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Space Studies Board Annual Report 2000 (2001)

Chapter: 4. Short Reports

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Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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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

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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:

  1. 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.

  2. 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.

  3. 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.

  4. National Research Council, Global Environmental Change: Research Pathways for the Next Decade , National Academy Press, Washington, D.C., 1998.

  5. National Research Council, The Atmospheric Sciences Entering the Twenty-First Century, National Academy Press, Washington, D.C., 1998.

  6. 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.

  7. 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 >.

  8. National Research Council, Toward a New National Weather Service—Continuity of NOAA Satellites, National Academy Press, Washington, D.C., 1997.

  9. National Research Council, A Vision for the National Weather Service: Road Map for the Future, National Academy Press, Washington, D.C., 1999.

  10. 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.

  11. National Research Council, Research Strategies of the U.S. Global Change Research Program, Committee on Global Change, National Academy Press, Washington, D.C., 1990.

  12. 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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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
  1. 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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

  1. 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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

applied in other spaceborne imagers (namely the Michelson Doppler Imager on the Solar and Heliospheric Observatory [SOHO] and the Transition Region and Coronal Explorer [TRACE]). However, the array utilizes two new features—back side thinning and back side illumination.26 Back side thinned and illuminated arrays are currently used in many earthbound astronomical instruments. Although there is a flight heritage for back side-illuminated arrays, Triana would be the first spaceborne application of a back side thinned and illuminated array. NASA has assured the task group that the filters, which are fabricated with ion-assisted surface deposition, have been built and tested, and closely meet the nominal specifications.

NISTAR

The NISTAR radiometers are absolute detectors that measure power directly, thereby precluding the need for complex transfer algorithms and inversions to obtain geophysical data products from detector signals, other than the transmission functions of the filters that isolate the solar and thermal signals. The approach relected in NISTAR 's inclusion on Triana for monitoring Earth's irradiance has not been utilized in the past because of the lack of absolute radiometric devices with sufficient sensitivity when operating near room temperature. Similar types of devices have for two decades measured the power from the Sun,27 and independent NASA instruments of this type will provide the measurements of incident solar energy needed to derive planetary albedo during the Triana mission. NISTAR will implement analogous, simultaneous measurements of integrated power from the full sunlit disk of Earth itself, permitting measurements of Earth's planetary albedo as a function of time, including visible and near-IR bands separately.

The NISTAR measurements should be possible because of significant radiometric advances that NIST has pioneered in the construction of radiometers. These new radiometers are designed to achieve adequate signals relative to noise at room temperature and are based on laboratory cryogenic radiometers used extensively as national power standards. 28 The filters that separate radiant fluxes into visible and near-IR spectral regions have ion-assisted deposition on their surfaces and are multiply redundant, features that help, respectively, to minimize and permit tracking of their in-flight stability drifts. Dual carriage filter and shutter wheels are designed for adequate thermal isolation of the receiver cavities from the surrounding environment.

The NISTAR hardware has been constructed and is currently undergoing laboratory testing at NIST. The task group notes that algorithms remain to be developed to derive the planetary parameters from the NISTAR radiation measurements. Since the sunlit disk albedo measurements planned by NISTAR are new observables, and the derived geophysical parameters from NISTAR and EPIC are new data products, all of which lack algorithm heritage, it is not possible yet to assess the effort required to deduce reliable geophysical data from these observations. However, experience with similar data sets (e.g., ERBE) suggests that a significant time investment will be required.

Plasma-Mag

The goals and scientific aims of the Plasma-Mag investigation are to (1) study plasma turbulence and structures in the solar wind using the fast (≈1 sec) time resolution capabilities of Plasma-Mag, (2) study the large-scale solar wind structures using multipoint and correlative observations from complementary space environment missions (ACE, WIND, Solar Terrestrial Relations Observatory [STEREO], and SOHO), and (3) provide real-time solar wind parameters required for space weather forecasting. The task group concluded that the likelihood that these objectives and goals will be achieved is high, because measurements of the type planned by Plasma-Mag are widely used in space environment missions.

26  

The back side thinning process removes excess silicon to enhance sensitivity in the ultraviolet region. Back side illumination, in which the array is illuminated from the side from which the signal is read out, improves sensitivity and makes the array less susceptible to on-orbit radiation degradation.

27  

The Sun' s signal of ∼100 milliwatt per square centimeter at LEO is five orders of magnitude higher than the 1 microwatt per square centimeter signal from Earth at L1.

28  

Examples of technological advances used in the design of these new radiometers include (1) positive temperature coefficient thermistors that achieve order-of-magnitude sensitivity determination of cavity temperature compared with the normally used platinum resistance wire; (2) AC bridge circuitry that minimizes noise by isolating the frequency of the measured signals; (3) stable phosphorous nickel surface coatings that maximize optical electrical equivalence; and (4) diamond turned apertures and precision optical aperture area determinations.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

The interplanetary environment is a highly turbulent medium that supports a great variety of wave motions. Shocks, discontinuities, and small-scale structures such as “magnetic holes” (in which the magnetic field nearly vanishes) are often present. A fast sampling (≈1-sec time resolution) such as would be provided by the Plasma-Mag solar wind instruments on Triana could be useful for further progress on these problems.29 For example, high-time-resolution measurements may help researchers better understand the wave damping and heating of particles expected to take place near the proton cyclotron frequency. Such measurements are likely to be useful to properly characterize discontinuities and shocks in the solar wind. High-time-resolution plasma data will enable studies of the smaller magnetic hole structures that have frequently been observed at lower time resolutions.30

Solar wind and magnetic field observations from Plasma-Mag will be valuable in studies examining a variety of large-scale structures such as the shocks, current sheets, and magnetic clouds often associated with coronal mass ejections. With a constellation of four spacecraft (Triana, ACE, WIND, and STEREO) separated by large distances (on the order of 200 Earth radii), the geometry of relatively stable structures in the near-Earth space environment can be determined. This configuration of four spacecraft will also enable determination of, for example, the size and configuration of larger magnetic holes and would allow multi-spacecraft studies of the geometric configurations and structures of coronal transient related disturbances.

The Plasma-Mag on Triana at L1 is designed to provide in near real time and on a continuous basis the primary set of measurements required by the Space Environment Center of NOAA to monitor and forecast Earth 's solar environment and provide accurate, reliable, and useful warnings of solar-terrestrial interactions. The required primary measurements are the solar wind plasma ion density, velocity, and temperature, and the magnetic field vector in standard coordinates. The required time resolution is 1 minute or faster. The Plasma-Mag instrument package is intended to take the measurements and compute on-board averages of solar wind and magnetic field parameters in real time once per minute. The launch of Triana in 2001 or later will provide overlap with ACE for many years, allowing for cross-calibration. The availability of real-time solar wind data from L1 spacecraft at two separate points in space would enhance the reliability of detecting the geoeffectiveness of disturbances not directly on the Sun-Earth line by providing additional information about the irregularities in the solar wind.

Data Products

The main advantage of Triana is that it will view the full sunlit disk of Earth, continuously and synoptically. The technique employed by EPIC (of combining a telescope with a CCD camera) allows particularly high spatial resolution considering the L1 vantage point. For stratospheric and upper-atmosphere studies based on total ozone column data, EPIC 's 8-km spatial resolution at nadir (and up to 14 km at the highest usable viewing angle) is far superior to that available for UV channels on the Total Ozone Mapping Spectrometer (TOMS) (≈ 80 km) (which uses a scanning spectrometer and photomultiplier in LEO). Coupled with the monitoring of diurnal variations obtained from L1, EPIC's 8-km spatial resolution will permit preliminary studies of stratospheric processes at time and space scales not resolved thus far with LEO satellites. The 8-km spatial resolution is also sufficient for lower-atmosphere studies of aerosol optical depth, precipitable water, and clouds (with some caveats as discussed below) but is much less optimal for surface process investigations. For surface processes the main advantage is the observation geometry, the so-called hot-spot view, which is rarely realized from other spacecraft and thus offers new opportunities, in particular for studying canopy properties.

Table 2 lists the data products that the Triana mission is intended to deliver in quasi-real time. Most algorithms needed to produce the EPIC and Plasma-Mag data have notable heritage, with some algorithms more mature than others. For instance, in the case of total column ozone measurements, the TOMS heritage is significant,31 and if the

29  

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.

30  

Burlaga, L.F., “Micro-Scale Structures in the Interplanetary Medium,” Solar Physics 4:67, 1968. Burlaga, L.F., and N.F. Ness, “Macro- and Microstructure of the Interplanetary Magnetic Field,” Can. J. Physics 46:S962, 1968. Fitzenreiter, R.J., and L.F. Burlaga, “Structure of Current Sheets in Magnetic Holes at 1AU,” J. Geophysics Res. 83:5579, 1978. Turner, J.M., L.F. Burlaga, N.F. Ness, and J.F. Lamarie, “Magnetic Holes in the Solar Wind,” J. Geophysics Res. 82:1921-1924, 1977.

31  

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

EPIC instrument functions according to specification, total column ozone should be a relatively straightforward data product for the Triana team to deliver from the start of the mission. On the other hand, in the case of aerosol optical depth estimation based on a ratio of UV radiances, the algorithm is less mature and has limited documentation. Some adjustments are likely to be necessary after launch, particularly over bright surfaces or at high viewing angles (e.g., arctic). So, while it can be expected that the generation of most data products will be achieved to a scientifically useful accuracy, the accuracy of some data products is expected to be higher than that of others. NISTAR in contrast is a new instrument, so that significant algorithm development, testing, and validation are needed to enable processing of its raw data into useful information. The relationship between the accuracy of the derived data products and the accuracy of the raw data is unclear.

To take full advantage of the new opportunities offered by Triana requires special attention to the accuracy and stability of the NISTAR and EPIC instruments. The accuracy will be obtained through on-board calibration of the instruments. For instance, NISTAR is a self-calibrating instrument by virtue of multiple redundant filters, an unfiltered absolute radiometric channel, and inter-calibration of EPIC with other spaceborne instruments, while EPIC stability will be assessed through monthly monitoring of the back side of the Moon. The level of accuracy to be achieved from inter-calibration is difficult to assess since most of the other instruments with which EPIC will be inter-calibrated are themselves poorly calibrated (e.g., the Advanced Very High Resolution Radiometer [AVHRR], the Visible Infrared Spin-Scan Radiometer (VISSR) on the U.S. Geostationary Meteorological Satellite [GOES]). The innovative and particularly attractive approach of using the Moon for performing instrument in-flight stability assessment appears to have been very well thought out, but operational experience may lead to refinements in the techniques with time.

With regard to the generation of atmospheric data products besides ozone (aerosol optical depth, total precipitable water), one issue of concern is the determination of cloud data in pixels that are only partially cloudy across their areas. The accuracy of the retrieved parameters will depend on the quality of the scene determination in cloud-free pixels. Cloudy pixel determination will be achieved using the commonly applied radiance threshold method. With relatively small pixels (≈1 km), such as those from AVHRR or the Moderate Resolution Imaging Spectroradiometer (MODIS) for instance, the cloud/clear distinction is relatively straightforward. However, it becomes more difficult as the spatial resolution decreases (i.e., the size of the pixels increases). Due to the typical cloud size, an 8-km pixel is more likely than a 1-km pixel to be partially cloudy. A lower threshold value will ensure that no clouds (or at least few clouds) are present and is likely to produce more accurate data, but it will limit the number of pixels usable in retrievals of geophysical data. A higher threshold will allow more partly cloudy pixels to be included, but will induce a reduction in the accuracy of the parameter retrieved. Also, since the Triana observations are made at high scattering angles (between 140 and 160º), the computed threshold value will have to account for this scattering angle. This means that thresholding algorithms developed for other instruments such as AVHRR and MODIS will need to be adjusted to the EPIC spatial resolution and observation geometry, and their performance evaluated. Some guidance could be obtained from the work done with the Polarization and Directionality of Earth 's Reflectances (POLDER) instrument,32 which has a similar resolution. This, however, suggests that the heritage from other sensors for cloud detection will not be directly applicable and that a significant amount of work will have to be done both before and after launch to adjust for the EPIC instrument and Triana viewing characteristics.

