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Space Studies Board Annual Report 2000 4 Short Reports During 2000, the Space Studies Board and its committees issued six short reports, the main texts of which this section presents in full in chronological order of release. 4.1 Review of Scientific Aspects of the NASA Triana Mission On March 3, 2000, Task Group Chair James J. Duderstadt, Acting Space Studies Board Chair Mark Abbott, Board on Atmospheric Sciences and Climate Chair Eric J. Barron, and Board on Earth Sciences and Resources Chair Raymond Jeanloz, sent the following letter report to Dr. Ghassem R. Asrar, NASA's Associate Administrator for Earth Science. At your request the National Research Council established a task group to evaluate the scientific aspects of the Triana mission. The charge to the Task Group on the Review of Scientific Aspects of the NASA Triana Mission was to review (1) the extent to which the mission 's goals and objectives are consonant with published science strategies and priorities, (2) the likelihood that the planned measurements can contribute to achieving the stated goals and objectives, and (3) the extent to which the mission can enhance or complement other missions now in operation or in development. Triana is a mission designed to be deployed into a stable orbit, at roughly a million miles from Earth in the direction of the Sun. An orbit at this location, known as Lagrangian point 1 (L1), is stable in the sense that the satellite remains on the Sun-Earth line and views the full sunlit disk of Earth continuously. From L1 Triana will observe Earth with two instruments, and a third will monitor the space environment in the direction of the Sun. Observed data are expected to be delivered in near real time to ground stations. As proposed, Triana is an exploratory mission to investigate the scientific and technical advantages of L1 for Earth observations. The continuous view of the full sunlit disk of Earth will complement and extend observations from low Earth orbit (LEO) or geostationary Earth orbit (GEO) satellites. Triana will provide a global synoptic view (a continuous, from sunrise to sunset, simultaneous view of the sunlit side) of Earth in a range of wavelengths including ultraviolet, visible, and infrared to observe variations in ozone, aerosols, clouds, and surface ultraviolet radiation and vegetation. Triana is a flight opportunity to extend and improve observation of the solar wind and space weather at a most meaningful site, supplementing the data from the Advanced Composition Explorer satellite. A detailed analysis of instrumentation, data collection and reduction, systems operation, and management was beyond the scope of the task group's effort and was precluded by the time and budgetary constraints placed on the preparation of this report. Nevertheless, the task group agreed on a number of general issues related to the likely scientific success of the mission based on its review of relevant documents and reports and briefings by NASA's
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Space Studies Board Annual Report 2000 Triana science team. In its evaluation, the task group relied heavily on presentations from NASA and members of the Triana science team, and on detailed questioning of the presenters. In the attached more detailed technical assessment, the task group relates Triana's scientific objectives and deliverable data products to the research strategies and priorities proposed in earlier National Research Council and government reports. The task group found that the scientific goals and objectives of the Triana mission are consonant with published science strategies and priorities for collection of climate data sets and the need for development of new technologies. However, as an exploratory mission, Triana's focus is the development of new observing techniques, rather than a specific scientific investigation. The apparent spaceflight heritage of some of the Triana technology and the applicable legacy of the data reduction algorithms should contribute to the achievement of the mission's objectives. The task group concluded that the planned measurements, if successfully implemented, will likely contribute to Triana's stated goals and objectives. It did not attempt to evaluate the applicability of this heritage for a mission at L1. The task group also found that the Triana mission will complement and enhance data from other missions because of the unique character of the measurements obtainable at the L1 point in space, which allows continuous imaging of the full sunlit disk of Earth and monitoring of the space environment upstream from Earth. Furthermore, the full-disk Earth observations provide a unique perspective from which to develop new databases and validate and augment existing and planned global databases. As an exploratory mission, Triana may well open up the use of deep-space observation points such as L1 for Earth science. The task group believes that the potential impact is sufficiently valuable to Earth science that such a mission might have been viewed as an earlier NASA priority had adequate technology been available at reasonable cost. The task group is concerned, however, that because of the compressed schedule there may not be adequate time for instrument testing and calibration prior to launch. The task group is also concerned that significant development, testing, and validation of the operational algorithms are needed, and it recommends that this work start immediately. The scientific success of the Triana mission will be judged, in large part, on the quality of the initial data delivered to the scientific community. The task group therefore recommends that NASA seriously consider increasing the level of effort invested in development and testing of data reduction algorithms for the core Earth data products as soon as possible. In addition, it is concerned that there may be insufficient funding for scientific analysis of the data. If Triana lasts longer than its nominal 2 years, it will be important for NASA to support the data processing activities for the mission's useful duration. The task group lacked the proper expertise, resources, and time to conduct a credible cost or cost-benefit analysis (such an effort might take many months and much detailed analysis) or an analysis of the mission goals and objectives within the context of a limited NASA budget or relative to other Earth Science Enterprise missions. However, based on the available information, the task group found that (1) the cost of Triana is not out of line for a relatively small mission that explores a new Earth-observing perspective and provides unique data; (2) since a significant fraction of the Triana funds (according to NASA and the Triana principal investigator, 50 percent of total funding and 90 percent of instrument development money) have already been expended, weighing cost issues would lead to only limited opportunities to save or transfer funds to other projects. In addition, the task group endorses the statement by Congress that the delay in the mission mandated to produce this report may mean additional costs. The task group emphasizes that the attached discussion of the ability of Triana to achieve the mission's stated goals and objectives is predicated on the assumption that the instruments and satellite have been, and will continue to be, subject to all necessary and appropriate exploratory-mission technical and quality control reviews. Under no circumstances should this report or the statements contained in it be used as a replacement for these technical evaluations. Signed by James J. Duderstadt Chair, Task Group on the Review of Scientific Aspects of the NASA Triana Mission Mark Abbott Acting Chair, Space Studies Board
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Space Studies Board Annual Report 2000 Eric J. Barron Chair, Board on Atmospheric Sciences and Climate Raymond Jeanloz Chair, Board on Earth Sciences and Resources Review of Scientific Aspects of the NASA Triana Mission INTRODUCTION In a letter of October 14, 1999,1 the National Research Council (NRC) was asked to evaluate the scientific goals of Triana, as specified in House Report 106-379.2 Accordingly, the NRC established the Task Group on the Review of Scientific Aspects of the NASA Triana Mission3 (referred to here as the task group) under the auspices of the Space Studies Board (SSB), the Board on Earth Sciences and Resources (BESR), and the Board on Atmospheric Sciences and Climate (BASC). The charge to the task group was to review (1) the extent to which the mission 's goals and objectives are consonant with published science strategies and priorities, (2) the likelihood that the planned measurements can contribute to achieving the stated goals and objectives, and (3) the extent to which the mission can enhance or complement other missions now in operation or in development. The task group met on January 12 and 13, 2000, at the National Academies ' Georgetown offices in Washington, D.C. Prior to this meeting, it held two teleconferences to discuss the charge to the task group and plans for the meeting, and it also reviewed all relevant NRC reports, relevant government reports, and background materials.4 On the first day of the meeting, the task group received presentations from NASA's Triana science team, among others.5 These presentations discussed the technical aspects of the mission, including the science goals and objectives, data products, and instrument specifications and included a variety of opinions regarding the mission. One presenter made a number of recommendations to improve the science return from the mission, including significant redesign of the mission, as well as changes in the science team and data analysis efforts. For example, he proposed postponing the mission “to allow the science analysis efforts to catch up and to possibly reverse some of the downgrades to assure a successful scientific Triana mission that achieves its stated scientific objectives.” The task group discussed these recommendations and concluded that several of them were beyond its statement of task; others are adequately covered in this report. 6 GENERAL MISSION DESCRIPTION Previous and existing solar and magnetospheric missions demonstrate the suitability of Lagrangian point 1 (L1)7 as a unique and opportune deep-space location for solar and space observation.8 Triana was proposed as an exploratory mission to investigate the scientific and technical advantages of L1 for Earth observations. It will have 1 See Appendix 1. 2 This conference report accompanied the VA-HUD-Independent Agencies appropriations bill for FY 2000, P.L. 106-379, Title III, p. 158, enacted October 13, 1999. 3 See Appendix 2 for the task group roster. 4 Valero, Francisco P. J., Jay Herman, Patrick Minnis, William D. Collins, Robert Sadourny, Warren Wiscombe, Dan Lubin, and Keith Ogilvie, Triana–a Deep Space Earth and Solar Observatory, NASA background report, December 1999. Available at < http://triana.gsfc.nasa.gov/home/ > posted as pdf file. 5 See Appendix 3 for the agenda. 6 This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise in accordance with procedures approved by the NRC's Report Review Committee. See Appendix 4. 7 The L1 point is where Earth's gravity reduces the Sun's gravity such that the orbital angular velocity of an object positioned there matches the orbital angular velocity of Earth. A spacecraft at the L1 point thus remains on a line connecting Earth and the Sun. 8 Stone, E.C., A.M. Frandsen, R.A. Mewaldt, E.R. Christian, D. Margolies, and J.F. Ormes, “The Advanced Composition Explorer,” Space Science Reviews 86:1-22, 1998. Zwickl, R.D., K.A. Doggett, S. Sahm, W.P. Barrett, R.N. Grubb, T.R. Detman, V.J. Raben, C.W. Smith, P. Riley, R.E. Gold, R.A. Mewaldt, and T. Maruyama, “The NOAA Real-Time Solar Wind (RTSW) System Using ACE Data,” Space Science Reviews 86:633-648, 1998.
