Letter to Solar System Exploration Director Dr. Carl Pilcher from Dr. Michael Drake, Chair of SSES

Dear Carl:

The Solar System Exploration Subcommittee (SSES) of the Space Science Advisory Committee (SScAC) met from July 18 - 20 in Washington, D.C. The purpose of this letter is to summarize the findings and recommendations of that meeting. The SSES would appreciate responses to specific recommendations (in bold italic) at the December SSES meeting in Cocoa Beach.

Dr. Bergstralh gave a general briefing on the state of the Planetary Program. Dr. Weiler briefed the SSES on the state of the Space Science Program.

Discovery

The SSES reiterates that the cost cap on the Discovery Program has not been adjusted in recent years for inflation, increase in launch vehicle cost due to retirement of Delta II-class vehicles, and increased costs associated with the re-evaluation of the acceptable degree of risk. The SSES notes that the loss of small delta II-class launch vehicles has implications for Mars Scout and Explorer Program mission. The SSES recommends raising the Discovery Program cost cap to an appropriate level.

Space Operations Management Organization (SOMO)

Paul Hertz briefed the SSES on major challenges facing the Space Operations Management Organization (SOMO). The Deep Space Network (DSN) has no amortization budget and consumes its maintenance budget to preserve operations. The SSES agrees that it is essential that the SOMO problem be resolved expeditiously as there are major DSN activities critical to the Solar System exploration Division concentrated initially in the December 2003/January 2004 time frame, but recurring at later times. An inability to communicate with planetary spacecraft during critical maneuvers is unacceptable.

These problems translate into a budget shortfall for SOMO of about $400M over about five years. The Office of Space Science uses about 98% of the DSN usage. The SSES endorses Associate Administrator Weiler's solution of paying those costs from the Office of Space Science budget in return for control of the DSN. The SSES strongly endorses protecting Research and Analysis and Data Analysis from budget cuts arising from this unbudgeted expense, and accepts as inevitable some delay in the Discovery Program and the Mars Program. The SSES expects to be fully involved in discussions of program slippage and the impact of such slippage.

Extended Missions

The Solar System Exploration Program does not budget for extended missions. At its February 2001 meeting, the SSES specifically recommended planning for extended missions be incorporated into the Solar System Exploration Program budget. The SSES did not receive a response to this recommendation, hence it is reiterated here.

Terminating an expensive, viable spacecraft that still has high quality peer-evaluated science to conduct is an unconscionable squandering of the Nation’s resources. Every successful planetary mission in recent memory has conducted one or more extended missions, stretching the Solar System Exploration Program severely as the Director reprograms funds. Recent examples of the investment of small amounts of money compared to the overall cost of the missions in which new high-quality data of great scientific importance have been or will be returned are Galileo, Mars Global Surveyor, and NEAR-Shoemaker.

The SSES recommends:

1. Develop a plan to fund extended mission(s) for the Cassini spacecraft. It would be irresponsible to turn off a functioning $3B+ spacecraft if high priority peer-reviewed science remains to be done.

2. For all future missions, plan in advance for MO&DA funds for extended missions.

Mars

Orlando Figueroa and James Garvin briefed the SSES on the state of the Mars Program.

The SSES commends NASA on the introduction of its Mars Fundamental Research Program. The SSES urges NASA not to restrict content. This program will engage young scholars, facilitate interdisciplinary studies, etc. Program direction is best driven by unrestricted peer-reviewed proposals.

The Mars Program is at present healthy, but significant challenges lie ahead. In the short term, it is noted that the Mars Exploration Rovers are on a very tight schedule. On both short and long terms, the DSN presents challenges. The "traffic jam" in December 2003/January 2004 has been noted above. In addition, communicating with missions in the 2007 time frame, including the Scout mission, challenge existing DSN capabilities.

Finally, budget problems related to SOMO (see above) and possible Congressional action have serious negative implications for the Mars Program from FY 2002 onwards. In particular, Scout missions, designed to fill in gaps in the Mars Program and respond to new discoveries, appear to be in jeopardy.

For these reasons, the SSES looks forward to a briefing concerning the status of these critical Mars missions at its December meeting in Cocoa Beach, and expects to play an active role in any discussions of Mars Program modification.

Outer Planets

Colleen Hartman briefed the SSES on Outer Planets exploration. Several issues point to the fragility of the Outer Planets exploration.

First, the only approved mission is the Europa Orbiter mission. Its run-out costs have now risen to $1.2B. This mission is complex, operating deep in Jupiter's gravity well in an extremely high radiation environment, and there is no evidence that these costs can be reduced. The SSES requests an interim report from the Europa Study Team, commissioned by you to investigate alternative and cheaper ways of achieving Europa science objectives, at its December meeting in Cocoa Beach.

Second, Congress may approve a Pluto-Kuiper Belt mission. The SSES reaffirms that a Pluto-Kuiper Belt mission is its highest priority for an outer planets mission because of the unique orbital characteristics of Pluto with attendant scientific and mission operations implications. However, NASA has only two available RTGs. If one is used for Pluto, inadequate power is available for Europa Orbiter. NASA must urgently address the problem of power sources for outer planets missions.

NASA does not have a viable Outer Planets Program. The exploration of the outer solar system after Cassini depends critically on the success of one approved mission. It will be clearer by the next meeting whether this situation has changed.