Another issue of concern is estimation from NISTAR and EPIC of Earth 's albedo. Because albedo concerns solar radiation reflected in all directions from the whole Earth disk, it cannot be measured directly from a look in a single direction. Extrapolating the data from one direction to others requires coming up with an angular distribution model that essentially transforms measurements from one direction into another. Such a model varies with surface type. EPIC data will be used to assign each pixel of the Earth disk to a particular surface type (cloud, water, vegetation, and so on). Given the surface type and the imaging geometry, a weight representing the angular distribution model will be assigned that accounts for the directional effects, and the weights will be aggregated to provide whole-Earth albedo. Angular distribution models can be built from the observations of other instruments (e.g., Clouds and Earth's Radiant Energy System [CERES]). The procedure employed is rather complex—since it

32  

The instrument will observe from space the polarization, and the directional and spectral characteristics, of solar light reflected by the Earth-atmosphere system.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

uses a combination of measurements from NISTAR, EPIC, and CERES, for instance, to build the albedo of the sunlit side of the planet —and will likely need some testing and adjustment.

For the concerns raised here, it is not the possibility of producing excellent data sets that is in question, but rather the level of effort that will be required to do so. Indeed, for the Triana mission to produce useful geophysical parameters will require that great care be taken in the development, testing, and validation of the operational algorithms. The expected resources needed for these functions are inconsistent with the current, very limited, level of effort to support development of these algorithms. In view of the extremely short time frame of the mission and the necessary algorithm adjustments alluded to above, substantial work on the data reduction algorithms should start immediately. Operational algorithms can take a long time to implement and fully test. 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 as soon as possible the level of effort invested in development and testing of data reduction algorithms for the core Earth data products. The more research-oriented data products can and will take more time to produce and test, and that is entirely acceptable. The Plasma-Mag algorithms have a long heritage and have been well proven; it is just a matter of transferring them to operational algorithms. Although this effort should not be neglected, it should require much less investment than that needed for the EPIC or NISTAR algorithms, data reduction, and analysis effort.

  1. Does Triana Enhance or Complement Other Missions Now in Operation or in Development?

The Triana science team asserts that, in addition to providing unique capabilities for remote sensing observation of Earth, Triana will enhance and complement other missions because of its L1 vantage point for continuous imaging of the full sunlit disk of Earth. The task group generally supports this view, although the nature and extent of enhancement will likely vary among the instruments. Many of the details of the complementary nature of Triana are discussed in the preceding sections.

Interactions with Earth-viewing missions at LEO and GEO will extend in time and coverage, and in accuracy through cross-calibrations, the data quality and value of all of the missions. For example: (1) EPIC will significantly extend TOMS, which samples data once a day at local noon at a nadir resolution of 80 km, to a near-continuous sampling at a nadir resolution of 8 km; (2) EPIC will also enhance the temporal coverage of MODIS, which, unlike Triana, covers the entire Earth's surface but does so every 1 to 2 days; (3) EPIC and the Multi-angle Imaging Spectroradiometer (MISR), POLDER, and the Along Track Scanning Radiometer (ATSR-2) fill in angular space for each other; (4) NISTAR augments CERES with continuous planetary albedo near 180º backscatter in similar spectral bands; and (5) Triana complements GEO satellites with high-latitude observations, although the utility of the data near the fringe of the disk is somewhat questionable.

Triana's synoptic view of Earth will help to put localized, ground-based, and airborne field observations into a global context. For example, measurements of tropical cirrus cloud microphysics and radiation during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) campaigns, planned for 2002 and 2004, can be correlated with concurrent observations by Triana at L1. Work at Department of Energy-Atmospheric Radiation Measurement (DOE-ARM) sites also, for example, will benefit from such correlative observation.33

Triana will also augment existing Sun-viewing satellites at L1. Plasma-Mag will enhance the time resolution and spatial coverage of solar wind data from WIND and ACE. It will complement, and may succeed, ACE in operational utility.

In turn, Triana will benefit from the presence of other satellites. Data from instruments with higher spatial resolution such as MODIS and the Sea-Viewing Wide Field Sensor34 (SeaWiFS) will improve EPIC data, especially aerosols, and add new information about cloud properties. Triana's in-flight validation should benefit from the calibration heritage of TOMS and MODIS. Radiation fields observed by CERES can be directly compared with NISTAR data.

33  

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 a pdf file.

34  

It provides global estimates of oceanic chlorophyll-a and other bio-optical quantities to the international research community.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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SUMMARY

The task group's assessment of Triana's scientific objectives and goals is based on its review of the relevant literature and presentations regarding the proposed scientific mission. The task group found that (1) 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; (2) if successfully implemented, the planned measurements will likely contribute to Triana's stated goals and objectives; and (3) the Triana mission will complement and enhance data from other missions now in operation or in development 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. Nevertheless, the task group 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 and ensure that all the appropriate technical and management reviews are performed. In addition, 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.

More specifically, the task group found that the scientific objectives and deliverable data products of the Triana mission as described by NASA's Triana science team are consonant with science strategies and priorities proposed by various NRC and government reports, as summarized in Table 2 of this report. The task group notes that Triana's primary focus is technique and technology development at L1, as the Pathways report recommended for future Earth Science System Pathfinder missions, rather than any one specific scientific problem. The task group concluded that the mission, if successfully implemented, is likely to achieve the stated goals and objectives, although as in most exploratory missions there can be no assurance of success. A detailed analysis of instrumentation, data collection and reduction, systems operations, management, cost, and risk was beyond the scope of the charge to this task group. However, it was impressed by the detailed efforts of the Triana science team and their extensive use of heritage technology and data reduction algorithms where they were available.

The task group found that the Triana mission will complement and enhance other missions because of the unique character of measurements made from the L1 point, which allow continuous imaging of the full sunlight disk of Earth and monitoring of solar wind properties relevant to space weather. Furthermore, such observations from L1 should provide a unique perspective to develop new databases and validate and augment existing and planned global and local interplanetary databases.

Triana is an exploratory mission that may 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 well have been viewed as an earlier NASA priority had adequate technology been available at reasonable cost.

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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4.2 Continuing Assessment of Technology Development in NASA's Office of Space Science

On March 15, 2000, Board Chair Claude R. Canizares and Task Group Chair Daniel J. Fink sent the following letter report to Dr. Edward J. Weiler, NASA's Associate Administrator for Space Science.

In your letter of February 17, 1999,1 you requested that the Space Studies Board (SSB) provide an external review of the Office of Space Science (OSS) technology development process. As requested, the review focused on assessing the OSS response to the recommendations in the SSB report Assessment of Technology Development in NASA's Office of Space Science (National Academy Press, Washington, D.C., 1998). The SSB established the Task Group on Technology Development in NASA's Office of Space Science (OSS) (task group),2 drawing heavily on individuals who developed the 1998 report, to conduct this assessment.3 The task group met on October 18 and 19, 1999, at the National Research Council's Georgetown offices in Washington, D.C. It received presentations by Edward Weiler (Associate Administrator, Office of Space Science), Granville Paules (Lead Technologist, Earth Science Enterprise), Arnauld Nicogossian (Associate Administrator, Office of Life and Microgravity Sciences and Applications), Peter Ulrich (Director, Advanced Technologies and Mission Studies Division, Office of Space Science), Michael Sander (Director, Technology and Applications Program, Jet Propulsion Laboratory), Mary Kicza (Associate Director, Goddard Space Flight Center), and William F. Dimmer (Program Analyst, Office of the Chief Financial Officer).

SUMMARY OF THE 1998 REPORT OF THE TASK GROUP ON THE TECHNOLOGY DEVELOPMENT IN NASA'S OFFICE OF SPACE SCIENCE

In the 1998 report, the task group recognized the transfer of NASA 's cross-agency technology function to OSS as a positive step for two reasons: (1) Programs under OSS are the largest consumers of space technology, and (2) OSS has a well-developed strategic planning process. NASA has grouped technologies with application to more than one enterprise under the label “Cross-cutting Technologies,” and these are also managed by OSS. In the 1998 report, the task group noted that the planning for the Cross-cutting Technology Program had not matured to a satisfactory level.

The task group also was concerned with NASA's definition of core competencies. Some NASA Centers claim that their competencies cover an extensive and broad range of technologies. No organization that has realistic fiscal constraints can hope to be competitive or world-class across such a wide range. The task group recommended that NASA narrow the core competencies to those that meet stringent criteria. Thus, individual NASA Centers would not have active programs in all technologies relevant to the mission requirements of the Center. The task group recommended that NASA explore alternatives to maintaining in-house, hands-on research and development programs to achieve smart buying.

To be successful, an advanced technology development (ATD) program should be a careful mix of centralized and decentralized activities. For NASA this means appropriate roles for Headquarters and the Centers. The task group recommended in the 1998 report that the planning and selection processes be maintained as Headquarters activities. Other activities, such as selection of near-term technologies for a particular mission, could be delegated to the Centers when they are not competing for these technology development activities.

Many of the recommendations in the 1998 report called for external review and advice, including planning, program reviews, evaluation of competing proposals, core competency selection, and Center quality review. Providing adequate Headquarters staff to manage the reviews, utilizing clear investment and performance metrics, and making Centers more accountable to Headquarters are essential elements of the review process.

1  

See Appendix 1.

2  

Task group membership: Daniel J. Fink, Chair (D.J. Fink Associates, Inc.), Robert S. Cooper (Atlantic Aerospace Electronic Corp.), Anthony W. England (University of Michigan), Donald C. Fraser (Boston University), Bruce D. Marcus (Consultant), Irwin I. Shapiro (Harvard-Smithsonian Center for Astrophysics), and Oswald Siegmund (University of California, Berkeley).

3  

The task group's assessment was reviewed by individuals other than the authors in accordance with procedures approved by the National Research Council 's Report Review Committee. See Appendix 2.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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RESULTS AND ASSESSMENT BASED ON THE 1999 REVIEW

The original report (Assessment of Technology Development in NASA's Office of Space Science, 1998) was organized into four main parts—planning, implementation, infrastructure, and performance measurement —and made 11 recommendations. The task group has chosen to retain this organization here. Each of the previous 11 recommendations is reprinted below, followed by a summary of and comments on NASA's progress in each area and further recommendations where warranted. The summary sections are based on the presentations made to the task group at the October 1999 meeting.

A. Planning

Recommendation 1. NASA's advanced technology development (ATD) planning process should be formally evaluated in 12 months, after changes that are just now being completed have had time to mature. Factors to be considered in the evaluation should include (1) responsiveness to input from the outside research community and (2) the extent to which program balance is addressed regarding such dimensions as technology push versus program pull, near-term versus far-term applications, and science instruments versus spacecraft systems. The evaluation should be conducted by an independent, external body such as the NASA Advisory Council. [1998 Assessment, p. 14]

Summary of NASA's Presentation to the 1999 Task Group

In response to the task group's recommendation and at the request of NASA's Space Science Advisory Committee (SScAC), OSS assembled the Task Force on Technology Readiness4 to provide findings and recommendations on OSS's current technology planning process to ensure appropriate linkage between science missions and technology opportunities and to ensure cross-theme coordination of technology requirements. Specifically, the OSS Task Force addressed four questions in 1999:

  1. Have missions for the near-term and visions for the far-term been articulated sufficiently to derive technology objectives and capabilities?

  2. Have technology objectives for near-term and technology capabilities for far-term been described appropriately from missions and visions?

  3. Have technology objectives and capabilities been well integrated across the four science themes into a single set of technology developments?

  4. Is the technology development currently planned in various program elements (core, focused, flight validation, advanced concepts, and cross-enterprise) appropriately scoped, scheduled and funded to satisfy the strategic missions and visions of the Space Science Enterprise?

NASA has produced integrated technology development plans for enabling technologies. These plans will be incorporated into the OSS strategic plan for FY 2000. The OSS Task Force will be augmented to provide an external review of the technology program during February/March 2000.

Extensive work has been completed by the science and technology roadmap teams with respect to the Focused Technology Program. The new process involves considerable external input and was reviewed at the OSS Strategic Planning Workshop in November 1999. NASA has devised an approach to restructure the New Millennium Program (NMP). If recent program termination decisions are reversed, there will be open competition for technologies to be flown, and Headquarters will make the final selections of Centers to which missions are assigned.

NASA reported that most in-house FY 2000 cross-enterprise activities have been competitively peer reviewed for quality and the relevance of the proposed tasks to NASA's mission. In FY 2001, NASA expects to com-

4  

OSS Task Force membership: Christine M. Anderson, Co-Chair (Phillips Laboratory), Daniel E. Hastings, Co-Chair (Massachusetts Institute of Technology), David Akin (University of Maryland), Thomas A. Brackey (Hughes Space and Communications Co.), Lynn Conway (University of Michigan), Dennis Fitzgerald (National Reconnaissance Office), Gordon P. Garmire (Pennsylvania State University), Edward Howard (NOAA), Kenneth Johnston (U.S. Naval Observatory), Ralph L. McNutt, Jr. (Applied Physics Laboratory), and David Miller (Massachusetts Institute of Technology).