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Space Studies Board Annual Report 2000 a continuous and simultaneous view of the sunlit face of Earth that is not possible to achieve with low Earth orbit (LEO)9 or geostationary Earth orbit (GEO)10 satellites. Triana is intended to provide a global synoptic view of Earth. It is designed to make measurements in a range of spectral channels to observe spatial and temporal variations in Earth's geophysical parameters, such as ozone, aerosols, clouds, and surface ultraviolet (UV) fluxes. Triana is designed to measure ozone and cloud distributions to enhance studies of their effects on climate and the amount of UV radiation that reaches the ground. The vegetation canopy structure is also intended to be observed in order to contribute to monitoring the status of Earth's vegetation. The global aerosol optical thickness 11 will be measured to increase knowledge of how pollution generated by humans and as a result of natural processes affects Earth. Simultaneously, instruments on Triana are designed to determine Earth 's planetary albedo in three regions of the spectrum—broadband long wave, near-infrared (IR), and UV/visible—to better characterize Earth's radiation budget. These measurements would provide the first direct determination of the radiant power emitted by the full sunlit disk of Earth in the direction of the Sun (i.e., Earth's radiance from which planetary albedo is determined by ratioing to solar irradiance), and therefore increase researchers' understanding of how much of the Sun's energy is absorbed in the atmosphere. In addition to Earth-viewing instruments, Triana includes an instrument package designed to measure solar wind and the interplanetary magnetic field at L1. Based on these observations Triana, during its limited lifetime, could provide early warning (about 1 hour) to communication satellites and ground-based systems that are susceptible to solar-related disturbances during space weather events. Triana imagery and science data would also be made available for educational purposes, including distribution of Earth full-disk images over the Internet. Instrumentation To accomplish its science goals, Triana has three instruments: the Scripps-Earth Polychromatic Imaging Camera (EPIC), the Scripps-National Institute of Standards and Technology (NIST) Advanced Radiometer (NISTAR), and the Goddard Space Flight Center (GSFC) Plasma-Magnetometer Solar Weather Package (Plasma-Mag). EPIC The EPIC instrument is designed to provide ozone, aerosol, and cloud reflectivity data for the full sunlit disk of Earth. EPIC is a framing camera with a charge-coupled detector (CCD) focal plane array that will image the whole Earth disk from the L1 vantage point. The size of the array, 2048 by 2048 pixels, coupled with the Cassegrain telescope of 30.5-cm aperture and 282-cm focal length (f 9.38), provides a nominal spatial resolution of about 8 by 8 km for pixels viewed at nadir,12 yielding a ground-projected pixel area of 64 km2. When observations approach the edge of the Earth disk, the effective pixel size grows and the pixel changes shape as Earth's surface tilts away from the instrument. At 70º view zenith angle, the nominal pixel area is 187 km2; at 80º, the nominal pixel size is 369 km2. The changing size and shape of the pixels at the edge of the disk will degrade the effective spatial resolution of the measurements. The effective spatial resolution is somewhat coarser due to the point-spread function of the optics, which is expected to be about 10 by 10 km (nadir). Earth's illuminated disk is expected to occupy about 60 percent of the array. The Epic camera's CCD array, operated at −40º C, has a high quantum efficiency beginning at about 250 nanometers (nm), thus permitting imaging in wavelengths from the UV to the near-IR. Through the use of a filter wheel fitted with filters whose surfaces are hardened by ion-assisted deposition, the camera records images of Earth 9 Satellites in low Earth orbit, typically about 400 to 500 miles above Earth's surface, image long strips of Earth's surface as they fly overhead. 10 Satellites in geostationary Earth orbit, about 22,000 miles above Earth's surface, remain perched above a single point on Earth's equator as Earth rotates on its axis. They can image about one-third of Earth's surface and track the progress of day and night within their view as Earth turns on its axis. 11 Aerosol optical thickness quantifies the extent to which a radiation beam passing through the atmosphere is weakened by scattering and absorption of atmospheric aerosols. A turbid or hazy atmosphere will thus have a larger aerosol optical thickness than will a clear atmosphere. 12 At the nadir view, the instrument looks directly “down” at the surface from directly above the surface—that is, at an angle perpendicular to the surface.
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Space Studies Board Annual Report 2000 TABLE 1 EPIC's Filters Specifications Band Center Wavelength (nm) Bandwidth (nm) Previous Space Flight Heritage Frequency Purpose 1 317.5 1 TOMS 1 hour Ozone 2 325 1 TOMS 1 hour Ozone, SO2 3 340 3 TOMS 1 hour Aerosols 4 388 3 TOMS 1 hour Aerosols, clouds 5 393.5 1 (New) 1 hour Cloud height 6 443 (blue) 10 MODIS 15 minutes Aerosols 7 551 (green) 10 MODIS 15 minutes Aerosols, ozone 8 645 (red) 10 MODIS* 15 minutes Aerosols, vegetation 9 870 15 MODIS 1 hour Clouds, vegetation 10 905 30 MODIS 1 hour Precipitable water *The MODIS band has a 50-nm bandwidth. in 10 spectral bands (Table 1). Shutter speeds are programmable to adjust for the wavelength-dependent sensitivity of the camera's detectors and for in-band scene brightness. The digital intensity conversion provides 12 bits of precision (0 to 4095) in the output signal. The signal-to-noise ratio of the array 's detectors is designed to equal 200:1 at median signal intensities. Measured, calibrated radiances will be observed hourly for bands 1 to 5 and 9 to 10, and every 15 minutes for bands 6 to 8. These radiances will be Earth-located by attaching a latitude and longitude tag to each pixel. They will be archived in Earth Observing System –Hierarchical Data Format (EOS-HDF). The Triana science team intends to calibrate this instrument before it is launched and to track its calibration in flight when the camera views the far side of the Moon as it comes between L1 and Earth. This event occurs about once per month and permits the monitoring of detector and filter degradation for the life of the mission. The technique assumes that the Moon's surface has a highly stable brightness and can thus be used as a reflectance standard. NISTAR The balance between incoming radiation from the Sun (in the near-UV, visible, and near-IR regions of the spectrum) that Earth reflects and absorbs, and radiation outgoing from Earth to space (in the thermal infrared spectrum) determines the budget of energy available for climate processes. By providing the first determination of the radiation reflected and emitted by the full sunlit disk of Earth in the direction of the Sun, the NISTAR instrument at L1 can contribute to researchers ' knowledge of this radiation balance. NISTAR is a suite of four radiation detectors mounted together with a filter wheel, shutter wheel, front-end baffles, and rear-end control and detection electronics, and boresight aligned with EPIC. Three of the four detectors are absolute devices, called electrical substitution active cavity radiometers,13 which measure the integrated power from a single source of radiation (i.e., irradiance), in this case Earth as a planet. The NISTAR instrument is designed so that during a typical observation of Earth's radiation flux, two filters in the filter wheel placed over two of the three active cavities permit the measurement of two bands of radiation (from 0.2 to 4 µm and from 0.7 to 4 µm) while an open position in the filter wheel admits the entire radiation spectrum at all wavelengths. Because the time response of active cavity radiometers is on the order of 3 minutes, a fourth channel of NISTAR contains a photodiode that has a much faster time response but inferior accuracy and stability. In addition to providing higher time resolution, the photodiode channel permits in-flight measurements of the transmittances of the filters (which can be positioned over the cavities or the photodiode). NISTAR is designed to use the in-flight filter transmittance measurements and periodic use of redundant filters to track the stability of the radiation flux measurements throughout the mission. 13 An active cavity radiometer makes accurate measurements of optical power by comparing it with equivalent electrical power at constant temperature when a shutter successively exposes and blocks the source of radiation. The active cavities respond to the electromagnetic spectrum from 0.2 to 100 µm, and thus to solar radiation that Earth reflects and to longer wavelength radiation that Earth emits.