Technology

Exploration of the outer solar system, interstellar space, and human missions will be greatly enabled with the development of two advanced technology lines. These technology lines should not be tied to specific missions, but should take the long view of enabling robust outer planets, interstellar, and human exploration.

The first technology line is In Space Propulsion. Current travel times to the outer planets are one to two decades. A robust Outer Planets Program requires the development of in space propulsion technologies. Such technologies would also reduce the exposure of humans on missions to Mars, and possibly make feasible robotic missions to nearby star systems.

The second technology line is Nuclear power. It is not practical to use solar cells for long term power on the surfaces of planets with dusty atmospheres like Mars, or in the outer solar system, and certainly not in interstellar space.

The SSES requests a briefing on the technology needs of the Solar System Exploration Division at its December meeting.

NASA HQ Reorganization

Colleen Hartman briefed the SSES on the reorganization of the Office of Space Science. The SSES was pleased to see clear lines of authority reestablished in the Office of Space Science and the Solar System Exploration Division.

Research and Analysis

Gunter Riegler briefed the SSES by telephone on the state of the Research and Analysis Program. The SSES commends Dr. Riegler on his responsiveness to SSES concerns outlined in its February 2001 letter. The SSES is particularly pleased to see the severe personnel shortage in Research and Analysis management addressed, and the introduction of procedures, which should reduce the processing time of grants.

Dr. Riegler also briefed the SSES on the outcome of the Senior Review. It is gratifying, if not surprising, to see that the peer-review process has ensured high quality, relevant research in almost all of NASA's Research Space Science Research and Analysis Programs. The Senior Review suggests that, with only about 1 in 3 proposals receiving funding, an across the board augmentation to Research and Analysis is warranted.

Astrobiology

Michael Meyer briefed the SSES on the state of the Astrobiology initiative, broadly defined. Both in basic research and education and public outreach Astrobiology appears to functioning very effectively.

Roadmapping

The SSES devoted a full day to the next Solar System Roadmap. An overarching theme of Solar System Evolution and Habitability emerged to guide our planning. Reports from the Inner Planets and the Outer Planets subcommittees, tasked at the February meeting, were received.

Ellen Stofan, chair of the Inner Planets subcommittee, reported on Evolution of a Habitable Planet. It was agreed that discussions of missions to Mercury were premature given that both MESSENGER and BEPI-COLUMBO are in development. Discussion centered on integrating Mars into his theme, even though it is a separate program. It was suggested that Venus missions might not be possible under the Discovery Program, with the probable exception of orbiters. The logical conclusion that the divergent paths of Venus, earth, and Mars should be the focus of this program, with mission to Venus and the Moon being an integral component. Sending technology demonstration packages to Venus' surface on any future Venus mission was also suggested. The Inner Planets subcommittee will recommend a specific strategy and mission set at the December meeting. A preliminary written document will be circulated by mid-September.

William McKinnon, chair of the Outer Planets subcommittee, reported on Exploring Organic Rich Environments. It was agreed that the objectives could best be met with an initial set of four missions. These missions, in priority order, are the Pluto-Kuiper Belt mission, the Europa Orbiter, the Comet Nucleus Sample Return (CNSR), and a Titan mission. The Pluto-Kuiper Belt mission will provide information on the building blocks available at the outer reaches of the solar system. The Europa Orbiter will provide information on the processing of outer solar system building blocks including possible biological evolution.. CNSR will provide information on the building blocks available in the region of the giant planets, from which Oort cloud comets are thought to be derived. A Titan mission, as a follow-on to the Cassini/Huygens mission, would provide information about prebiotic processing of material similar to that returned by the CNSR mission.

It was generally agreed that the objectives of the Titan mission must await the results of the Cassini-Huygens mission, arriving in 2005. Stardust should also return non-volatile cometary coma material in 2006, further guiding CNSR. The Outer Planets subcommittee will recommend a specific strategy and mission set at the December meeting. A preliminary written document will be circulated by mid-September.

Planetary Data System

Jay Bergstralh briefed the SSES on the results of a study commissioned by him and chaired by Rita Beebe. The SSES endorses the conclusions of the Beebe Report.

Curation of Extraterrestrial Materials

Carlton Allen briefed the SSES on the current state and future plans of the Johnson Space Center for the curation of lunar samples, cosmic dust, Antarctic meteorites, spacecraft parts, future Genesis solar wind samples, Stardust comet particles, and returned Mars samples. It is noted that many years lead-time is required for the scientific curation of returned samples. An appropriate facility is in place for Genesis, and workable plans are being developed for Stardust and Muses-C. Curation of the valuable samples from the latter missions may require new funding, since curation support was not considered when these missions were approved. The SSES urges NASA to develop concrete plans for curation of Mars samples and other returned samples, detail funding requirements, and plan for developing the necessary facilities.

Access to Space

A recurrent theme of the meeting was the loss of relatively inexpensive access to space with the retirement of the Delta II line and the difficulty of finding alternative access such as Arianne small-attached payloads (ASAP). Discovery missions are already being driven to the Program cost cap by lack of cheap access to space. This problem will likely affect Mars Scout missions as well. It is an Office of Space Science-wide problem that will also affect Explorer missions. It might be appropriate to examine the possible capabilities of planetary missions in the class of SMEX and MIDEX , with a view to initiating parallel Discovery missions.

With kindest regards.

Sincerely,

Michael J. Drake

Chair

Solar System Exploration Subcommittee