Space Studies Board Annual Report 2001 (2002)

A Report of the Committee on Planetary and Lunar Exploration

Samples of the planet Mars are expected to be collected by robotic spacecraft and returned to Earth for scientific study early in this century, perhaps as soon as 2015. There is a possibility, although it is acknowledged to be remote, that the samples will contain specimens of microorganisms that have lived on Mars, perhaps even in a viable state. The samples must be collected and handled in a way that will protect the terrestrial environment from contamination by these hypothetical organisms and also protect the samples from contamination by terrestrial organisms and other contaminants.

An essential element of the plan to handle martian samples responsibly is a quarantine facility, into which the samples will be received as soon as they arrive on Earth. Such a facility will perform the dual role of protecting the terrestrial environment and safeguarding the scientific integrity of the returned samples. In other words, it must combine the functions of a biological containment laboratory and a clean room.

Initial examination of the samples, including testing for potential biohazards, will be carried out in this facility, and the samples will be held there until conditions are met that permit release of aliquots¹ of the samples to the laboratories of investigators elsewhere in the United States and abroad who are qualified to carry out specialized studies of them, and who have been formally approved to do so.

COMPLEX has studied the time required to plan, build, and staff an adequate quarantine facility. The time needed is surprisingly long, 7 years (see Table 6.3 in Chapter 6). If Mars sample return and quarantine are to be taken seriously, this need must be addressed. It dictates the most important recommendation of this report:

COMPLEX considers that only the most basic operations should be conducted in the quarantine facility: unpacking, preliminary examination, baseline characterization, weighing, photography, splitting, repackaging, and storage. Another important operation will be the preparation of heat- and/or radiation-treated samples for distribution to the scientific community. In addition, certain life-detection studies that cannot be made on sterilized² samples—such as testing for biohazards—will have to be carried out in the quarantine facility. To try to bring other scientific studies with bulky, complex instrumentation into the containment facility, along with the personnel who conduct the studies, would unacceptably increase the complexity, cost, and potential for failure of the facility.

Recommendation

• The Mars Quarantine Facility should be designed to the smallest and simplest possible scale consistent with its role as a biological containment and clean room facility. No scientific investigations should be carried out in the quarantine facility that can be executed on sterilized samples outside the facility. [Chapter 6]

• Protocols should be developed that specify in detail the steps and procedures to be followed for handling Mars samples in the quarantine facility. Necessary protocols include those for inventorying and preliminary analyses of the samples, searching for evidence of biological activity, testing for biohazards, and preparing sterilized aliquots of the samples for distribution to the scientific community. [Chapter 6; see also Chapter 4.]

• Because it cannot be carried out on sterilized samples, biohazard assessment should be performed in the quarantine facility prior to any release of samples from the facility. Elements of these studies might include culturing experiments; attempts to infect animals, plants, and cell cultures; and genome detection via the polymerase chain reaction or similar techniques. [Chapter 6; see also Chapter 4.]

In addition to studying the optimal properties of a quarantine facility, COMPLEX has also considered life-detection techniques to be employed within (and outside) it, and the means of sterilizing samples within the facility so they can be removed from it. One important approach to life detection involves the extraction of key organic compounds (biomarkers, diagnostic of life processes) from samples for analysis at specialized laboratories outside the quarantine facility. Removal of these extracts from the facility will be contingent upon demonstration that the effects of the extraction process would be more than adequate to kill any known terrestrial organism.

Much of the program of life detection will depend on studies of organic compounds in samples that were sterilized so they could be removed from the quarantine facility. Unfortunately, COMPLEX’s recommended techniques for sterilization—treatment by heat and or gamma radiation to such a level as to kill any known terrestrial organism—damage organic compounds to some extent. The vulnerability of organic compounds to heat and gamma-ray treatment is only imperfectly known. It is important that studies be carried out to enlarge knowledge in this area.

The nature of the quarantine facility, which must satisfy dual and partly conflicting requirements, is an important topic of study.

COMPLEX considers that affiliation of the quarantine facility with an ongoing containment facility (e.g., the U.S. Army Medical Research Institute of Infectious Diseases, in Ft. Detrick, Maryland; the Centers for Disease Control and Prevention, in Atlanta, Georgia; or the Medical Branch of the University of Texas at Galveston, where a BSL-4 facility is being constructed) is preferable to independent construction, for several reasons. These include:

1. Institutional support. A collaborative agreement with a host institution would mean that the Mars Quarantine Facility could draw on that institution for personnel, training, experience, security, and specialized utilities.

2. Economy. Sharing the resources named under 1 above should effect a large economy in operation of the Mars Quarantine Facility.

3. Environmental impact. Clearing an environmental impact statement for a BSL-4 facility can take years. Ideally, the Mars Quarantine Facility would operate under the environmental impact statement of its host institution.

Several initiatives cited above should be begun prior to design of the quarantine facility and planning of quarantine protocols, i.e., immediately: research on the efficacy of supercritical fluids and commonly used organic solvents in killing organisms; on the effects of varying degrees of treatment by heat and by gamma irradiation on organic compounds; and on ways of combining biological containment with clean-room conditions. An oversight committee should be formed to monitor these activities (see below, “The Apollo Experience”).

It is possible that the Mars sample return program will be an international venture, with other nations playing an important role in flight operations. The role of international partners in a sample return program should be carefully defined. The potentially sizeable contribution of another nation to the Mars program raises questions of how the earliest access to and ultimate curation of the samples will be shared. It is beyond the scope of COMPLEX’s charge to comment on the ultimate curation of the samples, but the committee believes strongly that, for practical reasons, their preliminary examination, baseline description, cataloguing, and packaging should be carried out at a single quarantine facility in the United States.

COMPLEX considered the possible results of initial searches for evidence of life³ in the martian samples, especially analyses of the samples for total organic carbon. The committee recommends the following:

Recommendation

• If the samples returned from Mars contain evidence of life, or if evidence of life is equivocal (e.g., organic matter is present), aliquots that have been treated by the application of heat and/or gamma radiation to levels more than adequate to kill any known terrestrial organism (Chapter 5) should be certified for release from the Mars Quarantine Facility. [Chapter 4]

• If the samples contain evidence of life, or if evidence of life is equivocal, removal of untreated aliquots from the Mars Quarantine Facility for transfer to approved containment laboratories elsewhere should not be excluded, on the condition that containers and transfer procedures conform to protocols established by a panel of experts (e.g., from the Centers for Disease Control and Prevention) in containment.