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Space Studies Board Annual Report 2000 Preliminary laboratory operations indicate that the goal of 0.1 percent accuracy and noise levels of 10 nW are attainable. Stabilities are unknown, but NIST reported that it has made efforts in the design of NISTAR to minimize drift and to monitor in-flight the radiometric sensitivity. Extensive preflight testing, calibration, and characterization are also planned using the laboratory standards at NIST. The combination of NISTAR's full-disk measurements of Earth's radiance with EPIC's spatially resolved radiance measurements potentially offers a capability for future radiation budget monitoring with improved inflight calibration and stability. The technology in NISTAR is based on well-established laboratory practices,14 but its use in space will be new. Plasma-Mag The Plasma-Mag instruments are designed to measure the velocity distributions of solar wind electrons and ions (protons and alpha particles), and the interplanetary magnetic field at the L1 location. These are standard measurements that have been made previously and are currently being made on the Advanced Composition Explorer (ACE)15 and the Solar Wind Observatory (WIND), except that a ≈30-fold improvement in the time resolution of the solar wind ion measurements can be accomplished on a 3-axis stabilized spacecraft such as Triana using existing designs. The magnetic field vector is determined with a sensitivity level of less than 0.1 nanotesla (nT) and a dynamic range of 108 using standard technology optimized for small size and low power. Both the solar wind and magnetic field are sampled once every second. The Plasma-Mag instrument package consists of four parts: (1) a Faraday cup to measure the velocity distribution of solar wind protons and helium nuclei (typically about 1 kiloelectron volt per atomic mass unit [keV/amu]), (2) a “top-hat” type electrostatic deflection analyzer that is operated in the range of 3 electron volts (eV) to 2 keV and has a sufficiently broad field of view to allow inference of the 3-dimensional solar wind electron velocity spectra, (3) a triaxial flux-gate magnetometer, and (4) a data handling unit for processing the signals from the three instruments. The magnetometer and electron analyzers are mounted on a 3-meter boom to minimize the effects of spacecraft potential and the magnetic field. All three instrument designs have been used extensively in space applications,16 and algorithms for deriving the physical parameters (e.g., solar wind density, bulk speed and temperature, magnetic field strength and direction) from the raw data are well established and tested, but have only been used with instruments on spinning spacecraft. 17 The plasma and magnetometer instruments are nearly identical to corresponding sensors flown successfully on the WIND and Polar spacecraft. 18 Triana's Orbit and Earth-Viewing Geometry The L1 point provides a unique view of Earth for the EPIC camera and NISTAR radiometers and also allows observations of the solar wind upstream from Earth with the Plasma-Mag instrument. The L1 point is located on the 14 Rice J.P., S.R. Lorentz, and T.M. Jung, “The Next Generation of Active Cavity Radiometers for Space-based Remote Sensing,” American Meteorological Society conference proceedings: 10th Conference on Atmospheric Radiation: A Symposium with Tributes to the Works of Verner E. Suomi, pp. 85-88, 1999. 15 For more information about the NASA missions and instruments referred to in this report, see < http://www.earth.nasa.gov/missions/index.html > and < http://www.spacescience.nasa.gov/missions/index.htm >. 16 Ogilvie, K.W., D.J. Chornay, R.J. Fritzenreiter, F. Hunsaker, J. Keller, J. Lobell, G. Miller, J.D. Scudder, E.C. Sittler, Jr., R.B. Torbert, D. Bodet, G. Needell, A. J. Lazarus, J.T. Tappan, A. Mavretic, and E. Gergin, “SWE, A Comprehensive Plasma Instrument for the Wind Spacecraft,” Space Science Reviews 71(1/4):55-77, February 1995. 17 Scudder J., F. Hunsacker, G. Miller, J. Lobell, T. Zawistowski, K. Ogilvie, J. Keller, D. Chornay, F. Herrero, R. Fitzenreiter, D. Fairfield, J. Needell, D. Bodet, J. Googins, C. Kletzing, R. Torbert, J. Vandiver, R. Bentley, W. Fillius, C. McIlwain, E. Whipple, and A. Korth, “ Hydra - A 3-Dimensional Electron and Ion Hot Plasma Instrument for the Polar Spacecraft of the GGS Mission,” Space Science Reviews 71(1/4):459-495, February 1995. 18 Lepping R.P., M.H. Acuña, L.F. Burlaga, W.M. Farrell, J.A. Slavin, K.H. Schatten, F. Mariani, N.F. Ness, P.M. Neubauer, Y.C. Whang, J.B. Byrnes, R.S. Kennon, P.V. Panetta, J. Scheifele, and E.M. Worley, “The Wind Magnetic Field Investigation,” Space Science Reviews 71(1/4):207-229, February 1995. Acuña, M.H., K.W. Ogilvie, D.N. Baker, S.A. Curtis, D.H. Fairfield, and W.H. Mish, “The Global Geospace Science Program and Its Investigations, ” Space Science Reviews 71(1/4):5-21, February 1995. Harten, Ronald, and Kenn Clark, “The Design Features of the GGS Wind and Polar Spacecraft,” Space Science Reviews 71(1/4): 23-40, February 1995.
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Space Studies Board Annual Report 2000 direct line between Earth and the Sun, about one-hundredth of the distance from Earth to the Sun. The mission is designed so that the spacecraft will not actually be located directly at the L1 point. If it were, radio communication would be too noisy, since earthbound antennas focused on the spacecraft would also see the Sun, a strong source of radio noise directly behind the spacecraft. Instead, Triana is designed to orbit around the Earth-Sun axis in a near-circular ellipse centered on the L1 point. This small orbit (Lissajous orbit) requires about 6 months for a complete revolution and provides a view of Earth that diverges from the Earth-Sun axis by 4º. The orbit also changes shape on a 4-year cycle such that the initial 4º divergence of view point expands to 15º through the cycle. Thus, Triana's EPIC and NISTAR instruments will view Earth from a direction that diverges from the direction of the Sun 's illumination by an angle of 4 to 15º.19 The near-coincidence of view and illumination direction has important implications for the algorithms that transform EPIC radiances and NISTAR irradiances into geophysical data products. For example, the scattering angle of aerosol and cloud phase functions will be 165 to 177º, indicating scattering in nearly the backward scattering direction.20 Since some scattering functions show rapid change with angle in this angular region, Triana data reduction algorithms are designed to accommodate the effects of the change in viewing geometry that will be experienced over the life of the mission. Over water, Sun glint can brighten surface reflectance when the Sun is near the overhead position. As a result, some ocean retrievals will be limited to morning and afternoon observations when glint is not a problem. For land observations, the view is very near to the “hot-spot” (perfect backscatter) direction, at which surface bidirectional reflectance in reflective wavelengths is known to reach a peak. The hot-spot effect is produced by shadow hiding, in which structures or projections that cast shadows (e.g., plant canopies, individual plant leaves) also hide their own shadows when viewed from the same position as their illumination. While these directional effects may need to be “corrected” in some algorithms (e.g., to deduce albedos from NISTAR and EPIC observations), they can be a source of information for other algorithms (e.g., yielding potential Triana geophysical data products describing surface vegetation structure). Because of the unique viewing point, observations from L1 may also help to fill in the angular observation domains of LEO and GEO imagers, which acquire hot-spot data only under very limited conditions. A continuous view of Earth from the L1 point shows the changes in Earth's disk with the seasons. During the northern hemisphere summer, the arctic regions will be tilted toward the Sun and thus continuously visible, while antarctic regions will be continuously visible during the southern hemisphere summer. Polar visibility also depends on the position of Triana on its Lissajous orbit, which in turn depends on its launch date. If Triana is “above” the plane of the ecliptic during the northern hemisphere summer, its view of the arctic region will be better. The Triana science team prefers this scenario, as it will improve the quality and area of continuous measurement of ozone in the arctic. Data Processing and Distribution Triana's primary data products, as reported by the Triana science team, are shown in Table 2. Some of the data products will require both Triana data and ancillary data from other sources, such as ground-based instruments or other satellites. As envisioned, the Triana data system will provide multiple streams to accommodate different user needs. The Triana data would be received on Earth at five to seven ground stations and from there would be transmitted to the Mission Operations Center (MOC) at the Goddard Space Flight Center. At a ground station, the data would be parsed into three streams—spacecraft status, time-critical science and image data, and data that are not time-critical. Time-critical data, which would be forwarded immediately to the MOC, include EPIC visible channels (443-, 551-, and 645-nm bands) observed every 15 minutes, aerosol and ozone channels observed every hour, and the entire Plasma-Mag data stream. The remaining data would be forwarded within 8 hours. Because of their potential urgency, the Plasma-Mag data are proposed to be transmitted directly to the National Oceanic and Atmospheric 19 For clarity, this simple description assumes a static Earth-Sun axis, whereas the axis is actually in constant motion as Earth revolves around the Sun. 20 Radiation that is scattered in the backward scattering direction is exactly reversed in direction and so proceeds directly on a line toward its source.
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Space Studies Board Annual Report 2000 TABLE 2 NASA's Objectives for Triana Primary Data Products Resolution Data Product Coverage Spatial Real Time Full Accuracy Relevant NRC and Government Reports* EPIC Total column ozone 8-16 km ±3% 2, 3, 4, 5, 9, 12 Aerosol index 8-16 km ±3% 3, 10 Aerosol optical depth 8-16 km ±10% 2, 3, 4, 5, 9, 10, 12 Cloud height 16 km ±30 mb 4, 5, 9, 10, 11 UV radiance 8-16 km ±10% 3, 4, 5 Precipitable water 8-16 km ±10% 3, 4, 5, 9, 10, 11, 12 Volcanic SO2 8-16 km ±10% 4, 5** Cloud reflectivity 8-16 km ±5% 2, 4, 5, 10, 11, 12 NISTAR Broad band radiances 2, 12 0.2 to >100 microns Sunlit full disk of Earth ±0.1% 10, 11 0.2 to 4 microns ±0.1% 4, 10, 12 0.7 to 4 microns ±0.1% 10 Planetary albedo Measurements Sunlit full disk of Earth ± 0.003% absolute 10, 11 Plasma-Mag Solar wind proton density 1 minute 1.5 seconds ± 2% 1, 4, 6, 7, 8, 9 Solar wind velocity 1 minute 1.5 seconds ± 10% 1, 4, 6, 7, 8, 9 Solar wind proton thermal speed 1 minute 1.5 seconds ± 10% 1, 4, 6, 7, 8, 9 Solar wind electron thermal speed NA 1.5 seconds ±10% 1, 4, 6, 7, 8, 9 Magnetometer Vector measurements of the interplanetary magnetic field 1 minute 20 milli-seconds ±1% each component 1, 4, 6, 7, 8, 9 Note: Except for that in the right-hand column, the information in Table 2 was provided by the Triana science team and represents NASA's program plans and objectives. *Compiled by the task group, this column lists previously published NRC and government reports that describe the value of these kinds of data for advancing understanding. See the key below for corresponding full references. One of the ways the task group addressed the issue of whether the Triana mission and goals are consonant with published science strategies was to compare Triana's primary data products as defined by the science team with priorities in relevant NRC and government reports. **This report indicates the need to understand the contribution of volcanoes to the sulfur budget, radiation balance, and impact on stratospheric chemistry and physics. Key: Space Studies Board, National Research Council, An Assessment of the Solar and Space Physics Aspects of NASA's Space Science Enterprise Strategic Plan, National Academy Press, Washington, D.C., 1997. Space Studies Board, National Research Council, Issues in the Integration of Research and Operational Satellite Systems for Climate Research: I. Science and Design, National Academy Press, Washington, D.C., in preparation, February 2000. National Research Council, A Review of the U.S. Global Change Research Program and NASA's Mission to Planet Earth/Earth Observing System, National Academy Press, Washington, D.C., 1995. National Research Council, Global Environmental Change: Research Pathways for the Next Decade , National Academy Press, Washington, D.C., 1998. National Research Council, The Atmospheric Sciences Entering the Twenty-First Century, National Academy Press, Washington, D.C., 1998. Space Studies Board, National Research Council, A Science Strategy for Space Physics, Committee on Solar and Space Physics, National Academy Press, Washington, D.C., 1995. Space Studies Board, National Research Council, Space Weather: A Research Briefing, Committee on Solar and Space Research and Board on Atmospheric Sciences and Climate Committee on Solar-Terrestrial Research, National Academy Press, Washington, D.C., 1997. Available only as an electronic document at < http://www.nas.edu/ssb/cover.html >. National Research Council, Toward a New National Weather Service—Continuity of NOAA Satellites, National Academy Press, Washington, D.C., 1997. National Research Council, A Vision for the National Weather Service: Road Map for the Future, National Academy Press, Washington, D.C., 1999. Office of Science and Technology Policy, Our Changing Planet: A U.S. Strategy for Global Change Research. Committee on Earth Sciences, Washington, D.C., 1989. National Research Council, Research Strategies of the U.S. Global Change Research Program, Committee on Global Change, National Academy Press, Washington, D.C., 1990. Space Studies Board, National Research Council, Issues in the Integration of Research and Operational Satellite Systems for Climate Research: II. Implementation, National Academy Press, Washington, D.C., in preparation, 2000.