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

petitively peer review all thrust areas. The peer review panels consisted of extramural technology experts and user representatives. NASA panelists (58 out of 153 panelists) were involved chiefly to deal with the issue of relevance. Of the 567 proposals submitted, 264 were selected for funding. Depending on the thrust area, this represents 19 to 67% new work by task, averaging 44%. The first NASA Research Announcement (NRA) for the Cross-Enterprise Technology Development Program was released on October 29, 1999. This NRA provides for an open and broad competition in which NASA Centers can participate.

Task Group's Assessment

The task group found excellent responsiveness on the part of OSS to the task group's 1998 technology planning recommendations. Within OSS the process whereby technology plans are being linked with science objectives and program plans may well be a model of excellence in strategic planning. In addition, the task group lauds the progress (e.g., the number of new tasks funded) toward an objective and impartial technology program selection process administered at the NASA Centers. NASA's report that Center tasks were competitively peer reviewed during the FY 2000 selection process reflects a very positive change.

When applied to technology tasks, the concept of competitive peer review must be broadened to include not only peer experts in the specific technologies being addressed, but also expert engineering generalists who can provide a broad perspective on the overall relevance of technology development proposals to NASA's future needs. In addition, competitive peer review of NASA in-house Cross-Enterprise Technology Development Program activities should be conducted by experts both inside and outside the centers.

The task group supports the change in the NMP that refocuses it on flight demonstration of critical new technologies and applauds NASA 's intention to use flights of opportunity rather than exclusively dedicated flights. The division between OSS and Earth Science Enterprise (ESE) New Millennium missions could be misinterpreted as giving a science (rather than technology) objective to NMP. The task group understands it to be a budget convenience but hopes that this artificial division does not inhibit flying critical ESE technologies on OSS New Millennium missions, or critical OSS technologies on ESE New Millennium missions where it makes technical sense to do so.

The task group also would expect that using any flight opportunity includes “purchasing” demonstration rights on the science missions of OSS and ESE, if inclusion would not add significantly to the risk of mission failure. Subsidizing the use of new technologies on science missions even though the enhanced capabilities of the new technologies are not needed could be appropriate where flight validations of the new technologies have significant value for future missions. For example, it might prove a wise investment to use a new technology communication system that will be needed for future deep-space science missions on a low-cost near-Earth spacecraft even though the capabilities of the enhanced communications system are not needed on the near-Earth mission. In this case, the added cost of the new communications technology should not be charged against the near-Earth spacecraft, but could be borne by a flight validation effort such as the New Millennium or Focused Programs. However, the validation of flight hardware on such science missions must be balanced against possibly increased mission risk.

Before the Space Science Program budgets were augmented to do technology development and before the Advanced Concepts Program was started, the Cross-Enterprise Technology Development Program spanned Technology Readiness Level (TRL) 1-5. The Research and Analysis Program had some technology components that were far term and the NMP was expected to do technology development, although there was no money in the program to do so. Today, the Advanced Concepts Program addresses TRL 0-2. The Cross-Enterprise Technology Development Program addresses TRL 1-3 and ramps down with co-funding from the Focused Programs that fund TRL 3-6. The Research and Analysis Program still has far-term technology components. One of the objectives of the New Millennium Program is to take technologies to flight qualification. However, the space sciences portion of the NMP was terminated, and unless it is restored there will be no program dedicated to flight qualifications of technology. The portfolio mix of near-term versus far-term technology development remains of some concern to the task group, but appears to be moving in the right direction with the “visionary” pull for far-term efforts and use of strategic plans for near-term needs.

The task group views the technology development budget increase in FY 2000 as a very positive step, although budget earmarks will place constraints on NASA's ability to deploy those funds optimally for technology development.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

Recommendation 2. The planning process for cross-cutting technology should be modified so that it mirrors the process used by the Office of Space Science for space science technologies. Key attributes are the use of technology roadmaps that are linked to enterprise science roadmaps and that are developed with the broad participation of the research community. [1998 Assessment, p. 14]

Summary of NASA'S Presentation to the 1999 Task Group

Each science theme in OSS has developed a far-term vision to guide far-term technology. NASA reported that the Cross-Enterprise Program is now 100% competitively peer reviewed for quality and relevance, as discussed under 1998 Recommendation 1. Newly designated NASA Center thrust area managers (TAMs) have been able to exert NASA-wide perspective and management approaches and have acted in a non-parochial manner in their recommended funding allocations among NASA Centers. One example of this is that in 7 out of 10 cases, the funding to the Center where the TAMs worked decreased from FY 1999 to FY 2000. NASA reported that there is wide management support at all levels for open and broad competition for funding. In FY 1999, $6 million in Cross-Enterprise funds was allocated through the Explorer Technology NRA. The first Advanced Cross-Enterprise Technology Development for NASA Missions NRA was released October 29, 1999.

Task Group's Assessment

The task group agrees with NASA that considerable progress has been made in responding to 1998 recommendation 2. The restructuring of the cross-cutting technology program is moving in the right direction. The ESE has made excellent progress in linking technology planning and strategic planning. However, the task group did not see evidence of similar progress in the Office of Life and Microgravity Sciences and Applications and encourages it to make renewed efforts. The Cross-Enterprise Technology Program NRA is seen as a positive step by the task group. The TAMs have the potential to be effective extensions of Headquarters in enabling NASA's responses to several of the task group's past concerns (see also 1998 Recommendations 4 and 6). The task group believes that the TAMs' assignments and responsibilities should be formalized as an indication of their importance.

B. Implementation

Recommendation 3. NASA should establish a comprehensive Center evaluation process that includes regular, objective, external evaluations of core competencies. Those internal core competencies essential to achieving a Center 's mission should be identified and appropriate recommendations made to achieve and maintain excellence. As a result of these evaluations, NASA will have to make difficult choices about limiting internal research emphasis in some areas. External organizations with world-class capabilities should be selected competitively to complement the in-house work and ensure the maintenance of NASA's centers of excellence. ATD funds should not be set aside to provide support for in-house capability but should be earned by Centers through open competition with outside organizations. [1998 Assessment, p. 21]

Summary of NASA's Presentation to the 1999 Task Group

It is unfortunate that the task group, despite ample notification, could not receive any response from Headquarters regarding the agency response to recommendation 3 on the treatment of core competencies. The task group understands that the action had been assigned to the Office of the Chief Engineer, but a scheduling conflict apparently prevented a representative's attendance at the task group meeting. The task group did hear views from the Goddard Space Flight Center and the Jet Propulsion Laboratory and, while these presentations were interesting, there was no evidence of agency-wide guidance or direction to the process of selecting (and de-selecting) and maintaining core competencies. Goddard Space Flight Center's core competencies are defined as “those capabilities in which Goddard must excel and that must reside within the civil service workforce and facilities to achieve the mission of the Center.” Goddard's view is that it should have a core competency in a particular area if: (1) the capability is necessary to fulfill its mission and does not readily exist elsewhere, (2) having the capability is a necessary element within the larger NASA context and it does not readily exist elsewhere, or (3) having breadth and/or depth of a capability is essential to meeting Goddard 's customers' requirements. Goddard is emphasizing its

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

core competencies in the areas of experimental and theoretical research, sensors, instruments, and associated technologies, end-to-end mission systems engineering, advanced flight and ground systems development, large-scale scientific information systems, and program and project management. It is also competing for opportunities to establish competence in astrobiology.

JPL's core competencies are driven by its agency and enterprise assignments and strategic plans. It has program roles and responsibilities that contribute to three NASA strategic enterprises: OSS, ESE, and Human Exploration and Development of Space (HEDS). There are eight existing core competencies at JPL and three additional ones needed for the future. The existing core competencies include (1) complete-life-cycle deep-space missions design and architecture, (2) system engineering, (3) micro- and nano-technology for flight systems, (4) deep-space navigation, (5) deep-space communications, (6) mobility systems for planetary missions, (7) advanced science instruments, and (8) autonomous systems for deep-space systems. JPL would like to add large real and virtual space apertures, astrobiology, and planetary protection as future core competencies.

Task Group's Assessment

The task group views core competencies as central to implementing an effective ATD plan across the NASA Centers. The task group also recognizes that the issue of core competencies goes beyond the authority of OSS alone and must be addressed on a NASA-wide level.

Having now heard from several of the Centers on this subject, the task group finds little consistency in the selection processes or the criteria used to select the Center core competencies required to pursue NASA's mission. That mission includes the preservation of U.S. leadership (not just NASA leadership) in space science and technology. Thus the selection of NASA's core competencies must be made with a sense of responsibility to the nation's technological health and not just to the “care and feeding” of NASA Centers. It is natural that individual Centers might emphasize the latter, which is one reason that a Headquarters-led (with major Center participation) effort should be made in defining and locating NASA's internal core competencies.

An approach to the problem can be gleaned from a paper by Quinn and Hilmer,5 who use a classical “nine-block” to develop a matrix for selecting core competencies versus those that could be outsourced. Their criteria include industrial measures such as competitive edge versus strategic vulnerability. Such an approach can be modified to make judgments about NASA's core competencies. For example, Figure 1 shows a matrix whose axes now represent the potential for state-of-the-art advancement versus the depth of external capability. Every technology can be placed somewhere on that matrix. Those that have a very high potential and for which the external (to NASA) capability is very low are clearly candidates for a NASA core competency. In contrast, those technologies that are mature and widely available externally can be purchased virtually as “commodities.” Those with a high potential for advancement that are also widely available could be candidates for strategic purchasing requiring a “smart buyer.” There are many shades of gray in the matrix, all of which can be used to sharpen core competency selection. The task group shows this example not as a final solution, but as an illustration of an approach that could be used across NASA to select Center core competencies.

The task group strongly recommends that Headquarters, working with the Centers, take the issue of core competency seriously. At a time of shrinking budgets yet great opportunity to raise the technology level of our nation's space program, selection of the proper NASA Center core technologies with full knowledge of what capability is important and what is available in industry and academia will be a requirement for success.

Recommendation 4. With the support of external reviewers, NASA Headquarters should conduct make-or-buy decisions and competitive procurements for all long-term ATD. [1998 Assessment, p. 22]

Summary of NASA's Presentation to the 1999 Task Group

NASA reported that 1998 recommendation 4 is impractical, given the reduction in Headquarters staffing and transfers of responsibility to Centers. However, Headquarters has retained the role of formal selection official. The roles of Headquarters and Centers have been clarified in key areas such as the New Millennium, Cross-Enterprise

5  

James Brian Quinn and Frederick G. Hilmer, 1994, “Strategic Outsourcing,” Sloan Management Review, Figure 2, page 24.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

FIGURE 1 Sample matrix for selecting core competencies. Adapted from Quinn and Hilmer, 1994.

Technology Development, and Focused programs. For the New Millennium Program, Headquarters selects the technology, mission, and implementing Center. For the Cross-Enterprise Technology Development Program, Headquarters determines allocations to each thrust area, and the TAMs perform as an extension of Headquarters. For the Focused Programs, Headquarters periodically evaluates programs and projects, specifically make-or-buy decisions, as a part of program and project reviews.

Task Group's Assessment

Despite the “impracticality” of the task group's recommendation, it does appear that NASA is making considerable progress in satisfying the intent of the recommendation. It is clarifying the roles of Headquarters and the Centers, retaining certain important decisions at Headquarters, and expanding the “reach” of Headquarters through the effective use of the TAMs. In addition, the recent hiring of two additional senior staff at Headquarters should help considerably in leveling the workload. The effectiveness and clarity of the relative roles of Headquarters and the Centers in the make-buy process should become evident over the next year and should after that time be examined closely and evaluated by the task group.

Recommendation 5. For near-term technology development needed to support ongoing programs already under the direction of a particular Center, that Center should conduct make-or-buy decisions. However, if the Center decides to buy, then NASA should avoid real or perceived conflicts of interest by either administering the competition and external review from Headquarters or excluding from the competition all in-house organizations located at that Center. A Center decision to “make” should have Headquarters concurrence. [1998 Assessment, p. 22]

Summary of NASA's Presentation to the 1999 Task Group

Center-led processes are proposed, approved, and reviewed by NASA Headquarters.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×
Task Group's Assessment

NASA described a process that now captures the spirit of the 1998 recommendation, and the task group is satisfied with the implementation of this recommendation.