  Here “approved containment facilities elsewhere” refers principally to the case where a major international partner in the Mars sample return program wishes to establish an independent BSL-4 facility in which to study untreated samples (see Chapter 6). [Chapter 4]

• If the samples are shown to be altogether barren of organic matter, to contain no detectable organic carbon compounds and no other evidence of past or present biological activity, untreated aliquots of the samples should be released for study beyond the confines of the Mars Quarantine Facility. [Chapter 4]

The possibility that the martian samples will contain unequivocal evidence of life is very remote, and for this reason COMPLEX’s response is based on the far more likely contingency that evidence of life will be equivocal or absent altogether. Unequivocal evidence of life would dictate a very elaborate plan of handling, curation, and study, which COMPLEX has not attempted to develop.

Historically (e.g., with Apollo and the Viking Landers) there has been a degree of competition between biological and physical scientists for access to planetary research materials, and COMPLEX anticipates that this competition may be particularly intense where the martian samples are concerned. The above recommendation concedes that discovery of life in the samples would be of such supreme importance that the wishes of physical scientists should be subordinated to biological studies of the samples if this happens.

However, the discovery of life in the martian samples is unlikely, and in the far more probable case that only equivocal evidence of life is found, COMPLEX recommends that (sterilized) aliquots of the samples be made available to both biological and physical scientists for study. (Potential life-detection studies are not wholly compromised by sterilization.) COMPLEX is concerned that distribution of these samples not wait on resolution of uncertainties in the evidence, which can take a very long time (years) to occur. Scientists who have prepared their laboratories and staffs to study the samples should be allowed to begin work on them, and the results of their studies will provide important feedback for the planning of later Mars missions. Moreover, the public would find it difficult to understand why the study of samples from a much-publicized mission would be deferred for a period of years.

COMPLEX reviewed details of the Lunar Receiving Laboratory, a quarantine facility constructed and used during the Apollo program, and attempted to profit from its triumphs and failures. Lessons learned in the review (Chapter 7; see also Appendix B) led COMPLEX to make these recommendations:

Recommendation. A continuing committee of senior biologists and geochemists that includes appropriate international representation should be formed and charged with reviewing every step of the planning, construction, and employment of the Mars Quarantine Facility. The committee should be formed during the earliest stages of planning for a Mars sample-return mission. Members of the committee should also participate in the design of the spacecraft and those portions of the mission profile where biological contamination is a threat. [Chapter 6]

A Report of the Committee on the Organization and Management of Research in Astronomy and Astrophysics

In its fiscal year 2002 budget summary document¹ the Bush administration expressed concern—based in part on the findings and conclusions of two National Research Council studies²—about recent trends in the federal funding of astronomy and astrophysics research. The President’s budget blueprint suggested that now is the time to address these concerns and directed the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) to establish a blue ribbon panel to (1) assess the organizational effectiveness of the federal research enterprise in astronomy and astrophysics, (2) consider the pros and cons of transferring NSF’s astronomy responsibilities to NASA, and (3) suggest alternative options for addressing issues in the management and organization of astronomical and astrophysical research. NASA and NSF asked the National Research Council to carry out the rapid assessment requested by the President. This report, focusing on the roles of NSF and NASA, provides the results of that assessment.

Overall, the federal organizations that support work in astronomy and astrophysics manage their programs effectively. These programs have enabled dramatic scientific progress, and they show excellent promise of continuing to do so. Nonetheless, the existing management structure for the U.S. astronomy and astrophysics research enterprise is not optimally positioned to address the concerns posed by the mounting changes and trends that will affect the future health of the field.

The existing management structure for astronomy and astrophysics research separates the ground- and space-based astronomy programs. NSF has responsibility for the former and NASA has responsibility for the latter. The ground-based optical/infrared observatories funded by private and state resources constitute an important third component of the system. In astronomical and astrophysical research, NASA’s strength has been the support of work related to major space missions. NSF’s strength in astronomy and astrophysics has been the support of a broad spectrum of basic research motivated by the initiative of individuals and small groups in the scientific community and by its role in assuring the continued availability of broadly educated scientists. The NSF also funds research in related fields such as physics, geophysics, computation, chemistry, and mathematics, providing a broad multidisciplinary context for astronomy and astrophysics research that can promote productive connections among these fields.

Three important changes have occurred in the field over the last two decades. First, ground- and space-based research activities have become increasingly interdependent as well as increasingly reliant on large facilities, major missions, and international collaborations. Second, NASA’s relative role in astronomy and astrophysics research has grown markedly. (In 1980, most of the research grants in the fields of astronomy and astrophysics were provided by NSF. Today, most of the grants are provided by NASA.)³ And third, large state-of-the-art optical/ infrared telescopes built with non-federal funds now dominate this component of ground-based astronomy.

These changes necessitate systematic, comprehensive, and coordinated planning in order to sustain and maximize the flow of scientific benefits from the federal, state, and private investments that are being made in astronomy and astrophysics facilities and missions. The increasing financial and intellectual demands to be met by more than one nation in supporting large projects, particularly on the ground, require that the United States develop a unified planning and execution structure to effectively participate in such international ventures. To develop the needed integrated and comprehensive strategy for the field, the committee recommends the formation of an interagency planning board for astronomy and astrophysics.

The Committee on the Organization and Management of Research in Astronomy and Astrophysics was charged to consider, among other options, moving NSF’s astronomy responsibilities to NASA.⁴ Such a move would consolidate the bulk of the federal programs⁵ in a single agency and, to some degree, integrate space- and ground-based astronomy. The committee concluded, however, that moving NSF’s astronomy and astrophysics activities to NASA would have a net disruptive effect on scientific work. Because of its combined commitment to investigator-initiated research, interdisciplinary research, and educating the scientists of the future, NSF is the right institution to sponsor ground-based astronomy and astrophysics. And further, such a move would not necessarily address integration of the third component of the system (i.e., the ground-based optical/infrared private and state observatories). NSF’s close working relationship with the college and university community makes it the natural focus for integration of this third component. The committee’s recommendations address improving the present

overall management structure, as well as strengthening NSF’s ability to support ground-based astronomy and astrophysics and to work effectively in conjunction with the other two primary components of the system. The committee’s detailed recommendations are contained in Box ES.l.

In Chapter 1 the committee discusses the discipline of astronomy and astrophysics and the role of the periodic self-assessments carried out by the community.⁶Chapter 2 summarizes the roles and responsibilities of NASA and NSF and discusses some key aspects of their missions, program management approaches, and planning processes. Chapter 2 also describes the need for more cooperation and coordination between these two primary funding agencies for the discipline, and it mentions a few related issues that affect the implementation of the recommendations that arise from the community’s self-assessments. Chapter 3 specifically addresses the advantages and disadvantages of moving NSF’s astronomy and astrophysics responsibilities to NASA. In Chapter 4 the committee presents its findings and recommendations. Committee biographies, meeting agendas, detailed funding and organization data, and a glossary and acronym list are included as appendixes.