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Space Studies Board Annual Report 2000 Administration (NOAA) for use in space weather forecasts and advisories. Geophysical and image processing of data would occur at the Triana Science and Operations Center (TSOC) at Scripps Institution of Oceanography, University of California, San Diego. EPIC visible channels will be calibrated, geolocated, georegistered, and posted on the Triana Web site within 30 to 45 minutes after acquisition. The NISTAR data will be received as a continuous stream, processed, and stored at the TSOC. NIST will then confirm that the data were collected properly and did not arrive during filter movement, spacecraft slew, or during an instrument calibration period. The TSOC will store all raw and processed science and image data for the life of the mission (2 to 5 years) plus 3 years. The EPIC and NISTAR data will be managed at the Langley Distributed Active Archive Center. The task group did not review the data archiving or management plans. TECHNICAL ASSESSMENT Are Triana's goals and objectives consonant with published science strategies and priorities? The goals and objectives of the Triana mission fall within two general categories: (1) to launch a modest exploratory mission to demonstrate the value of remote sensing observations from L1 for Earth science and (2) to gather global climate data and fill operational needs related to global change and solar weather. In general, the task group found that the scientific goals and objectives are consistent with the strategies and priorities for collection of climate data sets, and the need for development of new technologies, as articulated in relevant reports published by the National Research Council and other similar organizations. The task group could not find within any of the recently published reports of the NRC a specific recommendation to use L1 as the point from which to gather Earth science information. Nevertheless, the task group found that observation from L1 has the potential to provide data that can address several high-priority and conceptual issues that the reports highlight. For example, the proposed Triana mission is consistent with some recommendations made in the recent NRC report Research Pathways for the Next Decade,21 such as the need to elucidate “the connections among radiation, dynamics, chemistry and climate” and the need for “a scientific understanding of the entire Earth System on a global scale” (p. 5), with the caveat that although Triana views the full sunlit disk of Earth it cannot determine the thermal budget of the planet as a whole. The Pathways report stresses three objectives: (1) the need for well-calibrated observations, which Triana is designed to accomplish by using both the Moon and absolute radiometry; (2) the need to adopt multiple observational approaches, which Triana is designed to provide in conjunction with LEO and GEO missions; and (3) the need for technical innovation, which the use of both L1 for Earth observations and the NISTAR instrument exemplifies. The Pathways report also recommends the use of “smaller and more focused missions along the lines of the new Earth System Science Pathfinders” (p. xi). Triana is a relatively small mission comparable to an Earth System Science Pathfinder, but its focus is on exploring the technique of using L1 for Earth observations, rather than addressing a specific scientific problem. Perhaps Triana's most important contribution to Earth science observations is the potential for using L1 observations of Earth to integrate data from multiple spaceborne as well as surface and airborne observation platforms into a self-consistent global database for studying the planet and documenting the extent of regional and 21 National Research Council, Global Environmental Change: Research Pathways for the Next Decade , National Academy Press, Washington, D.C., 1998.
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Space Studies Board Annual Report 2000 global change. The L1 view allows the continuous acquisition of data from the entire full sunlit disk of Earth. These data overlap in both space and time the data gathered by essentially all other networks. The caveat here, however, is that Triana observations have a particular scattering geometry (close to backscatter), and the integration will therefore require additional processing of the data sets. Data from L1 may be useful for cross-calibrating independent observations and hence for assembling improved, self-consistent global databases from the diverse set of existing observations. Moreover, because of its large spatial coverage and temporal continuity, the data from Triana at L1 can be used to fill in data gaps left by other networks and spaceborne platforms. Triana at the L1 view also has the potential to provide atmospheric observations (particularly of ozone) at a finer temporal and spatial resolution for a larger portion of the globe than can currently be obtained from either LEO or GEO. For example, it is well known that both the planetary-scale circulation and small-scale mixing are equally important to the transport of chemical substances in the stratosphere. Few LEO and GEO measurements of trace species encompass these widely separated scales simultaneously. The hemispheric, high-resolution (8 km) ozone and aerosol data to be sampled by EPIC on Triana will be a unique set of observations for elucidating transport processes at both large and small scales. Such data should be valuable in furthering understanding of the chemistry of the stratosphere (e.g., ozone layer) and its response to anthropogenic and natural perturbations. The observations proposed by the Triana science team also have the potential to address a number of more specific scientific issues related to climate and space weather. As Table 2 indicates, most of the principal data products anticipated from Triana are identified as priorities in relevant NRC reports. These reports were produced over a number of years and using a variety of methodologies. The task group concluded that it would be difficult, if not impossible, to establish more refined estimates of priorities among these reports. Therefore, for the primary data products listed in Table 2, the task group has noted which earlier reports have indicated that the data were desirable, but it has not attempted to establish relative priorities. The observations from EPIC and NISTAR are designed to address the connections between radiation dynamics, chemistry, and climate, a theme that is highlighted in many recent NRC reports.22 The Plasma-Mag instrument is designed to provide data on the small-scale structure of the solar wind with a high time resolution, objectives consistent with the recommendations of NRC reports.23 The Triana mission is also consistent with more general recommendations to adopt multiple observational approaches.24 It is also possible that the Triana Earth observations will secure useful near-real-time information on the occurrence and evolution of potentially harmful environmental events (e.g., forest fires, volcanoes, UV irradiance peaks), thereby demonstrating the utility of L1 imaging for future operational products of societal relevance. 22 Space Studies Board, National Research Council, Readiness for the Upcoming Solar Maximum, National Academy Press, Washington, D.C., 1998. Space Studies Board, National Research Council, Earth Observations from Space: History, Promise, and Reality, National Academy Press, Washington, D.C., 1995. Space Studies Board, National Research Council, An Assessment of the Solar and Space Physics Aspects of NASA's Space Science Enterprise Strategic Plan, National Academy Press, Washington, D.C., 1997. Space Studies Board, National Research Council, Letter Report: “Assessment of NASA's Plans for Post-2002 Earth Observing Mission,” National Academy Press, Washington, D.C., 1999. Space Studies Board, National Research Council, Issues in the Integration of Research and Operational Satellite Systems for Climate Research: I. Science and Design, National Academy Press, Washington, D.C., in preparation, February 2000. Space Studies Board, National Research Council, The Role of Small Satellites in NASA and NOAA Earth Observation Programs, National Academy Press, Washington, D.C., in press, February 2000. National Research Council, A Review of the U.S. Global Change Research Program and NASA's Mission to Planet Earth/Earth Observing System, National Academy Press, Washington, D.C., 1995. National Research Council, Global Environmental Change: Research Pathways for the Next Decade, National Academy Press, Washington, D.C., 1998. National Research Council, The Atmospheric Sciences Entering the Twenty-First Century, National Academy Press, Washington, D.C., 1998. National Research Council, Adequacy of Climate Observing Systems, National Academy Press, Washington, D.C., 1999. Space Studies Board, National Research Council, A Science Strategy for Space Physics, National Academy Press, Washington, D.C., 1995. Space Studies Board, National Research Council, Space Weather: A Research Briefing, National Academy Press, Washington, D.C., 1997. Available only as an electronic document online at < http//www.nas.edu/ssb/cover/html >. Office of Science and Technology Policy, Our Changing Planet: A U.S. Strategy for Global Change Research, Committee on Earth Sciences, Washington, D.C., 1989. National Research Council, Research Strategies for the U.S. Global Change Research Program, National Academy Press, Washington, D.C., 1990. 23 National Research Council, Adequacy of Climate Observing Systems, National Academy Press, Washington, D.C., 1999. Space Studies Board, National Research Council, Earth Observations from Space: History, Promise, and Reality, National Academy Press, Washington, D.C., 1995. Space Studies Board, National Research Council, An Assessment of the Solar and Space Physics Aspects of NASA's Space Science Enterprise Strategic Plan, National Academy Press, Washington, D.C., 1997. 24 National Research Council, Global Environmental Change: Research Pathways for the Next Decade, National Academy Press, Washington, D.C., 1998.