Recommendation 6. NASA should ensure that adequate resources, especially personnel, are available for Headquarters to organize, conduct, and respond to the needed number of external reviews to support competitive ATD procurements. [1998 Assessment, p. 22]

Summary of NASA'S Presentation to the 1999 Task Group

The appointment process is under way for NASA to finish hiring at Headquarters two new staff members at the Senior Executive Service level. NASA also reported that the TAMs are functioning effectively as extensions of NASA Headquarters.

Task Group's Assessment

The task group endorses NASA's efforts to fill two new positions and agrees that the description of the TAMs' role is appropriate. The TAMs are located at Centers but have job descriptions similar to those of NASA Headquarters program managers. Their performance is monitored by Headquarters, especially the parochial or non-parochial nature of their decisions. Headquarters is also involved in their performance evaluations.

C. Infrastructure

Recommendation 7. NASA should foster increased workforce mobility among Centers and between NASA and industry, universities, and other government agencies to facilitate the transfer of information, obtain fresh points of view, and maintain the expertise of its workforce. Expanded use of Intergovernmental Personnel Act (IPA) exchanges and cooperative agreements should be considered to facilitate these efforts. [1998 Assessment, p. 25]

Summary of NASA's Presentation to the 1999 Task Group

NASA reported that it is continuing the effort to increase workforce mobility. However, it has found this recommendation difficult to implement given employees' personal constraints, cost of living inequities, and other government restrictions. IPAs generally involve relocation and disruption of families for a three-year period or more and, thus, it is difficult to attract people to these positions.

Task Group's Assessment

The task group recognizes the difficulty in implementing this recommendation but believes that NASA has the ability to do more. There remains a need to encourage identification of alternative approaches to ensuring that Centers can be “smart buyers.” The smart-buyer argument should not be used to maintain unnecessary competency at the Centers. NASA routinely uses IPAs to operate its science programs. However, IPAs have not been effectively used to provide transfer of information into the technology programs. The task group continues to encourage NASA to expand its use of IPAs and other cooperative agreements at Headquarters and at the Centers, specifically to transfer technology information (or expertise) into NASA technology programs.

Recommendation 8. NASA should take prompt action to re-staff the Office of the Chief Scientist. [1998 Assessment, p. 25]

Summary of NASA's Presentation to the 1999 Task Group

Dr. Kathie Olsen was appointed as NASA Chief Scientist on May 24, 1999.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×
Task Group's Assessment

The task group commends NASA for filling the position of Chief Scientist. This position provides NASA Headquarters an important focus for evaluating the progress of technology investment in strengthening the nation 's science investment. A first step toward this might be a standing committee organized by the Chief Scientist to assess the progress in important technologies for OSS and other science programs defined by the roadmaps. If the Centers are to have essentially non-overlapping responsibilities in the development of new technologies, then it is essential that Headquarters management understand the status of the various projects to balance funding allocations in a manner that achieves a maximum number of significant enhancements to the science missions.

Recommendation 9. Full-cost accounting is essential to effective management of ATD programs, and NASA should provide sufficient resources to complete and implement a full-cost accounting system. NASA should also determine how it will address workforce issues that may be raised when funding allocations are guided by full-cost accounting and organizational excellence, as determined through full and open competition. [1998 Assessment, p. 26]

Summary of NASA's Presentation to the 1999 Task Group

Acting on this recommendation goes beyond the authority of OSS alone. NASA reported that it is making progress on implementing a full cost management system and that the FY 2002 budget will be the first to include it.

Task Group's Assessment

The task group realizes that 1998 recommendation 9 goes beyond the authority of OSS. But it also believes that full cost accounting is necessary to permit proper program management and will revolutionize the way NASA does business. The lack of full cost accounting makes it difficult to accurately determine and compare the costs of different programs. As pointed out in the task group's 1998 report, without accurate fiscal data about funds allocations and program costs, it is impossible for NASA to make informed judgments about Center roles, make-orbuy decisions, or contract awards for competitive procurements that include NASA Centers. However, the task group was encouraged to see that NASA's efforts to implement full cost accounting appear to be nearing fruition and that they are projected to be completed by FY 2002.

D. Performance Measurement

Recommendation 10. NASA should identify performance measurement approaches (including independent external reviews) and metrics (including adequate investment data) needed to effectively manage its ATD programs. The findings and recommendations of external reviews of the Centers should be reported to Headquarters as well as to senior Center management. Investment data should cover the current program, and these metrics should be tracked for future use. [1998 Assessment, p. 26]

Summary of NASA's Presentation to the 1999 Task Group

NASA reported that the annual technology inventory has been greatly improved and is available online. It provides quantitative information on resource allocations to each technology area. External reviews were cited for all major program elements, including the New Millennium Program, the Cross-Enterprise Technology Development Program, and the Focused Programs.

Task Group's Assessment

The task group recognizes that NASA is increasing the level of technology and programmatic external reviews. However, based on material presented to the task group there appears to be little change in Center external reviews. The task group has seen no evidence of Headquarters leadership or interest in the Center review process. There is no coordinated and consistent process for Center review. Each Center has developed its own method of review. In

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

some cases, their customers are reviewing Centers. These customer reviews do not equate to impartial external reviews. NASA might find value in benchmarking against some of our leading industrial organizations.

Recommendation 11. To ensure accountability, NASA should formally respond to the recommendations contained in this task group report. Regular status reports should be made to external bodies, such as the NASA Advisory Council. [1998 Assessment, p. 28]

Summary of NASA's Presentation to the 1999 Task Group

NASA is adopting this recommendation by reporting regularly to the NRC task group, the OSS Task Force on Technology Readiness, and the Space Technology Management Operations Working Group.

Task Group's Assessment

The task group has a very positive reaction to NASA's and OSS's efforts.

Signed by

Claude R. Canizares, Chair

Space Studies Board

Daniel J. Fink, Chair

Task Group on Technology Development in NASA's Office of Space Science

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

4.3 Scientific Assessment of Exploration of the Solar System—Science and Mission Strategy

On April 21, 2000, Space Studies Board Chair Claude R. Canizares and Committee Chair John A. Wood sent the following letter report to Carl Pilcher, NASA's Science Program Director for the Solar System Exploration Division.

In your letter of January 18, 2000, you reiterated a verbal request made in November 1999 for the views of the Space Studies Board's (SSB's) Committee on Planetary and Lunar Exploration (COMPLEX) on a number of issues concerning the Science and Mission Roadmap1 recently prepared as part of the Solar System Exploration science theme's contribution to strategic-planning activities conducted by NASA's Office of Space Science. In particular, you asked that COMPLEX provide you with the following:

  • Perspectives on the degree to which the Roadmap addresses the priorities outlined in past COMPLEX reports; and

  • Recommendations for strengthening the scientific rationale and mission priorities contained in the Roadmap.

COMPLEX understands that you need this assessment because the Roadmap, an integral part of the Office of Space Science's new strategic plan, is currently undergoing revision prior to publication.

Work on this assessment began at COMPLEX's November 1-5, 1999, meeting at the Arnold and Mabel Beckman Center in Irvine, California, and was conducted in parallel with the preparation of the committee's input to an SSB-wide assessment of the strategic plan resulting from the Office of Space Science's Strategic Planning Workshop held in Galveston, Texas, in November 1999. Subsequent to our November 1 presentation of the Roadmap, COMPLEX received additional perspectives from committee member Wendy Calvin and SSB director Joseph Alexander based on their role as observers at the Roadmap presentations held in Galveston on November 2.

In the course of this study COMPLEX reviewed two drafts of the Roadmap: the November 1999 and December 1999 drafts distributed to the committee prior to the November 1999 meeting and in January 2000, respectively. Although in the context of another activity, COMPLEX also was briefed on the technical and programmatic aspects of one of the new missions featured in the Roadmap, the Venus Surface Sample Return. In addition, the committee reviewed relevant reports issued by COMPLEX and other National Research Council (NRC) committees (e.g., The Search for Life's Origins: Progress and Future Directions in Planetary Biology and Chemical Evolution [1990], An Integrated Strategy for the Planetary Sciences: 1995-2010 [1994], The Role of Small Missions in Planetary and Lunar Exploration [1995], Review of NASA's Planned Mars Program [1996], “Scientific Assessment of NASA's Solar System Exploration Roadmap” [1996], Exploring the Trans-Neptunian Solar System [1998], The Exploration of Near-Earth Objects [1998], and A Science Strategy for the Exploration of Europa [1999]) and held extensive discussions in closed session.

COMPLEX's assessment of the program outlined in the Roadmap is mixed. The committee is generally positive about many of the near- and mid-term flight missions and related activities highlighted in the Roadmap because they address priorities outlined in the committee's past reports (see attached Assessment for full details). COMPLEX is particularly pleased to see that NASA continues to place a high priority on Mars exploration and that a new initiative relating to Mars sample handling and analysis is proposed. Similarly, COMPLEX is pleased that prominent attention is given to a comet nucleus sample-return mission. Moreover, the committee commends NASA for formulating a program of planetary exploration that attempts to systematically address key physical and chemical processes rather than merely cataloging and classifying planetary environments. Finally, the Roadmap appears to strike an appropriate balance between the broad thematic goals of understanding origins and understanding planets advocated in COMPLEX's Integrated Strategy.2

1  

Solar System Exploration Subcommittee, Exploration of the Solar System—Science and Mission Strategy, Jet Propulsion Laboratory, Pasadena, California, December 1999.

2  

Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 194, pages 33-34.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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These positives aside, COMPLEX has a number of serious concerns about particular aspects of the Roadmap and the program of solar system exploration it advocates. These concerns are, in approximate order of priority, as follows:

  • The Roadmap does not clearly indicate the scientific objectives of solar system exploration and the critical measurements that must be made to meet these objectives, nor does it describe how existing or proposed missions will make these measurements. These problems stem in large part from the Roadmap's emphasis on the three broadly scoped “Quests” and are compounded by the document's lack of a coherent structure, a consistent format, a cohesive introduction, and a comprehensive supporting text.

  • The scientific justification for both existing and proposed mission lines is not adequately presented.

  • The scheduling of, and the rationale for, several of the proposed missions (e.g., Europa Lander, Titan Explorer, and Saturn Ring Observer) relative to the flight programs they logically build on (e.g., Europa Orbiter and Cassini/Huygens) need to be clarified.

  • The Roadmap includes no information concerning the process by which it was assembled, the identity of the authoring group, or the means by which the recommended mission sequences were prioritized.

  • The scientific rationale for the selection of the Venus Surface Sample Return mission is unclear.

  • Many of the major missions in the proposed “To Build a Planet” mission line either are not identified as high priorities in existing COMPLEX reports or might more properly be justified in other programmatic contexts.

  • The handling of non-mission activities, such as R&A programs and education and public outreach, does not adequately indicate the importance of these activities.

  • Important linkages between the Solar System Exploration, Astronomical Search for Origins, and Sun-Earth Connection science themes and Astrobiology either go unmentioned or are obscured.

  • The asymmetry in the discussion of how the goals of Solar System Exploration relate to the Astronomical Search for Origins and the Sun-Earth Connection science themes, on the one hand, and to Astrobiology, on the other, might be taken to imply that the latter has a special status.

  • Any detailed discussion of technological issues has been excluded.

In its 1996 assessment of the Solar System Exploration Roadmap, COMPLEX commented that it is “important for the Roadmap's scientific objectives to be brought into sharper focus with some indication of priorities for study and critical measurements to be made.”3 Through a combination of the factors listed above, the new Roadmap 's scientific objectives have become even more diffuse than they were in the 1996 edition.

Given the structural deficiencies in the current Roadmap, COMPLEX reiterates its 1996 recommendation that this document must clearly indicate scientific objectives and the critical measurements that must be made to meet these objectives, describe how existing or proposed missions will make these measurements, and indicate relative priorities. Therefore COMPLEX recommends that the next Roadmap team be tasked to define a more scientifically compelling rationale for solar system exploration than that currently provided by the three Quests. As an intermediate step, COMPLEX provides some suggestions (see attached Assessment) as to how the current draft could be reorganized to make a more coherent document.

Because many of the criticisms outlined in COMPLEX's accompanying Assessment result from shortcomings in the Roadmap 's structure and format, they should not detract inordinately from the many favorable aspects of the program of planetary-exploration missions and supporting activities advocated in this document. The SSB and COMPLEX, in particular, look forward to the implementation of the Roadmap and will be pleased to review this phase of the solar system exploration program at an appropriate time.

Signed by

Claude Canizares

Chair, Space Studies Board

John A. Wood

Chair, COMPLEX

3  

Space Studies Board, National Research Council, “Scientific Assessment of NASA's Solar System Exploration Roadmap,” letter report to Jurgen Rahe, August 23, 1996, pages 2 and 9.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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Scientific Assessment of Exploration of the Solar System—Science and Mission Strategy

At its November 1-5, 1999, meeting, the Space Studies Board's Committee on Planetary and Lunar Exploration (COMPLEX), chaired by John A. Wood of the Harvard-Smithsonian Center for Astrophysics, began work on an assessment of Exploration of the Solar System—Science and Mission Strategy,1 the most recent update of the Roadmap of NASA's Solar System Exploration science theme.

This assessment was made at the specific request of Dr. Carl Pilcher, NASA's science program director for solar system exploration, and had two purposes. The first was a detailed comparison between the goals and objectives outlined in the Roadmap and those enunciated by COMPLEX and other relevant NRC committees. The second was to make recommendations for strengthening the Roadmap's scientific rationale and mission priorities.

ELEMENTS OF THE ROADMAP

The preparation of roadmaps is a key aspect of the strategic planning process currently adopted by NASA's Office of Space Science (OSS). Their primary purpose is to summarize the scientific objectives and programmatic recommendations put forward by each of OSS's four component groups, or science themes. The document under review was prepared for use by the Solar System Exploration science theme during OSS 's ongoing strategic planning activities.

The Roadmap identifies three overarching goals, or “Quests,” for solar system exploration:

  1. Explain the formation and evolution of the solar system and of Earth within it;

  2. Seek the origin of life and its existence beyond Earth; and

  3. Chart our destiny in the solar system.

These Quests are addressed by three continuing series of spacecraft missions—the Outer Planets, Mars Surveyor, and Discovery programs —and supporting research and analysis (R&A) programs, technology development, and education and public outreach (E&PO) activities. In addition, the Roadmap recommends that two additional programmatic elements are needed if the three Quests are to be addressed in an adequate manner. These additions are a new, continuing flight program called “To Build a Planet” and a facilities initiative within the Mars Surveyor program devoted to sample handling and analysis.

Within each of the flight programs, current and planned missions are described, explicit priorities for near-term (2003-2007) to mid-term (2008-2013) new starts are outlined (except for Discovery, which, by its nature, is community driven), and some examples of possible far-term (2013+) missions are indicated. The Roadmap also includes material explaining how solar system exploration activities relate to activities within the purview of OSS's Astronomical Search for Origins and Sun-Earth Connection science themes.

The organization of the current Roadmap is significantly different from that of the edition reviewed by COMPLEX in 1996.2 Although the Quests remain the same, the five subsidiary “Campaigns” and numerous “Portrait” missions featured in the 1996 edition have been replaced by directly linking the Quests to R&A, E&PO, and a relatively small number of prioritized missions within the various continuing mission lines.

STRUCTURE AND FORMAT OF THE ROADMAP

In general, COMPLEX found the Roadmap to be an exceedingly difficult document to review, owing, in part, to the Roadmap's format: a hybrid collection of color “vugraph”-style pages, backed up, in part, by facing pages containing supplementary text. The Roadmap is clearly intended to be presented to a reasonably sophisticated audience. Alternatively, its contents could be used selectively to provide supporting graphics for display in general presentations about NASA's planetary-exploration programs.

The Roadmap is not an easy read and is likely to be accessible only to readers with a strong background in planetary issues, processes, and recent discoveries. It is unclear whether non-specialists will understand why, for example, sampling at varying depth and location is important during a comet nucleus sample-return mission. Brief

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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descriptions of the current state of knowledge might be useful additions to the Roadmap because they would provide some context for setting priorities among diverse planetary objects and science goals.

Additional structural problems include the lack of a table of contents or outline and the fact that many program elements are scattered seemingly randomly throughout the text. A general discussion of R &A programs (pages 12-13) is, for example, introduced in the middle of text describing Quest 1. Similarly, the material on E&PO seems out of place. The document would benefit if the general text on E &PO (pages 30-34) were moved into an introduction and the remainder (pages 35-37), in the current structure, were integrated into the sections dealing with the relevant Quests.

Without a coherent structure and cohesive introductory material the Roadmap appears to be a haphazard collection of graphics that readers must flip through back and forth in an attempt to understand the focus and goals of the proposed program of planetary exploration.

GOALS, PRIORITIES, AND SCIENTIFIC FOUNDATIONS

While the Roadmap appears to strike an appropriate balance between the broad thematic goals of understanding origins and understanding planets advocated in COMPLEX's Integrated Strategy,3 the style of presentation is inadequate to convey the detailed goals, priorities, or scientific foundations motivating solar system exploration. Science justification for both existing and proposed mission lines is thin or missing and, as a result, does not substantiate NASA' s goals and priorities in solar system exploration. The primary reason for this is that the Roadmap's predominantly vugraph-style format inherently limits the amount of textual information that can be presented. This problem could have been solved in large part by the addition of a narrative on the pages facing the color graphics. This option, although used in certain places, is not exercised in a consistent manner.

More seriously, the Roadmap does not provide an adequate linkage between goals, directly addressable scientific investigations, and missions. While the Campaigns fulfilled this function in the Roadmap 's 1996 edition, the current version links missions and contributions from the R&A and E&PO programs directly to the three Quests. While these broad overarching statements are generally consistent with high-level goals enunciated in various SSB reports,4 it is not clear that they provide a suitable framework for specifying scientific goals and objectives addressable by specific science investigations and for defining critical measurements.

The Roadmap's attempt to justify the highly diverse and cross-cutting nature of the program in terms of goals such as “chart our destiny in the solar system” leads to a diffuse and incoherent description of solar system exploration and its science justification. Key elements are fragmented across the Quests (as is seen in the derived outline included as an Appendix to this report), and no clear description of the proposed program's science priorities is provided. Moreover, there is no synthesis of overall goals and objectives, nor any mention of how specific elements of the program relate to those goals.

THE PROCESS OF DEVELOPING THE ROADMAP

The Roadmap contains no information about the composition of the authoring group or the process by which it was developed. Additionally, with the exception of the Mars Surveyor line, the rationale for prioritization of goals and missions is absent both within and between mission lines.

This apparent anonymity of the text is in marked contrast to the previous edition of the Roadmap, which explicitly included material on how the document was created and by whom it was written, a factor COMPLEX regarded as a plus in its 1996 review.5 Without more information on the process used to draft the Roadmap, COMPLEX cannot comment on its fairness or credibility. The absence of details concerning the development of the Roadmap is a serious flaw.

MISSION LINES

The spaceflight component of NASA's solar system exploration program is performed within the context of several continuing line items in NASA's budget. Their establishment has brought new vitality and stability to the solar system exploration program, and NASA deserves much credit for this achievement. Three such lines currently exist: the Outer Planets, Mars Surveyor, and Discovery. The Roadmap proposes the addition of a new line, “To Build a Planet.” The following subsections review what the Roadmap has to say about each of the current lines.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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Outer Planets Program

The Outer Planets program, initiated as part of the “Origins” Initiative in NASA's FY 1998 budget, is, according to the Roadmap, intended to focus on “environments in the outer solar system that can provide insights into prebiotic chemistry and possible habitats for life” (page 43). The two missions currently included in this line are the Europa Orbiter and Pluto/Kuiper Express; both address fundamental scientific goals that are broadly consistent with those outlined in recent COMPLEX reports.6,7

The Roadmap identifies a trio of follow-on missions: the Titan Explorer, Europa Lander, and Neptune Orbiter. The selection of the first two might appear to be premature given that they will logically build on the results from ongoing or planned missions (Cassini-Huygens and Europa Orbiter, respectively) that are still many years from completion. COMPLEX recognizes that a combination of long mission design/development periods and the extended flight times necessary to reach the outer planets mandates that work on follow-on missions must begin promptly if we are to exploit the anticipated discoveries from Cassini-Huygens and the Europa Orbiter in a timely manner. These considerations might not, however, be apparent to all readers. The Roadmap does not clearly describe the relationship between the proposed missions and their logical precursors. Without clearly stated scientific priorities and goals, the proposed follow-on missions lack context and justification.

Similarly, the text of the Roadmap makes little or no mention of the fact that major infusions of new knowledge about Europa and Titan are expected before the launch of either the Europa Lander or the Titan Explorer. Indeed, the suggestion that, for example, the Europa Lander can be ready for launch in 2008 (page 46), the same year the Europa Orbiter reaches its destination (page 45), implies that there can be little or no synergy between these two missions. (COMPLEX notes that the mission summary chart (page 106) suggests a more reasonable schedule.)

More importantly, there is nothing in the Roadmap to suggest how priorities might change if, for example, the Europa Orbiter finds no evidence for an ocean beneath Europa's icy surface. The Roadmap 's scant justification for these missions and, in particular, their relationship to ongoing and approved missions is a serious flaw.

The Roadmap should clearly indicate that planning for these mid-term missions must be sufficiently flexible that they can be ready to exploit new exploratory niches uncovered by earlier missions. It would also be helpful if the Roadmap included some discussion of how mission priorities and sequences could be adjusted depending on the results from, or failure of, earlier missions.

While COMPLEX has indicated that Triton is the highest-priority target in the trans-neptunian region following the completion of a Pluto-Charon mission8 and has provided some encouragement for additional studies of Neptune 's magnetic environment,9 the rationale for the emergence of Neptune over, say, detailed study of Jupiter, as recommended by COMPLEX,10 should be justified more fully.

In general, as portrayed by the Roadmap this mission line seems to be suffering from an unresolved split identity. The Outer Planets program becomes “Exploring Organic-Rich Environments” early in the document (page 40) but turns back into the Outer Planets program further on (pages 101 and 103). Is the mission line devoted to organic environments or just to distant objects? The mention of “Interstellar Exploration” (on page 55) and “Interstellar Precursors” (on page 101) in the context of this program is particularly confusing. These mission concepts have deep roots in the space-physics community and have, seemingly, little to do with organic environments.11,12,13

The outer-planets/organic-environments duality seems to stem from the lack of focused scientific goals as the foundation for exploration and, subsequently, for the mission lines. Alternatively, this ambiguity may reflect an unfinished transition from the early approach of cataloging planetary bodies to the more recent science-driven approach. Given COMPLEX's preference for exploration programs formulated in terms of key physical and chemical processes rather than distance from the Sun,14 it believes that this mission line would be more compelling if explicitly directed toward the study of organic environments wherever they are found.

Mars Surveyor

Intensive exploration of Mars has long been identified as a high-priority activity by COMPLEX,15 and the committee is encouraged to see that Mars Surveyor and, in particular, the Mars sample-return program are featured prominently in the Roadmap. Similarly, COMPLEX is pleased to see that these programs maintain their focus on activities recommended in previous reports, 16 accommodate some of the recommendations made during the committee 's 1998 review of the Mars exploration architecture,17 and point to the importance of a robust communi-

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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cations network.18 COMPLEX also supports the high priority given to the proposed Mars Sample Handling and Analysis program, since such an initiative is essential both to ensure the scientific integrity of returned samples and to maximize the scientific information gleaned from the analysis of the samples.19 The necessary facilities and protocols are required to be in place well in advance of the return of the martian samples.20 The description of the Mars Surveyor line does perhaps the best job of linking scientific objectives to specific missions and their science goals.

Given the recent failures of Mars Polar Lander and Mars Climate Orbiter, it is not clear to what extent the contents of this part of the Roadmap will stand the test of time. Whatever the outcome of the ongoing efforts to revise the Mars exploration architecture, the scientific focus for Mars exploration remains the understanding of this planet as a possible abode of past or present life, and this requires a program of comprehensive studies aimed at understanding the origin and evolution of the martian environment.21 A central element of these studies will be the return to Earth of samples of the martian atmosphere and soil, and, more importantly, carefully selected samples from martian rocks.22

It is heartening to see that the Roadmap outlines a process (page 65) by which future mission goals and strategies will be reviewed. Whatever changes are made to the Mars Surveyor program in the aftermath of the recent failures, COMPLEX expects that a thorough and open review process will be defined and applied to future Mars missions, be they those outlined in the Roadmap (i.e., Synthetic Aperture Radar, Advanced Sample Return, and Robotic Outposts), or other mission concepts arising from the ongoing architecture-review process.

Discovery

COMPLEX has long maintained that priority objectives in the planetary sciences are best addressed by a range of mission sizes.23 The Discovery program has demonstrated that reasonable science can be achieved within the context of small- to mid-size missions.24

While the Roadmap emphasizes Discovery missions that are defined and led by the planetary-science community, it does not clearly state that selections are made based on compelling science and technical feasibility. Nor does the Roadmap mention that, in many instances, mission concepts emerge directly from activities supported by the R&A program. Another important aspect of Discovery that goes unmentioned is the program's ability to address important science goals that do not fit within the scope of the Outer Planets and Mars Surveyor lines.

The close identification between Discovery and Quest 1 is probably inappropriate. The study of comets and asteroids, for example, is of direct relevance to Quests 2 and 3 and is, and will likely remain, a major focus for Discovery missions. Finally, the Discovery summary chart (page 77) would be more useful if it clearly indicated which missions had flown, which are in progress, and which are still in preparation.

To Build a Planet

The Roadmap proposes a new mission line, “To Build a Planet,” designed to address questions relating to the formation and development of planetary environments. COMPLEX has very mixed feelings about this proposal. The line is justified on the grounds (page 42 and repeated verbatim on page 81) that Quest 1 is not “adequately addressed ” within the current-program structures. This rationale is thin and illustrates the difficulty in using the broadly scoped Quests to justify specific scientific investigations and measurements.

The basic scientific issues this line is designed to address are, however, important items identified in past NRC reports.25,26 Moreover, the first mission in the line, Comet Nucleus Sample Return, is consistent with prior advice from COMPLEX. Indeed, such a mission addresses the highest-priority goals identified in COMPLEX's Integrated Strategy.27 COMPLEX's most serious problem with this new line is that the suite of proposed missions lacks coherence and seems to be a catchall for large missions.

While the origins and justification for a comet nucleus sample-return mission are well documented, the same cannot be said for the other two missions proposed for this line, the Saturn Ring Observer and Venus Surface Sample Return. The former was featured as a Portrait mission in a Campaign, Astrophysical Analogs in the Solar System, in the 1996 Roadmap.28 The latter does not seem to have figured prominently in NASA's recent science-planning activities, although the European Space Agency recently published a major study concerning such an endeavor. 29 Why these missions were selected over other possible candidates is unclear and highlights the lack of discussion on how the Roadmap was created and what process was followed to select the proposed missions.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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This mission line's apparent lack of coherence is heightened by the discussion of follow-on missions. Why, for example, is the Mars Geophysical Network not part of the Mars Surveyor line? Similarly, why are the Jupiter Polar Orbiter and Giant Planet Deep Probes not part of the Outer Planets/Organic Environments line?

R&A PROGRAMS AND OTHER ACTIVITIES

The R&A program is extremely important because it is the origin of both new missions and continued discovery, it supports ground-based observational and laboratory studies, and it provides the framework and foundation upon which new information from spacecraft missions is integrated into a comprehensive understanding of solar system processes. As such, its importance has been documented in various SSB reports. 30,31

Indeed, in its review of the 1996 Roadmap, COMPLEX specifically noted the document's failure to recognize the role of non-flight activities supported by the R&A program. Therefore, the explicit mention of the R&A program in the context of the Roadmap and, by association, the Office of Space Science's strategic-planning activities is an extremely positive factor, one strongly recommended by the SSB.32 Unfortunately, the new Roadmap's handling of R&A and other non-mission activities such as E&PO is generally poor and not well integrated with the rest of the text.

While the general text on E&PO and that specifically related to the three Quests is consolidated in one place (pages 29-37), the text on R&A is fragmented. General text on R&A is introduced in the middle of the discussion of Quest 1 (pages 12-13) and is followed by specific text relating to Quest 1 (page 14). But the discussion of R&A activities relating to Quests 2 and 3 is deferred until pages 20 and 26, respectively.

SOLAR SYSTEM EXPLORATION AND OTHER SCIENCE THEMES

In the Roadmap, important linkages between the Solar System Exploration, the Astronomical Search for Origins, and the Sun-Earth Connection science themes and Astrobiology either go unmentioned or are fragmented. Text explaining how solar system exploration provides “ground truth ” for the astronomical search for origins appears in the report's brief introductory section (page 6), and additional text linking these two science themes appears in the summary section (pages 108-109). However, text relating the Solar System Exploration and Sun-Earth Connection science themes appears only in the summary (pages 110-111). In addition to these linkages receiving inconsistent and cursory treatment, discussion of them is not well integrated into the preceding text.

The discussion of Astrobiology's linkages to solar system exploration is equally brief and fragmented. Astrobiology is discussed only in the context of the three Quests (pages 15-16, 21-22, and 27-28). Even then, the discussion is often cryptic. The text, for example, makes reference to Astrobiology' s three fundamental questions (page 22), but nowhere is the reader told what all three questions are. Some introductory material is clearly needed. More importantly, the Roadmap's discussion of the linkages between the exploration of the solar system and Astrobiology in the context of the “Quests” rather than in the context of the “Integration of Space Science” (pages 107-111) could suggest that Astrobiology has a special status. Similarly, this treatment could be taken to imply that the goals of the Solar System Exploration theme are being justified on the basis of their relationship to the goals of Astrobiology. Scientific goals should be judged on their own merit and not on the basis of their connections to other goals of other scientific endeavors.

TECHNOLOGY ISSUES

The discussion of technological issues in the 1999 edition of the Roadmap differs significantly from that in the 1996 edition. Almost 25% of the earlier document was devoted to discussion of the key technologies and other capabilities necessary to enable the featured missions, whereas discussion of technological issues occupies less than 10% of the current document. What discussion there is is divided among the text devoted to the Outer Planets (pages 52-53), Mars Surveyor (66-67), and “To Build a Planet” (96-97) mission lines, and the summary (104-105). There is no discussion of the technology development necessary to enable future Discovery missions. More importantly, there is no indication of how any of the development activities are prioritized, nor is there any mention of the role played by the New Millennium program and the Planetary Instrument Definition and Development Program (PIDDP).

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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To be fair, COMPLEX notes that the Roadmap's introduction (page 2) states that “a companion technology roadmap will be published early in the year 2000.” Nevertheless, the apparent decoupling of science and missions from technology is unfortunate in that it negates what COMPLEX viewed as one of the strengths of the Roadmap's 1996 edition.33

FINDINGS AND RECOMMENDATIONS

COMPLEX finds that many of the missions and other activities identified in the current Roadmap address key priorities identified in reports issued by COMPLEX and other NRC committees. In particular, COMPLEX offers strong support for the Europa Orbiter, Pluto/Kuiper Express, and the Mars Surveyor and Discovery programs. COMPLEX also supports the proposed Comet Nucleus Sample Return (CNSR) mission and the new initiative concerning the handling and analysis of martian samples.

Nevertheless, COMPLEX has some significant concerns about the Roadmap and the program it presents. These concerns are, in order of priority, as follows:

  1. The Roadmap does not clearly indicate the scientific objectives of solar system exploration and the critical measurements that must be made to meet these objectives, nor does it describe how existing or proposed missions will make these measurements. As a result, the scientific justification for both existing and proposed mission lines is not adequately presented. These problems stem in large part from the Roadmap's emphasis on the three broadly scoped “Quests” and are compounded by the document's lack of a coherent structure, a consistent format, a cohesive introduction, and a comprehensive supporting text.

  2. The scheduling of, and the rationale for, several of the proposed missions (e.g., Europa Lander, Titan Explorer, and Saturn Ring Observer) relative to the flight programs they logically build on (e.g., Europa Orbiter and Cassini/Huygens) need to be clarified. Similarly, the priority of these missions relative to a number of possible eventualities needs to be spelled out. For example, does the Europa Lander remain in the queue if the Europa Orbiter finds no evidence of liquid water or, worse still, suffers a terminal failure?

  3. The Roadmap includes no information concerning the process by which it was assembled, the identity of the authoring group, and the means by which the recommended mission sequences were prioritized.

  4. The scientific rationale for the selection of the technologically challenging Venus Surface Sample Return (VSSR) mission is unclear. This is the case whether it is considered within the context of the proposed mission line, “To Build a Planet,” or within the context of other possible Venus missions. Moreover, other than CNSR, many of the missions in the proposed “To Build a Planet” mission line either are not identified as high priorities in existing COMPLEX reports or might more properly be justified in other programmatic contexts.

  5. The handling of non-mission activities, such as R&A programs and education and public outreach, does not adequately indicate the importance of these activities. Similarly, important linkages between the Solar System Exploration, Astronomical Search for Origins, and Sun-Earth Connection science themes and Astrobiology either go unmentioned or are obscured. In particular, discussing the relationship between the goals of the Solar System Exploration theme and Astrobiology in the context of the three Quests (pages 15-16, 21-22, and 27-28) but deferring much of the discussion of the corresponding relationships with the Astronomical Search for Origins and Sun-Earth Connection themes until later in the Roadmap (pages 107-111) might be taken to imply that Astrobiology has a special status. It could even be taken to indicate that the goals of solar system exploration are being justified on the basis of their congruence with the goals of astrobiology.

  6. Detailed discussion of technological issues has been excluded.

Given the deficiencies in the current Roadmap, COMPLEX reiterates the recommendation made in its assessment of the Roadmap's 1996 edition that this document must clearly indicate scientific objectives and the critical measurements that must be made to meet these objectives, must describe how existing or proposed missions will make these measurements, and must indicate relative priorities.34 Therefore COMPLEX recommends that the next Roadmap team be tasked to define a more scientifically compelling rationale for solar system exploration than that currently provided by the three Quests.

Such a restructuring is far beyond the scope of this brief report. Nevertheless, the new structure should, at a minimum, be organized around specific science goals and questions that can be directly related to critical measurements and focused priorities. It should, in addition, outline the rationale used for prioritization and describe

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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how existing and proposed activities can be achieved through R&A programs, individual missions, and other activities.

As an interim step to complete revision of the Roadmap, COMPLEX suggests that a somewhat more cohesive and substantive document could be made if the text relating to R&A programs, E&PO activities, and the cross-linkages between the various science themes were handled in a more consistent and efficient manner. To this end, COMPLEX suggests that the Roadmap 's introductory text be expanded to include material relating to the following:

  1. The organization of the Roadmap (relevant text is not included in the current draft);

  2. The process used to create the Roadmap (relevant text is not included in the current draft);

  3. General material on research and analysis programs (appropriate text is to be found on pages 12-13 of the current draft);

  4. General material on education and public outreach (appropriate text is to be found on pages 29-34 of the current draft); and

  5. General material on how the goals of Solar System Exploration relate to the Astronomical Search for Origins (appropriate text is to be found on pages 6 and 108-109 of the current draft) and Sun-Earth Connection (appropriate text is to be found on page 110 of the current draft) science themes, and to Astrobiology (relevant text is not included in the current draft). Particular care should be taken to ensure that the linkages between the various disciplines are treated in an evenhanded manner.

Addition of this material will help make the existing Roadmap more substantive until such time as a full revision can be undertaken.

REFERENCES

1System Exploration Subcommittee, Exploration of the Solar System—Science and Mission Strategy, Jet Propulsion Laboratory, Pasadena, California, December 1999.

2Roadmap Development Team, Mission to the Solar System: Exploration and Discovery—A Mission and Technology Roadmap (Version A), Jet Propulsion Laboratory, Pasadena, California, June 21, 1996.

3Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 33-34.

4Space Studies Board, National Research Council, “Scientific Assessment of NASA's Solar System Exploration Roadmap,” letter report to Jurgen Rahe, August 23, 1996, pages 6-7.

5Space Studies Board, National Research Council, “Scientific Assessment of NASA's Solar System Exploration Roadmap,” letter report to Jurgen Rahe, August 23, 1996, page 6.

6Space Studies Board, National Research Council, Exploring the Trans-Neptunian Solar System, National Academy Press, Washington, D.C., 1998, pages 42-43.

7Space Studies Board, National Research Council, A Science Strategy for the Exploration of Europa, National Academy Press, Washington, D.C., 1999, page 66.

8Space Studies Board, National Research Council, Exploring the Trans-Neptunian Solar System, National Academy Press, Washington, D.C., 1998, page 43.

9Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 9 and 172.

10Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 193-194.

11Space Studies Board, National Research Council, Space Science in the Twenty-First Century: Imperatives for the Decades 1995-2015—Solar and Space Physics, National Academy Press, Washington, D.C., 1988, pages 41-43.

12National Aeronautics and Space Administration, An Interstellar Precursor Mission, JPL77-70, Jet Propulsion Laboratory, Pasadena, California, 1977.

13Sun-Earth Connection 2000 Roadmap Team, Sun-Earth Connection Roadmap—Strategic Planning for 2000-2025, National Aeronautics and Space Administration, Washington, D.C., 1999, pages 152-155.

14Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, page 25.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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15Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press , Washington, D.C., 1994, pages 191-193.

16Space Studies Board, National Research Council, Review of NASA's Planned Mars Program, National Academy Press, Washington, D.C., 1996, pages 22-27.

17Space Studies Board, National Research Council, “COMPLEX's Assessment of NASA's Mars Exploration Architecture,” letter report to Carl Pilcher, November 11, 1998, page 10.

18Space Studies Board, National Research Council, A Scientific Rationale for Mobility in Planetary Environments, National Academy Press, Washington, D.C., 1999, page 3.

19Space Studies Board, National Research Council, “COMPLEX's Assessment of NASA's Mars Exploration Architecture,” letter report to Carl Pilcher, November 11, 1998, page 8.

20Space Studies Board, National Research Council, Mars Sample-Return: Issues and Recommendations, National Academy Press, Washington, D.C., 1997 , page 31.

21Space Studies Board, National Research Council, “COMPLEX's Assessment of NASA's Mars Exploration Architecture,” letter report to Carl Pilcher, November 11, 1998, page 2.

22Space Studies Board, National Research Council, “COMPLEX's Assessment of NASA's Mars Exploration Architecture,” letter report to Carl Pilcher, November 11, 1998, page 5.

23Space Studies Board, National Research Council, The Role of Small Missions in Planetary and Lunar Exploration, National Academy Press, Washington, D.C., 1995, page 27.

24Space Studies Board, National Research Council, Assessment of Mission Size Trade-offs for Earth and Space Science Missions, National Academy Press, Washington, D.C., 2000 (in press).

25Space Studies Board, National Research Council, Space Science in the Twenty-First Century—Planetary and Lunar Exploration, National Academy Press, Washington, D.C., 1988, pages 83-84 and 87.

26Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 13-14.

27Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 188-189.

28Roadmap Development Team, Mission to the Solar System: Exploration and Discovery—A Mission and Technology Roadmap (Version B), Jet Propulsion Laboratory, Pasadena, California, September 27, 1996, page 47.

29VSR Study Team, Venus Sample Return—Assessment Study Report, SCI(98)3, European Space Agency, Paris, June 1998.

30Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994, pages 186-187.

31Space 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, pages 1-6.

32Space 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, pages 3-4.

33Space Studies Board, National Research Council, “Scientific Assessment of NASA's Solar System Exploration Roadmap,” letter report to Jurgen Rahe, August 23, 1996, pages 5 and 10.

34Space Studies Board, National Research Council, “Scientific Assessment of NASA's Solar System Exploration Roadmap,” letter report to Jurgen Rahe, August 23, 1996 , pages 2 and 9.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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4.4 Review of NASA's Office of Space Science Strategic Plan 2000

On May 26, 2000, Space Studies Board Chair Claude R. Canizares sent the following letter to Dr. Edward J. Weiler, NASA's Associate Administrator for Space Science.

As you requested in your letter of September 2, 1999, the Space Studies Board (the Board) has reviewed the draft Office of Space Science (OSS) strategic plan received on February 8, 2000. In carrying out the requested review, the Board focused on the main areas listed in your letter:

  1. Responsiveness to the Board's guidance on key science issues and to opportunities provided in recent Board science strategies;

  2. Attention to interdisciplinary aspects and overall scientific balance;

  3. Identification and exposition of important opportunities for education and public outreach;

  4. Integration of technology development with the science program; and

  5. General readability and clarity of presentation.

The review was based, in part, on inputs received from relevant standing committees of the Board. Representatives of three discipline committees —the Committee on Solar and Space Physics (CSSP), the Committee on Planetary and Lunar Exploration (COMPLEX), and the Committee on Astronomy and Astrophysics (CAA)—attended the first day of the OSS Galveston strategic planning workshop in an observer status and heard the overview presentations given on November 2, 1999. In addition, COMPLEX was briefed on the maturing plan by Dr. Carl Pilcher on November 1; CSSP was briefed by Dr. Marc Allen and Dr. George Withbroe during its January 17-18 meeting; and Dr. Allen met with the Committee on International Space Programs on January 24 and with the full Board on March 8.

Using teleconferences and electronic mail, each of the committees subsequently developed and forwarded independent comments on the plan to the Board for consideration at its meeting on March 6-8. At that meeting, the Board reviewed and discussed the draft plan and the Board's discipline committees' responses and assembled this consensus assessment. In the remainder of this letter, the Board first offers some general observations about the draft OSS strategic plan and then addresses the five areas cited above that you asked the Board to emphasize in its assessment. A number of specific recommendations are offered at the end of the letter.

GENERAL OBSERVATIONS

The Board finds many aspects of the draft OSS strategic plan to be solidly grounded. For example, the section on “Principles” places a priority on scientific merit for program planning and budgeting, and it affirms that the OSS strategy is based on scientific goals. It emphasizes participation by the extramural community in planning, peer review, and research—hallmarks of the strength of the OSS program. Many advisory reports have endorsed these principles(1). Further, as explained below, the Board found the sections on recent accomplishments, the current program, and the flight program for 2003 and beyond to be particularly useful.

Elements of a Strategic Plan

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. Furthermore, the plan gives only a very general sense of time scales—i.e., near term, 2003-2007, and post-2007—and it does not provide any more specific information about mission time lines. Finally, the document is silent on resource requirements such as funding, workforce, and infrastructure. In entities outside the federal government, e.g., in private industry, an effective strategic plan would include attention to questions of decision making, priorities, time lines, and top-level budgets. Given the fact that the plan outlines a very ambitious set of future missions, a clear process for setting priorities will be crucial for OSS.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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The Board recognizes that, as a federal R&D agency, NASA operates in a different environment and with different constraints compared with the private sector. The Board also understands that at NASA the OSS strategic plan is intended to be used in connection with other management documents, including the “roadmaps” developed for each of the four science theme areas, the annual Government Performance and Results Act (GPRA) plans, and the annual budgets that are prepared by each office. Consequently, if OSS can cite comprehensive roadmaps developed in broad consultation with the OSS stakeholder communities and used to form a coherent basis for the plan, then the OSS plan and its accompanying documents can serve as useful strategic planning tools(2).

Missions, Science Goals, and Objectives

A particularly important point, both in terms of the Board's ability to review the document and in terms of the content of the OSS plan itself, pertains to what was missing from the draft plan. The draft plan refers to Appendix A-1, “Relation of Missions to Science Goals and Objectives,” but the appendix was not provided in the document available for the Board's review. Mapping the linkages between planned missions and science goals and objectives is a critical aspect of a viable strategic plan. This element of the plan will need to be more than a checklist; it should present a substantive discussion of how OSS expects to address its program's goals and objectives through its priorities for proposed missions. Because this essential part of the document was not available, the Board's comments are necessarily limited.

Roles and Relationships with Universities

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. An implicit blanket endorsement of the field centers ' broad lists of “core capabilities” is not consistent with recent recommendations that the centers should take a more focused and disciplined approach to identifying and sustaining critical core capabilities(3). 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(4). 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.

International Cooperation

The draft plan cites OSS's general support of international cooperation and international programs, but it is largely silent on any strategic approach in the arena of international programs. For example, the OSS approach to missions of opportunity, conducting international planning in an environment of “faster-better-cheaper” missions, the fit of international missions into the OSS portfolio of missions, or what OSS considers as appropriate costs in an international project are not addressed in the document. Some mention is needed of the extent to which OSS recognizes that international cooperation has its own set of challenges. These include the need to learn how to mesh differing agency policy and budget cycles, to provide funding for early stages of planning, and to cope with the implementation of export control regulations. Many of these issues reflect long-standing concerns(5).

Further, there appears to be an inconsistency between the OSS approach to international cooperation and the recommendations presented in the 1995 Academy report Allocating Federal Funds for Science and Technology(6). At section II-1, p. 2, the OSS draft strategic plan establishes as the criterion for international cooperation the following: “In general, NASA seeks to lead where possible, and participate with our partners through collaborative roles in other deserving areas. ” However, the 1995 Academy report (pp. 14-16) proposed that the United States determine those areas in which U.S. world leadership is essential for the national interest and then fund those accordingly, giving lower priority to other areas where it is only necessary that the United States be among the world leaders. That approach—rather than OSS's approach of striving to “lead where possible”—would seem to allow for more willingness to benefit from selective agreements on international collaborations in which the foreign partner clearly takes the lead. The Board returns to the issue of leveraging the strengths of foreign capabilities in the discussion of technology development below.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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RESPONSE TO THE FIVE CHARGE AREAS
Responsiveness of the OSS Plan to NRC Science Strategies

A considerable body of work has been prepared by advisory bodies over the past 5 years to recommend scientific directions and priorities in the space sciences(7), and that collection of reports remains timely and relevant to the OSS program. The Board finds that, by and large, the draft plan does respond to the prior scientific strategies, and it does reflect continuing efforts in OSS to align the OSS program with the advice of the NRC and others.

However, the Board has two concerns. First, as noted above, the strength of this plan depends on the extent to which it is founded on comprehensive roadmaps for the four science themes in OSS's Space Science Enterprise. The Board is concerned that the quality of some of those roadmaps could be improved. In particular, COMPLEX recently reviewed the Solar System Exploration roadmap(8) and noted that some aspects of that document appear deficient. Since the Board has not formally reviewed the other three roadmaps, it cannot comment on their strengths or weaknesses.

Second, as noted above, the version of the OSS draft plan provided to the Board for review did not address the question of how the program 's goals and objectives translate into the set of missions presented in the plan. Articulating this linkage is a critical aspect of demonstrating how the OSS space research program actually implements the science strategies.

Interdisciplinary Aspects and Scientific Balance

The treatment of interdisciplinary aspects of the OSS program and of scientific balance appears to be adequate, but there are areas where the document could be strengthened. First, and probably foremost, the draft document does not address the process by which the roadmaps were integrated or translated into the OSS strategic plan. The Board imagines that much of OSS's consideration of scientific balance and interdisciplinary activity would occur during that process, but the draft document gives no indication of it.

A second concern relates to several aspects of balance, including the long-standing problem of the treatment of the research and analysis (R&A) program(9). In its review of the 1997 OSS strategic plan(10) and in its 1998 report on NASA's research and data analysis programs(11), the Board recommended that NASA work to integrate the R&A program more completely into NASA's science programs as a whole and to treat R&A from a more strategic perspective. The same considerations apply to the need for more explicit attention to the OSS strategy for handling data management and analysis. NASA has made substantial investments over the years in the design, development, launch, and operation of an extraordinary suite of space research instruments and flight missions. The approach for reaping the returns on this investment through support of appropriate data management and data analysis resources should be addressed in the OSS strategic plan. The importance of this aspect of all space missions has been emphasized repeatedly in prior reports(12). 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. In the case of flight missions, the issue of balance also applies to balance in the mix of mission sizes(13). Explicit attention to ensuring a balanced mix of mission sizes and to achieving a balance between flight missions and other elements of the OSS program might be appropriate for elevation to a principle and inclusion in the set of principles identified in the plan.

Some more specific items deserve attention. For example, the discussion of the astrobiology program is not well characterized or integrated into the overall strategy. The discussion tends to be a very general recapitulation of ground-based research activity with some relevance to biology, but it lacks enumeration of specific areas of research or reference to priorities. Given that astrobiology is a major new thrust in the space sciences, it would be appropriate for the strategic plan to detail OSS's views of the impact of the astrobiology initiative on the R&A program, analysis of data from current missions, and planning of future missions. Some projection into the medium-term future of the extent to which OSS expects to see astrobiology grow, versus other disciplines of space science, would be appropriate for this strategic plan. Also important is a projection of the relative roles and importance of the Astrobiology Institute, the proposed National Astrobiology Laboratory, and distributed astrobiology R&A efforts.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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Finally, the concluding section of the plan, “A Vision of the Future,” anticipates a much more robust human presence in space and a much more substantial role for humans in space science flight missions. However, the plan provides little substantive insight (in section II-7 on “Partnerships” or elsewhere) about how NASA's Space Science Enterprise and the Human Exploration and Development of Space Enterprise will work together to make this vision feasible. Furthermore, it does not present a cogent view about what balance is expected between the roles of humans and robotic systems in the future.

Integration of Technology Development

In its review of the 1997 OSS strategic plan(14) the Board commented on the need to strengthen the discussion of technology. In its more recent reviews of the OSS technology development program(15) the Board noted that OSS had made substantial progress in this area. Nevertheless, the treatment of technology in the current document still needs improvement. For example, the connection of technology activity to future missions and the methodologies for making those connections are not clear. The plan should at least show the methodology for technology resource allocation, the interaction between this allocation and mission schedules, decision time lines, and the reallocation process that must occur if there are delays in meeting technology goals due to technical or funding shortfalls. The document also sends a message that OSS sees technology transfer as flowing largely in one direction—from NASA to industry and other outside entities. To the contrary, NASA has much to gain from being open to infusion of technologies from industry, academia (which again raises the issue of universities' roles as discussed above), other government agencies, and the international space community(16). There is also a sense throughout the document that the United States must be first in everything and that little need or interest exists in acquiring advanced technology or knowledge from abroad. The Board has not seen that attitude to be evident in practice, but the strategic plan could be improved by explicitly recognizing the importance of outside domestic and international sources of needed technology (see, e.g., the discussion of international cooperation on page 3).

Some of the future missions cited in the OSS plan will rely on very ambitious technologies whose costs are currently quite uncertain. Outlining how OSS expects to assess costs realistically as a particular program seeks to make the transition from the preliminary design phase into the development phase could strengthen the plan. Other areas that may deserve some explicit attention in the plan include a strategy for developing technologies needed for small missions (i.e., Explorers and Discovery) and a strategy for sustaining satisfactory flight hardware development capacity in U.S. universities.

Education and Outreach

The draft plan's discussion on education and public outreach presents a set of general objectives (in section I-4) and a general list of “new directions ” (in section I-6), but the document stops short of articulating a set of actions that OSS expects to take to implement those directions or to achieve its objectives. In its review of the 1997 OSS strategic plan(17), the Board noted that NASA's educational programs are necessarily small compared with the total federal or national education enterprise. Consequently, that review recommended that the plan should explicitly address how NASA would focus its efforts, so as to capitalize on NASA's unique capabilities and to fit into the larger national context. This point remains valid, and therefore, augmenting the draft plan's discussion in section II-6 to identify specific actions along these lines could strengthen the current strategic plan.

General Readability and Clarity

The document is generally clear and well written. According to the February 8, 2000, letter from Dr. Marc Allen that transmitted the draft plan to the Board, the document is targeted at a layperson who has a professional interest in the space science program but who may not have a substantial background in space science and technology. With that understanding of the principal audience for the plan, the Board also concludes that the level of detail is appropriate. Research professionals, however, are likely to want to understand the basis of the plan in more depth, and consequently the availability of comprehensive science roadmaps mentioned earlier in this report becomes especially important.

Two sections of the document stand out as being particularly effective —section II-2, “Recent Accomplishments and Current Program,” and section II-3, “Flight Program: 2003 and Beyond.” OSS has many accomplish-

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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ments to be proud of, and the discussion does a good job of capturing the excitement of recent results. Likewise, although there is some unevenness in the discussion of the future program, the approach used in section II-3 is a model that should be emulated elsewhere in the plan. Specifically, if the plan took the goals presented in the table on page 2 of section I-2 in education and public outreach, human spaceflight, and technology and treated them in the same manner as section II-3 treats the science goals, then the plan would be strengthened considerably.

CONCLUDING REMARKS

After the draft strategic plan was provided to the Board for review, several important reports were released that addressed NASA's recent mission failures(18). Some acknowledgment of the implications of these losses for the OSS program and its management strategy seems appropriate for the plan. For example, do the conclusions of the review committee reports lead to any additions or changes to the strategy's principles (section II-1)? How do actions that OSS may have to take to respond to internal and external reviews affect the plans for the Mars Surveyor program (sections II-2 and II-3)?

RECOMMENDATIONS

As indicated above, the Board believes that the OSS planning process is fundamentally sound and that there are many positive aspects to the draft 2000 strategic plan, just as was the case in the Board 's 1997 review. The articulation of principles, recent accomplishments, and elements of current and planned flight mission programs is a particularly strong feature. Furthermore, the program outlined in the plan is largely responsive to the science strategies and priorities presented in prior advisory reports. Nevertheless, there are a number of areas where the plan could be strengthened, and those are addressed in the following recommendations:

  1. The OSS strategic plan should be expanded to include more explicit attention to how priorities are set, to specifying those priorities, and to providing some information about program time lines and top-level resource requirements. This augmentation could be done by changing the strategic plan itself or by more explicitly describing how the strategic plan, the four science theme roadmaps, the GPRA performance plan, and the annual budget plans form an integrated whole. At a minimum, the plan should provide the methodologies for prioritizing and allocating resources.

  2. Appendix A-1, “Relation of Missions to Science Goals and Objectives,” which was not available for the Board's review, should be developed in a way that clearly and explicitly maps the linkages between planned missions and science goals and objectives. This aspect of the plan will need to be more than a checklist; it should present a substantive discussion of how OSS expects to address the program's goals and objectives through its priorities for proposed missions.

  3. The plan should address more thoroughly the OSS strategy regarding institutions outside NASA by indicating the extent to which OSS is responsible for supporting core capabilities of universities and the strategy for fulfilling its responsibility. Regarding international cooperation, the plan should be more explicit about how OSS will work to coordinate its own planning process with the planning, budgeting, and funding cycles of non-U.S. agencies and about the extent to which the OSS strategy provides for international partners to play a leading role in selected areas.

  4. The plan should provide a more thorough discussion of the research and analysis and data analysis programs that indicates how the strategy integrates research and data analysis into the overall OSS program. The document would benefit from a clearer sense of the priorities for research and data analysis, the linkages between research and data analysis and other parts of the program, and the overall importance of research and data analysis in the space science enterprise. Also needed is 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 plan should have a more complete presentation of how astrobiology, a high-visibility initiative in OSS, fits into the overall program. This discussion should communicate OSS's sense of the impact of the astrobiology initiative on the R&A program, on analysis of data from current missions, and on planning of future missions. It should also provide a projection into the medium-term future of the extent to which OSS expects to see astrobiology grow compared with other disciplines of space science and a projection of the relative roles and importance of the Astrobiology Institute, the proposed National Astrobiology Laboratory, and distributed astrobiology R&A efforts.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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  1. The treatment of technology in the OSS plan should more clearly address the connection of technology activity to future missions and the methodologies for making those connections. The plan should at least show the methodology for technology resource allocation, the interaction between this allocation and mission schedules, decision time lines, and the reallocation process that must occur if there are delays in meeting technology goals due to technical or funding shortfalls. It also should recognize that technology transfer and infusion flow both from NASA to outside entities and into NASA from industry, academia, and other domestic and international sources.

  2. The plan's discussion of education and public outreach should clearly articulate a set of specific actions that OSS expects to take to achieve its objectives and to implement its strategy. The plan should explicitly address how OSS will focus its efforts, so as to capitalize on NASA 's unique capabilities and to fit into the larger national context.

  3. The plan should acknowledge the recent mission failures and address the implications of NASA's failure assessments for how OSS defines and implements its strategy.

The Board hopes that these recommendations will be of help in revising the OSS draft strategic plan and looks forward to working with you to further strengthen space science.

Signed by

Claude R. Compares

Chair, Space Studies Board

NOTES

1. For example, see Space Studies Board, National Research Council, Managing the Space Sciences, 1995, pp. 56-61.

2. In a separate letter report (Space Studies Board, National Research Council, “On a Scientific Assessment of Exploration of the Solar System—Science and Mission Strategy” April 21, 2000), COMPLEX has provided recommendations for improvements in the Solar System Exploration roadmap to best meet the needs discussed here.

3. For example, see Space Studies Board, National Research Council, Assessment of Technology Development in NASA's Office of Space Science, 1998, p. 33, and Space Studies Board, National Research Council, “Continuing Assessment of Technology Development in NASA's Office of Space Science,” March 15, 2000, pp. 6-7.

4. NASA Advisory Council, National Aeronautics and Space Administration, Report of the University Relations Task Force, 1993, p. 14.

5. For example, see Space Studies Board, National Research Council, An International Discussion of Research in Solar and Space Physics, 1983, pp. 23-25; the Board has addressed these issues again in two recent reports (Space Studies Board, National Research Council, U.S.-European Collaboration in Space Science, 1998, and Space Studies Board, National Research Council, U.S.-European-Japanese Workshop on Space Cooperation, 1999).

6. Committee on Criteria for Federal Support of Research and Development, National Academy of Sciences, National Academy of Engineering, Institute of Medicine, Allocating Federal Funds for Science and Technology, 1995.

7. For example, see Space Studies Board, National Research Council, An Integrated Strategy for the Exploration of the Solar System: 1995-2010, 1994; Space Studies Board, National Research Council, A Science Strategy for Space Physics, 1995; Space Studies Board, National Research Council, A New Strategy for Space Astronomy and Astrophysics, 1997; Space Studies Board, National Research Council, Exploring the Trans-Neptunian Solar System, 1998; Space Studies Board, National Research Council, The Exploration of Near-Earth Objects, 1998; Space Studies Board, National Research Council, A Science Strategy for the Exploration of Europa, 1999; and Board on Physics and Astronomy and Space Studies Board, National Research Council, Astronomy and Astrophysics in the New Millennium, 2000, in press.

8. Space Studies Board, National Research Council, “On a Scientific Assessment of Exploration of the Solar System—Science and Mission Strategy,” April 21, 2000.

9. For example, see Space Studies Board, National Research Council, Assesssment of Programs in Solar and Space Physics, 1991, pp. 25-28; Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010,1994, pp. 174-180 and 186-187; and Space and Earth Sciences Advisory Committee, NASA Advisory Council, The Crisis in Space and Earth Science, 1986, pp. 38-39 and 69-72.

10. Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft Strategic Plan,” August 27, 1997, p. 2.

11. Space Studies Board, National Research Council, Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis, 1998, pp. 42-43 and 63-64.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

12. For example, see Space Studies Board, National Research Council, The Role of Small Missions in Planetary and Lunar Exploration, 1995, p. 23, and Space Studies Board, National Research Council, Supporting Research and Data Analysis in NASA's Science Programs: Engines for Innovation and Synthesis, 1998, pp. 63-64.

13. For example, see Space Studies Board, National Research Council, Assessment of Mission Size Trade-offs for Earth and Space Science Missions, 2000, in press, and Board on Physics and Astronomy and Space Studies Board, National Research Council, Astronomy and Astrophysics in the New Millennium, 2000, in press.

14. Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft Strategic Plan,” August 27, 1997, pp. 3-4.

15. Space Studies Board, National Research Council, Assessment of Technology Development in NASA's Office of Space Science, 1998, and Space Studies Board, National Research Council, “Continuing Assessment of Technology Development in NASA's Office of Space Science,” March 15, 2000.

16. Space Studies Board, National Research Council, Assessment of Technology Development in NASA's Office of Space Science, 1998, pp. 15-16.

17. Space Studies Board, National Research Council, “On NASA's Office of Space Science Draft Strategic Plan,” August 27, 1997, p. 4.

18. For example, see Mars Climate Orbiter Mishap Investigation Board, National Aeronautics and Space Administration, Report on Project Management in NASA, 2000, and National Aeronautics and Space Administration, Mars Program Independent Assessment Team Summary Report, 2000.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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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 [1978], An Integrated Strategy for the Planetary Sciences: 1995-2010 [1994], Evaluating the Biological Potential in Samples Returned from Planetary Satellites and Small Solar System Bodies [1998], A Science Strategy for the Exploration of Europa [1999], and Preventing the Forward Contamination of Europa [2000]) 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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×
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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

  1. 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.

  2. 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

  3. 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.

  1. 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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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 21stCentury.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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
×

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.

Suggested Citation:"4. Short Reports." National Research Council. 2001. Space Studies Board Annual Report 2000. Washington, DC: The National Academies Press. doi: 10.17226/10177.
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