A Report of the Task Group on Research on the International Space Station

The International Space Station has been officially under development by NASA since the late 1980s. Numerous changes in schedule and cost projections throughout the 1990s have prompted reevaluations of the number and scale of the major facilities that would eventually be placed on board; the schedule for developing, deploying, and utilizing those facilities; and the critical resources such as crew time and power needed to support ISS science research. As a result, specific concerns over schedule delays and potential downgrading of the ISS research capabilities have been growing for several years in the scientific community. In the fall of 2000, Congress directed the National Research Council (NRC) and the National Academy of Public Administration (NAPA) to organize a joint study of the status of microgravity research in the life and physical sciences as it relates to the International Space Station (ISS). The study is being conducted in two phases. This phase-1 report addresses the question of the scientific community’s readiness to use the ISS for life and physical sciences and assesses the relative costs and benefits of dedicating an annual space shuttle mission to research versus simply maintaining the current schedule for assembly of the ISS.

Subsequent to the initiation of this study, NASA announced large cost overruns for the construction of the ISS (Goldin, 2001). As a consequence, major changes were proposed by the agency in the ISS design that would reduce the total ISS crew capacity from six or seven to three, and cancel or delay indefinitely the development and deployment of many of the planned major research facilities. To accommodate both the possibility of a rescoped station and the uncertainty regarding the actual extent of such a rescoping, the Task Group on Research on the International Space Station chose to consider two alternate scenarios in developing its conclusions. In the first scenario the task group assumed that the August 2000 design for the ISS,¹ designated “Rev. F” by NASA,² remains unchanged. Under Rev. F, the ISS would support a full crew of six to seven astronauts and provide fully instrumented, dedicated facilities for research in a range of science disciplines. In the second scenario the task group assumed that the design and schedule changes contained in the proposed fiscal year (FY) 2002 budget for NASA are implemented. The proposed changes would result in a three-person crew and deletion or indefinite delay of a large number of research facilities, supporting hardware, and experiment modules. For convenience, this scenario is referred to as “proposed Rev. G” in this report.³

The task group was extremely concerned about the schedules for the development and deployment of ISS research facilities that were presented by NASA during the course of this study. In the task group’s view, a fully equipped ISS—including adequate crew support, electrical power, and experiment accommodations—needs to be in operation if NASA’s scientific objectives are to be achieved. Proposed reductions in crew size, facilities, and power have caused great concern in the scientific community. Specific concerns expressed by groups representing the ISS user community (Sekerka, 2001; Fettman, 2001; Katovich, 2001) have strengthened this task group’s view that the future of science on the ISS would be severely impaired under the proposed Rev. G scenario.

Based on a review of NASA’s program data—including ISS experiments planned, rates of proposal submission, and success and student funding levels—as well as input from members of the ISS user community, the task group reached the following conclusions:

• The U.S. scientific community is ready now to use the ISS.

• However, this readiness cannot be sustained if:

  • The proposed reductions in the scientific capabilities of ISS take effect, or

  • Slippage continues in both the development and science utilization schedules for the ISS as currently proposed, or

  • Uncertainties continue in funding for science facilities and flight experiments on the ISS.

Proposed reductions in available experiment accommodations, crew, and power raise concerns about the ultimate functionality of ISS and thus directly affected the task group’s consideration of whether additional shuttle flights dedicated to science should be flown during ISS assembly and outfitting.

The task group concluded that ISS science could not proceed without the appropriate crew support and a clearly defined time line for deployment and completion. If the present Rev. F design and schedule were maintained, then it would be preferable to proceed with construction of a fully equipped ISS rather than divert resources to fly ISS science on additional shuttle missions. However, if ISS capabilities were to be reduced below Rev. F levels and there were no annual microgravity research-dedicated shuttle flights, then the viability of the overall program in microgravity research would be seriously jeopardized, as would the ability of NASA to achieve its stated scientific goals for the ISS. Therefore, if it becomes apparent that the ISS will not be available for meaningful microgravity research by the beginning of FY 2006, then annual shuttle flights dedicated to microgravity experiments should be made a part of the program.

Specifically, the task group recommends that:

1. Assuming that the Rev. F schedule and capability are achieved, then:

   1. If ISS development were to be the funding source for additional microgravity shuttle flights, then no additional shuttle flights should be planned for microgravity research.

   2. If funding were to be provided from new sources, then it would be highly beneficial to fly additional annual flights until the ISS (with Rev. F capabilities) is complete.

2. Assuming that the proposed Rev. G schedule and capability are selected, then:

   1. If capabilities were to be reduced according to Rev. G projections, then annual shuttle flights devoted to science should be flown until the ISS reaches either the research capability planned for “assembly complete” under Rev. F, or a similar level of capability that has been reviewed and approved by an independent body of scientists that can credibly represent the interests of the ISS user community.

In case B above, it should be noted that plans to use the shuttle will have to be integrated into the overall NASA mission planning by 2004. These recommendations also assume that the currently planned space shuttle microgravity missions, STS-107 and STS-123 (R2), planned for 2002 and 2004 respectively, are conducted as scheduled. Also, the activities described above should not be accomplished in such a manner as to jeopardize the sustainability and readiness of the program for microgravity research in the biological and physical sciences.

Fettman, Martin J. 2001. Letter to Joel Rothenberg on funding for the Space Station Biological Research Project. Colorado State University, College of Veterinary Medicine and Biomedical Sciences, March 9. Photocopy.

Goldin, Daniel S. 2001. Statement before the U.S. House of Representatives Committee on Science, April 4. Available online at <http://www.hq.nasa.gov/office/legaff/goldin4-4.html>.

Katovich, Michael J. 2001. Letter to the Honorable Barbara A. Mikulski on funding for the Space Station Biological Research Project. University of Florida, College of Pharmacy, June 28. Photocopy.

Sekerka, Robert F. 2001. Letter to the Honorable Barbara A. Mikulski on the level of ISS research funding. Carnegie Mellon University, Department of Physics, June 27. Photocopy.

A Report of the Committee on Planetary and Lunar Exploration

Within the Office of Space Science of the National Aeronautics and Space Administration special importance is attached to exploration of the planet Mars, because it is the most Earth-like of the other planets in the solar system and the place where the first detection of extraterrestrial life seems most likely to be made. The failures of two NASA missions in 1999, the Mars Climate Orbiter and the Mars Polar Lander, caused the space agency’s program of Mars exploration to be systematically rethought, both technologically and scientifically, and a new Mars Exploration Program (Appendix A) was announced in October 2000. COMPLEX (the Committee on Planetary and Lunar Exploration), a standing subcommittee of the Space Studies Board of the National Research Council, was asked to examine the scientific content of this new program. The charge to COMPLEX was as follows:

• Review the state of knowledge of the planet Mars, with special emphasis on findings of the most recent Mars missions and related research activities;

• Review the most important Mars research opportunities in the immediate future;

• Review scientific priorities for the exploration of Mars identified by COMPLEX (and other scientific advisory groups) and their motivation, and consider the degree to which recent discoveries suggest a reordering of priorities; and

• Assess the congruence between NASA’s evolving Mars Exploration Program plan and these recommended priorities, and suggest any adjustments that might be warranted.