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Space Studies Board Annual Report 2000 Without doubt, the Triana mission will have valuable space weather operational applications, the importance of which both NRC reports and the National Space Weather Program25 confirm. In conjunction with the present ACE mission (also at L1 but in a different orbit), Triana's Plasma-Mag enhances the ability of NOAA's Space Environment Center to carry out its mission to provide warning of imminent solar storm events, especially those whose terrestrial impact is less certain. Because the environment at L1 is very benign, it is expected that the ACE spacecraft and its instruments will remain healthy and thus will be able to provide space weather data to NOAA 's Space Environment Center for at least 4 years beyond the end of ACE's prime mission in 2002 (providing NASA funds the mission's extension). However, if the ACE spacecraft is lost or its plasma or magnetometer instrument fails, then Triana as the only upstream monitor of solar wind and interplanetary magnetic fields could be critical to the Space Environment Center's mission. As an exploratory mission Triana has experimental and innovative aspects that carry higher than usual risks but have the potential to make unique scientific contributions. The use of L1 for making Earth observations is itself experimental, since it will test the algorithms used to reduce remotely sensed data from a new combination of solar zenith angle and viewing/backscattering angles. The NISTAR instrument is based on an established laboratory technology, but one that has never before been used on a space-based platform; it is a completely new technological application of both hardware and algorithms. If the instrument performs properly and suitable algorithms are developed to provide sufficiently accurate data, NISTAR may provide unique observations of Earth's radiation parameters. Similarly, the proposal to use hot-spot data from EPIC to infer forest canopy structure is experimental but has the potential to make a significant contribution to the area of terrestrial ecology. Can Triana's goals and objectives be achieved with the planned measurements? The task group conducted neither a technical review of the Triana instrumentation or satellite nor a risk analysis. Such activities were beyond its scope and were precluded by the time and budgetary constraints placed on the preparation of this report. Nevertheless, the task group agreed on a number of general issues related to the likely scientific success of the mission based on a review of relevant documents, reports, and briefings by the Triana science team. The task group emphasizes that the following discussion of the ability of Triana to achieve its goals and objectives is predicated on the assumption that the instruments and satellite have been and will continue to be subject to all necessary and appropriate exploratory-mission technical and quality control reviews. Under no circumstances should this report or the statements contained in it be used as a replacement for these technical evaluations. Space missions, by their very nature, are risky, and exploratory missions such as Triana typically carry additional risk. It appears that Triana has been subjected to an unusually tight schedule and constrained budget. It is not unreasonable, in the task group's view, to expect that missions implemented on a short time line and with a constrained budget might carry more risk, although no specific evidence suggests that this is the case for Triana. Suffice it to say that the short time line and tight budget for Triana should not be allowed to preclude the rigorous technical evaluations and quality controls normally carried out by NASA for exploratory missions. This applies especially to the NIST portion of the mission and NISTAR, since NIST has no experience in the construction, quality control, and implementation of space instrumentation and NISTAR has no prior flight heritage. Some aspects of the mission led the task group to be optimistic. Because the radiation environment at L1 is more benign than for LEO and GEO, once the platform reaches L1, the chances of instrument damage or degradation from radiation will be significantly less than for more typical space-based missions focusing on Earth. Because it is never eclipsed, the Triana spacecraft will experience less thermal stress than most LEO and GEO missions. Another encouraging sign is the fact that all three of Triana's instruments have been built and are now in the testing phase. However, a critical part of this phase—the thermal and vibration testing—has yet to be conducted. Successful completion of these milestones will enhance the prognosis for Triana's success. EPIC The EPIC camera relies on largely proven technology, and its fabrication is not apparently a significant technological challenge. According to the Triana science team, EPIC's basic CCD array technology has been 25 The National Space Weather Program, The Implementation Plan, FCM-P31-1997, Washington, D.C.
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Space Studies Board Annual Report 2000 4.5 On Scientific Assessment of Options for the Disposition of the Galileo Spacecraft On June 28, 2000, Space Studies Board Chair Claude R. Canizares and Committee Chair John Wood sent the following letter to Dr. John D. Rummel, NASA planetary protection officer. In your letter of April 13, 2000, you reiterated a verbal request made in March for advice from the Space Studies Board's (SSB's) Committee on Planetary and Lunar Exploration (COMPLEX) on planetary protection concerns and other issues related to the final disposition of the Galileo spacecraft now in orbit about Jupiter. In particular, you asked that COMPLEX “evaluate the Galileo Project's favored alternatives for the spacecraft's planned trajectory during the remainder of the mission” and provide “a short statement of [COMPLEX's] findings, conclusions and recommendations relative to that plan.” In addition, you indicated that it would be particularly useful if COMPLEX could address four subsidiary issues in terms of their implications for planetary protection. These issues concerned: The planned trajectory's ability to avoid impact with Europa; The likelihood of the spacecraft impacting Io during science operations or after the end of the mission; The possibility of the biological contamination of Io; and The eventual deposition of the spacecraft on Jupiter. Work on this assessment began at COMPLEX's March 29-31, 2000, meeting at the Arnold and Mabel Beckman Center in Irvine, California. Torrence Johnson (Jet Propulsion Laboratory), the Galileo Project Scientist, briefed the committee on the various options under consideration for the final disposal of the spacecraft and outlined the opportunities and risks associated with the last phase of Galileo's operational life. In the discussion following Dr. Johnson's presentation, COMPLEX received additional input from Robert Pappalardo (Brown University), an affiliate member of the Galileo Imaging Team. In addition, individual committee members consulted with Damon Simonelli (Cornell University), an affiliate member of the Galileo Imaging Team, and with Margaret Kivelson (University of California, Los Angeles), Louis Frank (University of Iowa), and Donald Williams (Applied Physics Laboratory), the principal investigators of Galileo's magnetometer, plasma subsystem, and energetic particle detector, respectively. The committee also reviewed relevant reports issued by COMPLEX and other National Research Council (NRC) committees (e.g., Recommendations on Quarantine Policy for Mars, Jupiter, Saturn, Uranus, Neptune, and Titan , An Integrated Strategy for the Planetary Sciences: 1995-2010 , Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies , A Science Strategy for the Exploration of Europa , and Preventing the Forward Contamination of Europa ) and held extensive discussions in closed session. In its deliberations, COMPLEX considered three separate issues: planetary-protection considerations affecting the disposal of Galileo in the Jupiter system; the unique scientific opportunities presented by the various end-of-mission scenarios being considered by the Galileo Project and their relative priorities; and general considerations arising from possible conflicts between planetary-protection requirements and scientific opportunities. Full details are contained in the attached assessment. With respect to planetary-protection issues, COMPLEX reached the following conclusions: There is no planetary-protection-related objection to the disposal of Galileo by intentional or unintentional impact with Io or Jupiter. There are serious planetary-protection objections to the intentional or unintentional disposal of Galileo on Europa. Qualitative limits on acceptable probabilities of contamination are contained in the recent report of the Task Group on the Forward Contamination of Europa. 1 The planetary-protection implications of the intentional or unintentional impact of Galileo with Ganymede or Callisto are intermediate in the broad range between those for disposal on Io and for disposal on Europa. 1 Space Studies Board, National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000.
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Space Studies Board Annual Report 2000 COMPLEX understands that operational considerations point to collision with Jupiter as NASA's preferred means for disposing of Galileo. COMPLEX concurs with this decision. With respect to scientific priorities they afford, COMPLEX believes that the most important of the various options being considered by the Galileo Project are a conservative trajectory leading to a close flyby of the small moon Almathea, a series of less conservative trajectories leading to one or more polar flybys of Io, and, possibly, a flyby of Almathea as well.2 Given this choice, COMPLEX believes that the Io flybys have the greatest potential for providing important scientific results because they directly address the processes responsible for the active generation of planetary magnetic fields, a key question outlined in COMPLEX 's Integrated Strategy.3 With respect to issues arising from possible conflicts between planetary-protection requirements and scientific opportunities, COMPLEX recognizes that its preference for an Io flyby requires the selection of one of the less conservative trajectory options. That is, choosing the Io encounters postpones for approximately 1 year Galileo's placement on a ballistic trajectory into Jupiter and thus increases the chance that the spacecraft may suffer a fatal failure and end up on an unintended trajectory. Unfortunately, the committee was not given quantitative estimates of the probability of spacecraft failure as a function of time. Nor was the committee given estimates of the likelihood of impact with the Galilean satellites associated with failure during the various trajectory options. Moreover, the committee is not qualified to make its own estimates of such eventualities. As a result, COMPLEX is not able to address the subsidiary question concerning the likelihood of unintentional impact with Europa. The subsidiary question concerning the likelihood of unintentional impact with Io is moot since there is no planetary-protection objection to impact with Io. Given this lack of information, COMPLEX recommends that the Galileo Project perform the necessary calculations to determine the probability of Galileo impacting Europa should control of the spacecraft be lost after the G29 flyby. These results can then be used to estimate the probability of contaminating the putative europan ocean with terrestrial microorganisms by following the procedure outlined in the report of the Task Group on the Forward Contamination of Europa.4 Only if such a quantitative analysis is undertaken can COMPLEX give an unequivocal recommendation about the degree to which the proposed trajectory options are consistent with the requirements necessary to avoid the forward contamination of Europa. In the interim, COMPLEX performed its own qualitative analysis. Based on the information supplied to the committee, an extra year of operations can be expected to increase the burden of radiation absorbed by Galileo by only about 20%. This estimate, plus the fact that Galileo retains full redundancy in all essential systems and that the radiation effects sustained thus far have not handicapped control of the spacecraft, suggests to COMPLEX that the probability of total loss of control during this extra year is relatively small. Moreover, the chances of total failure can be mitigated by prudent monitoring of the spacecraft 's health and by a commitment on the part of NASA to retarget Galileo onto a Jupiter-bound trajectory following the loss of redundancy in any major command and control subsystem. In summary, COMPLEX concurs with NASA's decision that impact with Jupiter is the most appropriate means of disposing of Galileo. COMPLEX recommends that the Galileo Project perform qualitative risk assessment of the various trajectory options. Pending the completion of these calculations, the committee reached a consensus that an appropriate interim course of action is to defer the destruction of Galileo until after the completion of the Io polar flybys, in order to obtain as much science as possible from the mission. Signed by Claude Canizares Chair, Space Studies Board John A. Wood Chair, COMPLEX 2 The Io plus Amalthea option is not consistent with Galileo's current budget plan. 3 Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, page 92. 4 Space Studies Board, National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000, Appendix.
