of new territory. Telescopic discoveries of new Kuiper Belt objects (KBOs) are being made monthly. With continued access to suitable telescopes, this rate of discovery will likely be maintained for many years since very little of the sky (<0.1% of the ecliptic for objects brighter than 17th magnitude)2,3 has been surveyed to date. While telescopes are showing us that trans-neptunian objects are relatively common and are providing information about their disk-averaged surface composition, spacecraft missions are necessary to explore the detailed nature of these icy bodies.

  2. Reservoirs of primitive materials. While KBOs may not be pristine relics of the original solar nebula, it is in the outer solar system that we might expect to find the least-modified materials as well as samples that have suffered a range of degrees of modification. These bodies can provide the links for understanding the relationships among the interstellar medium, the solar nebula, and current materials in the solar system.

  3. Processes that reveal the solar system's origin and evolution. The observable characteristics of objects tell us about the processes they have experienced. The distribution of a population of objects in orbital phase space provides clues about their origins and the dynamical processes that control them over long periods. The distribution of sizes within a population reveals the relative importance of accretion versus collisional erosion. The wide range of sizes and different collisional histories among objects in the trans-neptunian region implies varying degrees of internal differentiation. Surface geology provides important constraints on an object's thermal history. Surface chemistry and atmospheric properties reveal processes of outgassing, photochemistry, transport, and redeposition of volatiles.

* “Executive Summary” reprinted from Exploring the Trans-Neptunian Solar System, National Academy Press, Washington, D.C., 1998, pp. 1-6.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  1. Links to extrasolar planets. Studies of early stars similar to the Sun have shown that some are surrounded by disks of dust that are thought to be derived from collisions between comets. It is natural, therefore, to relate such dust disks to the Kuiper Belt. Applying knowledge of the Kuiper Belt to stellar dust disks suggests that the inner boundary exhibited by some disks may be an indication of the existence of planets. Comparisons of the Kuiper Belt with these dust disks is an important component of the new field of comparative studies of solar systems.

  2. Prebiotic chemistry. As remnants of the early solar system, trans-neptunian objects can provide critical clues about processes of prebiotic chemistry and about the materials that would have been delivered to the early Earth and may have formed the source of volatile materials from which life arose here and possibly on other planets of this and other solar systems.

These five themes are not on an equal footing. The first three are well-established areas of scientific investigation and are backed up by a substantial body of observational and theoretical understanding. The last two, however, are more speculative. They are included here because they raise a number of interesting possibilities that seem particularly suited to an interdisciplinary approach uniting planetary scientists with their colleagues in the astrophysical and life science communities.

Although not considered in any detail in this report, the distant outer solar system also has direct relevance to Earth and the other terrestrial planets because it is the source of comets that bring volatiles into the inner solar system. The resulting inevitable impacts between comets and other planetary bodies can play a major role in the evolution of planetary surfaces and atmospheres. Indeed, comets can also play major roles in the evolution of life as suggested by, for example, the Cretaceous-Tertiary boundary bolide and the extinction of the dinosaurs.

TRANS-NEPTUNIAN OBJECTS

The five major themes described above involve general scientific issues that apply to the trans-neptunian region as a whole. Below COMPLEX summarizes the current knowledge and outstanding issues of the separate major types of objects in the trans-neptunian region.

Triton

Triton is by far the best-explored icy body in the distant outer solar system,4 and, as such, sets the context for the discussion of the other bodies. Triton is thought to be a planetary body that was captured by Neptune in the distant past. Voyager 2's flyby of Triton demonstrated the wealth of information available only from a spacecraft mission. Triton 's density suggests that it has a rock core (70% by mass) surrounded by ice. Tidal heating due to orbital evolution and/or collision(s) with other satellites probably caused differentiation of the interior. Geological mapping indicates a youthful surface with few impact craters and with active volcanic eruptions. Its surface is uniformly cold (<38 Kelvin) and is covered with patches of volatile ices that appear to be strongly coupled to Triton's seasonally varying nitrogen atmosphere.

The outstanding issues at Triton are as follows:

  • When and by what process was Triton captured by Neptune?

  • What is the degree of differentiation of the interior?

  • Does Triton have an iron core and/or magnetic field?

  • What drives the volcanism?

  • How are the volatile ices brought to the surface and distributed?

  • What is the distribution of surface materials, and how are they related to geological units?

  • What are the structure and dynamics of Triton's atmosphere, and how do they vary with Triton's complex seasonal pattern?

Pluto and Charon

Pluto is both the smallest planet and the largest body in the outer solar system that is not in orbit around a giant planet. Our knowledge of Pluto and its satellite, Charon, is limited to telescopic observations. Other than the identification of certain ices on Pluto and Charon and the observation of strong variations in albedo on Pluto, little

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

can be said about their surfaces or geology, beyond speculation based on knowledge of other icy satellites. As with Triton, Pluto's atmosphere is strongly coupled to the surface volatiles so that differences in their atmospheres result from the different nature of their surfaces. Pluto's warmer atmosphere and enhanced methane abundance are consistent with the ice on Pluto's surface containing 30 times more methane than Triton's ices and with large dark regions where the surface must be warmer. Charon's capture by Pluto probably involved a disruptive collision of the two bodies.

The outstanding issues at Pluto and Charon are as follows:

  • What are the bulk densities of Pluto and Charon?

  • What are the interior composition and the state of differentiation of Pluto and Charon?

  • What were the effects of the initial collision and subsequent tidal stresses produced in each body as a result of Charon's capture by Pluto?

  • Is there activity on the surfaces of Pluto or Charon (e.g., plumes as on Triton)?

  • Are the large-scale variations in albedo on Pluto due to variations in crustal structure or frost deposits?

  • What is the structure of Pluto's atmosphere, and how does it change with time?

  • Why is Pluto's atmosphere so different from Triton's?

Kuiper Belt Objects

Very little is known about the approximately 60 KBOs detected to date. Measurements of their orbits suggest that many of them are in resonance with Neptune. Variations in brightness are attributed to variations in size but cannot be quantified accurately without information on albedos. Measurement of brightness at different wavelengths gives an indication of surface color, and suggests that surface compositions may vary among KBOs.

Outstanding issues for Kuiper Belt objects are the following:

  • What fraction of KBOs are in dynamically evolved orbits?

  • What is the rate at which their orbits are perturbed sufficiently to send KBOs inward where they might interact with the giant planets?

  • What does the size distribution of KBOs tell us about their accretion and erosion?

  • If the range in observed colors is a true indication of diversity in surface composition, what causes this diversity?

  • What is the degree of differentiation of these small bodies?

Centaurs

Other than spectroscopic observations that indicate diverse surface compositions, very little information is available about the half-dozen objects with eccentric orbits among the giant planets.

Outstanding issues for the Centaurs are these:

  • How many Centaurs are there?

  • What are their orbits and how did these objects get where they are?

  • How did their orbits evolve from the Kuiper Belt?

  • What causes their color diversity?

  • Does Chiron have a bound dust atmosphere, and, if so, what are the dynamical processes?

KEY MEASUREMENTS

The key measurements that will answer the outstanding issues for these different classes of objects can be obtained by similar methods. For example, to answer questions about dynamics researchers need to determine the objects' orbits by tracking their motions precisely over months to years. To answer questions about the processes of accretion and erosion it is necessary to determine each object's size by making separate measurements of brightness and albedo. The degree of internal differentiation is indicated by studying the surface geology and measuring gravitational and magnetic fields of larger objects. The distribution of surface volatile ices is derived by combining

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

spectroscopic measurements and multispectral imaging. Stellar occultations of major bodies such as Pluto and Triton have provided rare opportunities to detect and study the vertical structure of their tenuous atmospheres. Characterization of the distribution of atmospheric hazes, clouds, and winds requires imaging from a spacecraft that passes close to the object.

CONCLUSIONS AND RECOMMENDATIONS

Three of the thematic rationales for the exploration of the trans-neptunian region (exploration of new territory, reservoirs of primitive materials, processes that reveal the solar system's origin and evolution) involve using methods that have proven successful in the past—telescopic observations, spacecraft missions, and harnessing new technologies and human ingenuity—to push the boundaries of our knowledge beyond 30 AU. Making links to extrasolar planet detection and studies of prebiotic chemistry will require planetary scientists to take interdisciplinary approaches and to venture with astronomers, chemists, and biologists into new fields of research. The main tasks for the next 10 to 15 years on the path to exploring the new frontier of planetary science in the distant outer solar system are to search for new objects and, more importantly, to document fully the chemical and physical makeup of the known bodies that constitute the trans-neptunian region. Spacecraft missions, telescopic observations, and research and analysis are the categories in which COMPLEX makes its highest-priority recommendations, as well as recommendations for augmenting this baseline effort.

Spacecraft Missions

To explore the makeup of objects in the trans-neptunian region, COMPLEX recommends an approach that combines telescopic observations of the bulk properties of a large sample of Kuiper Belt objects with close-up, spacecraft studies of the detailed properties of a few specific objects. The highest scientific priority for the exploration of the trans-neptunian solar system is extensive and detailed measurement of the fundamental physical and chemical properties of the Pluto-Charon system, end members of the KBO population. Since Pluto and Charon are barely spatially resolvable from Earth, many of the relevant properties can be measured only by robotic spacecraft.

NASA's planning for a Pluto mission has undergone significant revision over the last few years. What was conceived of in the early 1990s as a Cassini-class mission requiring launch on a Titan-IV has been reformulated as a highly integrated spacecraft-payload combination capable of being launched on a Delta-II. The associated reduction in cost and the inclusion of a new start for a line of outer solar system missions in the administration's FY 1998 budget suggest that a Pluto mission is closer to realization than it has ever been since one was first conceived. Given Pluto's long rotation period (6.4 days) and the need for redundancy, COMPLEX recommends a dual spacecraft mission to Pluto. A single spacecraft would be able to observe only one hemisphere during its flyby. A second spacecraft would enable coverage of both hemispheres. Staggering the arrival times by, say, 6 months would also enable some retargeting of the second spacecraft based on results obtained during the first spacecraft's flyby.

Augmentations

Following a Pluto-Charon mission there are a number of future spacecraft projects that could be considered as part of a long-term program to explore the trans-neptunian solar system. These augmentations include:

  • Adding a flyby of a Kuiper Belt object to a Pluto-Charon mission. The scientific potential of any PlutoCharon mission would be greatly enhanced by the spacecraft continuing on to visit another Kuiper Belt object and thus providing measurements of the size and surface characteristics of two different KBOs that have different histories. Locating a suitable KBO along the trajectory of a Pluto mission should be a priority goal for search programs. This augmentation should be considered only if it has no serious cost or schedule impact on a PlutoCharon mission.

  • Conducting additional missions to Kuiper Belt objects. Objects in the trans-neptunian solar system are highly diverse, and the underlying causes for this diversity can be fully explored only by space missions. Scientific

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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priorities for spacecraft missions to the trans-neptunian region in the more distant future, after the successful conduct of a Pluto-Charon mission and a KBO flyby, are, in rank order, as follows:

  1. Returning to Triton,

  2. Visiting a Centaur, and

  3. Encountering a suite of Kuiper Belt objects and/or Centaurs with different spectral and/or orbital characteristics.

Spacecraft Technology

Exploration of the outermost regions of the solar system is a demanding task, especially in an era of tight financial limitations. Although considerable progress has been made in the development of new-style missions to the outer solar system, particularly Pluto flyby missions, the technological obstacles of returning substantial scientific data from >30 AU remain formidable. Although considerable cost savings can be realized by reducing the size of the spacecraft and the complexity of its instruments, missions to the outer solar system still will demand a high launch energy, have a long mission duration (>10 years), be in low sunlight, and have a long telecommunications link. Advanced missions, such as those to put a spacecraft into orbit around a trans-neptunian object or to conduct multiple flybys of different objects, will almost certainly require the use of advanced propulsion techniques. Thus, the development of mission-enabling technologies (e.g., propulsion, compact power sources, autonomous operations, active fault management, radiation-hardened electronics, and long-distance communications) is an important adjunct to any program for the exploration of the trans-neptunian solar system. In addition, compact scientific instruments capable of characterizing the physical and chemical properties of cold (<40 Kelvin), icy objects in the distant outer solar system are needed.

Telescopic Observations

Continued support for both ground- and space-based telescopic studies is an essential aspect of a program for the exploration of the trans-neptunian solar system. The highest priority for both ground- and space-based studies is significant access to existing and future moderate- to large-aperture telescopes equipped with modern instrumentation designed to meet the needs of planetary observers. Telescopes in the 2- to 4-meter class are ideally suited to searching for new KBOs. But larger telescopes (8 to 10 m) are required for spectroscopic studies of known KBOs.

Augmentations

Although access to suitable telescopes can provide much new data, with augmentations in a few critical areas ground- and space-based observations could provide even more information about the trans-neptunian solar system. These augmentations include:

  • Equipping future large space telescopes to study trans-neptunian objects. To be capable of making the critical measurements of trans-neptunian objects, future large space telescopes should be designed from the outset to incorporate the ability to track moving targets and to measure the thermal emission from small, cold (<40 Kelvin) objects.

  • Developing instrumentation for ground- and space-based telescopes. Studies of the statistical properties of Kuiper Belt objects would benefit greatly from the availability of large array detectors. In addition, studies of the physical and chemical properties of all trans-neptunian objects would be enhanced by the availability of highquantum-efficiency array detectors (∼1 to 10 microns for studies of reflected light and ∼10 to 100 microns for studies of thermal emission), and cooled telescopes.

Research and Analysis

Continued support for research and analysis programs and for relevant theoretical and laboratory studies is an essential component of a program of spacecraft and telescopic observations of the trans-neptunian solar system. Theoretical and laboratory studies of the physical and chemical processes that influence the structure and evolution

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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of cold (<40 Kelvin), icy bodies located in the trans-neptunian region should be fully supported to enhance the scientific return from spacecraft missions and telescopic observations.

REFERENCES

1. Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pp. 12-13.

2. C. Kowal, “A Solar System Survey,” Icarus 77: 118, 1989.

3. D.C. Jewitt, J.X. Luu, and J. Chen, “The Mauna Kea-Cerro Tololo (MKCT) Kuiper Belt and Centaur Survey, ” Astronomical Journal 455: 1225, 1996.

4. D.P. Cruikshank, ed., Neptune and Triton, University of Arizona Press, Tucson, Arizona, 1995.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.4 Development and Application of Small Spaceborne Synthetic Aperture Radars

A Report of the Committee on Earth Studies1

EXECUTIVE SUMMARY
SPACEBORNE SYNTHETIC APERTURE RADAR
Background and Task

Following a decline in imaging radar research in the 1970s and 1980s, the 1990s have witnessed a resurgence of activity as researchers apply active and passive microwave capabilities to Earth observations. In the past few years, in particular, there has been a remarkable increase in studies based on European, Canadian, and Japanese free-flying synthetic aperture radars (SARs), as well as on the series of Shuttle-based SAR flights (SIR [Shuttle Imaging Radar]-A, SIR-B, and the U.S.-Germany-Italy SIR-C/X-SAR). SAR interferometry is among the capabilities driving exciting applications in solid-earth studies. In addition, biomass estimation, ecosystem delineation, ice dynamics characterization, and biological water monitoring also have progressed. Multifrequency and multipolarization SAR systems are rekindling interest in the variety of unique Earth parameters that can be measured.

The present study originated in 1994 with a request from the National Aeronautics and Space Administration's (NASA's) Office of Earth Science (OES —formerly the Office of Mission to Planet Earth) to assess the utility of a third SIR-C/X-SAR mission. In a letter report dated April 4, 1995, the Committee on Earth Studies of the Space Studies Board concluded that a third flight would produce useful scientific results if the existing instrumentation were simply reflown, but that it would produce especially worthwhile results if it were modified for dual-antenna interferometric measurements of terrain topography. In the 1995 letter report, the committee also summarized the current capabilities of SAR applications in ecology, ice sheets and glaciers, oceanography, hydrology, and solidearth studies.

During the period following release of the letter report, events have unfolded regarding a proposed NASA small spaceborne SAR program, often referred to as “LightSAR” but called “small SAR” in this report to avoid confusion with a specific proposal from the Jet Propulsion Laboratory (JPL).2 The stated objective of the LightSAR program is “to validate key advances in synthetic aperture radar technology, and related systems, that will reduce the cost and enhance the performance of this and future U.S. [Earth-imaging] SAR missions.”3 NASA's interests in a small SAR are twofold: (1) to exploit the scientific utility of SAR data and (2) to investigate the opportunity for an innovative industry-government partnership for a small SAR that would take advantage of the potentially high commercial interest in SAR applications.

On December 5, 1996, NASA requested an update on the committee's perspective since the SAR study began. Specifically, NASA requested comments on the “value added” of a multifrequency small SAR as an alternative to a single-frequency operation, which was the baseline proposal, and an analysis of other SAR-related issues, such as reducing system costs, optimizing weight and power requirements, and increasing mission focus. In addition, NASA requested guidance in developing a strategy for a space-based, science-oriented, interferometric small SAR. This report responds to those requests, expanding on ideas presented in the committee's April 1995 letter report. In addition, this report emphasizes that a strategy for a space-based, science-oriented, interferometric small SAR must also consider mission focus, design trade-offs, and options for data availability.

1  

“Executive Summary” reprinted from Development and Application of Small Spaceborne Synthetic Aperture Radars, National Academy Press, Washington, D.C., 1998, pp. 1-5.

2  

The term “LightSAR” has been associated with proposals from NASA's Jet Propulsion Laboratory. However, unless otherwise noted, the term “small SAR” is used in this report to denote a generic class of comparatively small and inexpensive spaceborne synthetic aperture radars.

3  

Business Development and System Design Definition Study Contracts for the LightSAR Program, Commerce Business Daily Procurement Alert, November 20, 1996.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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STRATEGY AND RECOMMENDATIONS

Existing SAR systems have been severely constrained by their very large volume, mass, and power requirements. Such demands have inhibited the approval of even experimental systems but are especially problematic for operational systems whose requirements for coverage (geographic and repeat cycle) lead to system design concepts that require maintaining several spacecraft continuously in orbit. NASA and National Oceanic and Atmospheric Administration (NOAA) studies of future sensing needs describe research and operational requirements leading to a need for multiple spacecraft with markedly differing characteristics. However, the LightSAR baseline design proposed by JPL appears to incorporate new technologies in instrument design and antennas that could result in significant size, mass, power, and cost savings compared to existing international SAR systems, but it does not adequately address coverage requirements for multiple users.

In the committee's opinion, if NASA proceeds with a small SAR, it should give preference to a mission that optimizes for a specific scientific goal or related application. Additionally, consideration should be given to meeting the needs of public use and commerce within design constraints imposed by the science requirements. In addition, the goal or application should be selected to address ongoing public needs (e.g., natural disaster assessment and global topographic mapping), future high-profile commercial potential (e.g., forestry or agricultural assessment), or specific science demonstrations (e.g., ice-flow dynamics and volcanic lava flow rates). The duty cycle should be used to build orbit-by-orbit data sets related to these applications so that over the life of the mission, experience would increase and the global dimensions of the objectives could be further quantified and validated.

In the committee's judgment, spaceborne SAR will become increasingly important in achieving the objectives of NASA's Earth Science Enterprise (ESE—formerly Mission to Planet Earth) science strategy, which is a deeper understanding of the five major components of the Earth system: hydrological, biogeochemical, atmospheric, ecological, and geophysical processes. Different uses for small SAR will likely require different data acquisition modes, which may lead to conflicts unless a clear policy is defined early in the mission design process. The committee recommends that NASA consider the following strategy for a small SAR program.

1. Develop a well-defined focus for any small SAR mission.

It is important for NASA to consider what objectives are to be served by a potential spaceborne SAR system, in a broad sense, and their relative priorities. Three general areas are recognized: (1) providing scientific data (e.g., of the type required by ESE), (2) providing information in support of the general public good (e.g., environmental monitoring and hazard assessment), and (3) providing data for commercial interests (e.g., digital elevation models for cartographic applications, mineral exploration, or forest management). The committee recommends that the relative priorities and interests of all three use categories be weighed at the outset of the mission design process. End-to-end system engineering can then be optimized to serve the prioritized suite of information needs.

The committee notes that of the several proposed operating frequencies associated with SARs, the L-band is especially useful in forest and desert ecology applications, but other applications such as agriculture may lead to a small SAR design based on C-, X-, or Ku-band frequencies. These frequencies require smaller antennas than does the L-band, which may simplify deployment from a small spacecraft. In the committee's view, design parameters such as frequency, polarization, resolution, and swath width should be chosen to match the mission focus, while the results of all available research, including that from the 1960s and 1970s, are considered.

2. Adopt new technologies to reduce SAR costs.

In the committee's view, many new technologies may come from outside NASA. In addition, new technologies currently available for data capture and processing can be used to lower overall SAR system costs. Many of these technologies can be evaluated without resorting to costly spacecraft missions. According to JPL's LightSAR point design report, the estimated end-to-end mission cost of the baseline design is $125 million, which is only a fraction of the estimated mission costs of the single-frequency, single-polarization SARs of ERS-1 ($750 million) and Radarsat ($640 million). The significant reduction in cost is attributed to the incorporation of new technologies. As examples of cost-reducing technologies, L-band antennas are seven times lighter and require only half as much power as SIR-C's antenna. Small SAR synthesizers are seven times lighter than SIR-C's and require one-tenth the power.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3. Continue support of a vigorous research and analysis program in radar remote sensing.

Although considerable progress has been made in recent years in understanding signal-terrain interactions, there are many areas in which the physical link between the SAR signal and the geophysical phenomenon is less well known. For example, there is a soil-moisture signal present in SAR imagery that relates to the material's dielectric properties, but this component is difficult to extract from signal influences related to surface roughness and topography. More research is necessary to learn how to quantify the effects of roughness, topography, and surface cover on the soil-moisture signals. NASA should continue appropriate air- and spaceborne studies to strengthen these links. Such calibration and validation studies might be a suitable focus for a small SAR mission.

4. Establish a clearly defined small SAR data policy that will protect commercial interests while ensuring free and open access by the public and research communities.

SAR imagery has potentially important applications for research, the public sector, and commercial users. If NASA continues to seek commercial partners for a small SAR mission (to reduce costs), it must define data policies clearly to protect the proprietary interests of commercial entities while ensuring open access to other user communities. In addition, widely distributed data processing and dissemination may both lower costs and increase access to small SAR data. Such a “federated” approach is consistent with the strategy being pursued for the Earth Observing System Data and Information System (EOSDIS).

It is expected that much data will be dual-use in nature and can serve multiple interests (science, public use, and commerce). Innovative data access policies could protect both research and commercial communities. For example, most commercial applications may have a relatively short shelf life. When they no longer have commercial value, these older data sets may still be valuable to the research community. However, given the longer time scales for many terrestrial applications (e.g., glacial recessions), the commercial shelf life may be many years for some data sets.

Consideration of public use and commercial interests complicates issues of data access and distribution because of conflicting needs. At the same time, public use of data should also be expected and encouraged, but many such users may not be able to afford commercial rates for access to data.

The committee recognizes that flexibility must be maintained in the data acquisition and dissemination system. The concept of life-cycle mission design should be applied to minimize conflicts in scheduling SAR operating modes. The various scientific objectives of the LightSAR science plan imply that conflicts will arise and require dissimilar data types over common areas. Such conflicts will be exacerbated by the differing needs of public and commercial users. Mission life-cycle planning can be used to balance conflicting needs weighted by relative priority.

5. Consider an enhanced multifrequency small SAR configuration.

There is sufficient evidence to warrant consideration of a multifrequency small SAR. Single-frequency, singlepolarization spaceborne SAR systems cannot meet all of the scientific objectives outlined in the LightSAR science plan. These needs might be met at some level of accuracy by a single-frequency polarimetric small SAR as defined in the baseline plan. For some applications, the accuracy level is known to increase markedly with the addition of higher-frequency SAR data. Such increased accuracy may be very compelling to industrial partners seeking to satisfy commercial demands. Industry teams can be expected to pay close attention to the end-to-end costs of any system enhancements relative to the expected commercial value of such a system. The commercial value of LightSAR enhancements is currently being evaluated by the marketplace via the LightSAR business development and system design definition studies. It may be prudent for NASA to conduct a parallel evaluation of the relative scientific value of potential enhancements (e.g., C-band dual polarization and X-band single polarization).

6. Continue coordinating small SAR with other international SAR missions in an Integrated Global Observing Strategy framework.

Although there are difficult issues associated with international coordination of radar missions, the committee believes that NASA should continue to coordinate small SAR with other international SAR missions within the

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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Integrated Global Observing Strategy (IGOS) framework. No single nation has the resources to deploy the constellation of satellites necessary to exploit this technology fully or to test the advantages and disadvantages of different combinations of spectral bands or types of data from different sensors.

CONCLUSION

Recent technological advances that can significantly reduce the size and cost of spaceborne SAR, advances in data capture and processing, the advantages of SAR over electro-optical imaging, and potential trade-offs to reduce the weight of a SAR all led the committee to conclude that focused applications of a multifrequency small SAR mission, as opposed to one with a single-frequency system, could provide more and better information and understanding of earth, ocean, and atmospheric processes at lower costs than were heretofore possible.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.5 Readiness for the Upcoming Solar Maximum

A Report of the Board's Committee on Solar and Space Physics and the Board on Atmospheric Sciences and Climate's Committee on Solar-Terrestrial Research1

EXECUTIVE SUMMARY

Our Sun undergoes activity cycles characterized by increases in its output of electromagnetic and particle radiation over a broad range of energies every 9 to 13 years. The number of sunspots, recorded since the 1600s, shows that these cycles have occurred regularly (albeit with varying intensity) at least 22 consecutive times.

The approaching maximum of cycle 23 (expected to occur between 1999 and 2002) represents an unprecedented opportunity to understand the physics of the solar cycle and its effects on Earth. Knowledge has advanced to the point that researchers are able to investigate specific atmospheric and Earth-space responses, experimental capabilities have greatly improved, and models and laboratory tools make possible controlled simulations of cause and effect. There are also technological motivations for learning more about the solar cycle control of “ space weather” as society becomes increasingly dependent on systems (e.g., distributed power grids, satellite-based communications, and navigation networks) sensitive to space environment disturbances.

At the request of the Sun-Earth Connection science program director at the National Aeronautics and Space Administration (NASA), the Space Studies Board's Committee on Solar and Space Physics (CSSP), working jointly with its federated Committee on Solar-Terrestrial Research (CSTR) of the Board on Atmospheric Sciences and Climate, reviewed the nation's preparedness for the solar maximum.2 This consideration of readiness concerns both the unique research opportunities presented by the upcoming solar maximum, as well as our capability to mitigate technological problems that might result from the effects of the active Sun. NASA, the National Oceanic and Atmospheric Administration (NOAA), the National Science Foundation (NSF), the Department of Defense (DOD) (the Air Force and the Navy), and the Department of Energy (DOE) provided information for this review, in part during invited agency briefings to the CSSP/CSTR at their meeting in Washington, D.C., on February 26-28, 1997.

The committees' assessment is based on the following assumptions regarding the various agencies' roles:

  • NASA is the nation's space agency responsible for solar and geospace exploration as well as the human use of space;

  • NOAA is the major provider of civilian solar and space environment information;

  • NSF is a major sponsor of basic solar-terrestrial research and the lead agency for the National Space Weather Program;

  • DOD (and in particular the Air Force and the Navy) is both a user of space environment information and a sponsor of related research and monitoring; and

  • DOE is an additional user and sponsor concerned with national security aspects of the space environment.

AGENCY-SPECIFIC RECOMMENDATIONS
National Aeronautics and Space Administration

NASA has built an excellent multisatellite observatory to explore the Sun-Earth Connection; to yield maximum dividends, this investment should be exploited through the upcoming solar maximum. Moreover, continuing this

1  

“Executive Summary” reprinted from Readiness for the Upcoming Solar Maximum, National Academy Press, Washington, D.C., 1998, pp. 1-5.

2  

The committees' review of preparedness for the upcoming solar maximum does not include an analysis of the current capabilities of the nation's ground-based optical and radio solar observatories. This assessment is being performed as part of an ongoing National Research Council study by the Space Studies Board's Task Group on Ground-based Solar Research (TGGSR). The task group study is sponsored by the NSF and NASA, which requested a broad examination of the “health” and future prospects of ground-based solar research. In addition, the agencies requested a focused examination of issues related to the future of the National Solar Observatory. The TGGSR is expected to release its findings in early summer 1998. The CSSP/CSTR emphasize that the present report's lack of recommendations that are specific to ground-based solar facilities is a direct consequence of the ongoing TGGSR study and should in no way be construed as a lack of concern by the committees over the future of these facilities.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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observatory will aid construction of the International Space Station, which will require many extravehicular activities throughout the period of the solar maximum when the space environment will be disturbed. It is unlikely that a Sun-Earth Connection “great observatory” like the current one will be available in the foreseeable future, and NASA's projected budgets and plans do not include such an observatory for the solar maximum of cycle 24. Thus, the timing is right for the current observatory to have its maximum impact on the science issues it was designed to address.

  • The committees recommend that, at a minimum, NASA continue the existing International Solar-Terrestrial Physics (ISTP) program and related operating missions (ACE, Ulysses, Yohkoh, FAST, SAMPEX, and the Voyagers) through the upcoming solar maximum. This includes acquiring high-quality data (e.g., through the Deep Space Network) and then validating, archiving, interpreting, and publishing them.

  • The committees also recommend the timely launches of TRACE, TIMED, and IMAGE and encourage U.S. participation in Equator-S and Cluster, so that spacecraft capable of making unique contributions will be available during this unprecedented solar maximum observational campaign.

  • Finally, the committees recommend that a dedicated guest investigator program be initiated to complement the existing program during the solar maximum. Such a program would allow all selected investigators to have full use of the collected Sun-Earth Connection data to address the problems of the origin of solar activity and its effects in the solar system, especially its effects on Earth.

National Oceanic and Atmospheric Administration

NOAA is the leader of the nation's space environment monitoring program and a cornerstone of the interagency National Space Weather Program (NSWP). The agency has the unique responsibilities of distributing high-quality geophysical data to a broad-based national and international community and providing reliable space weather forecasts to the civilian sector. It is also the agency responsible for improving an operational space weather monitoring and forecasting system. NOAA played a key role in arranging for the research community to receive real-time data transmissions from ACE. However, NOAA resources have not been available for translating modern data-based or theoretical research models into improved monitoring and forecasting tools. The absence of a NOAA commitment to this unique and critical role will have a fundamental impact on the success of the NSWP.

  • The committees recommend that NOAA, through its Space Environment Center, develop and execute a plan to fulfill its responsibilities within the National Space Weather Program during the coming period of enhanced demand for space environment forecasting services.

  • The committees also recommend that NOAA ensure the certification and prompt dissemination of space environment and geophysical databases through its National Geophysical Data Center.

National Science Foundation

Overall, NSF appears well prepared to face the scientific opportunities and technological challenges of the upcoming solar maximum. The committees thus primarily encourage NSF to continue its efforts and to supplement them as much as possible.

  • The committees recommend that NSF continue its leadership role in the National Space Weather Program and champion stronger interagency involvement in the NSWP to maximize the nation's benefit from the program during the solar maximum.

  • The committees also recommend that NSF consider initiating interagency discussion of a specific solar maximum campaign similar to that developed for the comet Shoemaker-Levy 9 event.

Department of Defense

Although DOD preparations and activities are notable for their breadth and forethought, several areas might benefit from reassessment. In particular, the Air Force has invested primarily in space hardware at the expense of

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

basic research and analysis. Like NOAA, the DOD in general has not recognized the critical need for investment aimed at making data-based and theoretical research models operational.

The committees' findings and recommendations include two issues relating to both the Air Force and Navy:

  • Although the continued operation of Yohkoh, SOHO, and the other ISTP experiments through the solar maximum is NASA's responsibility, the committees recommend that DOD make its reliance on these missions (especially for solar and and interplanetary observations) known to NASA.

  • The continuing participation in and support for the National Space Weather Program on the part of both the Air Force and the Navy are critical to that program's success. The committees recommend that this participation be strengthened through joint endeavors such as the development of rapid prototyping systems for space environment forecasting.

Specific recommendations for the Air Force programs during the solar maximum include the following:

  • Further integrate the Air Force efforts with the National Space Weather Program, both to take advantage of the NSWP products and to provide insight on tools useful to the NSWP. This involvement would also provide ongoing peer review of those DOD efforts that can be discussed in an open forum, ensuring that DOD's investment will result in the greatest possible benefits.

  • Reassess the support and plans for the 55th Space Weather Squadron to ensure that the squadron will be well prepared for the demands of the upcoming solar maximum. This includes provisions for access to state-of-the-art knowledge and forecasting tools.

The committees' recommendations for the Navy solar maximum program include the following:

  • Consider an accelerated research initiative in solar physics to take advantage of the large data sets expected from the Yohkoh and SOHO experiments during the solar maximum, so that knowledge gained can be rapidly put to use.

  • Sponsor or cosponsor a community guest investigator program for collaborations on analysis and interpretation of the data from the Navy solar and upper-atmosphere experiments. By enhancing the productivity of those experiments and bringing in useful external expertise, such a program would help speed the National Space Weather Program's rapid application of new knowledge.

Department of Energy

Although DOE has reasons for its highly targeted commitment to the space environment endeavor, the committees believe that with minimal disruption of the status quo, DOE's contribution to the solar maximum activities described herein can be magnified.

  • The committees recommend that DOE participate in the dialogue of the interagency coordinating committee for the National Space Weather Program and reassess its own role in that activity (e.g., in the area of power transmission).

  • The committees also recommend that DOE continue its support for the flight of space radiation monitors, together with support for making its data available to the community at large, with special expediency during the solar maximum.

CONCLUDING OBSERVATIONS AND RECOMMENDATIONS

In addition to agency-specific recommendations, the committees offer the following general observations and recommendations on the nation 's readiness for the upcoming solar maximum:

  • For this solar maximum, an unprecedented solar-terrestrial spacecraft “armada” will be in orbit to use in studying the active Sun as well as Earth 's responses. These spacecraft must remain operational (to the maximum

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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extent possible) with sufficient supporting research to exploit the opportunity they afford—an opportunity unlikely to be equaled in the foreseeable future.

  • NSF and DOD have shown their support for the National Space Weather Program, but to realize the goals of the NSWP, NOAA should work to translate research models of the solar-terrestrial system to operational uses, perhaps through the creation of the proposed rapid prototyping center.

  • Increasing effects of solar and geospace environment disturbances on human activities are expected during the period of the solar maximum. The committees recommend that an interagency workshop (or summit) involving scientists, agency representatives, and industrial administrators and engineers be held to improve their state of preparedness through sharing of information.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.6 U.S.-European Collaboration in Space Science

A Report of the Board's Committee on International Space Programs and the European Science Foundation's Space Science Committee1

EXECUTIVE SUMMARY

The United States and Europe have been cooperating in space science for more than three decades. This history of cooperation has survived significant geopolitical, economic, and technological changes, such as the end of the Cold War, the pressure of budget reductions, and the increasing focus on economic competition and the global marketplace. Both Europe and the United States have learned from one another and acquired a knowledge base as well as an infrastructure to implement joint missions and research activities. More importantly, the decades of cooperative space research efforts between the United States and Europe have built a community of scientists whose joint scientific exchanges have established a heritage of cooperation on both sides of the Atlantic.

The scientific fruits of this heritage are plainly evident in achievements such as a signature for supermassive black holes provided by the Hubble Space Telescope (HST); the first views of the solar atmosphere and corona illuminated by the Solar and Heliospheric Observatory (SOHO); the sharing of expensive research facilities on the International Microgravity Laboratory (IML); and the impressive data on ocean altimetry from the Ocean Topography Experiment (TOPEX-POSEIDON) mission, which is significantly improving our understanding of global ocean circulation.

There were no guideposts for the emergence of space science cooperation between Europe and the United States. In the process of introducing new procedures and improvements to facilitate cooperation, missteps occurred, and there were political, economic, and scientific losses. This report takes stock of U.S.-European history in cooperative space endeavors, the lessons it has demonstrated, and the opportunities it suggests to enhance and improve future U.S.-European cooperative efforts in the sciences conducted in space.

THE JOINT COMMITTEE'S TASK

The Committee on International Space Programs (CISP) of the Space Studies Board (SSB) and the European Space Science Committee (ESSC) were charged by the National Research Council (NRC) and the European Science Foundation (ESF), respectively, with conducting a joint study of U.S.-European collaboration in space missions. The study was initiated jointly by the SSB and the ESSC after discussions over several years on the increasing importance of international activities and the need to assess previous experience. This study was conducted by a joint SSB-ESSC committee.

The joint committee's central task was to analyze a set of U.S.-European cooperative missions in the space sciences, Earth sciences from space, and life and microgravity sciences and to determine what lessons could be learned regarding international agreements, mission planning, schedules, costs, and scientific contribution. Although the charge is largely retrospective and relies on existing or past missions, the joint committee found that in some cases, missions in the development stage offered the best (or only) examples that met the study criteria. The joint committee also determined that though a retrospective study was requested, lessons learned from the analyses must be considered within a prospective context to be relevant to future cooperative activities.

APPROACH

The joint committee agreed on a set of selected missions in the space science disciplines to be used as case studies in this report (Table ES.1). Both National Aeronautics and Space Administration-European Space Agency (NASA-ESA) endeavors and missions conducted between NASA and national space agencies in Europe have been included. In addition, the selection includes both smaller-scale missions managed by principal investigators (PIs) and larger missions managed at the agency level.

1  

“Executive Summary” reprinted from U.S.-European Collaboration in Space Science, National Academy Press, Washington, D.C., 1998, pp. 1-9.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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TABLE ES.1 Missions Used as Case Studies in This Report, Selected by Discipline

Disciplines

NASA-ESA Case Studies

NASA-European National Space Agencies Case Studies

Astrophysics

HST, SOHO,a INTEGRAL

ROSAT

Planetary sciences

Cassini-Huygens, GMM

Space physics

ISPM [Ulysses], ISEE

AMPTE

Earth sciences

EOS-Polar platforms

UARS, TOPEX-POSEIDON

Microgravity research and life sciences

IML-1, 2

IML-1, 2

NOTE: AMPTE = Active Magnetospheric Particle Tracer Explorer; EOS = Earth Observing System; GMM = Generic Mars Mission; HST = Hubble Space Telescope; IML = International Microgravity Laboratory; INTEGRAL = International Gamma-Ray Astrophysics Laboratory; ISEE = International Sun-Earth Explorer; ISPM = International Solar Polar Mission [renamed Ulysses]; ROSAT = Roentgen Satellite; TOPEX = (Ocean) Topography Experiment; UARS = Upper Atmosphere Research Satellite.

a The Solar and Heliospheric Observatory (SOHO) is used by both astrophysicists and space physicists. Its mission addresses both disciplines. For the purposes of this study, SOHO was analyzed as an astrophysics mission.

Each mission was briefly characterized, with special emphasis on the particular problems and benefits posed by its international makeup. The joint committee analyzed the history leading up to the mission, the nature of the cooperation, and the benefits or failures that accrued from conducting the cooperation. The following questions helped guide the joint committee's survey of the missions:

  1. What were the scope and nature of the agreement? How did the agreement evolve, and how was it finalized? How long did it take to plan the mission?

  2. How was the cooperation initiated (e.g., by scientist-to-scientist or agency-to-agency contact)? What was the role of each partner and agency? Were the motivations the same for all partners?

  3. What were the expected benefits each partner offered?

  4. What were the extent and practical mechanisms of cooperation? At what level, if any, did hardware integration of multinational components take place? How were communications maintained? Was the project structured to minimize friction between international partners?

  5. What was the net impact of internationalization on the mission in terms of costs, schedule, and science output?

  6. What external influences affected the mission during its life cycle? What were their effects? Were problems caused by different internal priorities or by external (e.g., political, financial) boundary conditions (such as budget cycles)?

  7. Were there issues of competition versus cooperation? Did the desire to protect technological leadership create problems?

  8. What benefits did the cooperation actually produce?

  9. Which agreements succeeded and which did not, in both scientific and programmatic terms?

The questions are not formally asked and answered for each mission case study but serve instead as guideposts. In the end, the joint committee sought to know and present the lessons learned and how they can be applied in the future.

RECOMMENDATIONS

The joint committee, having surveyed and analyzed the 13 U.S.-European cases discussed in Chapter 3, identified several conditions that either facilitated or hampered bilateral or multilateral cooperation in space science. Some of these conditions are unique to their scientific disciplines and their “cultures,” whereas others are

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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cross-cutting and apply overall to the cooperative experience between the United States and Europe, as analyzed in Chapters 2 and 3. The joint committee determined that these overarching factors can be organized according to the various phases of a cooperative program, namely (1) goals and rationale for international cooperation, (2) planning and identification of cooperative opportunities, (3) management and implementation, (4) personnel, and (5) guidelines and procedures. These factors led to five sets of recommendations.

Goals and Rationale for International Cooperation

The joint committee's examination of U.S.-European missions over more than 30 years shows, in retrospect, that international cooperation has at times been used to justify a mission that may have lacked support from the scientific community at large or other factors important for successful cooperation. (This was particularly true for the International Gamma-Ray Astrophysics Laboratory [INTEGRAL] mission, which lacked broad support within the U.S. astronomical community.)

Finding: Based on its analysis of 13 case missions involving U.S.-European cooperation, the joint committee identified eight key elements that it believes are essential to success in international cooperation in space missions.

  1. Scientific support. The international character of a mission is no guarantee of its realization. The best and most accepted method to establish compelling scientific justification of a mission and its components is peer review by international experts. Expert reviewers can verify that the science is of excellent quality and meets high international standards, the methods proposed are appropriate and cost effective, the results meet a clear scientific need, there are clear beneficiaries in partners' countries, and the international program has clear requirements.

    From a budgetary and political point of view, the mission must have strong support from the scientific community in a timely manner to overcome budget restrictions (and political hurdles). All partners and funding agencies need to recognize that international cooperative efforts should not be entered into solely because they are international in scope.

  2. Historical foundation. The success of any international cooperative endeavor is more likely if the partners have a common scientific heritage—that is, a history and basis of cooperation and a context within which a scientific mission fits. This context encompasses a common understanding of the science that can lead to the establishment of common goals. A common heritage also allows the scientific rationale to be tested against other priorities.

  3. Shared objectives. Shared goals and objectives for international cooperation must go beyond scientists to include the engineers and others involved in a joint mission. One of the most important lessons learned from the years of space research is that “intellectual distance” between the engineering and scientific communities and the accompanying lack of common goals and objectives can have a detrimental effect on missions. The penalty is that the mission project is, at best, only partially successful and, at worst, a total failure. Close interaction is particularly important at the design phase—for example, the participation of scientists in monthly engineering meetings can help to support optimal planning when compromises are needed between scientific goals and technical feasibility.

  4. Clearly defined responsibilities. Cooperative programs must involve a clear understanding of how the responsibilities of the mission are to be shared among the partners, a clear management scheme with a well-defined interface between the parties, and efficient communication. In successful missions, each partner has had a clearly defined role and a real stake in the success of the mission.

  5. Sound plan for data access and distribution. Cooperative ventures should have a well-organized and agreed-upon process for data calibration, validation, access, and distribution.

  6. Sense of partnership. The success of an international space scientific mission requires that cooperative efforts—whether they involve national or multinational leadership—reinforce and foster mutual respect, confidence, and a sense of partnership among participants. Each partner's contributions must be acknowledged in the media and in publications resulting from joint missions.

  7. Beneficial characteristics. Shared benefits such as exchanges of scientific and technical know-how and access to training are not usually sufficient justification in themselves to sustain an international mission. Successful missions have had at least one (but usually more) of the following characteristics:

    • Unique and complementary capabilities offered by each international partner, such as expertise in specific technologies or instruments, or in particular analytic methods;

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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  • Contributions made by each partner that are considered vital for the mission, such as providing unique facilities (launchers, space observatories, or laboratories), instruments, spacecraft subsystems, or ground receiving stations;

  • Significant net cost reductions for each partner, which can be documented rigorously, leading to favorable cost-benefit ratios;

  • International scientific and political context and impetus; and

  • Synergistic effects and cross-fertilization or benefit.

  1. Recognition of importance of reviews. Periodic monitoring of science goals, mission execution, and the results of data analysis ensure that international missions are both timely and efficient. This is particularly important if unforeseen problems in mission development or funding result in significant delays in the mission launch or if scientific imperatives for the mission have evolved since the original mission concept or development. A protocol for reviewing ongoing cooperative activities may avert the potential for failed cooperation and focus efforts only on those joint missions that continue to meet a high priority for their scientific results.

Recommendation 1

The joint committee recommends that eight key elements be used to test whether an international mission is likely to be successful. This test is particularly important in the area of anticipated and upcoming large missions. Specifically, the joint committee recommends that international cooperative missions involve the following:

  • Scientific support through peer review that affirms the scientific integrity, value, requirements, and benefits of a cooperative mission;

  • An historical foundation built on an existing international community, partnership, and shared scientific experiences;

  • Shared objectives that incorporate the interests of scientists, engineers, and managers in common and communicated goals;

  • Clearly defined responsibilities and roles for cooperative partners, including scientists, engineers, and mission managers;

  • An agreed-upon process for data calibration, validation, access, and distribution;

  • A sense of partnership recognizing the unique contributions of each participant;

  • Beneficial characteristics of cooperation; and

  • Recognition of the importance of reviews for cooperative activities in the conceptual, developmental, active, or extended mission phases —particularly for foreseen and upcoming large missions.

Planning and Identification of Cooperative Opportunities

Because planning, implementing, and managing are done by people, the findings and recommendations in the next two sections overlap somewhat with those in the section on personnel. Each area is vital. Even good people find it difficult to overcome poor planning. The joint committee found the following:

Finding: Planning for international missions has typically not been well coordinated with other related national programs or activities. Missions have been developed with similar, if not redundant, capabilities.

Recommendation 2

With respect to cooperation between NASA and the European Space Agency, the joint committee recommends that coordination between the planning and priority-setting committees of these agencies be enhanced to ensure that in an era of declining resources, missions are carefully considered to ensure their unique scientific contribution and global interdependence as well as their national impact.

Recommendation 3

Regarding cooperation between NASA and European countries, the joint committee recommends that scientific communities in the United States and Europe use international bodies such as the International

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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Council of Scientific Unions (ICSU), the Committee on Space Research (COSPAR), and other international scientific unions to keep informed about planned national activities in the space sciences, to identify areas of potential program coordination, to discuss issues and problems (e.g., technology, data sharing and exchange, cultural barriers) related to international cooperation, and to share this information with national agencies.

Finding: Clear, open communications are particularly important for international missions in space science to ensure that the cooperative space efforts have clearly articulated common goals and responsibilities and that mission results will be freely available. Missions with active science working teams and external user committees provide the best communications both within the project team and with the greater community.

Furthermore, it is critical to foster an active sense of community with excellent communication among scientists, developers, engineers, and managers from all parties involved in carrying out the mission. Principal investigators2 have experienced cases in which poor communication with managers and developers resulted in science return that was significantly below expectations. On the other hand, when scientists, developers, and managers were a true community, mission and instrument requirements were sharpened, design was improved, performance was excellent, and the science return met or even exceeded expectations. Such successful cooperation usually has involved a strong program scientist whose basic responsibility was to carry out the mission.

Recommendation 4

Given the important role that PIs in Europe and the United States have in leading and coordinating joint PI missions, the joint committee recommends therefore that for non-PI missions (in particular, multiuser ones such as those for microgravity research and life sciences and Earth observation), two program scientists of stature, one U.S. and one European, be appointed at an early stage of joint planning to lead and coordinate the mission.

Recommendation 5

The joint committee recommends that only those international cooperative efforts be attempted in which participants consider themselves partners (even if their respective responsibilities and contributions are different) and have confidence in one another's reliability and competence as well as their dedication to the overall mission goals.

Management and Implementation

The management and implementation of cooperative missions rely not only on clearly established goals and rationale and good planning, but also on capable personnel. Similarly, poor management practices can significantly hamper even the most highly motivated team. The joint committee found the following:

Finding: A clear management scheme with well-defined interfaces between the parties and efficient communications is essential.

Recommendation 6

The joint committee recommends that, at the earliest stages of each international space research mission, the partners designate (1) two management points of contact, one U.S. and one European; (2) a project structure

2  

For the purposes of this report, the following definitions are used:

  • Principal investigator: a scientist who conceives of an investigation, is responsible for carrying it out, reports on the results, and is responsible for the scientific success of the investigation;

  • Program scientist: a scientist who defines the policy and scientific direction of a program, establishes the mission science and applications objectives, and guides the science team to ensure that the scientific objectives are met;

  • Project scientist: the scientist who leads a mission’s science team and coordinates with the program/project manager to ensure that the science requirements of an investigation are met;

  • Program manager: an individual responsible for cost, schedule, and technical performance of a multi- or single-project program and who oversees the project managers for integrated program planning and execution; and

  • Project manager: an individual who manages the design, development, fabrication, and testing of a project.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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led by two designated PIs or program scientists, one U.S. and one European; and (3) an International Mission Working Group (IMWG) established with the two PIs or program scientists as co-chairs.

Finding: The lessons learned show the importance of defining a protocol for reviewing the ongoing cooperative activities by independent bodies, to ensure that these endeavors are both timely and efficient and that the criterion for high-priority scientific research is still met.

Recommendation 7

The joint committee recommends that each international mission in the space-oriented sciences be assessed periodically for its scientific vitality, timeliness, and mission operations, if a significant delay in mission development or if mission descope is necessary because of funding difficulties or other factors. For each cooperative mission, the participating space agencies should appoint a separate International Mission Review Committee (IMRC) composed of distinguished peers in science and engineering to review the overall vitality and value of the mission. The IMRC should be independent from the IMWG and the mission PIs. After the primary mission phase, the extension of mission operations and funding allocations from participating agencies for mission operations and analysis phases should be assessed by the IMRC.

Personnel

A prerequisite for good cooperative efforts between people is that they be recognized for their particular contributions, responsibilities, and roles (as noted also in the discussion in the section on management and implementation).

Finding: Experience shows that the roles and contributions of some partners in the success and results of a mission have not been sufficiently recognized or have even been overlooked in publications and in the media.

Recommendation 8

The joint committee recommends that the participation of each partner in an international space-related mission be clearly acknowledged in the publications, reports, and public outreach of the mission.

Finding: Those missions with the smoothest cooperative efforts had project managers on both sides of the Atlantic with mutual respect for each other. Clear scientific leadership is important for all types of missions. PI-type missions such as the Active Magnetospheric Particle Tracer Explorer (AMPTE) gained from having dedicated PIs maintain fundamental objectives and ensure data quality and distribution throughout the project.

Finding: Having assessed several cases, the joint committee found that even the best and seemingly most precise formulations of Memorandums of Understanding (MOUs) and other agreements may be subject to differences in understanding (especially in times of financial or political difficulties). This is often because of cultural differences or lack of effective communication between key individuals.

Finding: Because of the observed intellectual distance among scientists, engineers, and managers, good communication among these team members is an important ingredient of successful and smooth international cooperation. These interface problems are more critical in international cooperation, because of the added barriers of culture, language, and agency procedures that can further impede effective communication.

Recommendation 9

The joint committee recommends that program and project scientists and program and project managers be selected who have (1) a strong commitment not only toward the recognized mission objectives, but also toward international cooperation, and (2) excellent interpersonal skills, since it is important that key leaders and managers seek practical means for minimizing friction in joint U.S.-European missions.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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Guidelines and Procedures

Finding: The joint committee found that international cooperation has been hampered by nonessential administrative requirements, lack of timely information on both sides of the Atlantic, and changes in budget policies.

There are many examples in which the two partners in a transatlantic cooperation succeeded, having overcome the difficulties imposed by their different selection and funding sequences. In the SOHO case, for example, there were points in the cooperative processes where agencies on both sides responded quickly and effectively to handle hardware problems, schedule delays, launch difficulties, and other unforeseen challenges in order to bring the mission and the cooperative effort to fruition. Other cases were not successful, and the envisaged cooperation did not materialize.

Recommendation 10

The joint committee recommends that NASA, ESA, and other international partners review their own internal rules and processes (particularly those that influence international collaboration and cooperation) and seek changes that might foster and improve opportunities for international cooperation. At a minimum, the agency partners should improve procedures so that the existing rules and processes can be more effectively explained to all participants. In particular, the necessary financial commitments should be provided on all sides, and contingencies should be agreed upon. These commitments must be made more stable, especially on the U.S. side.

Finding: International cooperation may be hampered by national interests and issues involving political, economic, and trade policies that may extend well beyond the boundaries of the individual space agencies involved:

  • Export-import difficulties may affect the exchange of technology or technical information critical to a joint mission opportunity.

  • Data exchange policies and commercial interests may also impede access to scientific data on cooperative missions.

  • Laws governing intellectual property rights may restrict information flow or lead to difficulties in bilateral or multilateral U.S.-European space cooperation; and

  • Failings within the MOU process can create delays, loss of scientific opportunities, lost economic investments, and a decline in international goodwill, all of which can weaken the foundation for future cooperative activities.

Recommendation 11

In light of the importance of international cooperative activities in space and given the changing environment for cooperation, the joint committee recommends that the national and multinational space agencies advise science ministers and advisers on the implications that particular national trade export-import, data, and intellectual property policies may have on important cooperative space programs. As these types of problems on a particular mission arise, the agencies should encourage these ministers or advisers to bring such issues to the agenda of the next G-8 meeting.

Finding: To better phase the development of missions, the joint committee found that establishing milestone agreements in cooperative missions would be useful. The agreement between agencies (generally the MOU) is the key formal document defining the terms and scope of cooperation. Often, the comprehensiveness and clarity of this agreement have contributed significantly to the success of international cooperation in each discipline. Conversely, some of the difficulties encountered in several case studies can be traced in part to inadequate specificity in the agreement, or to misunderstanding or differing perceptions as to the status or interpretation of the agreement and the level of commitment implied by it. The observation that bilateral agreements between NASA and individual national space agencies appear generally less problematic than those between NASA and ESA may reflect the fact that NASA is itself a national agency, whereas ESA is a multinational organization with necessarily different

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

perspectives. NASA-ESA cooperation refers to larger, more expensive, and more complex missions than cooperative activities between NASA and European countries.

The joint committee believes that the interests of all parties are best served when agreements have maximum clarity and specificity as to the scope, expectations, and obligations of the respective agencies and relevant scientific participants. Given the inevitable discrepancies between the procedures, practices, and budget cycles of NASA and ESA, the agreements must serve as essential interface control documents. Because the expectations and the level of commitment evolve as a mission is defined and developed, the need for written agreements also changes. Establishing clear agreements would be facilitated if NASA and ESA could agree on a set of generic mission milestones with clear definitions and on template agreements that certify the passage of such milestones, the anticipated progress toward the next milestone, and the expectations and time line for achieving it.

Recommendation 12

The joint committee recommends that for cooperative missions in space-based science NASA and ESA establish a clearly defined hierarchy of template agreements keyed to mutually understood mission milestones and implementation agreements.

A suggested example of a set of template agreements is given in Table ES.2, which describes a progression, with the Letter of Mutual Interest, Letter of Mutual Intent, Study MOU, and Mission MOU corresponding roughly to the usual Pre-phase A, Phase A, Phase B, and Phase C/D of space science missions. Only a fraction of missions would be expected to proceed through the full cycle, and each agreement could clearly state the likelihood of proceeding to the next stage.

TABLE ES.2 Hierarchy of Template Agreements for Cooperative Missions

Mission Phase

Agreement

Content

Pre-phase A

Letter of Mutual Interest

• Identify potential high-priority missions under consideration

• Identify which bodies are studying them

• Determine how many are likely to be confirmed, and when

Phase A

Letter of Mutual Intent

• Establish an early program management and project structure and an International Mission Working Group (IMWG) with two program scientists or principal investigators as co-chairs

• Define objectives, scope, and expectations for Phase B

• Review project management scheme

Phase B

Study Memorandum of Understanding (MOU)

• Clarify objectives and scope

• Formulate anticipated implementation plan

• Outline responsibilities

• Select launcher

• Provide a rough schedule

• Determine expectations for funding

Mission MOU

• Create full definition of objectives, scope, plan, schedule, contingencies, and data issues

• Include project management plans

Phase C/D

Eventually, when necessary, appointment of an International Mission Review Committee (IMRC)

• Conduct periodic reviews of mission and effectiveness of its service to user community

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Recommendation 13

In light of the continuing scarcity of future resources, the volatility of the U.S. budget process, and the importance of trustworthy international agreements supporting cooperative efforts in space, the joint committee recommends that international budget lines be added to the three science offices within NASA to support important peer-reviewed, moderate-scale international activities.3

Finding: The free and open exchange of data lies at the heart of international scientific cooperation.4 When it is missing (as in the case of NASA and ESA in the area of Earth science) significant scientific international cooperation is difficult, if not almost impossible.

Recommendation 14

The joint committee recommends the following:

  • NASA and European space agencies should make a commitment to free and open exchange of data for scientific research as a condition for international scientific cooperation after any proprietary period established for principal investigators;

  • The scientific community, through their international organizations (e.g., ICGANSU, COSPAR), should openly and forcefully state their commitments to this concept and where there are difficulties; and

  • U. S. and European space agencies should ensure that programs plan and reserve adequate resources for management and distribution of data and develop and implement strategies for long-term archiving of data from all space missions.

3  

Although multiyear appropriations for international missions might be preferred, Congress has been reluctant to authorize such multiyear commitments because of the inflexibility it creates in the appropriations process.

4  

National Research Council, Preserving Scientific Data on Our Physical Universe: A New Strategy for Archiving the Nation's Scientific Information Resources, National Academy Press, Washington, D.C., 1995.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.7 A Strategy for Research in Space Biology and Medicine in the New Century

A Report of the Committee on Space Biology and Medicine*

EXECUTIVE SUMMARY

The core of the National Aeronautics and Space Administration's (NASA's) life sciences research lies in understanding the effects of the space environment on human physiology and on biology in plants and animals. The strategy for achieving that goal as originally enunciated in the 1987 Goldberg report, A Strategy for Space Biology and Medical Science for the 1980s and 1990s,1 remains generally valid today. However, during the past decade there has been an explosion of new scientific understanding catalyzed by advances in molecular and cell biology and genetics, a substantially increased amount of information from flight experiments, and the approach of new opportunities for long-term space-based research on the International Space Station. A reevaluation of opportunities and priorities for NASA-supported research in the biological and biomedical sciences is therefore desirable.

The strategy outlined in the Goldberg report had two main purposes: “(1) to identify and describe those areas of fundamental scientific investigation in space biology and medicine that are both exciting and important to pursue and (2) to develop the foundation of knowledge and understanding that will make long-term manned space habitation and/or exploration feasible.”2 To achieve these purposes, the Goldberg report identified four major goals of space life sciences:

  1. To describe and understand human adaptation to the space environment and readaptation upon return to earth.

  2. To use the knowledge so obtained to devise procedures that will improve the health, safety, comfort, and performance of the astronauts.

  3. To understand the role that gravity plays in the biological processes of both plants and animals.

  4. To determine if any biological phenomenon that arises in an individual organism or small group of organisms is better studied in space than on earth.”3

These goals remain valid and form the basis of the present report.

Both the Goldberg report and the 1991 follow-up assessment, Assessment of Programs in Space Biology and Medicine 1991,4 emphasized basic research and the importance of vigorous ground-based programs aimed at addressing the fundamental mechanisms that underlie observed effects of the space environment on human physiology and other biological processes. The present report strongly reemphasizes that strategy and calls for an integrated, multidisciplinary approach that encompasses all levels of biological organization—the molecule, the cell, the organ system, and the whole organism—and employs the full range of modern experimental approaches from molecular and cellular biology to organismic physiology.

The sections that follow summarize the Committee on Space Biology and Medicine's priorities for NASA-supported research, its recommendations for high-priority research in individual disciplines, and its recommendations for overall priorities for NASA-sponsored research across disciplinary boundaries. The final section outlines significant concerns in the program and policy arena and offers related recommendations.

PRIORITIES FOR RESEARCH

Taking into account budgetary realities and the need for clearly focused programs, the highest priority for NASA-supported research in space biology and medicine in the new century should be given to research meeting one of the following criteria:

  1. Research aimed at understanding and ameliorating problems that may limit astronauts' ability to survive and/or function during prolonged space/light. Such studies include basic as well as applied research and ground-

* “Executive Summary” reprinted from A Strategy for Research in Space Biology and Medicine in the New Century, National Academy Press, Washington, D.C., 1998, pp. 1-18.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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  1. based investigations as well as flight experiments. NASA programs should focus on aspects of research in which NASA has unique capabilities or that are under emphasized by other agencies.

  2. Fundamental biological processes in which gravity is known to play a direct role. As above, programmatic focus should emphasize NASA 's capabilities and take into account the funding patterns of other agencies.

A lower priority should be assigned to areas of basic and applied research that are relevant to fields of high priority to NASA but are extensively funded by other agencies, and in which NASA has no obvious unique capability or special niche.

HIGH-PRIORITY DISCIPLINE-SPECIFIC RESEARCH

Because the recommendations for research, and research priorities, in the discipline-specific chapters cover a wide range of fields relevant to space biology and medicine, the committee chose not to reproduce all of those recommendations in full in this executive summary. Instead the committee sought to capture the essence of what is recommended in Chapters 2 through 12, an approach that was best served by condensation, full quotation, or addition of supplemental detail as seemed useful to preserve the intent of the recommendations in their full form and context. The recommendations are numbered only in instances in which the committee considered that there was a clear priority order.

Cell Biology

Rapid advancement in the field of cell biology offers novel opportunities for studying the effects of spaceflight, including weightlessness, on cells and tissues. This possibility for progress stems both from developments in technology and advances in basic concepts of cell structure and function at the molecular level. Reasonable goals for the next period of NASA investigation are to clearly delineate the specific cellular phenomena that are affected by conditions of microgravity, to develop an understanding of the molecular mechanisms by which these changes are induced, and to begin to suggest strategies for countermeasures where indicated. Experience from previous inflight and ground-based studies has highlighted certain pitfalls that must be avoided in the design and analysis of future experiments. Cellular systems should be emphasized that are known to be affected by gravitational force (e.g., bone, muscle, and vestibular systems in animals; gravitropic systems in plants) or by other aspects of the space environment (e.g., stress-induced phenomena). Consideration should be given to using molecular techniques for the analysis of gene expression and cell architecture and function, and to extending cell culture studies to the analysis of cellular physiology in intact tissues and whole organisms.

The committee makes the following specific recommendations for research in cell biology:

  • General mechanisms of mechanoreception and pathways of signal transduction from mechanical stresses are areas of special opportunity and relevance for NASA life sciences. Studies of mechanisms of cellular mechanoreception should include identification of the cellular receptor, investigation of possible changes in membrane and cytoskeletal architecture, and analysis of pathways of response, including signal transduction and resolution in time and space of possible ion transients.

  • Studies of cellular responses to environmental stresses encountered in spaceflight (e.g., anoxia, temperature, shock, vibration) should include investigation of the nature of cellular receptors, signal transduction pathways, changes in gene expression, and identification and structure and function analysis of stress proteins that mediate the response.

  • The successful conduct of sophisticated cell biological experiments in space will require the development of highly automated and miniaturized instrumentation and advanced methodologies. NASA should work with the scientific community and industry to foster development of advanced instrumentation and methodologies for space-based studies at the cellular level.

Developmental Biology

The specific physiological systems in humans and animals for which gravity is likely to play a critical role in development and/or maintenance include the vestibular system, the multiple sensory systems that interact with the

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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vestibular system, and the topographic space maps that exist throughout the brain. Major changes in perspective in recent years in the general field of developmental biology could greatly affect our ability to study and understand these systems. In particular, the use of saturation mutagenesis to identify genetic components of development, the recognition that molecular mechanisms are conserved across phylogeny, and the information provided by genome sequencing projects have transformed basic developmental studies since the publication in 1987 of the Goldberg report.5 In the present report the committee stresses the importance of two types of studies, those looking at life cycles and those examining development of gravity-sensing systems such as the vestibular system.

Complete Life Cycles in Microgravity
  • The committee recommends that key model organisms be grown through two complete life cycles in space to determine whether there are any critical events during development that are affected by space conditions. Because no critical effects have been seen in model invertebrates, the highest priority should be given to testing vertebrate models such as fish, birds, and small mammals such as mice or rats. If developmental effects are detected, control experiments must be performed on the ground and in space, including the use of a space-based 1-g centrifuge, to identity whether gravity or some other element of the space environment induces the developmental abnormalities.

Development of the Vestibular System

Analysis of the development of gravity-sensing systems, including the vestibular system and other systems that interact with it in vertebrates, should be carried out to determine the importance of gravity to their normal development and maintenance. The recommended investigations summarized below should be performed first in ground-based studies to identify appropriate experiments to be performed in space.

  • Studies should be performed to define the critical periods for development of the vestibular system. Thus, the critical periods for cellular proliferation, migration, and differentiation and programmed cell death should be identified and the effects of microgravity on these processes assessed.

Neural Space Maps

Neurons composing the brainstem, hippocampal, striatal, and sensory and motor cortical space maps should be investigated as part of the following recommended studies:

  • The role of otolithic stimulation on the development and maintenance of the different neural space maps should be investigated.

  • Studies should be designed to address how neurons of the various sensory and motor systems interact with vestibular neurons in the normal assembly and function of the neural space maps. Factors should be identified that are supplied by and to the sensory neurons that produce the orderly assembly of these maps in precise coordinate registration.

  • The influence of microgravity on the development and maintenance of the neural space maps should be studied.

Neuroplasticity

It is important to characterize neuroplasticity using multidisciplinary approaches that combine structural and molecular with functional investigations of identified cell populations. The process should be characterized at several different times following perturbation, in order to determine the sequence of intermediate events leading to the plastic change. Controls for the effects of nongravitational stresses of the types likely to be encountered in space (such as loud noise and vibration) must also be performed on the ground, so that the space-based experiments can be designed to isolate the effects of microgravity from the effects of other stresses. The committee makes the following recommendations for research on neuroplasticity, including one recommendation taken from Chapter 5, “ Sensorimotor Integration.”

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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  • Studies are needed to determine whether the compensatory mechanisms that normally function in the vestibulomotor pathways are altered by exposure to microgravity. These experiments should be given the highest priority, because these compensatory mechanisms operate in astronauts entering and returning from space and may have a profound effect on their performance in space and their postflight recovery on Earth.

  • Experiments are needed to critically test the role of gravity on the development and maintenance of the vestibular system's capability for neuroplasticity.

  • Because the vestibule-oculomotor system is capable of learning new motor patterns in response to sensory perturbations, it is important to determine if and how these mechanisms are affected by exposure to microgravity.

  • Functional magnetic resonance imaging (fMRI) should be employed to investigate the following:

    • Changes in sensory and motor cortical maps in human bed-rest studies mimicking different flight durations.

    • The effects of microgravity on cortical maps in the human. Pre-and postflight fMRI studies should be conducted with astronauts.

Plants, Gravity, and Space

The study of plants in the space environment has been driven by three main needs: (1) learning how to grow plants successfully in space (space horticulture) either for research or for eventual use in long-term life support systems, (2) determining whether there are any plant developmental or metabolic processes that are critically dependent on gravity, and (3) learning how plants alter their patterns of growth and development to respond to changes in the direction of the gravity vector.

Space Horticulture

A major goal of the Advanced Life Support (ALS) program is to develop an effective, completely closed plant growth system capable of growing plants for a bioregenerative life support system. Toward this end, the committee makes the following recommendations:

  • The ALS program should concentrate its ground-based research on developing a completely enclosed plant growth system. This effort will require close collaboration between engineers and plant environmental scientists.

  • The ALS spaceflight program should focus on testing the potentially gravity-sensitive components of the closed plant growth system, such as the nutrient delivery system.

Role of Gravity in Plant Development

Whether gravity is required for any specific aspect of the development or metabolism of a plant can best be determined by growing a model plant in space through at least two successive generations (seed-to-seed experiment) and examining carefully the development of the resulting plants to ascertain whether any aspect of the development is altered by a lack of gravity. Specifically, the committee recommends the following:

  • The seed-to-seed experiment should be the top priority in this area. The promising results obtained with Brassica rapa should be confirmed and extended, using Arabidopsis thaliana plants. This experiment must be conducted on the ISS, because the plants should be grown through at least two generations in space.

  • To conduct a meaningful seed-to-seed experiment, NASA needs to develop the following:

    • A superior plant growth unit, with adequate lighting, gas exchange, and water and/or nutrient delivery; and

    • Arabidopsis thaliana plants that are insensitive to expected environmental stresses and that contain indicator genes for all the expected environmental stresses, such as high levels of CO2, vibration, anaerobiosis, water stress, and temperature stresses.

  • In the interim, before the ISS is functional, studies on specific stages of plant development in space should be limited to small plants with short life cycles (e.g., Arabidopsis thaliana or Brassica rapa). Whenever possible, a 1-g on-board centrifuge should be available.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Responses of Plants to Change in Direction of the Gravity Vector

Plants respond to the specific direction of the gravity vector in several ways. Among these are the direction of growth of stems and roots (gravitropism) and the swimming direction of some unicellular algae (gravitaxis). Among the committee's recommendations regarding this area of research, the following have the highest priority:

  • A primary focus of NASA-sponsored research in plant biology should be on the mechanisms of gravitropism. In particular, modern cellular and molecular techniques should be used to determine the following:

    • The identity of the cells that actually perceive gravity, and the role of the cytoskeleton in the process;

    • The nature of the cellular asymmetry set up in a cell that perceives the direction of the gravity vector;

    • The nature and mechanism of the translocation of the signals that pass from the site of perception to the site of reaction; and

    • The nature of the response to the signal(s) that leads to alterations in the rate of cell enlargement.

  • A secondary focus should be on the mechanisms of graviperception in single cells, including gravitropic responses of mosses and gravitaxic responses of algae.

Sensorimotor Integration

Sensorimotor integration is an essential element in the control of posture and locomotion, as well as in coordinated body activities such as manipulation of objects and use of tools. The transition from normal gravity to microgravity disrupts postural control and orientation mechanisms. Spatial illusions, and often motion sickness, occur until adaptation to the new force background is achieved. On reentry, severe disturbances of postural, locomotory, and movement control are experienced with reexposure to the normal terrestrial environment. Thresh-olds for angular and linear accelerations, vestibulo-ocular reflexes, postural mechanisms, vestibule-spinal reflexes, and gaze control all have been studied extensively in humans, but the development of animal models has lagged. Some of these areas require additional study, and a number of new experimental questions arise, given current knowledge and the need to consider human performance during extended-duration space missions.

Spatial Orientation

Future work should emphasize mechanisms related to the active control of body orientation and movement rather than passive thresholds for the detection of angular or linear acceleration. Briefly summarized, the committee's research recommendations are as follows:

  1. It is of critical interest to determine how microgravity and other unusual force environments, including rotating environments, affect the integrative coordination of eye, head, torso, arm, and leg movements.

  2. It is important for the success of long-duration space missions to identify the sensory, motor, and cognitive factors that influence adaptation and retention of adaptation to different force environments, including rotating environments.

  3. The influence of altered force levels, including microgravity, on spatial coding of position should be explored in parallel experiments with humans and animals.

Posture and Locomotion

The severe reentry disturbances of posture and locomotion experienced by astronauts and cosmonauts after even short-duration spaceflight pose potentially dangerous operational problems. These disturbances would be especially critical in long-duration missions that require accurate postural, locomotory, and manipulatory control during transitions in background force level. The committee recommends the following:

  • The time course for adaptation of locomotion and posture to variations in background force level should be determined.

  • Techniques should be developed to provide ancillary sensory inputs or aids to enhance postural and locomotory control during and after transitions between different force levels.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Vestibulo-Ocular Reflexes and Oculomotor Control

Considerable progress has been made in understanding how microgravity affects vestibulo-ocular reflexes, pursuit and saccadic eye movements, and control of gaze. The following studies, which can be carried out in parabolic flight, orbital flight, and rotating rooms, are recommended to achieve closure on understanding these critical functions.

  • Systematic parametric studies of pursuit, saccadic, and optokinetic eye movements should be carried out as a function of background force level in humans from microgravity to 2 g.

  • The coordination of eye-head-torso synergies in different force levels and their adaptation to changes in force level should be assessed, with the goal of developing a comprehensive three-dimensional model of the vestibulo-ocular reflex and cervical control of gaze.

Space Motion Sickness

Space motion sickness is an operational problem during the first 72 hours of flight, despite the use of medication, and is a hazard for initial transitions between force environments. The use of virtual environment devices in spaceflight to augment training in long-duration missions and for experimental purposes will likely exacerbate motion sickness. Research is recommended on the following:

  • The relationship of motion sickness to altered sensorimotor control of the head and body in microgravity and greater than 1-g force backgrounds generated in parabolic flight and rotating rooms; and

  • The relationship of the vestibular system to autonomic function, especially cardiovascular regulation.

Bone Physiology

One of the best-documented pathophysiological changes associated with microgravity and the spaceflight environment is bone loss, which can exceed 1 percent per month in weight-bearing bones even when an in-flight exercise regime is followed. Within the discipline of bone physiology, the phenomenon of bone loss in astronauts is clearly the issue of greatest concern to NASA. Both the extent and the reversibility of the bone loss are crucial questions for long-term crewed flights on the space station and for future space exploration and should be addressed by collecting data from each astronaut to build up the necessary database.

Studies on Humans

The committee recommends that questions about microgravity-induced bone loss in humans be studied as follows:

  1. To obtain a detailed description of human bone loss in space, a record of skeletal changes occurring during microgravity and postflight should be generated for each astronaut and correlated with age and gender, muscle changes, hormonal changes during flight, diet, and genetic factors (e.g., susceptibility to osteoporosis) if and when these genetic factors become known.

  2. Bone turnover studies should establish if bone loss is due to increased bone destruction (resorption), decreased bone formation, or both.

  3. To develop effective countermeasures, different modalities of mechanical stimulation, the use of exercise (e.g., impact loading), and pharmacological means to prevent bone loss should be evaluated.

Animal Models

If applicable to humans, a considerable amount of useful data on bone loss could be generated using animal models. The committee' s priority recommendations are summarized as follows:

  1. It should be determined if mechanisms of the bone changes produced by microgravity in animal models are similar to those in humans. Rodent models should include mice, given their smaller size and the availability of

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

genetic variants and transgenic animals. Adult animals should be used. In-flight experiments should include animals exposed to centrifugal forces that reproduce 1-g conditions.

  1. When an animal model is identified that mimics human bone changes in spaceflight, it should be used in ground-based models of microgravity, such as hindlimb-suspension unloading. If the ground-based model reproduces the changes observed under microgravity conditions, it should be used extensively to address questions of mechanisms.

Skeletal Muscle

A better understanding of the deleterious effects on skeletal muscle of spaceflight and reloading upon return to Earth is necessary to maintain performance and prevent injury. Even after missions of a few weeks, the locomotion of astronauts is very unstable immediately after they return to Earth, owing to a combination of orthostatic intolerance, altered otolith-spinal reflexes, reliance on weakened atrophic muscles, and inappropriate motor patterns. The committee 's high-priority research recommendations are summarized below:

  • Priority should be given to research that focuses on cellular and molecular mechanisms underlying muscle weakness, fatigue, incoordination, and delayed-onset muscle soreness.

  • Ground-based models, including bed rest for humans and hindlimb unloading in normal and genetically altered rodents, should be used within and across disciplines to investigate the mechanisms underlying in-flight and postflight effects on muscle mass, protein composition, myogenesis, fiber type differentiation, and neuromuscular development.

  • The mechanisms should be determined whereby muscle cells sense working length and the mechanical stress of gravity. Signal transduction pathways for growth factors, stretch-activated ion channels, regulators of protein synthesis, and interactions of extracellular matrix and membrane proteins with the cytoskeleton should be investigated.

Cardiovascular and Pulmonary Systems

The cardiovascular and pulmonary systems undergo major changes in microgravity, including reduced blood volume that is redistributed headward, increased heart volume, altered blood pressure and heart rate, and improved gas exchange in the lungs despite the surprising persistence of lung ventilation-perfusion inequalities. Many observational research questions have been answered. Future research should focus more on mechanisms. The committee developed a number of recommendations for specific research studies which are broadly summarized below.

Cardiovascular System
  • Reevaluate current antiorthostatic countermeasures, and develop and validate new ones. Priority should be given to interventions that may provide simultaneous bone and/or muscle protection.

  • Extend current knowledge regarding the magnitude, time course, and mechanisms of cardiovascular adjustments to include long-duration microgravity.

  • Determine the mechanisms underlying inadequate total peripheral resistance observed during postflight orthostatic stress.

  • Identify and validate appropriate methods for referencing intrathoracic vascular pressures to systemic pressures in microgravity.

Pulmonary System
  • Characterize gravity-determined topographical differences of blood flow, ventilation, alveolar size, intrapleural pressures, and mechanical stresses in microgravity during rest and exercise.

  • Determine the extent to which pulmonary vascular and microvascular pressures and lymphatic flow are altered by microgravity and whether these changes have any impact on either aging or disease processes.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  • Examine patterns of aerosol deposition, and determine whether ventilatory and nonventilatory responses to particulate or antigen inhalation are altered by microgravity.

  • Identify changes in pulmonary function that occur during extravehicular activity (EVA), and establish resuscitation procedures for crew members in the event of loss of cabin pressure or EVA suit pressure.

  • Evaluate respiratory muscle structure and function in microgravity, at rest, and during maximal exercise.

Endocrinology

The endocrine, nervous, and immune systems regulate the human response to spaceflight and the readjustment processes that follow landing. The principal spaceflight responses to which there is a significant endocrine contribution are the fluid shifts, perturbation of circadian rhythms, loss of red blood cell mass, possible alterations in the immune system, losses of bone and muscle, and maintenance of energy balance. With the advent of the space station era, the focus shifts from early responses to spaceflight to the long-term adaptive responses. The three chronic responses that are areas of serious concern are bone loss, muscle atrophy, and possibly the question of maintaining energy balance at an acceptable level. Priority should be given to studies that are designed to do the following:

  • Ensure adequate dietary input during spaceflight. Energy intake must meet needs, and physiological measurements must be made on subjects that are in approximate energy balance so that measurements are not confounded by an undernutrition response. The relationship between the amount of exercise and the protein and energy balance in flight should be investigated.

  • Obtain a human hormone profile early and late in flight and, as a control, preflight measurements on the same individuals over an extended period of time.

  • Determine the effects of spaceflight on human circadian rhythms. If significant degradation of performance is found and it can be attributed to the disturbed circadian rhythm, explore the use of countermeasures, including a combination of light and melatonin.

Immunology

As individuals stay longer in space, the potential effects of spaceflight on immune function become more significant. There is now convincing evidence that immunological parameters are affected by spaceflight, and important questions should be answered regarding both the biological and the medical significance of these effects and their mechanisms. Future immunological studies should concentrate on functional immunological changes that have been shown to be biologically and medically significant.

Animal Studies

Rodent studies can be used to help determine the biological and/or biomedical significance of spaceflight-induced changes in immune responses. Both short- and long-term studies should be carried out, with priority given to those briefly summarized below:

  1. Resistance to infection should be examined in animals immediately after their return from spaceflight.

  2. Acquired immune responses should be examined, including specific humoral and cellular immune responses.

Human Studies

Immunological measurements and testing of humans should be carried out to examine parameters with potential functional consequences. The recommended studies are briefly summarized below:

  1. Acquired immune responses should be examined as described above for animals.

  2. Innate immune responses should be examined, including natural killer cell and neutrophil function.

  3. Epidemiological studies should be conducted, as the population of astronauts and cosmonauts increases, to assess the potential risk of infection and, in particular, of the development of tumors.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Radiation Hazards

Exposure of crew members to radiation in space poses potentially serious health effects that need to be controlled or mitigated before long-term missions beyond low Earth orbit can be initiated. The levels of radiation in interplanetary space are high enough and the missions long enough that adequate shielding is necessary to minimize carcinogenic, cataractogenic, and possible neurologic effects for crew members.

The knowledge needed to design adequate radiation shielding has both physical and biological components: (1) the distribution and energies of radiation particles present behind a given shielding material as a result of the shield being struck by a given type and level of incident radiation and (2) the effects of a given dose on relevant biological systems for different radiation types. Each component involves significant uncertainty that must be reduced to permit the effective design of shielding, given that the level of uncertainty governs the amount of shielding.6

The execution of the recommended strategies will require considerably more beam time at a heavy-ion accelerator than is currently available, and it is recommended that NASA explore various possibilities, including the construction of new facilities, to increase the research time available for experiments with high-atomic-number, high-energy (HZE) particles. Priority should be given to the following studies:

  1. Determine the carcinogenic risks following irradiation by protons and HZE particles.

  2. Determine how cell killing and induction of chromosomal aberrations vary as a function of the thickness and composition of shielding.

  3. Determine whether there are studies that can be conducted to increase the confidence of extrapolation from rodents to humans of radiation-induced genetic alterations that in turn could enhance similar extrapolations for cancer.

  4. Determine if exposure to heavy ions at the level that would occur during deep-space missions of long duration poses a risk to the integrity and function of the central nervous system.

  5. Determine if better error analyses can be performed of all factors contributing to the estimation of risk by a particular method, and determine the types and magnitude of uncertainty associated with each method.

  6. Determine how the selection and design of the space vehicle affect the radiation environment in which the crew has to exist.

Behavioral Issues

Long-duration missions in space are likely to produce significant changes in individual, group, and organizational behavior. Future missions in space will involve longer periods of exposure to features of the physical environment unique to space and features of the psychosocial environment characteristic of isolated and confined environments. Evidence from previous space missions and from analogue studies suggests that behavioral responses to these environmental stressors will be influenced by characteristics of the individuals, groups, and organizations involved in long-duration missions.

The following list broadly summarizes, in order of priority, the recommended research for behavior and performance during long-duration missions in space:

  1. Develop noninvasive qualitative and quantitative techniques for the ongoing assessment of preflight, inflight, and postflight behavior and performance.

  2. Investigate the neurobiological and psychosocial mechanisms underlying the effects of physical and psychosocial environmental stressors on cognitive, affective, and psychophysiological measures of behavior and performance. Such research should be conducted both in space and in ground-based analogue environments.

    • Research on environmental factors should include an assessment of affective and cognitive responses to microgravity-related changes in perceptual and physiological systems and behavioral responses to perceived physical dangers, restricted privacy and personal space, and physical and social monotony.

    • Research on physiological factors should include studies of behavioral correlates of changes in circadian rhythms and sleep patterns; changes in and stability of individual physiological patterns in response to psychosocial and environmental stress and their applicability to measures of in-flight behavior and performance; and the relationship between self-reports and external performance-related and physiological symptoms of stress.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  • Research on individual factors should include studies of specific coping strategies and behavioral and physiological indicators of coping-stage transitions during long-duration missions; associations between general and mission-specific personality characteristics and performance criteria of ability, stability, and compatibility; changes in problem-solving ability and other aspects of cognitive performance in flight; and changes in personality and behavior postflight.

  • Research on interpersonal factors should include studies of the influence of crew psychosocial heterogeneity on crew tension, cohesion, and performance during a mission; factors affecting ground-crew interactions; and the influence of different styles of leadership and decision-making procedures on group performance.

  • Research on organizational factors should include studies of the effect of differences in the cultures of the participating agencies on individual and group performance and behavior; the association between mission duration and changes in behavior and performance; and the organizational requirements for effective management of long-duration missions as they relate to task scheduling and workload and to the distribution of authority and decision making.

  1. Evaluate existing counter-measures and develop new countermeasures that effectively contribute to optimal levels of crew performance, individual well-being, and mission success. These countermeasures include the following:

    • Screening and selection procedures that are based on a “select-in” assessment of individual personality characteristics and interpersonally oriented psychological assessments of crew compatibility;

    • Training programs that are team oriented and that enable crews to successfully address the social, cultural, and psychological issues likely to occur in flight;

    • Organizational countermeasures for filling unstructured time and reducing boredom and monotony;

    • Clinical countermeasures, such as the use of psychoactive medications in microgravity environments and the use of voice analysis for monitoring the interpersonal performance of crews; and

    • Design of spacecraft interiors and amenities to maximize control over the physical environment and reduce the impacts of physical monotony on behavior and performance.

CROSSCUTTING RESEARCH PRIORITIES

This section summarizes the committee's recommendations for the highest-priority research across the entire spectrum of space life sciences. In the near term, until the research facilities of the International Space Station come online or an additional Spacelab mission is provided, NASA-supported research will necessarily be directed primarily toward ground-based investigations designed to answer fundamental questions and frame critical hypotheses that can later be tested in space. Indeed, as this report emphasizes, understanding the basic mechanisms underlying biological and behavioral responses to spaceflight is essential to designing effective countermeasures and protecting astronaut health and safety both in space and upon return to Earth. For these reasons, the following recommendations for high-priority areas of crosscutting research place emphasis on ground-based studies.

Physiological and Psychological Effects of Spaceflight

Priority should be given to research aimed at ameliorating problems that may limit astronauts' health, safety, or performance during and after long-duration spaceflight. The committee emphasizes that specific priorities may shift to a significant degree depending on the types of missions to be carried out in the future, particularly as related to long-term human exploration of space. For this reason, the recommended areas of research are not given an order of priority.

Loss of Weight-bearing Bone and Muscle

Bone loss and muscle deterioration are among the best-documented deleterious effects caused by spaceflight in humans and animals. Exercise has been only partially successful in preventing muscle weakness and bone loss. Development of effective countermeasures requires advances in several areas of research:

  • Research should emphasize studies that provide mechanistic insights into the development of effective countermeasures for preventing bone and muscle deterioration during and after spaceflight.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  • Ground-based model systems, such as hindlimb unloading in rodents, should be used to investigate the mechanisms of changes that reproduce in-flight and postflight effects.

  • A database on the course of microgravity-related bone loss and its reversibility in humans should be established in preflight, in-flight, and postflight recording of bone mineral density.

  • Hormonal profiles should be obtained on humans before, during, and after spaceflight.

  • The relationship between exercise activity levels and protein energy balance in flight should be investigated.

Vestibular Function, the Vestibular Ocular Reflex, and Sensorimotor Integration

During the transitions in gravitational force that occur going into and returning from spaceflight, the vestibular system undergoes changes in activity that can result in debilitating symptoms in astronauts.

  • The highest priority should be given to studies designed to determine the basis for the adaptive compensatory mechanisms in the vestibular and sensorimotor systems that operate both on the ground and in space.

  • In-flight recordings of signal processing following otolith afferent stimulation should be made to determine how exposure to microgravity affects central and peripheral vestibular function and development.

  • Motor learning should be investigated in spaceflight and the results compared with findings obtained in ground-based studies of this process.

Orthostatic Intolerance Upon Return to Earth Gravity

Orthostatic hypotension, present since the very earliest human spaceflights, still affects a high percentage of astronauts returning from spaceflights even of relatively short duration and is an even greater problem for shuttle pilots, who must perform complex reentry maneuvers in an upright, seated position. The problem remains despite the use of extensive antiorthostatic countermeasures by both U.S. and Russian space programs. Studies should focus on determining physiological mechanisms and developing effective countermeasures.

  • Current knowledge of the magnitude, time course, and mechanisms of cardiovascular adjustments should be extended to include long-duration exposure to microgravity.

  • The specific mechanisms underlying inadequate total peripheral resistance observed during postflight orthostatic stress should be determined.

  • Current antiorthostatic countermeasures should be reevaluated to refine those that offer protection and eliminate those that do not. Priority should be given to interventions that may provide simultaneous bone and/or muscle protection.

  • Appropriate methods for referencing intrathoracic vascular pressures to systemic pressures in microgravity should be identified and validated, given the observed changes in cardiac and pulmonary volume and compliance.

Radiation Hazards

The biological effects of exposure to radiation in space pose potentially serious health effects for crew members in long-term missions beyond low Earth orbit. High priority is given to the following recommended studies:

  • Determine the carcinogenic risks following irradiation by protons and high-atomic-number, high-energy (HZE) particles.

  • Determine if exposure to heavy ions at the level that would occur during deep-space missions of long duration poses a risk to the integrity and function of the central nervous system.

  • Determine how the selection and design of the space vehicle affect the radiation environment in which the crew has to exist.

  • Determine whether combined effects of radiation and stress on the immune system in spaceflight could produce additive or synergistic effects on host defenses.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Physiological Effects of Stress

The immune system interacts closely with the neuroendocrine system. Results indicate a close association between the neuroendocrine status of the host and host defense systems.

  • The role that the host response to stressors during spaceflight plays in alterations in host defenses should be determined.

Psychological and Social Issues

The health, well-being, and performance of astronauts on extended missions may be negatively affected by many stressful aspects of the space environment. Mechanisms of response to physiological and psychosocial stressors encountered in spaceflight must be better understood in order to ensure crew safety, health, and productivity.

  • Highest priority should be given to interdisciplinary research on the neurobiological (circadian, endocrine) and psychosocial (individual, group, organizational) mechanisms underlying the effects of physical and psychosocial environmental stressors. Cognitive, affective, and psychophysiological measures of behavior and performance should be examined in ground-based analogue settings as well as in flight.

  • High priority should be given to evaluation of existing countermeasures (screening and selection, training, monitoring, support) and development of effective new countermeasures.

Fundamental Gravitational Biology
Mechanisms of Graviperception and Gravitropism in Plants

Plants respond to changes in the direction of the gravitational vector by altering the direction of the growth of roots and stems. The gravitropic response requires (1) perception of the gravitational vector by gravisensing cells; (2) intracellular transduction of this information; (3) translocation of the resulting signal to the sites of reaction, i.e., sites of differential growth; and (4) reaction to the signal by the responding cells, i.e., initiation of differential growth.

  • Studies of graviperception should concentrate on three problems:

    • The identity of the cells that actually perceive gravity;

    • The intracellular mechanisms by which the direction of the gravity vector is perceived; and

    • The threshold value for graviperceptionthis will require a spaceflight experiment.

  • Studies of gravitropic transduction should focus on the nature of the cellular asymmetry that is set up in a cell that perceives the direction of the gravity vector.

  • Studies on the translocation step should concentrate on the nature and mechanism of the translocation of the signals that pass from the site of perception to the site of reaction.

  • Studies on the reaction step should focus on the mechanism(s) by which gravitropic signals cause unequal rates of cell elongation, and on the possible effects of gravity on the sensitivity of these cells to the signals.

Mechanisms of Graviperception in Animals

It is known that in several systems sensory stimulation plays a role in the development of the neural connections necessary for normal processing of sensory information. The potential role of gravity in the normal development of the gravity-sensing vestibular system of animals is therefore an important area for ground- and space-based research.

  • Ground-based studies should identify the critical periods in vestibular neuron development before initiation of experiments on the effects of microgravity on vestibular development.

  • Pre- and postflight functional magnetic resonance imaging (fMRI) studies should be conducted with astronauts to determine the effects of microgravity on neural space maps.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Effects of Spaceflight on Reproduction and Development

To determine whether there are developmental processes that are critically dependent on gravity, organisms should be grown through at least two full generations in space.

  • Key model animals should be grown through two life cycles; the highest priority should be given to vertebrate models. If significant developmental effects are detected, control experiments must be performed to determine whether gravity or some other element of the space environment induces these developmental abnormalities.

  • An analogous experiment should be carried out with the model plant Arabidopsis thaliana to confirm results obtained on Mir with a preliminary experiment using Brassica rapa.

PROGRAMMATIC AND POLICY ISSUES

Although NASA has responded effectively to many of the programmatic and policy issues raised in the 1987 and 1991 reports,7,8 significant concerns in the program and policy arena remain unresolved. These concerns focus on issues relating to strategic planning and conduct of space-based research; utilization of the International Space Station (ISS) for life sciences research; mechanisms for promoting integrated and interdisciplinary research; collection of and access to human flight data, specifically; publication of and access to space life sciences research in general; and professional education.

Space-based Research
Development of Advanced Instrumentation and Methodologies

Future life sciences flight experiments on the ISS will depend on the availability of advanced instrumentation to carry out the measurements and analyses required by the research questions and approaches described in this report. In addition, facile data and information transfer between space- and ground-based investigators are crucial.

  • NASA should work with the broad life sciences community to identify and catalyze the development of advanced instrumentation and methodologies that will be required for sophisticated space-based research in the coming decade.

  • NASA should take advantage of advanced instrumentation developed in other countries.

  • The capability for direct, real-time communication between space-based experimenters and principal investigators at their home laboratories should be a high-priority objective for the ISS.

Utilization of the International Space Station for Life Sciences Research

Issues relating to the design and use of the ISS are a major concern of the committee. These issues include (1) changes in the design of the ISS, (2) the diversion of funds intended for scientific facilities and equipment into construction budgets, (3) the adequacy of power and transmission of data to and from Earth, (4) the availability of crew time for research, and (5) an extended hiatus in flight opportunities for life sciences research owing to delays in ISS construction. These issues have alarmed the life sciences communities.

  • To better ensure that the ISS will adequately meet the needs of space life sciences researchers, NASA should continue to bring the external user community as well as NASA scientists into the planning and design phases of facility construction.

  • NASA should make every effort to mount at least one Spacelab life sciences flight in the period between Neurolab and the completion of ISS facilities.

  • NASA should determine whether continuation of shuttle missions for short-term flight experiments after the opening of ISS would be economically and scientifically sound.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
Science Policy Issues
Peer Review

The Division of Life Sciences initiated a universal system of peer review in 1994 for all NASA-supported investigators. The new process has the committee's strong support.

  • Responsibility for the establishment of peer review panels and for funding decisions should remain a function of the Headquarters Division of Life Sciences.

  • NASA should regularly evaluate the composition of scientific review panels to ensure that the feasibility of proposed flight experiments receives appropriate expert evaluation.

Integration of Research Activities
  • Principal investigators of projected flight experiments should be brought together with NASA managers and design engineers at the beginning of the planning process to function as an integrated team responsible for all phases of the planning, design, and testing. This integration should continue throughout the life of the project.

  • NASA should regularly review and evaluate the NASA Specialized Centers of Research and Training (NSCORT) program to determine whether this mechanism provides the best way to foster interdisciplinary research and increase the scientific value of the life sciences research program.

  • NASA should regularly review and evaluate the performance of the National Space Biomedical Research Institute and the impact of its funding on the overall life sciences research budget and program.

Human Flight Data: Collection and Access

The disciplinary chapters of this report repeatedly stress the need for improved, systematic collection of data on astronauts preflight, in space, and postflight.

  • NASA should initiate an ISS-based program to collect detailed physiological and psychological data on astronauts before, during, and after flight.

  • NASA should make every effort to promote mechanisms for making complete data obtained from studies on astronauts accessible to qualified investigators in a timely manner. Consideration should be given to possible modifications of current policies and practices relating to the confidentiality of human subjects that would ethically ensure astronaut cooperation in a more effective manner.

Publication and Outreach

An essential outcome of scientific research is publication—dissemination of results to the scientific community at large. The record of peer-reviewed publication, especially of spaceflight experiments, by funded investigators in NASA's life sciences programs needs to be improved, as does the usefulness of the Spaceline Archive to the scientific community.

  • NASA should provide funding for data analysis and publication of flight experiments for a sufficient period to ensure analysis of the data and publication of the results.

  • NASA should insist on timely dissemination of the results of space life sciences research in peer-reviewed publications. For investigators with previous NASA support, the publication record should be an important criterion for subsequent funding.

  • NASA should take as a high priority the completion of data entry into the Spaceline Archive and should ensure that access to the archive is simple and transparent.

Professional Education

NASA should make every effort to ensure the professional training of graduate students and postdoctoral fellows in space and gravitational biology and medicine.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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  • NASA should take as high priority the support of a small, highly competitive program of postdoctoral fellowships for training in laboratories of NASA-supported investigators in academic and research institutions external to NASA centers.

REFERENCES

1. Space Science Board, National Research Council. 1987. A Strategy for Space Biology and Medical Science for the 1980s and 1990s. National Academy Press, Washington, D.C.

2. Space Science Board, 1987, A Strategy for Space Biology and Medical Science for the 1980s and 1990s, p. xi.

3. Space Science Board, 1987, A Strategy for Space Biology and Medical Science for the 1980s and 1990s, p. 4.

4. Space Studies Board, National Research Council. 1991. Assessment of Programs in Space Biology and Medicine 1991. National Academy Press, Washington, D.C.

5. Space Science Board, National Research Council. 1987. A Strategy for Space Biology and Medical Science for the 1980s and 1990s. National Academy Press, Washington, D.C.

6. Wilson, J.W., Cucinotta, F.A., Shinn, J.L., Kim, M.H., and Badavi, F.F. 1997. Shielding strategies for human space exploration: Introduction. Chapter 1 in Shielding Strategies for Human Space Exploration: A Workshop (John W. Wilson, Jack Miller, and Andrei Konradi, eds.). National Aeronautics and Space Administration.

7. Space Science Board, National Research Council. 1987. A Strategy for Space Biology and Medical Science for the 1980s and 1990s. National Academy Press, Washington, D.C.

8. Space Studies Board, National Research Council. 1991. Assessment of Programs in Space Biology and Medicine 1991. National Academy Press, Washington, D.C.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.8 Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies: Framework for Decision Making

A Report of the Task Group on Sample Return from Small Solar System Bodies1

EXECUTIVE SUMMARY

As advances in the biological and planetary sciences enable a shift from mere observation to active exploration of the solar system, space missions are increasingly likely to collect samples from planetary satellites and small solar system bodies and return them to Earth for study. This is an exciting development that offers the opportunity to search for extraterrestrial life forms and improve understanding of the origin and composition of the solar system. But sample return also involves potential risks that need to be understood and managed properly.

Accordingly, the National Aeronautics and Space Administration (NASA) asked the Space Studies Board of the National Research Council (NRC) to assess the potential for a living entity to be contained in or on samples returned from planetary satellites and other small solar system bodies such as asteroids and comets. In response to NASA' s request, the Space Studies Board established the Task Group on Sample Return from Small Solar System Bodies to address the following specific tasks:

  • Assess the potential for a living entity to be contained in or on samples returned from planetary satellites or primitive solar system bodies, such as asteroids, comets, and meteoroids;

  • Identify detectable differences among small solar system bodies that would affect the above assessment;

  • Identify scientific investigations that need to be conducted to reduce the uncertainty in the above assessment; and

  • Assess the potential risk posed by samples returned directly to Earth from spaceflight missions, as compared to the natural influx of material that enters Earth's atmosphere as interplanetary dust particles, meteorites, and other small impactors.

Concerns about potential risks from returned extraterrestrial materials are not new, having been raised initially more than three decades ago with the return of lunar samples during the Apollo program. In 1997, the National Research Council revisited these issues for samples returned from Mars and updated previous recommendations (NRC, 1992) for handling returned samples and avoiding planetary cross-contamination (NRC, 1997). This report of the Task Group on Sample Return from Small Solar System Bodies builds on and extends that earlier work.

STUDY APPROACH

Because there is no direct evidence that a living entity evolved or exists on any small solar system body, the task group examined indirect evidence based on data from Earth, meteorites, and the Moon and on astronomical observations of distant objects in an effort to assess whether NASA needs to treat samples returned from small solar system bodies differently from samples returned from Mars. To identify the requirements for the origin and survival of living organisms, the task group examined contemporary views on the range of conditions under which life can originate, the conditions required for the preservation of metabolically active organisms in terrestrial environments, and the somewhat different conditions needed to preserve living organisms in a dormant form. Based on this analysis, the task group identified six parameters (liquid water, energy sources, organic compounds, temperature, radiation intensity, and natural influx to Earth) as relevant to its assessment and formulated the following six questions to help determine how returned samples should be handled.

  1. Does the preponderance of scientific evidence indicate that there was never liquid water in or on the target body?

  2. Does the preponderance of scientific evidence indicate that metabolically useful energy sources were never present?

1 “Executive Summary” reprinted from Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies, National Academy Press, Washington, D.C., 1998, pp. 1-7.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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  1. Does the preponderance of scientific evidence indicate that there was never sufficient organic matter (or CO2 or carbonates and an appropriate source of reducing equivalents)2 in or on the target body to support life?

  2. Does the preponderance of scientific evidence indicate that subsequent to the disappearance of liquid water, the target body has been subjected to extreme temperatures (i.e., >160 °C)?

  3. Does the preponderance of scientific evidence indicate that there is or was sufficient radiation for biological sterilization of terrestrial life forms?

  4. Does the preponderance of scientific evidence indicate that there has been a natural influx to Earth, e.g., via meteorites, of material equivalent to a sample returned from the target body?

For the purposes of this report, the term “preponderance of scientific evidence” is not used in a legal sense but rather is intended to connote a nonquantitative level of evidence compelling enough to research scientists in the field to support an informed judgment. In applying the questions, the task group drew on existing data on the origin, composition, and environmental conditions (past and present) of each small body or planetary satellite examined and then determined whether the quality and weight of the evidence were convincing enough to allow making judgments and deriving findings. The answers to the questions, taken together, were used by the task group to reach a considered conclusion that the potential for a living entity to be in or on a returned sample was either “negligible” or “not negligible.” Because of the incomplete current state of knowledge about small solar system bodies, there are no definitive answers to the questions, and so all judgments regarding biological potential are qualitative (not quantitative).

The questions allow for a conservative, case-by-case approach to assessing whether or not special physical and biological isolation and handling of returned samples (containment) would be warranted, taking into account information about the different small bodies, natural influx to Earth of material from small bodies, and the possible nature of putative extraterrestrial life. An answer of “yes” to any question argues against the need for special containment beyond what is needed for scientific purposes. (Sample-handling requirements to support scientific investigations are currently under study by NASA.) For containment procedures to be necessary, an answer of “no” needs to be returned to all six questions. For such samples, strict containment and handling as outlined in Chapter 7 are required.

The task group chose to consider only two possible alternatives for containment and handling of samples returned from small solar system bodies: either (1) strict containment and handling of returned samples as outlined in the Mars report (NRC, 1997) or (2) no special containment beyond what is needed for scientific purposes. The task group ruled out intermediate or compromise procedures involving partial containment. In certain cases (e.g., P-and D-type asteroids) the limitations of the available data led the task group to be less certain, and therefore more conservative, in its assessment of the need for containment.

The following section summarizes the task group's findings with regard to the potential for a living entity to be present in samples returned from select planetary satellites and small solar system bodies. The selection was based on scientific interest and the likelihood of possible sample return missions to those destinations in the near future. These findings provided the basis for the task group's conclusions and recommendations, which are presented directly afterward.

FINDINGS
Planetary Satellites

Satellites are natural consequences of planetary formation processes. The task group considered the possibility of sample return from the major satellites of the innermost planets. These include the satellite of Earth (the Moon), satellites of Mars (Phobos and Deimos), and selected satellites of Jupiter (Io, Europa, Ganymede, and Callisto). The potential for a living entity to be present in samples returned from the Moon and Io is negligible. The potential for a living entity to be present in samples returned from Phobos, Deimos, and Callisto is extremely low, but the task group could not conclude that it is necessarily zero. Importantly, the task group found that there is a significant potential for a living entity to be present in samples returned from Europa and Ganymede.

2  

For the purposes of this report, CO2 or carbonates and an appropriate source of reducing equivalents is equivalent to “organic matter” to accommodate chemolithoautotrophs.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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Asteroids

Asteroids are the remnants of planetesimals—small primordial bodies from which the planets accumulated. Common asteroid types include undifferentiated, primitive types (C-, B-, and G-types); undifferentiated metamorphosed types (Q- and S-types [ordinary chondrites]); and differentiated types (M-, V-, J-, A-, S- [stony irons], and E-types). Other types of asteroids have been defined, including the common P- and D-types in the outer parts of the asteroid belt, but little is known about their composition and origin. Others are subdivisions of the types listed above, whereas still others are rare, new types, generally seen only among the population of very small asteroids. For undifferentiated, primitive (C-type) asteroids, the potential for a living entity to be contained in returned samples is extremely low, but the task group could not conclude that it is necessarily zero. Because of a fundamental lack of information about P- and D-type asteroids, the potential for a living entity to be present in returned samples cannot be determined and, therefore, was considered conservatively by the task group as possible at this time. For all C-type asteroids, undifferentiated metamorphosed asteroids, and differentiated asteroids, the potential for a living entity to be present in returned samples is extremely low, but the task group could not conclude that it is necessarily zero.

Comets

Comets are believed to have formed in the protoplanetary disk, at distances from the Sun ranging from the distance of proto-Jupiter to far beyond the distance of proto-Neptune. It is unlikely that a living entity could exist on comets, but the possibility cannot be completely ruled out except in a few cases, such as in the outer layers of Oort Cloud comets entering the solar system for the first time. Thus, the potential for a living entity to be present in returned samples from all comets was considered by the task group to be extremely low, but the task group could not conclude that it is necessarily zero.

Cosmic Dust

Because interplanetary dust particles (IDPs) are derived from a variety of sources, including interstellar grains and debris from comets, asteroids, and possibly planetary satellites, IDPs cannot be viewed as a distinct target body. As a result, the assessment approach used in this study does not lend itself readily to IDPs. Instead, the task group considered the potential source(s) of any IDPs that might be returned in samples. For the purposes of this study, IDPs are viewed as originating from either a single identifiable parent body or multiple sources. Particles collected near a particular solar system body are viewed as originating from that body, possibly including grains recently released from that body. Thus, the potential for a living entity to be present in returned samples, and the associated containment requirements, will be the same as those for the parent body. On the other hand, IDPs collected in the interplanetary medium may represent a mixture of dust originating from many parent bodies. Because IDPs in the interstellar medium are exposed to sterilizing doses of radiation, the potential for IDPs to contain viable organisms or a living entity is negligible.

CONCLUSIONS AND RECOMMENDATIONS

Table ES.1 summarizes the task group's assessment of the level of containment and handling warranted for samples returned from the planetary satellites and small solar system bodies examined in this study. Box ES.1 summarizes the requirements that apply to samples for which strict containment and handling are advisable. It is important to note that the task group's recommended approach is provided only as a guide and not as an inflexible protocol for determining whether containment is required. The final decision must be based on the best judgment of the decision makers at the time and, when possible, on experience with samples returned previously from the target bodies.

Containment of Returned Samples

On the basis of available information about the Moon, Io, dynamically new comets (specifically the outer 10 meters), and interplanetary dust particles (sampled from the interplanetary medium, sampled near the Moon or Io,

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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TABLE ES.1 Summary of Currently Recommended Approach to Handling Samples Returned from Planetary Satellites and Small Solar System Bodies Assessed by the Task Group on Sample Return from Small Solar System Bodies

I

No Special Containment and Handling Warranted Beyond What is Needed for Scientific Purposes

Ia

High Degree of Confidence

Ib

Lesser Degree of Confidencea

II

Strict Containment and Handling Warranted

The Moon

Phobos

Europa

Io

Deimos

Ganymede

Dynamically new cometsb

Callisto

P-type asteroids

Interplanetary dust particlesc

C-type asteroids

D-type asteroids

Undifferentiated metamorphosed asteroids

Interplanetary dust particlesd

Differentiated asteroids

All other comets

Interplanetary dust particlese

a Subcolumn Ib lists those bodies for which confidence in the recommended approach is still high but for which there is insufficient information at present to express it absolutely. This lesser degree of confidence does not mean that containment is warranted for those bodies; rather, it means that continued scrutiny of the issue is warranted for the listed bodies as new data become available. The validity of the task group's conclusion that containment is not warranted for the bodies listed in Ib should be evaluated, on a case-by-case basis, by an appropriately constituted advisory committee in light of the data available at the time that a sample return mission to the body is planned.

b Samples from the outer 10 meters of dynamically new comets.

c Interplanetary dust particles sampled from the interplanetary medium and from the parent bodies listed in subcolumn Ia.

d Interplanetary dust sampled from the parent bodies in column II and collected in a way that would not result in exposure to extreme temperatures.

e Interplanetary dust particles sampled from the interplanetary medium and from the parent bodies listed in subcolumn Ia.

BOX ES.1 Summary of Requirements for Samples That Need Strict Containment and Handling

All samples returned from planetary satellites and small solar system bodies that must be contained should be treated as potentially hazardous until proven otherwise. As in the 1997 Mars report (NRC, 1997), strict containment is recommended for all pristine sample material, and special handling procedures are needed for samples en route to and on Earth. If sample containment cannot be verified en route to Earth, the sample, and any spacecraft components that may have been exposed to the sample, should either be sterilized or not returned to Earth. Integrity of containment should be maintained through reentry of the spacecraft and transfer of the sample to an appropriate receiving facility. Furthermore, distribution of unsterilized materials returned from small bodies should be controlled and should occur only if rigorous analysis shows that the materials do not present a biological hazard. Finally, the planetary protection measures adopted for the first sample return mission to a small solar system body should not be relaxed for subsequent missions without a thorough scientific review and concurrence by an appropriate independent body.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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or sampled in a way that would result in exposure to extreme temperatures), the task group concluded with a high degree of confidence that no special containment is warranted for samples returned from those bodies beyond what is needed for scientific purposes.

Recommendation: Samples returned from the Moon, Io, the outer 10 meters of dynamically new comets, and interplanetary dust particles (from the interplanetary medium, near the Moon, Io, or dynamically new comets), or sampled in a way that would result in exposure to extreme temperatures (e.g., spike heated), should not be contained or handled in a special way beyond what is needed for scientific purposes.

For samples returned from Phobos and Deimos, Callisto, C-type asteroids, undifferentiated metamorphosed asteroids, differentiated asteroids, and comets other than dynamically new comets, the potential for a living entity in or on a returned sample is extremely low, but the task group could not conclude that it is zero. Based on the best available data at the time of this study, the task group concluded that containment is not warranted for samples returned from these bodies or from interplanetary dust particles collected near these bodies. However, this conclusion is less firm than the conclusion for the Moon and Io and should be reexamined at the time of mission planning on a case-by-case basis.

Recommendation: For samples returned from Phobos and Deimos, Callisto, C-type asteroids, undifferentiated metamorphosed asteroids, differentiated asteroids, comets other than dynamically new ones, and interplanetary dust particles sampled near these bodies, a conservative, case-by-case approach should be used to assess the containment and handling requirements. NASA should consult with or establish an advisory committee with expertise in the planetary and biological sciences relevant to such an assessment. The goal of such an assessment should be to use any new, relevant data to evaluate whether containment is still not warranted. This assessment should take into account all available information about the target body, the natural influx to Earth of relevant materials, and the likely nature of any putative living entities. Such an advisory committee should include both NASA and non-NASA experts and should be established as early in the mission planning process as possible.

For samples returned from Europa and Ganymede, the task group concluded that strict containment and handling requirements are warranted. Because the knowledge base for P- and D-type asteroids is highly speculative, the task group concluded conservatively that strict containment and handling requirements are warranted at this time. Strict containment and handling requirements are also warranted for interplanetary dust particles collected near these bodies unless they are sampled in a way that would result in exposure to extreme temperatures, e.g., spike heated.

Recommendation: Based on currently available information, samples returned from Europa, Ganymede, P- and D-type asteroids, and interplanetary dust particles sampled near these bodies should be contained and handled similarly to samples returned from Mars (NRC, 1997). Interplanetary dust particles sampled in a way that would result in exposure to extreme temperatures, e.g., spike heated, should not be contained or handled in a special way beyond what is needed for scientific purposes.

Handling of Returned Samples

For samples that are returned from planetary satellites and small solar system bodies and that warrant containment, the concerns about biohazards or large-scale adverse effects on Earth are similar to those identified earlier for Mars (NRC, 1997). The task group concluded that the risks of pathogenicity from putative life forms are extremely low, because it is highly unlikely that extraterrestrial organisms could have evolved pathogenic traits in the absence of host organisms. However, because there are examples of opportunistic pathogens from terrestrial and aquatic environments that have not co-evolved with their hosts, the risk cannot be described as zero. The recommendations on containment and handling in the Mars report (NRC, 1997) represent a strong basic framework for addressing potential risks associated with returned samples warranting containment.

The microbial species composition of most anaerobic environments on Earth is not known, and consequently it is also not known how the species composition of these anaerobic microbial communities might change over time, what environmental factors might influence these changes, or what the incidence of and successful colonization by

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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new species of microorganisms in these habitats might be. Accordingly, the task group concluded that although there is a low likelihood of a viable anaerobic microorganism surviving transport through space and finding a suitable anaerobic habitat on Earth, growth in a suitable habitat if found might be possible. This conclusion is necessary because of the current lack of information about anaerobic environments on Earth that may be analogous to environments on other solar bodies, and the likelihood that the metabolic properties of such an extraterrestrial anaerobe would resemble an Earth anaerobe from a similar environment.

For overall evaluation of returned samples that warrant containment, it will be necessary to apply a comprehensive battery of tests combining both life-detection studies and biohazard screening.

Recommendation: Returned samples judged to warrant containment should be quarantined and screened thoroughly for indications of a potential for pathogenicity and ecological disruption, even though the likelihood of adverse biological effects from returned extraterrestrial samples is very low.

Recommendation: NASA should consult with or establish an advisory committee of experts from the scientific community when developing protocols and methods to examine returned samples for indicators of past or present extraterrestrial life forms.

Recommendation: The planetary protection measures adopted for the first sample return mission to a small body whose samples warrant special handling and containment should not be relaxed for subsequent missions without a thorough scientific review and concurrence by an appropriate independent body.

Scientific Investigations to Reduce Uncertainty

Identified by the task group in Chapters 2 through 6 is scientific research that could help to reduce the uncertainty in its assessment of the potential for a living entity to be contained in or on samples returned from planetary satellites and small solar system bodies. Because most of the suggested research topics are general in scope, they are not repeated here. However, one topic is of sufficient importance that it requires emphasis.

Because organisms subjected to sterilizing conditions for a sufficient time period pose no threat to terrestrial ecosystems, it is important to assemble a database on the survival capacity of a wide range of terrestrial organisms under extreme conditions. Despite the existence of a rich literature on the survival of microorganisms exposed to radiation and high temperatures, the studied taxa represent only a small sampling of the microbial diversity known to exist in the biosphere and, in general, have not been taken from extreme environments. Little is known about the radiation and temperature resistance of microorganisms from environments on Earth that have the chemical and physical characteristics likely to be encountered in or on small solar system bodies.

Recommendation: NASA should sponsor research that will lead to a better understanding of the radiation and temperature resistance of microorganisms from environments on Earth that have the chemical and physical characteristics likely to be encountered in or on small solar system bodies. Information on the survival of organisms subjected to long- or short-term ionizing radiation needs to be collected for both metabolically active and dormant stages of diverse groups of microorganisms, including hyperthermophiles, oligotrophic chemoorganotrophs, and chemolithoautotrophs. Likewise, it is important to establish short- and long-term temperature survival curves for similarly broad groups of metabolically active and dormant organisms. In particular, data are required on survival of diverse microorganisms under flash heating (1- to 10-second exposures) to temperatures between 160 °C and 400 °C.

REFERENCES

National Research Council (NRC). 1992. Biological Contamination of Mars: Issues and Recommendations. Washington D.C.: National Academy Press.

National Research Council (NRC). 1997. Mars Sample Return: Issues and Recommendations. Washington D.C.: National Academy Press.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.9 Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis

A Report by the Task Group on Research and Analysis Programs1

EXECUTIVE SUMMARY

Effective science, clearly a mandate for the National Aeronautics and Space Administration (NASA), involves asking significant questions about the physical and biological world and seeking definitive answers. Its product is new knowledge that has value to the nation. NASA' s flight projects are highly visible and usually the most costly elements of this process, but they are only a part of the science enterprise. Flight projects are founded on research that defines clear scientific goals and questions, designs missions to address those questions, and develops the required technologies to accomplish the missions. This research is funded primarily by NASA's research and analysis (R&A) programs. Data from flight projects are transformed into knowledge through analysis and synthesis—research that is funded both by R&A and by the data analysis (DA) portion of mission operations and data analysis (MO&DA) programs. R&A and DA programs are the subject of this report and are grouped for convenience under the heading of research and data analysis (R&DA).2

Although there has been relatively widespread agreement about the importance of R&DA within the scientific community, senior agency managers and key decision makers outside NASA often have found the roles filled by these programs difficult to articulate and to prioritize. The diversity and “softness” of R&DA activities compared to the sharp outlines of specific spaceflight missions have made R&DA particularly vulnerable during times of constrained resources and changing institutional structure and strategy. With the emergence of NASA's emphasis on streamlining missions, accelerating development cycles, accentuating innovation, and reducing costs—the “smaller, faster, cheaper” approach—the roles of R&DA in framing scientific issues, developing the necessary new technologies for future missions, and mining the data from extant missions to produce new scientific knowledge have become even more critical.

In 1996 the Space Studies Board (SSB) formed the multidisciplinary Task Group on Research and Analysis Programs to study R&DA programs and trends in light of new agency approaches to space research. In creating the task group, special attention was given to involving a mix of scientists with long-standing familiarity with NASA science programs and “newcomers” who could bring a fresh perspective to the SSB's analyses. Efforts were also made to seek wide input from the research community via consultations with the SSB's discipline-specific standing committees, invitations for comments from members of key professional societies, and solicitation of comments to the task group on the Internet. The task group also engaged a consultant with expertise in the budgeting process to assist in compiling historical data on NASA science budgets for use in studying trends in resource allocations.

The statement of task for the study identified a number of areas that would be appropriate topics for review. These included evolution of the character of R&DA projects; evolution of the relative roles of universities and NASA centers in R&DA programs; the relationship between R&DA, advanced technology development, and MO&DA programs; characteristics of R&DA projects judged to be successful in supporting a smaller, faster, cheaper approach to flight missions; assessment of the expectations for R&DA in different NASA science offices; management issues for R&DA; and options for strengthening the program in the current NASA environment. These areas provided general guideposts at the beginning of the study; specific topics emerged during the review to become focal points for attention.

1  

“Executive Summary” reprinted from Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis, National Academy Press, Washington, D.C., 1998, pp. 1-6.

2  

The task group originally coined the composite term “R&DA” to designate research and data analyses that were funded outside of spaceflight projects. Because NASA budgets do not separate cleanly this way, R&DA became a catch-all surrogate for all science-related activities that were funded outside of spaceflight projects. More specific alternatives to “R&DA” were defined for the discussion of budget trends in Chapter 4. See also section 3.2 in Chapter 3.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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SCOPE AND CONTENT OF REPORT

Chapter 1 of this report provides an introduction to the role and character of projects included in R&DA and summarizes the motivation for the study. Chapter 2 focuses on questions of the actual breadth and depth of impact of R&DA programs. In reviewing the history of research conducted under R&DA in NASA's three science offices—space science, Earth science, and life and microgravity science —the task group developed a sampler of specific accomplishments that illustrate the return on investments in R&DA. These examples highlight seven different kinds of contributions, namely:

  1. Discoveries that influence societal and economic issues and policies;

  2. Breakthroughs that change scientific understanding;

  3. Technologies that enable new observations;

  4. Information that improves mission designs;

  5. Investments that increase the productivity of flight projects;

  6. Research that complements the work of other federal agencies; and

  7. Science-driven adventure that stimulates interest in math, science, or engineering education.

Although the treatment of R&DA in different NASA offices often has been fragmented and nonuniform, the task group adopted (Chapter 3) a set of seven elements that form a suitable organizing framework:

  1. Theoretical investigations;

  2. New instrument development;

  3. Exploratory or supporting ground-based and suborbital research;

  4. Interpretation of data from space missions;

  5. Management of data;

  6. Support of U.S. investigators who participate in international missions; and

  7. Education, outreach, and public information.

A fundamental premise of this study is that these seven activities are integral elements of an effective research program strategy; thus, they must be explicitly linked to the strategic plan of the science organization.

The task group's analysis of NASA budget data (Chapter 4) focuses on four areas:

  1. Overall funding trends for R&DA from FY 1991 to 1998;

  2. Distribution of funding for basic research among NASA laboratories, private industry, academia, and other organizations from FY 1991 to 1997;

  3. Distribution of funding to universities by type of activity (e.g., research, development, operations, training) from FY 1986 to 1995; and

  4. Number and size of research awards to universities from FY 1986 to 1995.

These data illuminate a number of issues regarding the balance between funding for R&DA and for flight programs and the balance between different kinds of activities within NASA's R&DA portfolio.

Chapter 5 summarizes a number of concerns and perceptions about R &DA support as viewed, often anecdotally, in the research community and notes where the task group's budget trend analysis can illuminate the concerns quantitatively. In Chapter 6, the task group's conclusions are framed in terms of a set of strategic principles, an overarching finding that emerges from the study, and a set of six recommendations to NASA regarding the management of R&DA programs in the three science offices. These six recommendations cover the following areas:

  1. Principles for strategic planning,

  2. Innovation and infrastructure,

  3. Management of the R&DA programs,

  4. Participation in the R&DA programs,

  5. Creation of intellectual capital, and

  6. Accounting as a management tool in R&DA programs.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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FINDINGS AND RECOMMENDATIONS
Principles for Strategic Planning

Finding: The task group finds that R&DA is not always thoroughly and explicitly integrated into the NASA enterprise strategic plans and that not all decisions about the direction of R&DA are made with a view toward achieving the goals of the strategies. The task group examined the trend and balance of R&DA budgets and found alarming results (Chapter 4, Sections 5.1 and 5.3); it questions whether these results are what NASA intends.

Recommendation 1: The task group recommends that each science program office at NASA do the following:

  • Regularly evaluate the impact of R&DA on progress toward the goals of the strategic plans.

  • Link NASA research announcements (NRAs) to addressing key scientific questions that can be related to the goals of these strategic plans.

  • Regularly evaluate the balance between the funding allocations for flight programs and the R&DA required to support those programs (e.g., assess whether the current program can support R&DA for the International Space Station).

  • Regularly evaluate the balance among various subelements of the R&DA program (e.g., theoretical investigations; new instrument development; exploratory or supporting ground-based and suborbital research; interpretation of data from individual or multiple space missions; management of data; support of U.S. investigators who participate in international missions; and education, outreach, and public information).

  • Use broadly based, independent scientific peer review panels to define suitable metrics and review the agency's internal evaluations of balance.3

  • Examine ways to maximize familiarity with contemporary advances and directions in science and technology in the process of managing R&DA, for example, via the appropriate use of rotators.4

Innovation and Infrastructure

Finding: Although there are sporadic funding opportunities for research infrastructure, there is no systematic assessment of the state of the research infrastructure, nor are there coherent programs to address weaknesses in the infrastructure base (Section 5.2).

Recommendation 2: The task group recommends that NASA take the following actions on research infrastructure:

  • Conduct an initial assessment of the need and potential for acquiring and sustaining infrastructure in universities and field centers.

  • Determine options for minimizing duplication of expensive research facilities.

  • Evaluate the level of support for infrastructure in the context of the overall direction and plans for R&DA activities.

  • Maximize the use of infrastructure by supporting partnering between universities and field centers.

  • Explore approaches for providing peer review and oversight of infrastructure investments, which should include regular evaluation of a facility 's role and contribution as a national academic resource, its degree of scientific and technical excellence, and its contribution to NASA 's long-term technology planning and development.

  • Institute periodic assessment of the research infrastructure in university and NASA field centers to ensure that the infrastructure is appropriate for current programs.

3  

National Research Council (NRC), Space Studies Board, “On NASA Field Center Science and Scientists,” letter to NASA Chief Scientist France Cordova, March 29, 1995; NRC, Space Studies Board and the Committee on Space Biology and Medicine, “On Peer Review in NASA Life Sciences programs,” letter to Dr. Joan Vernikos, director of NASA's Life Sciences Division, July 26, 1995; NRC, Space Studies Board, “On the Establishment of Science Institutes, letter to NASA Chief Scientist France Cordova, August 11, 1995.

4  

Federal agencies have used rotators—scientists from outside the federal government—for 1 to 2 years to participate in management of research programs. NASA has used interagency personnel appointments—visiting scientists administered by the Universities Space Research Association and the Jet Propulsion Laboratory—as rotators to circulate new ideas and new individuals, on temporary appointments, into the agency system.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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Management of the Research and Data Analysis Programs

Finding: The median of NASA research grants to universities decreased in 1995 dollars from $64,000 per year in FY 1986 to $59,000 in FY 1995 for the Office of Space Science disciplines, remained relatively flat at $79,000 for Earth science disciplines, and grew from $69,000 to $100,000 for life and microgravity science disciplines during the period from 1986 to 1995 (Section 4.4, Figure 4.3). (These award sizes compare to a median of $85,000 at the National Science Foundation (NSF) and a mean of between $110,000 and $120,000 at the Environmental Protection Agency.) It is well known that a single researcher cannot support a salary and a graduate student at grant levels of $50,000 and that such researchers must seek additional grants to maintain a viable research program.

Recommendation 3: NASA should routinely examine the size and number of grants awarded to individual investigators to ensure that grant sizes are adequate to achieve the proposed research and that their number is consistent with the time commitments of each investigator. The differences in award sizes for the Offices of Space Science, Earth Science, and Life and Microgravity Science and Applications should be reconciled with program objectives, especially those for space sciences, which often are funded at levels of less than $50,000 to $60,000. Where warranted, actions should be taken to address the deficiencies.

Participation in the Research and Data Analysis Programs

Finding: The task group recognizes that university-based instrument development projects led by principal investigators (PIs) can provide important training and versatility for graduate students in NASA-funded sciences. Often, innovative instrument prototypes can be developed at a fraction of the cost of facility instruments, and the analysis of instrument data and preparation of high-quality scientific results are closely coupled with understanding of and experience in the design of scientific instrumentation. However, although the university arena frequently offers these opportunities, the task group also recognizes that some research facilities do not offer training advantages, that the economies of scale for some facility development projects are high, and that support of nonuniversity, multiuser facilities is sometimes necessary.

Recommendation 4: NASA should preserve a mix of PI-university awards and nonuniversity funding for the development of technologies, instruments, and facilities. NASA should make these decisions within the agency's overall plan for R&DA activities (Recommendation 1), with sensitivity to the advantages of the academic environment but guided by peer review of scientific and technical merit.

Creation of Intellectual Capital

Finding: NASA's principal graduate student fellowship programs are all tied to student research interests or concentrations.

Recommendation 5: NASA should explore using training grants like those of the National Institutes of Health or the National Science Foundation for first-year graduate students as a possible alternative to supporting these students as research assistants or NASA fellows. These training grants should be designed to ensure breadth in graduate education and thereby may expand students' opportunities for employment within or beyond NASA-funded sciences.

Accounting as a Management Tool in Research and Data Analysis Programs

Finding: NASA does not use the extended records of its budgets and expenditures as management tools to monitor the health of its R&A and DA programs. Moreover, the fragmented budget structure for R&DA makes it difficult for the scientific community to understand the content of the program and for NASA to explain the content to federal budget decision makers.

Recommendation 6: NASA's science offices should establish a uniform procedure for tracking budgets and expenditures by the class of activities and the types of organizations (including intramural and extramural

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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laboratories, industry, and nonprofit entities) that are actually performing the work. These data should be gathered and reported annually and used to inform regular evaluations of R&DA activities (Recommendations 1 and 2). One approach would be to itemize the following elements in the budget: theoretical investigations; new instrument development; exploratory or supporting ground-based and suborbital research; interpretation of data from space missions; management of data; support of U.S. investigators who participate in international missions; and education, outreach, and public information. In addition, these data should be made publicly available and reported annually to the Office of Management and Budget and to Congress.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.10 Assessment of Technology Development in NASA's Office of Space Science

A Report of the Task Group on Technology Development in NASA's Office of Space Science1

EXECUTIVE SUMMARY

The 1995 Space Studies Board report Managing the Space Sciences (NRC, 1995) examined the changing environment in which science is conducted at NASA, alternative organizational structures for managing science, prioritization of science at NASA, and development of technology in support of science. The management of technology development was emphasized because NASA's new approach to smaller, more frequent, lower-cost missions requires ongoing new technical developments in order to ensure the continuing flow of achievements in space science that our nation has enjoyed. In addition to actions taken in response to the 1995 report, NASA has made a number of organizational changes that affect the technology development programs. Most pertinent was the assignment of responsibility (and budget) for cross-program technology development to the Office of Space Science (OSS). The increasing enabling power of new, flight-ready technology (recognized also by an interested Congress), coupled with important organizational changes within NASA, prompted OSS to request this NRC follow-on study to assess NASA's current approach to technology development. The Space Studies Board established the Task Group on Technology Development in NASA's Office of Space Science to conduct this study.

The importance of planning as the first step in the technology development process was emphasized in Managing the Space Sciences. In that regard, the task group recognizes the transfer of the technology function to OSS as a positive action. Programs under the space science enterprise (one of four mission program areas in NASA's strategic plan) are the largest consumers of space technology. Furthermore, OSS has a well-developed strategic planning process. OSS enlists a large segment of the external scientific community, through a broad advisory committee structure, in the development of its science roadmaps. This process is being extended to include development of time-phased technology roadmaps in support of OSS's science missions. Maturation of this process should be continued and subjected to external review 2 within 1 year.

Much advanced technology development (ATD) has application to more than one NASA enterprise. Advances in the use of lightweight structures, autonomous navigation, precision pointing, electronic component miniaturization, detector development, and data compression, for example, have application not only to space science missions but also to those pertaining to other NASA enterprises. It would be fiscally irresponsible to allow separate, overlapping technology development programs in such fields. Accordingly, NASA has grouped such technologies under the label “Cross-Cutting Technologies,” which also have been assigned to OSS. Unfortunately, in this case the planning has not matured to a satisfactory level. The establishment of the position of Chief Technologist in the Office of the Administrator is a useful step, but the position of Chief Scientist, which has stood vacant for 2 years, also should be filled. Management of such a cross-enterprise program is more difficult than management of enterprise-specific programs. Effective management of cross-cutting technologies by OSS requires improved collaboration and communication among enterprises and individuals, even if many of the latter are already stretched. The task group recommends a planning process that mirrors the one used by OSS for the space science technologies.

The 1995 report made a number of recommendations regarding the selection and management of technology programs using the best-qualified individuals or teams within NASA, industry, and academia as determined by peer review. The report went on to note that where NASA in-house capability is unable to compete on the basis of quality, NASA should decide whether to abandon the activity or to improve its quality so that it can compete. The task group believes that true, world-class competency is required to compete on such a basis and does not believe that NASA's current definition of “core competency” would meet this test of competition in many of its technolo

1  

“Executive Summary” reprinted from Assessment of Technology Development in NASA's Office of Space Science, National Academy Press, Washington, D.C., 1998, pp. 1-4.

2  

The term “external review” as used in this report signifies evaluation by independent, objective experts whose outside perspective and expertise in the subjects at hand can broaden and strengthen the feedback they provide. “Peer review” is the term commonly used throughout the scientific community. The task group has elected to use “external review” to emphasize that it does not mean simply the review of technology by scientists, but merit review by appropriate, independent, relevant experts.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

gies. For one thing, some NASA Centers3 claim that their core competencies cover an extensive and broad range of technologies. No organization that has realistic fiscal constraints can hope to be competitive or world class across such a sweep. Modern industrial organizations are confining their core competency technologies to those that are key to their competitive survival and that are not available to be purchased at a lower cost on the outside. NASA should develop equivalent constructs for defining the core competencies of the Centers. NASA should recognize that when a technology important to its missions is available on the outside from either academic or industrial organizations, this fact represents a NASA success. In many cases NASA provided the vision and funding for that technology sometime in the past. NASA should now leverage that success and confine its core technologies to those needs that cannot be met better by outside developers. External review can assist NASA in defining its core competencies, but competitive results in terms of degree of innovation, advances in the state of the art, and impact on cost and performance will be the ultimate test of those competencies.

Some of NASA's core competency groups are already world class and should be able to compete successfully with external groups for technology programs. Other areas may require some nurturing before achieving true core competency status. In such cases it may be necessary to target some limited ATD funds for this purpose, but a deadline should be set for accomplishing the objective, not to exceed 3 years. ATD funds should not be used more broadly to bolster in-house capability.

A narrowing of core competencies to those that meet stringent criteria will mean that NASA personnel will not be the performers in all technologies that support the principal mission responsibilities of a particular Center. In the past, NASA has relied on the “smart-buyer” argument for maintaining many of these technology development activities even when they may have been available externally. Neither the concept of core technology nor NASA's budget constraints should be invoked simply to support the continuation of past practice. Further, there is ample evidence that there are alternatives to maintaining in-house, hands-on R& D programs that can be used to achieve smart buying. The variation in approaches used by agencies of the Department of Defense such as the Defense Advanced Research Projects Agency (DARPA), the National Reconnaissance Office (NRO), and the three military services demonstrates that there is no single avenue for procuring technology. Each agency, including NASA, can point to stunning successes (as well as unfortunate failures). The most appropriate strategy for maintaining the expertise needed to be a smart buyer can vary depending on the nature of the organization and its missions. Thus, NASA would do well to examine alternatives and develop an explicit strategy for remaining a smart buyer.

Increasingly, successful approaches to acquiring the skills needed to be a smart buyer involve enhancements to workforce mobility. Increasing workforce mobility can improve organizational effectiveness in many ways, by facilitating the transfer of information, obtaining fresh points of view, and maintaining workforce expertise. Use of the Intergovernmental Personnel Act and cooperative agreements with outside organizations are options that NASA can use to support exchanges of technical staff.

To be most successful, an ATD program should have its planning and execution involve a careful mix of centralized and decentralized activities, which, in NASA, means appropriate roles for headquarters and the Centers. Planning should be a headquarters-led effort with execution residing at the Centers. The 1995 NRC report made it clear that management of the technology selection process, including make-vs.-buy decisions, should be retained at headquarters. The selection process for near-term technologies for particular missions can be delegated to the Centers when they are not competing for the technology development activities. This division of responsibility is necessary to eliminate both perceived and real conflicts of interest. As NASA exits from non-core-competency technology execution, it should be possible to delegate more of the management and selection process to the Centers.

Collecting cost data within NASA for analysis purposes is very difficult. Part of the difficulty is associated with NASA not operating on a full-cost basis. More important than analysis, however, is the problem that this lack presents to rational management decision making. NASA wholeheartedly agreed with the Managing the Space Sciences recommendation to move to full-cost accounting. Unfortunately, 3 years later NASA still states that it is a year or two away from the goal. The task group cannot emphasize too strongly the necessity, for NASA's own management purposes, to accomplish this task expeditiously. The task group was surprised, when conducting this review, that useful historical data were not readily available on such items as the breakdown of long- versus short-term research support, in-house versus academic versus industrial technology performance, and the amounts

3  

To distinguish between NASA Centers (e.g., Ames Research Center or Goddard Space Flight Center) and NASA's centers of excellence, the former is capitalized (“Centers”), and the latter is referred to in lower case (“centers”).

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

competitively awarded. The task group hopes that when it shifts to a new accounting system, NASA will access, track, and use such information in the related planning process.

Many of the recommendations of the above mentioned 1995 NRC report, as well as the present report, call for external review and advice. External review is recommended for the planning function, review of programs, evaluation of competing proposals, core competency selection, and Center quality review. Providing adequate headquarters staff to handle the reviews, utilizing clear investment and performance metrics, and making Centers accountable to headquarters are essential elements of the review process. Effectively implementing the review and advisory process depends on a synergistic relationship between NASA, academia, industry, and other government organizations that has, in large part, already been achieved and needs to be increased and maintained. It carries on a tradition that goes back to NASA 's predecessor organization, the National Advisory Committee for Aeronautics. Nevertheless, the final decision making is always a government responsibility, putting a premium on the quality of NASA's personnel. The task group hopes that the recommendations of this and the previous NRC report will assist in promoting excellence in all aspects of the nation 's space endeavors. To that end, NASA should make regular formal reports to appropriate external bodies on its response to the recommendations.

REFERENCE

National Research Council (NRC). 1995. Managing the Space Sciences. Space Studies Board and Aeronautics and Space Engineering Board. Committee on the Future of Space Science. National Academy Press, Washington, D.C.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.11 Ground-based Solar Research: An Assessment and Strategy for the Future

A Report of the Task Group on Ground-based Solar Research1

EXECUTIVE SUMMARY

Solar physics is a critical part of the nation's natural science program and a research area of fundamental importance to physics and astrophysics. The Sun is the only star that can be resolved in detail in its interior, on its surface, and in its outer atmosphere, thus making it an important and unique laboratory for fundamental physics, astrophysics, fluid mechanics, and magnetohydrodynamics. Further, the radiative and particle outputs of the Sun, and their variation, have a controlling influence on Earth's atmosphere, climate, and near-space environment. The field of stellar astrophysics would not include knowledge about starspots, prominences, differential rotation, flux tubes, flares, coronal mass ejections, tenuous supersonic winds, the nature of hot, dense X-ray coronal loops, or the variation of the total brightness of a star over years and decades without the discoveries of these phenomena on the Sun.

Scientists understand the physics of these diverse phenomena only insofar as they have worked out the physics from studies of the Sun. In the broadest terms, it remains only partially understood why the Sun, or any other star, is obliged by the laws of physics to carry on the many curious phenomena that are collectively known as magnetic activity. In particular, the existence of a million-degree corona surrounding a 6,000-degree surface is not understood except in outline. This is a fundamental problem in the physics of stellar systems, and a solution is required if there is to be any confidence in the interpretation of X-ray and extreme-ultraviolet emission of astrophysical objects. The Sun is the only laboratory where these questions can be studied in some detail.

This report reviews the scientific challenges posed by the active and variable Sun, and it is those challenges that drive the recommendations of the report. The general behavior of the major phenomenological components of solar activity are effectively pursued with the ongoing space program and existing and proposed ground-based telescopes. However, scientific understanding of the basic physics of these phenomena is stymied by an inability to resolve many aspects of the fundamental magnetic energy release processes that are occurring at scales of approximately 75 km or less. Clearer understanding requires observations with better than 0.1 arc-second (") resolution, but existing telescopes provide at best approximately 0.3" to 1.0" resolution.

THE ROLE OF GROUND-BASED PROGRAMS IN SOLAR RESEARCH

The activity of the Sun varies over years, decades, and centuries, evidently reflecting diverse internal magnetic and convective states. A number of the fundamental scientific challenges noted above require spatial and temporal resolution and long-term synoptic coverage that can only be realistically achieved through a program of ground-based observations. Ground-based solar research programs provide easy accessibility to facilities for the entire solar-physics community and are a means for the hands-on education of the next generation of solar researchers. They can be responsive to rapid intellectual, technical, or solar activity developments, as instrumentation on the ground is comparatively easy to repair, modify, calibrate, and replace. In addition, the costs of a ground-based facility are also typically far lower than those of space-based equivalents.

Observations from space have opened up a new world unknown to and inaccessible from the ground, but ground-based observations are credited with the discovery of the Sun's cyclic magnetic activity, the million-degree temperature of the corona, the fine-scale, fibril state of the solar magnetic fields, and the surface pressure waves (p-modes). Further, ground-based observations provide the critical data required by the designers of space missions. Finally, ongoing nighttime observations of brightness and magnetic activity of distant solar-type stars are demonstrating the varying states of activity the Sun may have achieved in other centuries. These observations, combined with data on Earth's atmosphere, indicate that variations in the Sun's radiative and plasma emissions are capable of influencing the weather and climate at Earth's surface.

1  

“Executive Summary” reprinted from Ground-based Solar Research: An Assessment and Strategy for the Future, National Academy Press, Washington, D.C., 1998, pp. 1-7.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

The task group believes that the primary tasks of ground-based telescopic research should be the following:

  • Obtaining a long-term synoptic record of solar activity: The National Solar Observatory, the High Altitude Observatory (HAO), and independent observatories—including, for example, Mt. Wilson, Stanford-Wilcox, Big Bear, San Fernando, and Marshall Space Flight Center—have an important role in this effort.

  • Studying the solar interior and the generation of magnetic fields by mapping subsurface flows and interior magnetic fields through long-term helioseismological observations; and

  • Observing the interaction of convection, magnetic fields, and radiative transfer by imaging with high spatial, temporal, and spectral resolution.

THE CURRENT U.S. GROUND-BASED SOLAR RESEARCH PROGRAM

For convenience, the task group divided its discussion of the current U.S. ground-based solar research program into (1) major solar observational facilities; (2) data, theory, and modeling; and (3) people, programs, and institutions—the means by which elements 1 and 2 are integrated to advance scientific understanding.

Major Solar Observational Facilities

The National Solar Observatory, a multisite facility of the National Optical Astronomy Observatories (NOAO), is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The current responsibilities of the NSO include the following:

  1. Continued operation of the Kitt Peak (NSO/KP), Sacramento Peak (NSO/SP, “Sac Peak”), and Tucson facilities;

  2. Operation and upgrade of the multisited telescopes of the Global Oscillations Network Group (GONG) for continuous studies in helioseismology;

  3. Fabrication and operation of the SOLIS array for synoptic optical long-term investigation of the Sun; and

  4. Archiving and distribution of data, and providing specialist-supported access to NSO observing facilities.

The NSO operates the two largest U.S. telescopes for ground-based solar observation—the McMath-Pierce telescope at Kitt Peak (commissioned in 1961) and the Vacuum Tower Telescope (VTT) at Sac Peak (commissioned in 1969). NSO facilities are available to both local staff and visiting scientists worldwide. To maximize scientific productivity, NSO policy provides for visiting observers to be assisted by experienced NSO staff. This support is unique among all other solar observatories worldwide and exemplifies the collaborative role of the NSO in the solar physics community.

Although the task group's assessment of U.S. observatories focused on NSO facilities, important solar research facilities exist elsewhere. For example, vector magnetograms are recorded by the University of Hawaii's Mees Solar Observatory, California State University at Northridge's San Fernando Solar Observatory, NASA's Marshall Space Flight Center, and the New Jersey Institute of Technology's Big Bear Solar Observatory.2 Similarly, the Stanford University Wilcox Solar Observatory specializes in low-resolution magnetograms designed to show the current sheet separating the northern and southern magnetic hemispheres of the Sun and the large-scale surface velocity patterns. Facilities outside the NSO also provide data essential to supporting ongoing NSO programs. For example, data from the Mt. Wilson 60- and 150-foot solar tower telescopes complement data from GONG and other helioseismic experiments. Finally, U.S. solar radio observatories also are outside the NSO set of solar observation facilities. Solar observations in the radio part of the electromagnetic spectrum provide a unique perspective on phenomena in the solar atmosphere.

Many excellent solar observing facilities also exist outside the United States, although none operates a wide range of well-documented instruments and also provides resident observers who aid in their operation. Nevertheless, the non-U.S. programs illustrate the worldwide interest in the active Sun and suggest the possibility of a

2  

On July 1, 1997, the management of Big Bear Solar Observatory was transferred from the California Institute of Technology to the New Jersey Institute of Technology.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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vigorous international collaborative effort should the United States choose to go forward with plans for the demonstration of adaptive optics and development of the Advanced Solar Telescope discussed in this report.

The past decade of solar research has shown that spatial resolution of fractions of an arc-second and temporal resolution of a few seconds are required to characterize the interaction of solar magnetic fields and convective flows on the scales at which they actually occur. Further, the need for high sensitivity to magnetic fields necessitates an infrared observational capability out to wavelengths of approximately 15 microns. Operating at such long wavelengths with even minimally acceptable resolution requires a larger-aperture telescope than any that currently exists. No solar optical telescope operating today has the attributes needed to enable studies of the energy release processes that occur at very small scale sizes. In addition, addressing several of the fundamental solar science questions mentioned in this report would require upgrades to the capabilities of existing solar radio observatories.

Data, Theory, and Modeling

Studies of the Sun and its influence on the interplanetary and Earth environment often involve making correlations between various observed physical parameters. Achieving a readily usable and accessible data archive requires developing an easily searchable catalog of data, ensuring access to data through user-friendly software, and guaranteeing the ability to handle the large quantities of data now available and that are planned in the future. Such data archiving is essential to maintaining and providing ready access to already existing, ongoing, and future data sets.

Several centers and institutions in the United States have, or will soon have, online images and other data available through the Internet. However, sifting through the vast quantities of data for observations of specific solar phenomena is often a formidable task without an intimate knowledge of a particular institution's archive structure or a catalog that goes beyond a simple list of the available data. As a result, several efforts are being advanced to provide a mechanism to identify and retrieve data from a large number of sources. Acknowledging the importance of providing data to the community, the task group encourages the cooperation and participation of observatories and institutions in efforts to archive and provide access to their data.

Historically, many of the innovations that have led to new observational facilities have had their origins in small-scale university and institutional research. Although much of the current solar data analysis and theoretical work continues to be done in universities and national institutes with NSF funding, today an increasing amount of solar physics research is conducted at institutes and universities that focus more on space-based projects, with only indirect attention to ground-based studies supported by research and technology contracts from NASA. Thus, for example, the Big Bear Solar Observatory, the Lockheed Martin Solar and Astrophysics Laboratory, NASA's Marshall Space Flight Center, and others reflect the changing pattern away from research traditionally supported by NSF to research oriented toward space-based observations of the Sun for which there is support. New academic research groups at Michigan State University, California State University at Northridge, Montana State University, and the New Jersey Institute of Technology also reflect this trend.

In addition to an adequate complement of supporting instruments, the success of the priority facility projects discussed in this report (SOLIS, the upgrade of GONG, and the Advanced Solar Telescope) rests on the availability of adequate funds for data analysis, modeling, and theoretical investigations. Plans for this intellectual infrastucture need to be incorporated at the start of new projects, as has been proposed for the Solar Magnetism Initiative, a multi-institutional proposal to the NSF for an integrated study of solar magnetism and variability.

People, Programs, and Institutions

The critical elements that enable the capacity of state-of-the-art observing systems and the potential of richly populated data collections to be translated into scientific understanding are people, programs, and institutions. That is, progress in science depends on being able to draw on a critical-mass-size research community (people) who, in turn, are supported by adequate intellectual and physical infrastructure (institutions). Specific programs can serve to integrate the contributions of various kinds of research (e.g., observations, theory, and modeling) and promote the synthesis of new perspectives on critical scientific problems.

The task group notes the importance of a balanced NSF approach to facility development and scientific grant support for the optimum long-term handling of solar research. This requires NSF research grants for individual solar scientists in universities, institutes, and observatories, as well as active communication and coordination

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

between the major solar research centers (NSO and HAO), agencies (NSF, NASA, DOD, and NOAA), and the national infrastructure of universities, observatories, and institutes. The task group believes that the magnitude of the grants program for individual researchers should be commensurate with the funding of the centers.

At present, there is a strong space-based solar research program that is able to analyze and interpret observational data effectively. Solar space research is conducted in university space science groups, NASA field centers, Department of Defense research laboratories, and some corporate research facilities. However, historically strong, university-based research groups that carry on ground-based solar research (for example, those at the California Institute of Technology, Stanford University, the University of Maryland, and the University of Colorado) are losing or have lost tenured solar faculty.

Institutions such as the New Jersey Institute of Technology and Montana State University have stepped in with new faculty hires, but the task group remains concerned about the trend away from traditional ground-based solar research and the likely effect on training for the next generation of graduate students. The task group is also concerned about the current state of university-based instrumentation programs, which are widely seen as essential to future instrument development, as well as the reduced access of new researchers to hands-on observing experience. Existing instrumentation and training programs are few in number and rely on precarious grant-based funding.

A STRATEGY TO STRENGTHEN GROUND-BASED SOLAR RESEARCH

The task group believes that although there is great strength in the current ground-based solar research program, it is nevertheless fragile. Specifically, there is an urgent need to develop a coherent strategy for ground-based research that will address the following issues:

  • Aging national facilities;

  • Limited capabilities to pursue the most important scientific problems;

  • Concerns about the health of the research community, especially in academia; and

  • The need for a workable plan to effectively integrate the diverse pieces of ground-based solar research into a synergistic whole.

The task group concluded that such a strategy can be built around the three elements mentioned above: (1) major observing facilities; (2) data, theory, and modeling; and (3) people, programs, and institutions. Within this strategy, the task group believes that the highest priority should be accorded to major observing facilities. This is so for several reasons. First, new observing facilities are required to address the major scientific questions in solar research. Second, new facilities are needed to replace certain of the aging facilities now in operation. Third, but especially importantly, major new facilities will constitute the most effective way to attract and engage the next generation of outstanding researchers who will bring vigor and momentum to ground-based solar research in the United States.

Recommendations Regarding Facilities

The following four recommendations are presented in priority order.

Recommendation 1: Complete fabrication of the SOLIS facility over the next 3 years, operate it at an appropriate site, and provide funding for U.S. scientists for data analyses.

Recommendation 2: Upgrade the GONG system by installing appropriate 1024 × 1024 CCD sensors, and operate GONG over a whole solar cycle with funding for data analysis in the United States.

Recommendation 3: Develop, construct, and operate a 3- to 4-meter Advanced Solar Telescope (AST). The AST might also be called the “Solar Microscope” because it would, for the first time, peer into the mysterious world of the active magnetic microstructure. Work toward the AST by:

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×
  1. Strengthening the NSO adaptive optics program immediately, including an augmentation in funding of approximately $1.5 million for the next fiscal year;

  2. Demonstrating the required adaptive optics (0.1" or better resolution in visible light at 0.5 microns) on a telescope with an aperture of approximately 1.0 to 1.5 meters;

  3. Beginning preliminary design of the 3- to 4-m AST so as to be ready for the final design when the adaptive optics has been convincingly demonstrated; and

  4. Carrying on site testing to determine an accessible site with the best available seeing as quickly as possible so as to define the task for the adaptive optics and be ready for construction of the AST.

Recommendation 4: Begin exploratory development of a high-resolution, frequency-agile solar radio telescope (FASR), using existing radio observatories to demonstrate its scientific potential. The FASR would provide unique diagnostics of solar flare plasmas, detect and locate the myriads of microflares, and provide maps of magnetic fields over surfaces of constant density within active regions.

Recommendations Regarding Data, People, Programs, and Institutions

The four recommendations above relate to priority actions for major observing facilities. The next set of recommendations focuses on addressing the issues that emerge in the two other major elements of the U.S. ground-based solar research program, which are (1) data, theory, and modeling and (2) people, programs, and institutions. Unlike the recommendations on facilities, they are not presented in priority order.

Recommendation 5: Facilitate efficient and timely development and utilization of the AST through enhancements to the management and organization of the NSO.

Recommendation 5a: Consolidate the NSO science, engineering, and operations site when the AST is operational.

Recommendation 5b: Establish an independent management council of the NOAO management organization to represent solar research, thereby recognizing the unique requirements for a program in ground-based studies of the Sun and placing such a program on an equal footing with the other major initiatives of NOAO.

Recommendation 5c: Establish an advisory committee to the NSO director that would include leading solar physicists from NSO, HAO, universities, NASA, DOD, NOAA, and U.S. and international research partners.

Recommendation 5d: Foster communication within the solar physics community by considering creation of an NSO national fellowship program, perhaps structured along the lines of the visiting scientist program that has been in place for many years at HAO.

Recommendation 6: Establish the essential national infrastructure for the effective operation and scientific exploitation of the U.S. solar observing facilities.

Recommendation 7: Develop a collaborative NSF and NASA distributed data archive with access through the World Wide Web.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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3.12 Failed Stars and Super Planets: A Report Based on the January 1998 Workshop on Substellar-Mass Objects

A Report of the Steering Group for the Workshop on Substellar-Mass Objects1

EXECUTIVE SUMMARY

The first direct observation of a bona fide brown dwarf, Gliese 229B in 1995, coupled with the indirect detections of a number of objects of jovian mass or larger, has brought the study of substellar-mass objects (hereafter SMOs) into a new phase of observational investigations. This success, after many years of failed searches and false alarms, is a consequence of the advent of new detectors, refinement of long-standing observing techniques through the use of novel technologies and data-processing schemes, and the persistence of searchers. Observational successes have been mirrored by advances in the theoretical modeling of both the spectra and the structure and evolution of SMOs. Developments in theoretical understanding of SMOs have been enabled by more capable computers, new laboratory data on the properties of materials at high pressure, and the stimulus of discoveries of actual objects. These advances have coincided with, and reinforced, increasing public and NASA interest in the broader issue of how unique our own planetary system is, the likelihood of life elsewhere, and what is required to make discoveries that will answer these questions.

Although the intellectual linkage between study of SMOs and the question of the frequency of planetary systems is a firm one, for various programmatic reasons the future investigation of SMOs with both ground-and space-based telescopes has not been well thought through to date. Past reports from the National Research Council's (NRC's) Committee on Planetary and Lunar Exploration (COMPLEX) and NASA advisory groups on the detection and study of extrasolar planets have concentrated primarily on the study of SMOs as the first step toward detecting Earthlike planets around other stars, the ultimate programmatic goal of NASA's new “Origins” initiative. Comparatively less attention has been given to the intrinsic value of studies of SMOs for answering high-priority questions in astronomy and planetary science, including those related to the physics of star and planet formation, the abundance of luminous and dark matter throughout the cosmos, and the basic physics of matter under extreme conditions.

The recently demonstrated ability to observe and study SMOs is significant for reasons additional to and unconnected with extrasolar planets. The eventual determination of the abundance of low-luminosity, low-mass objects will place constraints on models of the nature of the dark matter on astrophysical scales ranging from the solar neighborhood through the cosmological both directly (in terms of the contribution of SMOs) and indirectly through their constraints on the stellar initial-mass function. The local SMO contribution is starting to be constrained by sensitive surveys of the Sun's galactic neighborhood to determine directly the abundance of such objects as free-floaters, companions, and cluster members. Attempts to determine the galactic and extragalactic mass contribution of SMOs by detecting their gravitational-lensing effect on background stars have been under way for several years and are beginning to yield constraints.

THE WORKSHOP ON SUBSTELLAR-MASS OBJECTS

Given the recent successes in discovering SMOs by direct and indirect means, and the shared interest in them by research communities with very different goals and perspectives, the Space Studies Board organized a workshop to conduct a systematic cross-disciplinary examination of the state of the field. Its purpose was to assess the current state of the field and identify future studies that might contribute to important research goals in star and planet formation, the frequency of planetary systems, the nature of non-luminous matter on scales up through cosmological, the behavior of matter under extreme conditions, and the evolution of atmospheres of objects ranging in mass from planetary through stellar.

The state of the field as summarized at the workshop by 21 invited experts is vigorous: substellar-mass objects are now being detected or characterized, on a regular basis, by roughly a half dozen different techniques, both

1  

“Executive Summary” reprinted from Failed Stars and Super Planets: A Report Based on the January 1998 Workshop on Substellar-Mass Objects, National Academy Press, Washington, D.C., 1998, pp. 1-5.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

ground- and space-based, with additional approaches nearing the maturity necessary to conduct successful searches. Much of the activity is a result of individual or small-team, principal-investigator-based, projects, rather than large-scale “mission-type” programs, although some of the discoveries have been made with instruments (e.g., the Hubble Space Telescope and Keck telescope) that are the result of large-scale public or private programs. Additional to the availability of large or space-based telescopes are the maturation and ready availability of sensitive detector systems. However, a substantial ingredient in the success of the searches is the invention of novel data-processing schemes (in turn enabled by high-speed and high-capacity computers), calibration techniques (such as the iodine cell utilized in the radial-velocity program), and the autocatalytic growth of observing networks linked by electronic mail and able to confirm transient events (e.g., microlensing networks).

Powerful computers also have allowed modeling efforts to move from highly approximate schemes to capabilities more in line with the new data available. In particular, frequency-averaged or “gray” model atmospheres have given way to fully frequency-dependent models, handling tens of millions of spectral lines, essential both for synthesizing spectra to compare with data and for properly characterizing atmospheric energy balance.

The discovery of a cohort of Jupiter-mass planets in close orbits around their parent stars has stimulated more elaborate hydrodynamical models of SMO formation, again enabled by high-speed computers. Because SMO interiors are under high pressure and (except for the most massive or youngest objects) moderately degenerate, the behavior of matter under extreme conditions is a crucial issue in understanding the formation and evolution of these bodies. Theoretical and experimental advances in high-pressure physics have led to improved characterization of the physical properties of SMOs.

FINDINGS

As a result of the presentations and discussions at the workshop and subsequent deliberations, the Steering Group for the Workshop on Substellar-Mass Objects formulated a number of findings about the current state of research related to SMOs. These findings are organized under headings related to the five questions posed in NASA 's request for an examination of pertinent issues (see preface).

Status of Current Research Activities

The study of SMOs is currently in a state of high vigor after several decades of false starts and frustrations. The key to the new successes lies in technological advancements in ground-based telescopes buttressed by results from key spacecraft programs and theoretical studies of growing power and fidelity. The challenge for NASA and other funding agencies is to foster these programs in such a way that they contribute to NASA's ultimate programmatic goal of discovering terrestrial planets in orbit around other stars, but without encouraging a premature narrowing of focus toward a single, high-cost technique or mission.

The Most Compelling Issues for Near-Term Study

Investigations of SMOs are still in their infancy. The number of known brown dwarfs and extrasolar giant planets is still relatively small and provides an insufficient basis for drawing definitive conclusions about the range of properties exhibited by these objects. Detailed information on the properties of most SMOs is still lacking. Thus the most compelling issues to be addressed in the near term are the following:

  • Devising detection strategies to increase the population of known SMOs beyond the several hundred expected from the Deep Infrared Survey of the Southern Sky (DENIS) and the 2-Micron All-Sky Survey (2MASS) and, thus, increase the extent of SMO parameter space accessible for study; and

  • Performing spectroscopic and other diagnostic studies to characterize individual, nearby SMOs.

In the first of these, the ground-based radial-velocity surveys that have moved to the new generation of large-aperture telescopes, coupled with the continued development of astrometry, will increase the sample size of SMOs by an order of magnitude. The next phase is to use space-based facilities to undertake measurements not possible from Earth. The Space Interferometry Mission (SIM) and the Kepler photometric mission both represent efforts in this direction.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

A balanced program that fully explores as much as possible of the relevant parameter space is essential. In particular, to advance SMO studies in the near term and to optimize the development of space-based facilities, NASA must balance its major space expenditures with adequate funding for the early steps involving ground-based techniques and flight demonstrations.

For characterizing individual objects, the technique of choice will continue to be spectroscopic studies. The technologies needed to probe the spectra of SMO candidates have direct application to the goal of acquiring the spectra of terrestrial planets around nearby stars using space-based telescopes. However, the continued advancement of SMO studies requires that NASA encourage a range of approaches that will have broad scientific benefit for the detection and characterization of SMOs. Success in this effort will have the additional benefit of providing the potential for alternative and unexpected solutions to the problem of characterizing extrasolar terrestrial planets.

Close-in orbit companions such as 51 Pegasi B may not be amenable to spectroscopic study in the foreseeable future. Multiple techniques, including astrometry and detection of broadband reflected light, will need to be applied to understand the nature of these objects.

Contributions to Broader Scientific Goals

SMOs are a bridge between stars and planets, in that the physics of their atmospheres and interiors represents a genuine transition from stellar physics to planetary physics. Moreover, the ability to model the structure, evolution, and appearance of SMOs represents an important test of basic physics in a little-explored range of parameter space. In addition to greatly improving current understanding of the general theory of star and planet formation, studies of SMOs are likely to contribute to broader scientific goals in areas such as those represented by the following three compelling examples:

  • Modeling the atmospheres and interiors of SMOs;

  • Testing models of the formation of SMOs; and

  • Understanding the stability and evolution of multiplanet systems.

To advance these areas requires that:

  • Laboratory and associated computational efforts be undertaken to construct accurate spectral-line lists;

  • Parallel, vector, or superscalar processors become widely available so that theoretical models can take full advantage of current understanding of the physics of SMOs;

  • Larger telescopes and more sensitive detectors be brought to bear on characterizing brown dwarfs;

  • Experimental and theoretical studies of the behavior of materials at high pressure continue to be supported and to increase in capability; and

  • A broad range of observational strategies for detection (i.e., astrometric, photometric, radial-velocity, and microlensing studies) and characterization (e.g., spectroscopic studies over a broad range of the electromagnetic spectrum) of SMOs be undertaken to ensure that the sample space of these objects is large enough to generalize the frequency and mechanisms of formation.

Opportunities for Interdisciplinary Research
The Contribution of Studies of SMOs to Achieving Long-Term Scientific Priorities

The study of SMOs is necessarily interdisciplinary in nature, and progress in this field will require planetary scientists and astronomers to communicate and collaborate with each other as well as with colleagues from across a broad range of disciplines in the physical sciences.

Studies of SMOs have direct relevance to a number of long-standing scientific goals and priorities, their most obvious role being to provide a testing ground for honing the instrumentation and observational techniques necessary to detect extrasolar terrestrial planets. Another key area is the contribution of SMO studies to constraining the identification of missing mass in the universe. Although it appears that SMOs do not constitute the

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
×

bulk of the matter in the universe, they represent unique probes of galactic structure. Observations of microlensing events have particular promise for probing the mass function of brown dwarfs and understanding the composition of the galactic halo. With appropriate developments, microlensing could provide a shortcut to the detection of extrasolar terrestrial planets.

To ensure continued progress in this area, NASA and other agencies should foster coordination and collaboration among various search programs to enable ongoing discoveries and to follow up on possible candidate events. Because microlensing groups have different primary goals, the various agencies supporting primary and follow-up microlensing observations should work together to minimize potential disruptions caused by differences in their prime goals.

Measurement of higher-order microlensing events is required to determine the sources of lens effects in some cases. The reflex motion resulting from Earth's orbit around the Sun, for example, causes the trajectory of the background star relative to the lensing object to deviate from a straight line. This parallax effect induces asymmetries in the light curve of microlensing events which should be of order 1% if the lenses lie in the halo, but negligibly small if the lenses are in the Large Magellanic Cloud. Thus, a search for parallax asymmetries as an adjunct to the microlensing program will yield additional important information on the nature of the objects creating the lensing events.

CONCLUDING REMARKS

The ultimate programmatic goal of NASA's Origins program—discovering another Earth—is a laudable one upon which no specific recommendation is laid. In addressing this goal, however, NASA should take the following actions:

  • Continually assess the new information that studies of SMOs are providing on the formation, frequency, and characteristics of planetary systems, and invest judiciously in developing observational and theoretical techniques that will foster new discoveries. This investment should be in addition to the funding NASA is already providing for technological development of future large projects such as the Space Interferometry Mission and the Terrestrial Planet Finder. The funding must be flexible and peer-reviewed in recognition of the nature of the activities, which are distributed, principal-investigator-based projects to observe and model SMOs by using a variety of different approaches. The small-scale nature of these activities suggests that existing procedures (e.g., periodic peer review of proposals and resulting publications) will be adequate to identify and prioritize the approaches and techniques deserving of additional investment.

  • Invest with care in select ground-based facilities, instrument, and computational programs that will significantly broaden the near-term opportunity for innovation in the identification and characterization of SMOs. Addressing the broader issue of the appropriate balance of support for ground-based programs among NASA, the National Science Foundation, and other appropriate agencies is beyond the scope of this report. This important topic is best addressed by the decadal survey committee in the context of the findings of the study on the federal funding of astronomical research currently being conducted by the NRC's Committee on Astronomy and Astrophysics.

  • Consult with other agencies (e.g., the National Science Foundation) to avoid duplication and to open a broader set of opportunities for research and discovery through cooperative or collaborative funding.

In sum, SMO research is at the heart of trying to understand the matter content of the universe, the ubiquity and properties of planetary systems, and the relationship (in both genesis and physical properties) between stars and objects not massive enough to ever become stars. By studying SMOs we extend our understanding of the cosmos from the ubiquitous macroscale of stars through to the planets and, hence, ever closer to the human realm.

Suggested Citation:"3. Summaries of Major Reports." National Research Council. 1999. Space Studies Board Annual Report 1998. Washington, DC: The National Academies Press. doi: 10.17226/10075.
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