COMPLEX comprehensively reviewed Mars science in nine disciplinary areas, working its way from the interior of the planet (Chapter 2) outward to the upper atmosphere (Chapter 10). The committee heard presentations by experts in all these areas and wrote chapters structured to reflect the charge: Each chapter begins with a review of the present state of knowledge and then discusses near-term opportunities, presents recommended scientific priorities, and offers an assessment of priorities in the mars exploration program. COMPLEX drew on the publications of 11 earlier committees (including COMPLEX in years past) to compile its recommended scientific priorities; these sets of previously published recommendations appear in Appendix B. A document prepared in 2001 by James B. Garvin and Orlando Figueroa of the NASA Office of Space Science, titled “The Mars Exploration Program: A High-level Description” (reprinted in Appendix A), provided the basis for comparisons with the recommendations, which appear in the “Assessment of Priorities in the Mars Exploration Program” sections of Chapters 2 through 10.

Chapter 12 is a synthesis of the assessments of priorities that appear in Chapters 2 to 10. COMPLEX judged NASA’s responsiveness to the past recommendations of advisory panels to be, on the whole, good, although there is weakness in some areas. COMPLEX acknowledges that budgetary constraints prevent all worthy research goals from being pursued simultaneously, and endorses the space agency’s concentration of its effort in areas related to the fundamental question, Did life ever arise on Mars? It is important that efforts to answer this question are broadly based, and that they be equally prepared for the answer to be negative or positive. The implications of either answer to the question will only be fully understood once there is a broad and deep understanding of Mars.

The new Mars Exploration Program recognizes the importance of gaining information about the surface, atmosphere, hydrosphere, and interior of the planet to arrive at an understanding of the Mars dynamic system and a global context for assessment of the biological potential of Mars (Chapter 12). However, COMPLEX notes that

NOTE: "Executive Summary" reprinted from republication version of Assessment of Mars Science and Mission Priorities, approved for release November 7, 2001

NASA has no plans for missions that address high-priority questions about the interior of Mars. Similarly, there is an absence of NASA missions that specifically address Mars’s atmosphere, climate, polar science, ionosphere, and solar wind interactions. Direct measurements of the distribution and behavior of near-surface water are needed. Some but not all of these goals will be addressed by upcoming foreign Mars missions such as Nozomi, Mars Express, Beagle 2, and the NetLanders. COMPLEX urges NASA to continue its support for U.S. participation in Mars missions conducted by NASA’s international partners. A full picture of the science of Mars is needed to support the quest for martian life.

Water is a topic of particular interest on Mars, not only for its own sake but because it is a prerequisite for life. This is so widely recognized as to have engendered the slogan in advisory and planning circles, “Follow the water.” In light of this, there is surprisingly little emphasis on spacecraft experiments designed to detect and study crustal water and ice. COMPLEX believes that this subject needs more attention. In Chapter 12 COMPLEX offers for consideration 10 spacecraft experiments that it considers would advance Mars science, but the committee attempts to be realistic about the factors that mitigate against them.

COMPLEX attaches special importance to the prospect of sample return missions to Mars (Chapter 11). The return of Mars samples has been consistently advocated by advisory panels for over 20 years as the most effective way to greatly increase our understanding of the origin and evolution of the martian environment. No other single strategy can answer so many of the questions about martian chemistry, geology, climatology, and the presence of or potential for life, past or present. Irrespective of the number of orbiters or rovers sent to Mars, we will not come to grips with these fundamental issues until documented samples are available for study in terrestrial laboratories.

The committee feels enough information is at hand already, much of it from the Mars Global Surveyor mission, to choose the first sites to be sampled intelligently, and sample return need not wait on additional reconnaissance missions (Chapters 11, 12). Even if the first returned samples are not optimal in terms of siting, they will provide a greatly enhanced view of the geologic processes on Mars. Even a grab-sample of soil from a randomly chosen site on the planet would reveal the character of martian surface material: its chemistry, oxidation state, content of organic materials, mineralogy, and the history of weathering reactions that have affected it. Detailed knowledge of the surface material will permit a more intelligent choice of measurements to be made by future remote sensing missions. Exercise of selectivity in landing sites will open additional doors: Samples from a formerly fluvial environment, for example, might be found to include rocks with diverse compositions and ages, sedimentary rocks that contain a record of acqeuous activity on the martian surface, conceivably even fossil evidence of life.

Since sample return missions are expensive and will tend to preempt the resources of the Mars Exploration Program, a key question is how many of them are needed. COMPLEX concluded that it cannot be realistically anticipated that the first sample return from Mars will unlock all of the planet’s secrets, because orbital observations have shown that Mars’s geologic and climatic history is best exposed in widely separated, isolated locations, and a complete picture of Mars history is unlikely to be obtained from samples collected at a single location. Instead the first sample return should be seen as a trailblazer for future sample return missions, and it should be used to develop the key technologies, procedures, and infrastructure necessary to embark on a future program in which samples are returned from many locations on the planet. COMPLEX estimates that the order of 10 sample return missions, necessarily executed over a protracted period of time, may be required to learn the most important things researchers want to know about Mars. A protracted schedule of exploration will allow time for the information gained by each mission to be digested and fed into the planning of the next mission, and it will permit substantial redesign of the spacecraft and sampling system between missions.

Considerations of planetary protection dictate that stringent measures be taken during a sample return mission to prevent biological contamination of either Earth or Mars. An essential measure is the construction of a quarantine facility to receive and contain the samples when they arrive on Earth. COMPLEX reiterates the conclusion of its recent report (Space Studies Board, 2001) that a long lead time is required to prepare the Mars Quarantine Facility. On the basis of prior experience with facilities of this type, COMPLEX estimated that 7 years will be required to design, construct, and staff the facility. To this must be added the time needed to clear an environmental impact statement and to carry out several reconnaissance studies (identified in Space Studies Board, 2001) that are needed to inform the design and operation of the facility. The aggregate of time required may strain the schedule even of a 2011 launch. The message is plain: Preparations for a sample return should not be delayed any longer than they already have been (Chapter 12).

Chapter 7 elaborates on this recommendation, reiterating the recommendations of Space Studies Board (2001).

• The Mars Quarantine Facility in which Mars samples will be processed, stored, and released for scientific study, and in which a very limited range of studies will be carried out, must be designed, built, and certified (Space Studies Board, 2001).

• Research must be initiated on several outstanding questions that will affect the design of the Mars Quarantine Facility (e.g., combining biological isolation with clean-room conditions; establishing the efficacy and detrimental effects of sterilization techniques) (Space Studies Board, 2001).