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Space Studies Board Annual Report 2000 Scientific Assessment of Options for the Disposal of the Galileo Spacecraft At its meeting March 29-31, 2000, the Space Studies Board's Committee on Planetary and Lunar Exploration (COMPLEX) began work on an assessment of options for the orderly disposal of the Galileo spacecraft at the end of its mission. This assessment was made at the specific verbal and, subsequent, written request of John D. Rummel, NASA's Planetary Protection Officer. COMPLEX was asked to provide “findings, conclusions, and recommendations” about the various end-of-mission options currently being considered by the Galileo Project. In addition, the committee was asked to comment on four subsidiary issues relating to the possibility of impacting Io and Europa and the biological contamination of Jupiter and Io. BACKGROUND Galileo entered orbit about Jupiter in December 1995 on a 2-year mission to conduct intensive observations of Jupiter's atmosphere, rings, satellites, and radiation environment. In 1997, the mission was extended for an additional 2-year period to allow for additional studies of Europa and the first close-up observations of Io. In 1999, the mission was extended for another year to enable more studies of Io and Europa, and, in addition, concerted observations of Jupiter 's magnetosphere with the Saturn-bound Cassini spacecraft in December 2000. Galileo's frequent passages through Jupiter's intense radiation belts have exposed the spacecraft to a radiation dose some three times larger than that specified by its design. Nevertheless, the radiation-induced problems experienced so far have been limited to intermittent interference with spacecraft operations, and no catastrophic failures of subsystems and/or total-radiation-dose effects have been observed to date. Moreover, except for stuck gratings in the ultraviolet spectrometer and near-infrared mapping spectrometer (NIMS),1 Galileo's instrument complement remains fully operational. PLANETARY-PROTECTION CONSIDERATIONS Despite Galileo's general spaceworthiness, it is unrealistic to assume that it will remain both controllable and scientifically useful for the indefinite future. It is, therefore, prudent to begin planning for the most scientifically productive use of the spacecraft's remaining life and to make provision for its safe disposal. The latter issue arises because of NASA planetary-protection policy. Obligations imposed by the United Nations' Outer Space Treaty2 mandate that spacecraft missions be conducted in such a way as to minimize the inadvertent transfer of living organisms from one planetary body to another. Given the complex interplay of the gravitational fields of Jupiter and its four large satellites, the stability of Galileo's orbit cannot be guaranteed indefinitely. Monte Carlo simulations of the spacecraft's orbit indicate that Galileo has a relatively high probability of eventually colliding with one of Jupiter's satellites unless some action is taken to achieve an alternative result. Thus, Galileo must be disposed of in a controlled fashion and in a manner that does not compromise the scientific integrity of any planetary body likely to be of interest for future biological studies. One option for the disposal of Galileo is controlled impact on Jupiter or one of its satellites. Another option is to take advantage of the gravitational interactions between Galileo and Jupiter and its large satellites to engineer a controlled ejection into a heliocentric orbit. The latter possibility, though intriguing from a technical perspective, might mandate a nuclear-material, launch-safety review of the type Galileo underwent prior to leaving Earth in 1989. The reason for this is the very small, but nonzero, chance of eventual impact with Earth. The anticipated cost of such a review is so great —in excess of Galileo's current annual operations budget of some $7 million—that NASA has no option but to dispose of the spacecraft within the jovian system. 1 The ultraviolet spectrometer is no longer operational, but NIMS can still be used in a fixed-grating mode providing 14 spectral channels in the 1- to 5-µm band. The extreme ultraviolet spectrometer remains operational. 2 United Nations, Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, U.N. Document No. 6347, January 1967.
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Space Studies Board Annual Report 2000 Given below is COMPLEX's assessment of the likely planetary protection implications of disposing of Galileo by having it collide with one of the Galilean satellites or with Jupiter itself. No consideration was given to disposing of the spacecraft by impact with one of Jupiter's minor satellites. Io: The prospects for indigenous biological activity on or below Io's surface are slight due to its incessant high-temperature volcanic activity, the absence of water on its surface, the absence of evidence for subsurface liquid water now or in the past, and the extreme surface radiation environment.3 Similarly, the prospects for the survival of terrestrial organisms deposited by Galileo on Io are bleak. Thus COMPLEX sees no planetary-protection objection to the disposal of Galileo by intentional or inadvertent impact with Io. Europa: The strong indirect evidence for a global ocean beneath this moon 's icy surface makes it one of the places in the solar system with the greatest potential for the existence of life.4 Although any terrestrial organisms on Galileo have now been exposed to the vacuum of space and irradiated along with the spacecraft, it is impossible to be certain that none have survived. Nor is it possible to be certain that all surviving organisms will perish upon impact with Europa and not pose a biological threat to a hypothetical europan ocean.5 Thus, COMPLEX sees serious planetary-protection objections to the intentional or unintentional disposal of Galileo on Europa. Qualitative limits on acceptable probabilities of contamination are contained in the recently released report of the Task Group on the Forward Contamination of Europa.6 Ganymede and Callisto: These bodies, two of the largest satellites in the solar system, are very different. Ganymede is fully differentiated, possesses a dynamo-driven magnetic field, and has a surface that displays evidence of substantial internal geologic activity in its early history.7 It is conceivable that hydrothermal processes may have been active near the boundary between its silicate mantle and surface ice, and that the chemical and/or biological products of this activity may have been transported to Ganymede's surface via solid-state convection, cryovolcanism, or some similar process. As such, Ganymede's biological potential cannot be shown to be zero, but it is certainly lower than that of Europa.8 On the other hand, Callisto's surface is heavily cratered and shows little or no evidence of internal geologic activity.9 Nevertheless, Callisto displays magnetic characteristics indicative of a global ocean of saltwater—the same characteristics displayed by Europa.10 Callisto's interior is only partially differentiated and,11 thus, the absence of a distinct rocky or rocky-metallic core implies that volcanism and hydrothermal activity are unlikely. Therefore, even if water exists, a biologically useful energy source may be absent.12 Given these considerations, COMPLEX sees the planetary-protection implications of the intentional or unintentional impact of Galileo on Ganymede or Callisto as being intermediate in the broad range between disposal on Io and disposal on Europa. Given the limited scientific basis for judging the biological potential of these bodies, COMPLEX was not able to quantify the exact locations of Ganymede and Callisto on the Io-Europa spectrum of planetary-protection concerns. For this reason, prudence dictates a preference for end-of-mission scenarios that involve a minor risk of impact with either Ganymede or Callisto. Jupiter: Assuming any terrestrial organisms survive the destruction of Galileo during entry into Jupiter's atmosphere, the only environment in which they can conceivably survive is in the atmosphere itself. But any free- 3 Space Studies Board, National Research Council, Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies—Framework for Decision Making, National Academy Press, Washington, D.C., 1998, pages 31-77. 4 Space Studies Board, National Research Council, A Science Strategy for the Exploration of Europa, National Academy Press, Washington, D.C., 1999, pages 3, 22-23, 26-27, and 64. 5 Space Studies Board, National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000. 6 Space Studies Board, National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000. 7 A.P. Showman and R. Malhotra, “The Galilean Satellites,” Science 286: 77, 1999. 8 Space Studies Board, National Research Council, Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies—Framework for Decision Making, National Academy Press, Washington, D.C., 1998, page 34. 9 A.P. Showman and R. Malhotra, “The Galilean Satellites,” Science 286: 77, 1999. 10 M.G. Kivelson et al., “Europa and Callisto: Induced or Intrinsic Fields in a Periodically Varying Plasma Environment,” Journal of Geophysical Research 104: 4609, 1999. 11 A.P. Showman and R. Malhotra, “The Galilean Satellites,” Science 286: 77, 1999. 12 Space Studies Board, National Research Council, Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies—Framework for Decision Making, National Academy Press, Washington, D.C., 1998, page 77.