• The study of life in extreme environments on Earth, which can aid in the design of life detection tests, should be supported (this is already being done). In general, research areas that improve the sensitivity of life detection techniques must be supported, and a life detection protocol to be implemented and tested in the Mars Quarantine Facility must be developed.

• Techniques must be developed for the collection, packaging, and return of samples.

• The research programs of Mars orbiter and lander missions must be designed to support the collection of those samples with the greatest potential for life detection (under way).

COMPLEX also considered several other topics important to Mars exploration (Chapter 12).

An extremely important consideration in establishing the capabilities of landed packages on Mars, static or roving, is the power supply they rely on, the options being solar panels and radioactive power sources (RPS). The limitations placed on landed spacecraft by solar power supplies are reviewed. From a science viewpoint the advantages of nuclear power—long-lived missions and access to any point on Mars—are clear. COMPLEX urges the use of nuclear power sources, if at all feasible, on advanced Mars lander missions.

There is concern in the Mars science community that the Scout Program, the youngest and smallest element of the Mars Exploration Program, may also be the most vulnerable. The fear is that the Scout Program may not achieve its potential because it will be sacrificed in times of budget stringency. COMPLEX considers that this would be unfortunate.

COMPLEX also noted that the Mars Exploration Program, with its missions at 2-year intervals, presents a new problem in fully exploiting the amount and variety of data that will be collected. The volume and quality of data returned by Mars Global Surveyor alone have been extraordinary, and the analysis of these data is only beginning. With the rapid pace of Mars missions planned for the next decade, the flood of data can be expected to increase. This problem should be recognized, and NASA’s data analysis and science programs should be structured to accommodate and support the broad range of Mars science that is to come.

The Mars Exploration Program consists of a queue of flight missions, so the present assessment of the program also discusses flight missions and rarely touches on Earth-based research. However, the latter is an essential component of the total program of Mars research, and in Chapter 1 COMPLEX acknowledges several areas of Earth-based Mars research, urging continued support of these and other areas of Earth-based research because they are essential to a balanced program of Mars research.

Space Studies Board, National Research Council, The Quarantine and Certification of Martian Samples, National Academy Press, Washington, D.C., released 2001.

A Report of the Committee on Microgravity Research

The portfolio of the Physical Sciences Division (PSD) at NASA is centered largely on microgravity research, which includes research on the effects of gravity on a wide array of physical and chemical processes, as well as the use of reduced gravity to perform experiments that cannot be undertaken on Earth. The majority of the current PSD portfolio consists of research in the following disciplines:

• Fluid behavior,

• Combustion science,

• Materials science,

• Fundamental physics, and

• Biotechnology.

Research in each of these areas has been performed by an extensive cadre of ground-based and flight investigators from academia, government, and industry, with the flight investigators utilizing an array of carriers ranging from the International Space Station to KC-135 aircraft. The access to the microgravity environment provided by these platforms, and the extensive engineering and technical support provided to the investigators, are distinctive assets offered by the PSD research program.¹

As a result of recent NASA reorganizations and the realignment of research areas, the Committee on Microgravity Research was asked to consider the expanded portfolio of the PSD, which now includes biomolecular physics and chemistry, nanotechnology, and technology relevant to human exploration and development of space (HEDS). These are research areas in which reduced gravity does not necessarily play an important role. Specifically, in this Phase I report, the committee was asked to identify, in general terms, research opportunities within these broad new areas that could profitably be pursued by the PSD. It should be noted that when identifying new opportunities the committee considered only research that fell within these new areas defined by NASA. In addition, the committee was asked to develop an overall mission statement that would encompass the expanded portfolio of the physical sciences research program, and broad guidelines for determining whether specific research questions should fall within the expanded program.

In composing a broad mission statement for PSD research, the committee examined the scope of the program’s existing research portfolio as well as NASA’s plans for the future. The committee is, in principle, in favor of PSD plans to take on the new areas of biomolecular physics and chemistry, nanotechnology, and research supporting HEDS technology development, since they are relevant to questions of both scientific and practical importance to NASA. For example, novel insights into nanoscale phenomena and the availability of an increasing number of nanoanalytical tools will have a major impact on NASA’s ability to generate and store power in space, manufacture lightweight materials on the ground and in space, design materials with integrated sensory functions, and develop new sensor technologies. With its strong record and tradition of supporting basic and cross-disciplinary research at the interfaces between physical sciences, engineering, and—lately—cellular biotechnology, as well as extensive experience in the study of fundamental phenomena, the PSD is the most suitable division at NASA to address the new areas of nanoscale materials and processes, biomolecular physics and chemistry, cellular biophysics and chemistry, and integrated systems for HEDS.

However, the committee notes that over the past 20 years the PSD has built up a unique set of expertise, skills, infrastructure, and facilities that allow it to design and execute sophisticated experiments in space. Access to the microgravity environment continues to be a necessary requirement for the elucidation of a host of scientific questions, ranging from fundamental physical laws to basic fluid flow, materials, and combustion phenomena. In fact, a large program of experiments in these areas, representing a considerable investment of time and effort by the scientific community, is now awaiting flight on the International Space Station. Therefore the committee recommends that while assuming responsibilities for new areas, the PSD should strive not to sacrifice or jeopardize the investment in research programs and proven capabilities that it has developed to date.

When selecting research topics in the emerging areas involving nanotechnology, including nanoscale materials and processes, biomolecular physics and chemistry, cellular biophysics and chemistry, and integrated systems for HEDS, the PSD should focus on those that meet both of the following criteria:

1. Directly address challenges at the interface between the physical sciences, engineering, and biology in support of NASA’s mission, preferentially capitalizing on existing expertise or infrastructure in the Physical Sciences Division, and

2. Support research either not typically funded by other agencies or to be conducted in close partnership with other agencies.

The committee encompassed all of these considerations in a mission statement for the Physical Sciences Division:

The mission of the Physical Sciences Division is threefold: to conduct research in a low-gravity environment; to probe the role of gravity in physical processes; and to investigate the fundamental physical principles behind emerging technologies relevant to NASA’s mission.

The new areas being added to the PSD program encompass emerging fields and thus can be characterized in various ways. To minimize overlap, the committee divided the areas into (1) nanoscale materials and processes, (2) biomolecular physics and chemistry, (3) cellular biophysics and chemistry, and (4) integrated systems for HEDS. A unifying theme of nearly all the research in these areas is that the processes of interest occur at the nanoscale. The confluence of the biological, physical, and engineering sciences at the nanoscale is an ideal area for NASA to effectively leverage the investments made by the National Science Foundation, National Institutes of Health, and other organizations to accelerate its own mission. Further, the committee believes that these areas do provide promising opportunities to build on PSD’s scientific capabilities and leverage its current research activities. However, because the PSD is likely to have only limited resources for research in these very broad fields of endeavor, it should seek out those research niches where its unique capabilities and expertise will allow it to have a maximum impact.

The committee selected a few examples, listed below, of broad research topics within each of the new areas that would meet the recommended selection criteria. Many other suitable topics are likely to emerge from the research community in the coming years.

• Nanoscale Materials and Processes

  • Nanoparticle formation

  • Integrated nanomaterials

  • Micro- and nanofluidics

• Biomolecular Chemistry and Physics

  • Proteins in confined space

  • Energy storage and chemically driven nanosystems

  • Smart and self-healing materials

• Cellular Biophysics and Chemistry

  • Long-term stabilization of cell cultures

  • Low-gravity effects on cellular and subcellular processes

• Integrated Systems for HEDS

  • System integration of nanoengineered particles and devices

A Report of the Steering Committee on Space Applications and Commercialization

Over the past decade renewed interest in practical applications of Earth observations from space as coincided with and been fueled by significant improvements in the availability of remote sensing data and in their spectral and spatial resolution. In addition, advances in complementary spatial data technologies such as geographic information systems and the Global Positioning System have permitted more varied uses of the data. During the same period, the institutions that produce remote sensing data have also become more diversified. In the United States, satellite remote sensing was until recently dominated largely by federal agencies and their private sector contractors. However, private firms are increasingly playing a more prominent role, even a leadership role, in providing satellite remote sensing data, through either public-private partnerships or the establishment of commercial entities that serve both government and private sector Earth observation needs. In addition, a large number of private sector value-adding firms have been established to work with end users of the data.

These changes, some technological, some institutional, and some financial, have implications for new and continuing uses of remote sensing data. To gather data for exploring the importance of these changes and their significance for a variety of issues related to the use of remote sensing data, the Space Studies Board initiated a series of three workshops. The first, “Moving Remote Sensing from Research to Applications: Case Studies of the Knowledge Transfer Process,” was held in May 2000. This report draws on data and information obtained in the workshop planning meeting with agency sponsors, information presented by workshop speakers and in splinter group discussions, and the expertise and viewpoints of the authoring Steering Committee on Space Applications and Commercialization. The recommendations are the consensus of the steering committee and not necessarily of the workshop participants.

Rather than trying to cover the full spectrum of remote sensing applications, the steering committee focused on civilian remote sensing applications in the coastal environment.¹ The workshop featured three case studies in coastal management involving (1) the application of Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) data in monitoring harmful algal blooms, (2) the use of airborne lidar bathymetry for monitoring navigation channels, and (3) the use of both satellite and aerial remote sensing to identify sewage outflows. All three provided detailed information on the applications as well as problems encountered in developing them, allowing the steering committee to learn from the real-world experiences of particular users.

In addition, participants in five workshop splinter sessions—on education and training, institutional, technical, and policy issues in technology transfer, user awareness and needs-identified and discussed more general barriers bottlenecks that interfere with the development of remote sensing applications and also explored ways to overcome such problems. Plenary presentation focused on research on technology transfer; science and policy issues in the coastal zone; a comparison of remote sensing technology transfer with respect to geographic information systems and the Global Positioning System; and new directions in the use of remote sensing data. This material provided a basis for much of the steering committee’s analysis and figured significantly in its development of the report’s findings and recommendations.

To encourage finding more effective ways to develop new and useful applications of remote sensing data, the steering committee considered barriers to as well as opportunities for developing successful applications through

the transfer of knowledge and technology.² Its examination of the remote sensing technology transfer process led to the identification of a number of gaps that must be bridged in order to develop effective civilian applications:

• The gap between the raw remote sensing data collected and the information needed by applications users. Users need information, and the process of transforming data into information is a critical step in the development of successful remote sensing applications.

• The gap in communication and understanding between those with technical experience and training and the potential new end users of the technology. Producers and technical processors of remote sensing data must be able to understand the needs, cultural context, and organizational environments of end users. Education and training can also help to ensure that new end users have a better understanding of the potential utility of the technology.

• The financial gap between the acquisition of remote sensing data and the development of a usable application. The purchase of data is only the first of a large number of steps affecting the cost of a successful application. An organization, commercial firm, or government agency that wants to incorporate remote sensing applications into its operations must be prepared for a long-term financial investment in staff, ongoing training (both technical and user training), hardware, and software, at a minimum. Alternatively, the potential user organization should be prepared to purchase these services from a value-adding provider.

Another recurring theme in workshop discussions was the need for data continuity. In light of the heavy, up-front investment required to develop and use remote sensing applications, organizations as well as individual users have to be assured of a reliable and continuous source of both data and information.

Finding. The full, life-cycle cost of developing and using remote sensing data products goes beyond obtaining the data and includes, among others, staff for data processing, interpretation, and integration; education and training; hardware and software upgrades; and sustained interactions between technical personnel and end users (see Chapter 3). Although many of these costs are incurred at the time a technology is first employed, the life-cycle costs and benefits of remote sensing applications are not well understood.

Recommendation 1. NASA’s Office of Earth Science, Applications Division, in consultation with other stakeholders (e.g., agencies that use remote sensing data, such as the U.S. Geological Survey, Department of Transportation, Environmental Protection Agency, and U.S. Department of Agriculture; private companies; state and local government users; and not-for-profit institutions), should mount a study to identify and analyze the full range of short- and long-term costs and benefits of developing remote sensing applications and the full costs of their implementation by public, nongovernmental, and other noncommercial users. In addition, NASA should support economic analyses to reduce the start-up costs of developing new remote sensing applications.

Finding. Training is an integral component of efforts to bridge the gap between remote sensing professionals and end users (see Chapters 3 and 4). Remote sensing involves sophisticated technology, and specialized

training is required to process the data, convert it into information, and interpret the results. Many agencies and organizations either lack the financial resources to provide such training or do not understand the importance of periodic retraining for technical staff.

Recommendation 2. Federal agencies such as NASA, the National Oceanic and Atmospheric Administration (NOAA), the U.S. Department of Agriculture, U.S. Geological Survey (USGS), and others should provide the seed funding developing remote sensing training and educational materials. Agencies should consider, as an initial step, using the Small Business Innovation Research (SBIR) program to solicit proposals for developing training materials and courses, to foster the uses of remote sensing data in applications, and to encourage commercial enterprises to provide these services.

Finding. Reducing the social distance between application developers and end users is a means of encouraging successful technology transfer (see Chapter 2 and 3). Unless those who create applications (e.g., scientists, engineers, and technicians) and those who use them (e.g., government, not-for-profit, and private sector applied users, policy makers, and natural resource managers) understand the roles of others involved in the process, they will not be able to communicate effectively and the development of applications will suffer.

Recommendation 3. Federal agencies, including those that produce remote sensing images and those that use them, should consider creating “extern” programs with the purpose of fostering the exchange of staff among user and producer agencies for training purposes.

For example, NASA, NOAA, and USGS could create an extern program collaboration with potential user agencies, such as the Environmental Protection Agency, the U.S. Army Corps of Engineers, the U.S. Department of Agriculture, the Department of Transportation, and others and in so doing could produce trained staff to serve as brokers for information and further training. Similar exchanges could be organized between universities and state and local governments and between commercial companies and government.

Recommendation 4. The Land Grant, Sea Grant, and Agricultural Extension programs should be expanded to include graduate fellowships and associateships to permit students to work at agencies that use remote sensing data. Such programs could help to improve communication and understanding among the scientists and engineers who develop applications for remote sensing data and the agencies that use them.

NASA ‘s Space Grant program could be extended to include these training activities, much as the Land Grant program has fostered the development of agricultural extension agents.

Finding. Although many remote sensing applications emerge from basic research, the development of applications is not accorded the recognition associated with publication in scientific journals. Researchers have few professional incentives to produce applications. The research-to-applications model developed in other fields, such as pharmaceutical research and many fields of engineering could be emulated by the Earth sciences. Yet even if this model were to be adopted in areas related to remote sensing, there are at present few funding opportunities for work that spans the divide between research and applications.

Recommendation 5. Resources, separate from funding for basic research, should be made available to federal agencies such as NASA, the National Oceanic and Atmospheric Administration, the Environmental Protection Agency, the U.S. Geological Survey, the Department of Transportation, the National Science Foundation, and others for support of research on remote sensing applications and remote sensing applications derived from basic research. In addition, these agencies should establish joint research announcements aimed at fostering the development of applications for remote sensing data through basic research.

Finding. Many remote sensing applications have specific requirements, including continuity in data collection, consistency in format, frequency of observations, and access to comparable data over time. It is important that the requirements of those who use applications are communicated to both public and private sector data producers throughout the process of designing new technologies and producing and disseminating remote sensing data.

Recommendation 6. Both public and private sector data providers should develop mechanisms to obtain regular advice and feedback on applications requirements for use in their planning processes. Advisory bodies that are consulted for input to these decisions should routinely include applications users.

Recommendation 7. Data preservation should be addressed by all data providers as a routine part of the data production process to ensure continuity of the data record and to avoid inadvertent loss of usable data.

Finding. The lack of standard data formats, open and available protocols, and standard validation and verification information inhibits the spread of remote sensing applications (see Chapter 3).

Recommendation 8. The use of internationally recognized formats, standards, and protocols should be encouraged for remote sensing data and information. The work of the OpenGIS Consortium and the Federal Geographic Data Committee serves as an important international and national coordinating mechanism for efforts in standards development that should be continued.

These and other entities pursuing common remote sensing data formats and standards should consult with the sensor and software vendors to ensure that data acquired from the use of new technologies for data acquisition, analysis, and storage and distribution are consistent with other data sets.

Finding. In general, the workshop as a mechanism for gathering data provided the steering committee with the information and insight it needed to understand issues related to technology transfer and remote sensing applications and to make recommendations about more effective ways to foster the development of applications.

In retrospect, as outlined in Chapter 4, the steering committee recognizes several strengths, and some areas for improvement, in the use of a workshop format.

A Report of the Committee on the Origins and Evolution of Life

A workshop to assess the science and technology of life detection techniques was organized by the Committee on the Origins and Evolution of Life (COEL) of the Board on Life Sciences (BLS) and the Space Studies Board (SSB). Topics discussed in the workshop included the search for extraterrestrial life in situ and in the laboratory, extant life and the signature of extinct life, and determination of the point of origin (terrestrial or not) of detected organisms. Areas not covered or covered only to the extent of their connection to the main topics included mechanisms of terrestrial contamination of other planetary bodies by spacecraft (although techniques to detect such contamination in spacecraft were covered), sterilization of spacecraft components, and quarantine of returned samples. These topics, especially the last, have been considered extensively in recent National Research Council (NRC) reports.

The workshop was designed around a series of four general questions, to be addressed in the papers presented by the participants:

1. How does one determine if living terrestrial organisms are on a spacecraft before launch?

2. How does one determine if there are living organisms in a returned sample?

3. How does one determine if living organisms have been present at some earlier epoch and have left fossil remnants behind in a returned sample?

4. How does one determine whether there are living organisms or fossils in samples examined robotically on another solar system body?

The nature of questions 2 through 4, as formulated, is such that a single, declarative answer to each is not possible given the great uncertainties that remain in our understanding of the possible range of chemistry and morphology that could constitute life. Question 1 can be answered more definitively because of our direct study of terrestrial organisms, but there remains intense debate over the level to which spacecraft sterilization should be achieved for missions to particular solar system bodies. For these reasons, the questions served primarily to frame the scope of the discussions that took place at the workshop and of the contributed papers.

The workshop opened with an introduction to the history and scope of the search for life to date. The next session enumerated current understanding of solar system targets for sample return (including meteorites and interplanetary dust particles for which samples are available at present). The final two sessions dealt with techniques for detecting viable (including spore-forming) organisms and the signs of past life, respectively. Appendix A of this report gives the workshop agenda. Appendix B lists (and the enclosed CD-ROM contains) the set of papers written by the invited speakers at the workshop. The report itself presents introductory and concluding material written by COEL to relate the papers to the questions to be addressed. To facilitate discussion of the papers and workshop sessions, the introductory material is organized in parallel with the workshop sessions rather than the four questions listed above. The conclusions and recommendations (Chapter 5), however, are grouped in parallel with the questions themselves. The committee emphasizes that this is a workshop report, rather than a detailed strategy study, and so drawing very specific conclusions and recommendations is not appropriate.

The most strikingly definitive result coming from the workshop concerns the dramatic improvement in laboratory techniques designed to detect terrestrial organisms, with principal application to spacecraft sterilization and hence forward planetary protection. As new techniques become available, they have to be incorporated into planetary protection protocols because current NASA protocols (based on culturing techniques) could miss up to 99 percent of microorganisms. Also, some techniques may not be suited to distinguishing between viable and nonviable organisms, a key issue in considering forward and back contamination.

Recommendations regarding specific sterilization techniques and levels of sterilization in order to avoid contamination of other planetary bodies were beyond the original purview of the workshop and this report. The main issue regarding sterilization from the point of view of the workshop is the ability to sample, poststerilization, the remaining level of terrestrial microorganisms to ensure that it is below the value required for a particular mission. Because all terrestrial organisms rely on the same basic biochemistry—specifically and most importantly, the RNA and DNA nucleic acid bases—amplification techniques to detect very small remnant levels of contamination are well understood.

The committee recommends that studies of future missions to astrobiologically interesting targets include explicit consideration of the types of sterilization for spacecraft systems, subsystems, and components and that sterilization costs be included in a realistic fashion. The committee recommends that special near-term emphasis be given to the issues of sample selection, spacecraft sample handling, and sample characterization. The committee also encourages further work to refine sterilization approaches so as to minimize impacts on mission costs and success.

The committee is strongly encouraged by the multidisciplinary efforts to define the possible range of processes indicative of living organisms. Given the extreme difficulty (or impossibility) of inductively describing all possible living processes based on terrestrial biochemistry, no single approach, or even combination of approaches, will guarantee success with a given sample. Multiple approaches, both chemical (including isotopic and molecular) and microscopic, are key to the successful detection of life in a sample. Because of the rapid improvements in the technology for a variety of techniques, coupled with the realization that return of a sample from Mars (the highest-priority target in life detection) remains a decade away, it would be premature to recommend a particular technique or set of techniques at present.

The committee concludes that a number of very sensitive and specific techniques are available for detecting living or once-living organisms in a returned sample; however, these techniques depend on the organisms’ being composed of essentially terrestrial biopolymers. While other techniques exist for detecting a potentially broader suite of nonterrestrial-like (but carbon-based) organisms, their results will not be as definitive. Hence, multiple approaches will be required to establish the presence of life in a definitive fashion, unless such life happens to be essentially terrestrial in nature. There is a pressing need to develop methods for the detection in single cells of evidence of metabolic activity and of specific macromolecules, including an analysis of their chemical structure and isotopic signature.

The committee recommends that a focused study be done in the near future to address the detection of microorganisms with varying degrees of nonterrestrial biochemistry, and the possible threat that such organisms might pose to terrestrial organisms.

To the extent possible, reasonable efforts (defined through carefully deliberated scientific strategies) should be made to assess the potential for extant life on other planetary surfaces in situ, using robotic missions. Some of the approaches available for the detection of living organisms are available in miniaturized form and are potentially space qualifiable for an in situ life detection mission. The results will markedly increase confidence about the risk factors associated with a given sample that could be returned to Earth for further study and will provide scientific evidence to further justify the expense of a return mission. Since life (or past life) will concentrate in habitats that provide suitable nutrients and chemical or physical conditions, its distribution on any planetary body will be patchy and of varying local abundance. Appropriate site selection for sample return

is critical and will determine the amount of sample required for testing and the need for possible sample concentration.

Multiple measurements with different techniques will be required to perform triage on a set of field samples at a given landing site, so as to select the most promising samples for in situ or returned life detection. This recommendation holds as well for selection of sites for in situ life detection (extant or extinct), as noted below.

The committee concludes that the search strategy for evidence of extinct life must include the identification of suitable landing sites, the selection of the appropriate rock types, and multiple analytical techniques that, in the aggregate, are capable of distinguishing between abiogenic and biogenic signatures. The assessment of extinct biosignatures will likely require a sample-return mission to carry out the sophisticated set of measurements needed to make this determination.

The most vigorous debate at the workshop centered on interpretation of potential signatures of life in samples available today in the laboratory and, in particular, in the SNC meteorite ALH84001, which is generally accepted to have originally been a part of the Martian crust. Important disagreements exist within the community over the interpretation of properties of this meteorite in terms of their biological significance, and at least some of the disagreements are the result of a lack of repeat analysis of a particular sample or phase by multiple groups. The committee recommends that any plans for analysis of returned extraterrestrial samples include a provision for repeat analyses of a subset of the same material, preferably by different teams. The committee encourages early development and testing of appropriate protocols using existing samples of high astrobiological interest (e.g., ALH84001).

The committee recommends that attention be given to understanding thoroughly the rates and nature of degradation of biosignatures in planetary environments. Theoretical and experimental studies should be supplemented with comparative analysis of putative samples of extraterrestrial biomarkers (e.g., ALH84001), with a specific eye to better understanding the issue of degradation of signatures of past life. Additionally, the identification and development of new and possibly universal biosignature approaches should be an active area of study.

In contrast with the detection of extraterrestrial life, analysis of extraterrestrial organic material is a mature field with a number of important results based on direct analysis of meteorites (including SNCs, which are likely Martian) and cosmic dust. Remote sensing analysis of organic molecules in various bodies in the outer solar system and in molecular clouds has provided a foundation for understanding the distribution and abiotic evolution of carbon-bearing material. The absence of detectable organic molecules at the surface of Mars played an important role in the interpretation of the Viking life detection experiments. Detection of simple organic molecules (e.g., methane) has been accomplished for the atmospheres of very cool brown dwarf stars and will play a key role in the protocol for the eventual remote spectroscopic assessment of the habitability of extrasolar planets. Continued increases in sensitivity and in the diagnostic value of techniques to detect organic molecules in extraterrestrial samples, particularly in situ, will be an important part of the overall effort to assess the existence of past or present life in the solar system. The committee concludes that it is crucial to continue the development of techniques to detect and analyze in situ organic chemical systems of either biotic or abiotic origin, with the goal of increasing the techniques’ sensitivity and diagnostic capability.

In situ life detection will require commitment to a small subset of available techniques because spacecraft resources will always be constrained, at least for the foreseeable future. Hence, a specific set of hypotheses regarding the samples to be analyzed must be made prior to launch; this intrinsically decreases the likelihood of successfully detecting life, because such hypotheses are invariably based on Earth-centric assumptions. On the other hand, in situ analysis is not subject to the concern of back contamination of Earth; hence sample handling is, in that respect, greatly simplified. Whether and to what extent attempts to detect life in situ will be made prior to return of a sample to Earth is an unresolved issue in NASA’s Mars Exploration Program. Potential confusion of the results by terrestrial contaminants is a particular concern for in situ studies, because of the limited number and types

of tests that can be done. Accurate knowledge of the prelaunch level of terrestrial contamination and a method of tagging terrestrial organisms would maximize the chances of an interpretable result.

Because of the continuing rapid improvements in technology, it is not appropriate at this time to recommend a specific set of techniques for in situ life detection, but in situ life detection will require commitment to a small set of potential techniques with significant lead time to ensure that they can be space qualified. The committee encourages continued efforts to develop innovative and miniaturizable techniques for in situ life detection. It must be stressed that selecting the combination of techniques for in situ life detection is dependent as well on the physical and chemical characteristics of the sampling site on a particular planetary body.

Appropriate site selection is crucial to maximizing the chances of finding evidence for extant or extinct life in samples either analyzed in situ or collected for return to Earth. While this point seems obvious, the committee notes that over the history of Mars exploration the engineering constraints associated with safe operations usually have conflicted with reaching the most scientifically interesting sites. For Mars, this means that landing site selection cannot be based primarily on issues of spacecraft safety. Furthermore, proper site selection will require a series of missions including orbital reconnaissance followed by exploration of selected sites by landed vehicles. An informed and continuing dialogue between scientists engaged in life detection and mission planners is essential if astrobiologically interesting samples from Mars are to be obtained.