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Space Studies Board Annual Report 2000 FIGURE 1 A timeline of possible trajectory options leading to the disposal of the Galileo spacecraft by collision with Jupiter. floating organism that finds itself in a benign region of the atmosphere will be rapidly convected into a less favorable region and, thus, the chances of survival are essentially nil.13 In addition, the committee notes that no special planetary-protection procedures (e.g., bioload reduction or sterilization) were applied to the Galileo Probe, which was specifically designed to survive penetration to the 10-bar level in Jupiter's atmosphere. Therefore, COMPLEX sees no objection based on planetary-protection considerations for the disposal of Galileo by impact with Jupiter. Thus, COMPLEX concludes that collision with either Io or Jupiter is the most appropriate planetary-protection strategy for the disposal of Galileo. Based on Dr. Johnson's presentation, the committee understands that operational considerations point to Jupiter as NASA's preferred option. COMPLEX concurs with this decision. SCIENTIFIC CONSIDERATIONS Dr. Johnson told COMPLEX that NASA has considered four different options for placing Galileo on a collision course with Jupiter (see Figure 1). The most conservative option involves an orbital maneuver in the summer of 2000 and a flyby of Ganymede (G2914) in December 2000, an option that places Galileo on a ballistic trajectory guaranteed to impact Jupiter in December 2002. This trajectory would permit a flyby of the small inner moon Amalthea (A30) in August 2001. The least conservative options involve a different orbital maneuver in mid-2000, followed by flybys of Ganymede (G29) and Callisto (C30) and multiple flybys of Io (I31, I32, and I33). This sequence then leads to three additional options. An orbital maneuver at the apoapsis following I32 can be used to fine-tune the exact circumstances of I33 to place Galileo on a ballistic trajectory designed to impact Jupiter in either December 2002, or September 2003, or January 2004. Two of these ballistic trajectories permit flyby of Amalthea (A34) in either September or November 2002. 13 Space Science Board, National Research Council, Recommendations on Planetary Quarantine Policy for Mars, Jupiter, Saturn, Uranus, Neptune, and Titan, National Academy of Sciences, Washington, D.C., 1978, pages 14-15. 14 The nomenclature indicates an encounter with Ganymede on Galileo's 29th orbit about Jupiter since December 1995.
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Space Studies Board Annual Report 2000 The most interesting scientific opportunities presented by these options are as follows: A relatively close passage by Amalthea, one of Jupiter's innermost known satellites. This should yield an estimate of the mass and, correspondingly, the bulk density for the satellite. This estimate is important because Amalthea may be a fragment of an object that formed closer to Jupiter than the Galilean satellites, where temperatures in the circumjovian nebula would have been higher. Given that Amalthea's volume is currently known to an accuracy of about 10%, a mass accurate to even 20% may allow conclusions to be drawn about conditions in the jovian nebula and the satellite-formation processes, in general. Mass determination requires no functional instruments, only tracking of the spacecraft 's trajectory through monitoring of its downlinked radio signals. If remote-sensing observations are possible during the flyby, then monochromatic (clear filter) imaging would allow several secondary goals to be pursued. These include high-resolution images of streaks and crater interiors, searches for evidence of layering, and accurate crater counts. One or more relatively close passes over Io's north and/or south pole to complete the survey of this satellite 's magnetic properties. Polar flybys are needed to establish the presence and identify the nature of possible internal sources of the magnetic field measured during Galileo's earlier encounters with Io. This field may, according to some computer simulations, be generated by deep internal flows driven by the nonuniform tidal heating of Io's mantle. If present, this type of dynamo action would provide constraints on the nature of Io's core that would, in turn, contribute information central to theories of planetary evolution. In addition, inductive currents, responding to the time-varying component of Jupiter's field at Io 's location, might produce an induced magnetic moment whose amplitude and phase would characterize the nature of near-surf ace conducting layers. Polar passes will also provide critical information on the plasma flow characteristics and ion pickup in the polar regions for comparison with previous observations made during low-latitude flybys. Such a comparison may help identify the mechanism that produces field-aligned beams of energetic electrons previously observed in Io's plasma wake and provide information about Io's ionospheric structure and composition. Measurements in the polar regions were attempted earlier in the mission but were not successful because a transient fault placed the spacecraft in a safe mode during the I25 flyby. Moreover, valuable remote-sensing opportunities exist during polar flybys for Galileo's imaging, NIMS, and photopolarimeter-radiometer instruments, following up on the array of discoveries made during Galileo's previous close flybys of Io.15,16,17 If a choice must be made between flybys of Amalthea and Io,18 COMPLEX believes that scientific priority should be given to the latter because it has the greatest potential for providing important results. This is the case because the Io encounter or encounters will directly address the processes responsible for the active generation of planetary magnetic fields, a key question outlined in COMPLEX 's Integrated Strategy.19 This prioritization is also in accord with the committee's general preference for formulating exploration programs that attempt to systematically address key physical and chemical processes rather than cataloging and classifying planetary environments.20 INTERPLAY OF SCIENTIFIC AND PLANETARY-PROTECTION ISSUES COMPLEX'S preference for an Io flyby requires the selection of one of the less-conservative trajectory options. Such a selection raises the immediate question of whether the scientific potential of this option justifies the risk associated with delaying from December 2000 to January 2002 the decision to place the spacecraft on a ballistic trajectory designed to intercept Jupiter. Would an additional year during which control over Galileo may be lost make it impossible to place the spacecraft on a Jupiter-bound trajectory? 15 A.S. McEwen et al., “Galileo at Io: Results from High-Resolution Imaging,” Science 288: 1193, 2000. 16 J.R. Spencer et al., “Io's Thermal Emission from the Galileo Photopolarimeter-Radiometer,” Science 288: 1198, 2000. 17 R. Lopes-Gautier et al., “A Close-Up Look at Io from Galileo's Near-Infrared Mapping Spectrometer,” Science 288: 1201, 2000. 18 COMPLEX was told that the trajectory options allowing flybys of both Io and Amalthea may be inconsistent with the mission's current financial resources. 19 Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, page 92. 20 Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 33-34.
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Space Studies Board Annual Report 2000 In attempting to make such a determination, COMPLEX is at a disadvantage because it was not given quantitative estimates of the probability of failure as a function of time. Nor was the committee given estimates of the likelihood of impact with the Galilean satellites associated with the various trajectory options. Moreover, the committee is not qualified to make its own estimates of such eventualities. As a result, COMPLEX was unable to address the subsidiary question concerning the likelihood of impact with Europa. The question concerning the likelihood of collision with Io is moot since such an event has no obvious planetary-protection consequences. Given this lack of information, COMPLEX recommends that the Galileo Project perform the calculations required to determine the spacecraft 's risk of impact with Europa should control over the spacecraft be lost after the G29 flyby. These results should then be used to estimate the probability of the inadvertent contamination of a europan ocean by terrestrial microorganisms from Galileo, using the procedure outlined in the recently released report of the Task Group on the Forward Contamination of Europa.21 Comparison of the resulting probabilities with the contamination limit set in the task group's report will provide an appropriate planetary-protection basis for determining options concerning Galileo 's future trajectory. Given that the recommended calculations are complex and may take some time to perform, as an interim measure the committee performed its own non-quantitative assessment of the situation. The threat of loss of control of the spacecraft comes mostly from additional damage to its electronic systems that will be caused by continued charged-particle irradiation in the Jupiter system. Based on the information supplied by Dr. Johnson, the committee estimated that an extra year of operations will increase the burden of radiation absorbed by Galileo by only approximately 20%. This estimate, plus the fact that Galileo remains healthy—it still possesses full redundancy in all of its major subsystems, and the radiation damage incurred thus far has not handicapped control of the spacecraft—suggests to COMPLEX that the probability of total loss of control during this extra year is relatively small. Based on these considerations, COMPLEX reached a consensus that deferring the destruction of Galileo until after the completion of the Io polar flybys is an appropriate course of action, pending the completion of a quantitative assessment of the risk of contaminating the putative europan ocean with terrestrial organisms hitchhiking aboard Galileo. Although this judgment falls short of being unequivocal, COMPLEX believes that it is appropriate. It is a relatively simple task for the Galileo Project to reassess the risk at each major juncture in the trajectory and plan accordingly. That is, there is sufficient time between each satellite flyby (i.e., G29, C30, I31, and so on) for the Galileo Project to assess the health of the spacecraft and, if a significant degradation in performance is detected, to initiate the appropriate maneuver at the subsequent apoapsis to place the spacecraft on a ballistic trajectory into Jupiter. Thus, as an adjunct to its conclusion that Galileo undertake the Io flybys, COMPLEX suggests the following risk-mitigation strategy. The spacecraft's health should be closely monitored, and the detection of loss in redundancy in any critical command and control subsystem should trigger the initiation of the appropriate maneuvers necessary to place Galileo on a ballistic trajectory designed so that the spacecraft will collide with Jupiter. 21 Space Studies Board, National Research Council, Preventing the Forward Contamination of Europa, National Academy Press, Washington, D.C., 2000, Appendix.
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Space Studies Board Annual Report 2000 4.6 Interim Assessment of Research and Data Analysis in NASA's Office of Space Science On September 22, 2000, Space Studies Board Chair John H. McElroy sent the following letter report to Dr. Edward J. Weiler, associate administrator for NASA's Office of Space Science. As you requested in your letter of June 16, 2000 (Appendix A), the Space Studies Board (the Board; Appendix B) has conducted a brief review of actions taken by the Office of Space Science (OSS) that are relevant to recommendations in the Board's 1998 report Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis.1 The statement of task for this review is provided in Appendix C. The Board conducted this assessment on an ambitious schedule in accordance with your request for feedback by September 2000. The Board was provided with relatively little written documentation of NASA's plans for improving the OSS R&DA program. The review was based, in part, on inputs received from relevant standing committees of the Board—the Committee on Solar and Space Physics, the Committee on Planetary and Lunar Exploration, and the Committee on Astronomy and Astrophysics. A major source of information for the review was a pair of short papers provided to the Board on July 25, 2000, by Dr. Guenter Riegler, director of the OSS Research Program Management Division (Appendixes D and E). Dr. Riegler then briefed the Board's executive committee and standing committee chairs at a meeting on August 16 at the National Academies' study center in Woods Hole, Massachusetts. At that meeting, members of the Board reviewed and discussed the information from NASA and the Board's discipline committees' responses and assembled this consensus assessment. 2 The Board concluded that the proposals that Dr. Riegler described for responding to the 1998 report are appropriate; however, a final assessment awaits action guided by a concrete implementation plan. GENERAL OBSERVATIONS The 1998 Space Studies Board report analyzed the roles and contributions of R&DA grants in the research programs of NASA's three science offices, and it presented a set of strategic and programmatic recommendations to enhance the R&DA programs. The Board reaffirms the conclusions of the 1998 report: research and data analysis activities are critical elements of a viable space science program.3 The Board is aware of a number of actions within OSS that are under way or planned that will strengthen the R&DA programs and that will be entirely consistent with the recommendations of the 1998 report. For example, Dr. Riegler described plans to reallocate current budgets and to seek funds for new projects that will provide selected increases in data analysis funding at an overall rate of 8% per year. He also reported on the OSS intent to provide explicitly for data analysis funding in all new projects when they are initially proposed. Further, Dr. Riegler described a regular process of “senior reviews” of the research grants program that would complement the senior reviews of operating spacecraft mission programs and provide a mechanism to accomplish a number of actions recommended by the Board in the 1998 report. 1 Space Studies Board, National Research Council, Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis, National Academy Press, Washington, D.C., 1998. 2 This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council's (NRC's) Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the NRC in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The contents of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report: Anthony W. England, University of Michigan; Richard Goody, Harvard University (emeritus); Gordon Pettengill, Massachusetts Institute of Technology; Paul G. Steffes, Georgia Institute of Technology; and Robert E. Williams, Space Telescope Science Institute. While these individuals have provided many constructive comments and suggestions, responsibility for the final content of this report rests solely with the authoring board and the NRC. 3 Space Studies Board, National Research Council, Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis, 1998, pp. 11-33 and 37-42.
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Space Studies Board Annual Report 2000 While the Board supports the steps noted above, there are still two concerns to be addressed. First, many of the OSS responses to the 1998 report's recommendations are planned rather than ongoing activities, and so any assessment of their effectiveness must await their implementation. Second, there are areas where the plans appear to be incomplete or where the attention being given may be inadequate. In the remainder of this report, the Board provides additional comments on those areas by addressing each of the six major recommendations in the 1998 report in order. ASSESSMENT OF THE OSS RESPONSE TO THE 1998 SSB RECOMMENDATIONS 1. Principles for Strategic Planning The first recommendation of the 1998 report addressed a number of aspects of managing R&DA programs strategically. To be able to do so requires, of course, a strategic plan for the program as a whole and an approach that integrates attention to R&DA into that plan. In its May 2000 review of the OSS draft 2000 strategic plan, the Board indicated that while many aspects of the draft were solidly grounded, the document still lacked several important aspects of a strategic plan, as follows: Although the draft document is called “The Space Science Enterprise Strategic Plan,” it lacks, in fact, some key characteristics of a strategic plan. For example, the document does not explicitly discuss how choices were or are made in setting priorities, and it does not identify priorities for missions or other program elements that are presented in the plan. . . .4 Regarding the integration of R&DA into that strategic plan, the Board's May 2000 report said: The OSS draft plan should reflect a clearer sense of the priorities for R&DA, the linkages between R&DA and other parts of the OSS program, and the overall importance of R&DA in the space science enterprise. Finally, also needed is a more explicit discussion of the OSS strategy for achieving balance between flight mission development, supporting ground and suborbital research, theory and modeling, and data analysis. . . .5 The Board is aware of OSS's plans to institute a new senior review process for evaluating the research grants program (Appendix D), probably on a triennial basis, to complement the senior reviews for operating satellites. Together these two reviews will go a long way toward responding to regular evaluations of balance as recommended in the 1998 report. What is apparently missing, however, is a process to integrate these decisions and to look across the whole program strategically. This integrating function is particularly important for handling cases in which senior reviews of operating missions and of the grants program might arrive at different conclusions. The NASA Space Science Advisory Committee may be a possible venue for integrating the senior reviews and evaluating balance across OSS. 2. Innovation and Infrastructure The second recommendation addressed the need to examine strategically the requirements, priorities, and health of research infrastructures at universities and NASA field centers. This issue was also addressed in the Board's review of the OSS draft strategic plan: The OSS draft document says little about what responsibility OSS assumes for universities. It notes the intention to “maintain essential technical capabilities at the NASA centers,” and although it recognizes the role of scientists at universities in research and planning, and in developing the next generation of space research professionals, it is silent about intentions of OSS to maintain essential capabilities at universities. . . . Furthermore, a long-standing question within NASA has concerned the extent to which universities should be considered to be vendors, sources of members of the technical workforce, integral partners, or some mix of those roles. The OSS plan could be strengthened by more clearly recognizing that the universities are elements of the fabric of space science and that their capabilities also need to be nurtured.6 4 Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft 2000 Strategic Plan,” May 28, 2000, p. 2. 5 Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft 2000 Strategic Plan,” May 28, 2000, pp. 4-5. 6 Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft 2000 Strategic Plan,” May 28, 2000, p. 3.
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Space Studies Board Annual Report 2000 Dr. Riegler called the Board's attention to plans within the executive branch to strengthen governmentuniversity partnerships, based on the “Principles of the Federal Partnership with Universities in Research” laid out in the National Science and Technology Council's report Renewing the Federal Government-University Research Partnership for the 21st Century.7 He cited several proposed NASA initiatives to increase university involvement in developing space hardware and infrastructure. These plans, if implemented, will enhance the research infrastructure in some areas. However, based on the information provided by OSS, the Board concluded that a more systematic assessment of research infrastructure along the lines recommended in the 1998 report is still needed. 3. Management of the Research and Data Analysis Programs The third recommendation focused on the need to assess the distribution of grant sizes in each of NASA's science program areas. NASA presented data regarding grant sizes in different areas of the OSS research program as well as a description of the logic and history of the differences in sizes among those research areas. However, there does not appear to have been any systematic assessment across the program. In addition, the Board recognizes that a response to Recommendation 6 of the 1998 report is required in order to conduct such an assessment. Finally, the planned senior review of the research grants program described by NASA could be an appropriate vehicle for carrying out this systematic review. 4. Participation in the Research and Data Analysis Programs The fourth recommendation emphasized the value in preserving a mix of university and non-university participation in technology, instrument, and facility development. OSS did not provide the Board with any information indicating that OSS has conducted or plans to conduct a systematic evaluation of the mix of university principal investigator awards and non-university funding for technology, instrument, and facility development. The Board notes that in assessing the mix of institutions involved in technology development, NASA should also promote university-industry-field center partnerships. 5. Creation of Intellectual Capital The fifth recommendation addressed the use of training grants as a way to ensure breadth in graduate education. NASA indicated an intent to increase the number of (or introduce a new element into) training grants in the university program; however, no actions had been undertaken at the time of this review. The Board is interested in seeing an implementation plan for this initiative. 6. Accounting as a Management Tool in the Research and Data Analysis Programs The sixth recommendation addressed the need to establish a uniform procedure for collecting data on R&DA funding and funding trends for use as a management tool. This issue was also raised in the Board 's reports on technology development in OSS8 and in the report Federal Funding of Astronomical Research.9 NASA presented plans for acquiring the types of data recommended in the 1998 report, and the Board views this plan as a positive response. These plans would involve using a single contractor to administer the proposal review process as a means for collecting the data. If appropriate data are collected (e.g., on trends with respect to discipline, class of activity, and type of performing institution), they will provide a useful management tool for assessing the balance among elements and participants in the R&DA program. However, these data on R&DA funding will be incomplete until 7 National Science and Technology Council, Office of Science and Technology Policy, Renewing the Federal Government-University Research Partnership for the 21st Century, Office of Science and Technology Policy, Washington, D.C., April 1999, pp. 10-14. 8 Space Studies Board, National Research Council, Assessment of Technology Development in NASA's Office of Space Science, National Academy Press, Washington, D.C., 1998, p. 25, and Space Studies Board, National Research Council, “Continuing Assessment of Technology Development in NASA's Office of Space Science,” March 15, 2000, p. 10. 9 Space Studies Board and Board on Physics and Astronomy, National Research Council, Federal Funding of Astronomical Research, National Academy Press, Washington, D.C., 2000.
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Space Studies Board Annual Report 2000 NASA implements full-cost accounting at the NASA field centers.10 In addition, these data will be required before OSS can respond appropriately to Recommendation 3 of the 1998 report. CONCLUDING REMARKS The Board believes that OSS's proposals for responding to the recommendations of the 1998 report are moving in the right direction. It cannot, however, be confident that these recommendations will be met until an explicit implementation plan is available. The Board is prepared to assist OSS in any way it can. Signed by John H. McElroy Chair, Space Studies Board 10 Space Studies Board, National Research Council, Assessment of Technology Development in NASA's Office of Space Science, 1998, pp. 25-26, and Space Studies Board, National Research Council, “Continuing Assessment of Technology Development in NASA's Office of Space Science,” March 15, 2000, p. 10.
Representative terms from entire chapter: