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1 Introduction ASTROBIOLOGY AT NASA In its current usage, the term âastrobiologyâ is variously defined as the study of the origin, evolution, dis- tribution, and future of life in the universe; the study of life as a planetary phenomenon; the study of the living universe; or the origin and co-evolution of life and habitable environments.1-3 The term was apparently coined in the 1940s4 and was used periodically in the 1950s.5 In about 1960 âastrobiologyâ appears to have been supplanted by the more restricted term âexobiologyâ and then independently reinvented in 1995 by Wesley Huntress, NASAâs then-associate administrator for space science.6 The history of NASAâs involvement in astrobiology and its modern precursor, exobiology, can be divided into three periods. The first lasted from the late 1950s to the time of the Viking Mars program in 1976. During this period, NASAâs Office of Life Sciences devoted many resources to the study of the origins and evolution of life on Earth and elsewhere in the universe. The second period began after the Viking spacecraft failed to unambiguously detect evidence of life on Mars. This disappointment reduced NASAâs eagerness to fund follow-on missions to Mars or other major activities relating to the search for life beyond Earth. In 1996, exobiology experienced revitaliza- tion in the aftermath of an announcement claiming the discovery of evidence of past life in the martian meteorite ALH 84001, and the subject of exobiology began its transformation into the current-day field of astrobiology. The revitalization and transformation mark the third historical period. Beginnings to Viking NASAâs involvement in exo/astrobiology stems from repercussions generated by an international conference focused on studying the origins of life that took place in August 1957 in Moscow. The location of the conference, in conjunction with the Cold War-driven political climate of the time, spread fears among U.S. officials that the Soviet Union had discovered the secret behind the origins of life. Joshua Lederberg, a young Nobel Prize-winning biologist, had recently begun pondering the notion of life on other worlds and was able to use the fears generated by the 1957 conference to persuade the newly formed NASA to devote resources to studying the origin of life. Lederberg argued that NASA would need to understand the origins of life on Earth in order to plan the search for extraterrestrial life. He coined the term âexobiologyâ to describe studies relating to the origins of life on Earth and the development of instruments and methods to search for signs of life in the cosmos. 7
ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE In 1960, NASA created the Office of Life Sciences. One function of this office was to award grants for exo- biology research. This research included studying life-detection techniques, learning how to prevent forward and back contamination of planetary environments by spacecraft, and studying the origins of life. After the founding of NASAâs Office of Life Sciences, exobiology continued to grow. Many scientists who were unable to achieve funding through agencies, such as the National Science Foundation (NSF) and the National Institutes of Health (NIH), that required that their work fit into a rigidly defined scientific discipline were success- fully courted by NASA and encouraged to apply for exobiology grants. NASAâs Office of Life Sciences invested a considerable amount of money in the design and development of life-detection instruments. Three of these instruments were chosen to fly aboard the 1976 Viking mission to Mars. The twin Viking landers were designed to land on the Red Planet and search for the presence of life or organic materials on the surface. Post-Viking Era The Viking landers touched down on the surface of Mars in July and September 1976. Although the results were eagerly awaited by many on Earth, scientists were disappointed to find that the data from the landers were ambiguous. While one of the instruments did seem to show a positive detection of life, 8 the other two life-Âdetection instruments did not.9,10 Moreover, a fourth experiment revealed no sign of organic material in the samples of mar- tian regolith analyzed.11 Scientists later demonstrated that the positive results from the single experiment likely resulted from abiotic processes related to the highly oxidizing nature of the martian surface material. 12 In the wake of Vikingâs failure to unambiguously detect biological activity or, even, organic compounds in the martian soil, the exobiology program experienced a decrease in political support. The public, which had been so enthusiastic about the possibility of life on other planets, became disillusioned by the negative results of Viking. Not only did the prestige of exobiology suffer, but the entire Mars exploration program also experienced a lull in the two decades following Viking. Although funding did not reach pre-Viking levels in this era, work in the field continued. The scientific community remained interested in studying the origins of life, and internal NASA advisory committees and inde- pendent groups continued scientific planning for future endeavors in this area. Many significant discoveries were also made in this time period. Indeed, NASAâs strategy of actively seeking out interdisciplinary projects that did not readily find a home in other funding agencies was extremely successful and resulted in the funding of many seminal research activities that proved of lasting value. Examples of important research opportunities funded by the Exobiology program include the following: Lynn Margulisâs work on the endosymbiotic origins of eukaryotic cells, Carl Woeseâs discovery of the Archaea, Luis Alvarezâs theory of an asteroid as the cause of the Cretaceous- Tertiary mass extinction, the discovery of microfossils of the earliest life on Earth, and James Lovelockâs Gaia hypothesis.13 This does not mean that other agencies made no contributions to the nurturing of what would later be called astrobiology. NSF, for example, was instrumental in funding many important research activities, including the following: Stanley Millerâs work on prebiotic synthesis; the collection of lunar, martian, and other meteorites in Antarctica; and Geoffrey Marcyâs search for exoplanets, i.e., planets around other stars. 14 In 1995, astronomers announced the discovery of an extrasolar planet orbiting the star 51 Pegasi. Although this planet orbits very close to its parent star and is far too hot to harbor life as we know it, this unexpected dis- covery, taken together with the earlier discovery of planets in orbit around a pulsar, generated enthusiasm for the possibility for countless yet-to-be-discovered planetary systems, some of which could have the potential to sustain life. At about the same time, the Hubble Space Telescope obtained spectacular images of disks around young stars, which were interpreted as possible sites for future formation of planets, perhaps including ones with environmental conditions suitable for life. Much work was also being done at this time on the existence of life in extreme terrestrial environments, such as deep-sea hydrothermal vents. These new âextremeâ life forms expanded the limits of what were once considered to be acceptable conditions for life to develop and proliferate. Finally, observations from the Galileo spacecraft suggested that liquid water existed below Europaâs icy surface, raising the tantalizing idea that life could be found elsewhere in the solar system outside the traditional habitable zone.
INTRODUCTION Transformation and Revitalization The August 16, 1996, issue of Science contained an article that once again ignited interest in the possibility of life beyond Earth. The authors of the article claimed that they had discovered evidence suggesting that ancient fossilized bacteria were present in the meteorite ALH 84001, a piece of Mars collected in Antarctica in 1984. 15 They based this claim on four pieces of evidence: (1) the presence of carbonate globules which had been formed at temperatures favorable for life, (2) the presence of biominerals (magnetites and sulfides) with characteristics nearly identical to those formed by certain bacteria, (3) the presence of indigenous reduced carbon within martian materi- als, and (4) the presence in the carbonate globules of features similar in morphology to biological structures. The extraordinary claim of past life from Mars was eagerly reported by the media but received a very skeptical reaction from many researchers. Very little time passed before criticisms of the article were published, sparking a debate over the true nature of the supposed martian âbacteria.â The authors of these opposing articles argued that the putative nanometer-scale microfossils proposed by the discovery team were highly suspect and likely to be of abiotic origin. The formation temperature of the carbonate globules was soon controversial and, in some cases, suggested a value far above the upper limit for life. Some features were very similar to artifacts produced by the application of conductive coatings onto samples during their preparation for study using scanning electron micros- copy. In many cases, the supposed biotic features were regarded as too small to support cellular-based metabolisms. It was known that many features resembling morphological and chemical biomarkers are actually formed by abiotic processes. In addition, most of the organic compounds extracted from ALH 84001 showed radiocarbon activity, indicating that they were very young and had been introduced after the meteorite landed on Earth. The debate concerning the validity of the claims about ALH 84001 played a pivotal role in the development of astrobiology.16 Although the initial suggestions surrounding ALH 84001 have not been sustained, the announce- ment triggered a political and programmatic reaction out of all proportion to its scientific significance. In response to congressional calls for a space summitâto discuss âthe recent evidence that life may have existed on Mars, as well as other significant advances in space science and technologyâ17âthe White Houseâs Office of Science and Technology Policy and NASA requested that the NRCâs Space Studies Board organize a workshop to discuss the implications of ALH 84001 and other recent advances in the space sciences. The resulting workshop was held on October 28-30, 1996, and concluded that the study of the origins of life, planetary systems, stars, galaxies, and the universe is a powerful organizing theme for NASAâs space science activities. A subsequent briefing of the workshop results to Vice President Gore concluded that the recent discoveriesâsuch as those concerning life in extreme environments, planets around other stars, a subsurface ocean on Europa, and the transfer of material from planet (e.g., Mars) to planet (e.g., Earth) in the form of meteoritesââ. . . are astonishing returns being reaped from years of investment in many scientific disciplines. Now is the time to leverage that investment and to pursue the quest for origins into the 21st Century.â18 On February 6, 1997, President Clinton proposed that funds be appropriated for a major new NASA activityâthe Origins Initiativeâto focus on studying the origins of life in the context of the formation of planets, stars, and galaxies. This initiative included funding for missions to Mars and Europa, several astrophysical projects, and the initiation of a major program in astrobiology. THE NASA ASTROBIOLOGY INSTITUTE The planning for NASAâs Astrobiology program built on several parallel activities that had taken place earlier in the 1990s. As is mentioned above, NASAâs long-standing Exobiology program had achieved much success by concentrating on the funding of activities that did not readily fit within the more rigid disciplinary boundar- ies favored by other funding agencies. Thus, the Exobiology program naturally gravitated to inter- and cross- d Â isciplinary activities. The concept of a virtual institute focusing on interdisciplinary research related to the origin, evolution, and distribution of life in the universe was pioneered in 1992 within the context of a program to establish several so-called NASA Specialized Centers of Research and Training (NSCORTs). An NSCORT focusing on issues relating to the origins and evolution of life, the so-called NSCORT in Exobiologyâinitially consisting of five principal investigators (PIs) and 20 students divided among the Salk Institute for Biological Studies, Scripps Institution of Oceanography, Scripps Research Institute, and University of California, San Diegoï£§was established
ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE soon thereafter. The NSCORT program proved so popular that, a few years later, a second NSCORTâthe New York Center for Studies on the Origins of Lifeâwas established, linking researchers and students at Rensselaer Polytechnic Institute, the State University of New York at Albany, and the College of St. Rose. The NSCORTs in New York and California were eventually funded for periods of 5 and 10 years, respectively. In parallel with the NSCORT activity, scientists at NASAâs Ames Research Center drew up plans for a âlife in the universeâ program that would open up many new scientific possibilities by merging many different research activities underway at the center. The proposal was well received by NASA officials, but the name of the proposed endeavor was changed to astrobiology, thus independently reinventing the term that fell out of usage in the late 1950s. The Ames initative, as well as the subsequent efforts to define astrobiology, laid the foundations of modern astrobiology. Ames was named NASAâs Lead Center in Astrobiology by Administrator Dan Goldin in May 1995. Ames personnel soon began holding workshops and meetings to explore models for the best way to perform astrobiology and related multidisciplinary research. Meanwhile, Gerald Soffen, then the head of University Programs at NASAâs Goddard Space Flight Center and formerly the principal scientist on the Viking missions to Mars, independently developed a concept for an institute focusing on astrobiology. Soffenâs vision was for an institute having the following characteristics: â¢ Play a key role in determining the future of astrobiology; â¢ Be both real and virtual, using modern communications technology; â¢ Provide access to a continuous council of technical experts; â¢ Employ an interdisciplinary approach; and â¢ Recommend research directions, priorities, experiments, missions, and technology developments to NASA management. The culmination of efforts of both Soffen and researchers at Ames came in May 1998 when 11 geographi- cally dispersed teams of scientists (see Table 1.1) were named as the initial members of the NASA Astrobiology Institute (NAI). The teams, selected on a competitive basis in response to a cooperative-agreement notice (CAN) issued in 1997, were awarded funding of approximately $1 million a year for 5 years. The NAI formally opened for business in July 1998 under the leadership of Interim Director Scott Hubbard. Nobel laureate Baruch S. Blumberg was named the first NAI director in 1999. From its founding, the NAI has actively nurtured partnerships with international organizations interested in astrobiology. Such partnerships are entered into on the basis of no exchange of funds and have the overall goal of providing collaborative opportunities for NAI researchers via, for example, access to unique scientific facilities and field sites outside the United States. Foreign astrobiology organizations can propose to become either an associate or an affiliate member of the NAI. The former arrangement involves a formal agreement between NASA and a foreign government, and the associated entity has the same status as one of the NAIâs domestic nodes, whereas the latter is a much looser arrangement that does not involve a formal government-to-government agreement. The NAIâs affiliate and associate members are selected via an application process that considers their organizational nature, the types of scientific activities in which they are engaged and their relationship to NAI objectives, and the likely productivity of the proposed activities. The Centro de AstrobiologÃa in Spain became the first associate member of the NAI in 1999. A second CAN was issued in 2000 and resulted in the selection of four new NAI teams, bringing the total number of NAI institutions to 15 (see Table 1.1). The Australian Centre for Astrobiology was also established, and it became the second associate member of the NAI. In 2000, in response to a request from NASAâs Office of Space Science, the National Research Councilâs Com- mittee on the Origins and Evolution of Life (COEL), a joint committee of the Space Studies Board and the Board on Life Sciences, was charged to assess the state of the NASA Astrobiology program. COELâs report, entitled Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology, was published in 2002. In 2003, the 5-year funding period for the 11 original NAI members teams ended. Six of these teams suc- cessfully applied for and were awarded funding for an additional period of 5 years. In addition, six new teams were funded (see Table 1.1). Bruce Runnegar, a professor in UCLAâs Department of Earth and Space Sciences and
INTRODUCTION the Institute of Geophysics and Planetary Physics, also became the new director of the NAI. In addition, NASA released a revised version of the original 1998 Astrobiology Roadmap outlining the fundamental goals and objec- tives of astrobiology (Table 1.2).19 The year 2004 marked the establishment of the Federation of Astrobiology Organizations (FAO), whose goal is âto create an architecture that can implement cooperative international activities central to the interests of the indi- vidual astrobiology networks, associations, institutes, and societies that comprise [the] federation.â The federation consists of the NAI as well as groups from Britain, Australia, Mexico, Spain, France, Germany, and Sweden. Carl Pilcher, the former director of NASAâs solar system exploration program, took over as NAI director in 2006. The four teams that received funding in 2001 also completed their 5-year agreements, and membership in the NAI dropped to 12 teams. Because of budgetary restrictions, these four teams were not replaced until 2007. The NAI currently consists of 16 teams (see Table 1.1) and involves the work of approximately 600 investiga- tors distributed across some 150 institutions. The NAI is administered by its director 20 and a small staff, through an office known as NAI Central,21 located at the NASA Ames Research Center. The NAIâs teams (ânodesâ) are supported through cooperative agreements between NASA and the teamsâ institutions;22 these agreements involve substantial contributions from NASA and each of the teams. The NAI Handbook outlines the expectations of membership in the institute, emphasizing active participation in realizing all aspects of the NAIâs mission.23 The principal investigators of each team, together with the NAI director and deputy director, constitute the executive council.24 Its role is to advise NAI management in matters of institute-wide research, space mission activities, technological development, and external partnerships. Other aspects of the NAI include the Directorâs Seminar Series, which brings the community together monthly via videoconference to share scientific progress;25 focus groups that mobilize expertise within the community on relevant topics;26 the annual report, which describes the most recent activities of each of the NAIâs teams; 27 the online Research Archive, which highlights top scientific discoveries and advances; 28 and the NAI Newslet- ter, which provides the latest news about activities and opportunities.29 Special attention to the next generation of astrobiologists is exemplified by the NAIâs Postdoctoral Fellowship Program 30 and the Lewis and Clark Fund for Exploration and Field Research.31 NAI Central also organizes institute-wide workshops, such as the Strategic Impact Workshop,32 to facilitate collective discussion and planning for the NAIâs research. The NAI continues to adapt and evolve in a changing environment. Most recently, the NAIâs 2007 Directorâs Discretionary Fund competition emphasized a strategic impact on NASAâs ability to achieve its goals, 33 especially in the areas of flight missions, cross-program synergies, collaborations with other funding agencies, and external partnerships. CURRENT STATUS OF NASAâS ASTROBIOLOGY PROGRAM NASAâs Astrobiology program currently resides within the Planetary Science Division of NASAâs Science Mission Directorate and consists of four different programmatic elements: â¢ The NASA Astrobiology Institute (NAI), a consortium of 16 competitively selected, principal investigator- led teams conducting interdisciplinary research at geographically dispersed research institutions. The NAIâs budget for fiscal year 2008 is about $16 million. â¢ The Exobiology and Evolutionary Biology grants programs, which currently fund some 150 individual principal investigators located at U.S. universities, research institutions, federal laboratories, and NASA centers. The combined budget of these two programs in fiscal year 2008 is about $11 million. â¢ The Astrobiology Science and Technology Instrument Development (ASTID) program, which funds the initial development of new, astrobiology-relevant instruments that may be selected for future flight opportunities. The program currently funds some 49 instrument-development projects at U.S. universities, research institutions, federal laboratories, and NASA centers. The ASTID program budget for fiscal year 2008 is about $9 million. â¢ The Astrobiology Science and Technology for Exploring Planets (ASTEP) programs, which fund the field- testing of new, astrobiology-relevant instruments in terrestrial settings representative in some way of the extrater-
10 ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE TABLE 1.1 Members of the NASA Astrobiology Institute, 1998 to Present Selected in Competition Principal for CAN Period of Node Node Name/Theme of Research Investigator Number NAI Funding Arizona State Exploring the Living Universe: Origin, Evolution, and John Cronin 1 1998-2003 University Distribution of Life in the Solar System Jack Farmer NASA Ames Linking Our Origins to Our Destiny David Des Marais 1, 3 1998-2008 Research Center Carnegie Astrobiological Pathways: From the Interstellar Sean Solomon 1, 3 1998-2008 Institution of Medium, Through Planetary Systems, to the Emergence Washington and Detection of Life Harvard The Planetary Context of Biological Evolution Andrew Knoll 1 1998-2003 University Jet Propulsion Definition and Detection of Biosignatures Kenneth Nealson 1 1998-2003 Laboratory NASA Johnson Center for the Study of Biomarkers in Astromaterials David McKay 1 1998-2003 Space Center Marine Marine Biological Laboratory Astrobiology Science Mitchell Sogin 1, 3 1998-2008 Biological Team/Environmental Genomes and Evolution of Laboratory Complex Systems in Simple Organisms Pennsylvania Penn State Astrobiology Research Center/Evolution of Hiroshi Ohmoto 1, 3 1998-2008 State a Habitable Planet University Scripps Self-Producing Molecular Systems and Darwinian Reza Ghadiri 1 1998-2003 Research Chemistry Institute University of From Stars to Genes: An Integrative Study of the Bruce Runnegar 1, 3 1998-2008 California, Prospects for Life in the Cosmos Edward Young Los Angeles University of University of Colorado Center for Astrobiology Bruce Jakosky 1, 3 1998-2008 Colorado Michigan State Center for Genomic and Evolutionary Studies on Michael Tomashow 2 2001-2006 University Microbial Life at Low Temperatures restrial environments in which they may be eventually deployed. The program currently funds six field campaigns and/or two advanced-instrument projects based at U.S. research institutions, universities, and NASA centers. The ASTEP program budget for fiscal year 2008 is about $5 million. In response to language in the NASA Authorization Act of 2000 and a subsequent request from NASA, the Astrobiology program and related U.S. and international programs relating to the detection of life in the universe were formally reviewed by the National Research Council. The resulting report, Life in the Universe: An Assess- ment of U.S. and International Programs in Astrobiology, commented that âremarkable progress has been made over a short period of time in defining the key scientific questions, initiating research and training programs, and developing collaborations on a national and international scale.â34 The report identified five issues that NASA needed to address in the near term to ensure the health of the Astrobiology program: 35
INTRODUCTION 11 TABLE 1.1 continued Selected in Competition Principal for CAN Period of Node Node Name/Theme of Research Investigator Number NAI Funding University of Subsurface Biospheres Steven DâHondt 2 2001-2006 Rhode Island University of Planetary Habitability and Evolution of Biological Peter Ward 2 2001-2006 Washington Complexity California Virtual Planetary Laboratory/Exploring the Habitability Victoria Meadows 2, 4 2001-2006 Institute of and Biosignatures of Extrasolar Terrestrial Planets and Technology 2007-2012 University of BioMars/Biospheres of Mars: Ancient and Recent Jillian Banfield 3 2003-2008 California, Studies Berkeley NASA Goddard Origin and Evolution of Organics in Planetary Systems Michael Mumma 3 2003-2008 Space Flight Center Indiana Indiana-Princeton-Tennessee Astrobiology Institute Lisa Pratt 3 2003-2008 University SETI Institute SETI Institute NAI Team/Planetary Biology, Evolution Christopher Chyba 3 2003-2008 and Intelligence Rocco Mancinelli University of Life and Planets Astrobiology Center/Astronomical Neville Woolf 3 2003-2008 Arizona Search for the Essential Ingredients of Life: Placing Our Habitable System in Context University of Origin, History and Distribution of Water and Its Karen Meech 3 2003-2008 Hawaii, Manoa Relation to Life in the Universe Massachusetts Requirements for Development and Maintenance of Roger Summons 4 2007-2012 Institute of Multicellular Life Technology Montana State Astrobiology Biocatalysis Research Center John Peters 4 2007-2012 University University of Organic and Mineralogical Signatures and Clark Johnson 4 2007-2012 Wisconsin, Environments of Life on Earth and Other Planetary Madison Bodies â¢ Definition of astrobiology and its goals. In particular, the perception in some circles at the time the study was undertaken that astrobiology as both an intellectual endeavor and a NASA program is ill-defined. â¢ Evaluation of the impact of the NAI on astrobiology. Has the NAI affected astrobiology in a way that a standard, principal-investigator grants program could not have? The report recommended as essential that a review of the impact of the NAI on astrobiology be conducted. â¢ Review/retirement of existing programs. Should existing NAI nodes be forced to recompete for funds every 5 years or should some other mechanism be devised to ensure the continuation of productive research teams? â¢ Insularity of the NAI. The report expressed concern about the potential tendency to regard astrobiology as a private club whose membership is exclusively confined to those researchers affiliated with the NAI. â¢ The âastroâ in astrobiology. Despite considerable overlap in areas of scientific interest, the astronomical community had little involvement in astrobiology at the time the report was drafted.
12 ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE TABLE 1.2 Astrobiology Roadmapï£§Fundamental Goals and Objectives of Astrobiology Goals Objectives 1.0 Understand the nature and 1.1 Investigate how solid planets form, acquire liquid water and other volatile species distribution of habitable environments in and organic compounds, and how processes in planetary systems and galaxies affect the universe by determining the potential their environments and habitability. Use theoretical and observational studies of the for habitable planets beyond the solar formation and evolution of planetary systems and their habitable zones to predict system, and characterize those that are where water-dependent life is likely to be found in such systems. observable. 1.2 Conduct astronomical, theoretical, and laboratory spectroscopic investigations to support planning for and interpretation of data from missions to detect and characterize extrasolar planets. 2.0 Explore for past or present habitable 2.1 Through orbital and surface missions, explore Mars for potentially habitable environments, prebiotic chemistry and environments, as evidenced by water or aqueous minerals. Study martian meteorites to signs of life elsewhere in the solar guide future Mars exploration. Develop the methods and supporting technologies for system by determining any chemical the in situ characterization of aqueous minerals, carbon chemistry and/or life. precursors of life and any ancient 2.2 Conduct basic research, develop instrumentation to support astrobiological habitable climates in the solar system, exploration and provide scientific guidance for outer solar system missions. Such and characterize any extinct life, missions should explore the Galilean moons Europa, Ganymede and Callisto for potential habitats, and any extant life on habitable environments where liquid water could have supported prebiotic chemical Mars and in the outer solar system. evolution or life. Explore Saturnâs moon, Titan, for environments favorable for complex prebiotic synthesis or life. 3.0 Understand how life emerges from 3.1 Characterize the cosmic and endogenous sources of matter (organic and inorganic) cosmic and planetary precursors by for potentially habitable environments in the solar system and in other planetary and performing observational, experimental protoplanetary systems. and theoretical investigations to 3.2 Identify multiple plausible pathways for the condensation of prebiotic monomers understand the general physical and into polymers. Identify the potential for creating catalytic and genetic functions, and chemical principles underlying the mechanisms for their assembly into more complex molecular systems having specific origins of life. properties of the living state. Examine the evolution of artificial chemical systems that model processes of natural selection to understand better the molecular processes associated with prebiological evolution in the universe. 3.3 Identify prebiotic mechanisms by which available energy can be captured by molecular systems and used to drive primitive metabolism and polymerization reactions. 3.4 Investigate both the origins of membranous boundaries on the early Earth and the associated properties of energy transduction, transport of nutrients, growth, and division. Investigate the origins and early coordination of key cellular processes such as metabolism, energy transduction, translation and transcription. Without regard to how life actually emerged on Earth, create and study artificial chemical systems that undergo mutation and natural selection in the laboratory. 4.0 Understand how past life on Earth 4.1 Investigate the development of key biological processes and their environmental interacted with its changing planetary consequences during the early history of Earth through molecular, stratigraphic, and solar system environment by geochemical, and paleontological studies. investigating the historical relationship 4.2 Study the origins and evolution of life forms that eventually led to more complex between Earth and its biota by integrating multi-cellular biota that appear in the fossil record or exist today. evidence from both the geologic and biomolecular records of ancient life and 4.3 Examine the records of the response of Earthâs biosphere (both the habitable its environments. environment and biota) to extraterrestrial events, including asteroid and comet impacts.
INTRODUCTION 13 TABLE 1.2 continued Goals Objectives 5.0 Understand the evolutionary 5.1 Experimentally investigate and observe the evolution of genes, metabolic mechanisms and environmental limits pathways, genomes, and microbial species. Experimentally investigate the forces of life by determining the molecular, and mechanisms that shape the structure, organization, and plasticity of microbial genetic, and biochemical mechanisms genomes. Examine how these forces control the genotype-to-phenotype relationship. that control and limit evolution, Conduct environmental perturbation experiments on single microbial species to metabolic diversity, and acclimatization observe and quantify adaptive evolution to astrobiologically relevant environments. of life. 5.2 Experimentally examine the metabolic and genetic interactions in microbial communities that have determined major geochemical processes and changes on Earth. Investigate how these interactions shape the evolution and maintenance of metabolic diversity in microbial communities. Investigate how novel microbial species establish and adapt into existing communities. 5.3 Document life that survives or thrives under the most extreme conditions on Earth. Characterize and elucidate the biochemical capabilities that define the limits for cellular life. Explore the biochemical and evolutionary strategies that push the physical-chemical limits of life by reinforcing, replacing, or repairing critical biomolecules (e.g., spore formation, resting stages, protein replacement rates, or DNA repair). Characterize the structure and metabolic diversity of microbial communities in such extreme environments. 6.0 Understand the principles that will 6.1 [Characterize] [e]nvironmental changes and the cycling of elements by the biota, shape the future of life, both on Earth communities, and ecosystems. and beyond by elucidating the drivers 6.2 Explore the adaptation, survival and evolution of microbial life under and effects of ecosystem change as a environmental conditions that simulate conditions in space or on other potentially basis for projecting likely future changes habitable planets. Insights into survival strategies will provide a basis for evaluating on time scales ranging from decades the potential for interplanetary transfer of viable microbes and also the requirements to millions of years, and explore the for effective planetary protection. potential for microbial life to adapt and evolve in environments beyond its planet of origin. 7.0 Determine how to recognize 7.1 Learn how to recognize and interpret biosignatures which, if identified in signatures of life on other worlds and on samples from ancient rocks on Earth or from other planets, can help to detect and/or early Earth by identifying biosignatures characterize ancient and/or present-day life. that can reveal and characterize past 7.2 Learn how to measure biosignatures that can reveal the existence of past or or present life in ancient samples from present life through remote observations. Earth, extraterrestrial samples measured in situ, samples returned to Earth, remotely measured planetary atmospheres and surfaces, and other cosmic phenomena. SOURCE: Excerpted from revised NASA Astrobiology Roadmap; see http://nai.arc.nasa.gov/roadmap/. Despite the concerns about these five issues, the report concluded that NASAâs Astrobiology program âis well poised to catalyze fundamentally important discoveries concerning the origins of life, its distribution in the cosmos, and the long-term fate of life on Earth.â36 Now, 5 years after Life in the Universe was drafted, the first and fifth items above are no longer regarded as issues of general concern. The remaining three items, all focusing on the NAI, are directly or indirectly the subject of this report. A discussion of the role of astrobiology in the context of a traditional space-science discipline can be found in Astronomy and Astrophysics in the New Millennium,37 the most recent astronomy and astrophysics decadal survey report, which comments that â. . . researchers can recognize the signature of life elsewhere only by understanding better the history of life on Earth over the past 4 billion years and exploring more deeply the possibility that life has
14 ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE also had an independent history on Mars or other planets and moons in our solar system. This study is an essential part of the new synergy between astronomy, planetary science, and biologyâwhat has been called astrobiologyâ (p. 157). The decadal survey continues by noting (pp. 157-158) that astrobiology has the potential to: â¢ â. . . encourage collaborations across . . . disciplines in order to address questions that compel the imagina- tions of scientists and citizens alike.â â¢ â. . . draw together investigators from disciplines that in the past have shared little except a common interest in understanding the natural world.â â¢ â. . . [bring] diverse scientific cultures together at the right moment in time.â â¢ â. . . [generate] extraordinary public interest . . . by [its] attempts to understand our origins and the ubiquity of life in the universe.â â¢ â. . . link the seemingly abstract world of research at the frontiers of knowledge to questions that have excited the human imagination since people first gazed at the heavens.â Another discussion of the role of astrobiology in the context of a traditional space-science activity can be found in New Frontiers in the Solar System: An Integrated Exploration Strategy,38 the first solar system explora- tion (SSE) decadal survey. That document highlights the role of astrobiology in (p. 158): â¢ â. . . [providing] a scientific organizational structure that integrates a wide subset of solar system issues and questions that span the origins, evolution, and extinction of life.â â¢ â. . . [allowing] nonexperts to grasp the connections between different component disciplines within planetary science and to do so in a way that most people will appreciate as addressing core themes in human thought.â â¢ â. . . [being] the primary means by which NASA tries to implement one of its prime objectivesâunder- standing lifeâs origins and its distribution in the universe.â â¢ â. . . [becoming] a fundamental part of the solar system exploration strategy.â In summary, the SSE decadal survey report â. . . encourages NASA to continue the integration of astrobiology science objectives with those of other space science disciplines. Astrobiological expertise should be called upon when identifying optimal mission strategies and design requirements for flight-qualified instruments that [will] address key questions in astrobiology and planetary scienceâ (p. 9). The goals of astrobiology have not only figured prominently in NRC reports. In outlining plans to implement the Vision for Space Explorationâthe initiative to return humans to the Moon and, ultimately, to MarsâPresident George W. Bush charged NASA to conduct robotic exploration of Mars to search for evidence of life; to explore Jupiterâs moons, asteroids, and other bodies to search for evidence of life; and to undertake advanced telescopic searches for Earth-like planets and habitable environments around other stars. 39 These fundamental, astrobiology goals, enunciated by President Bush in 2004 as the science component of the Vision, figure prominently in NASA strategy planning documents.40 The most recent NRC comments on the role, scope, and status of NASAâs Astrobiology program are made in An Assessment of Balance in NASAâs Science Programs.41 This document makes the following points (p. 20): â¢ âThe decadal surveys for astrophysics and for solar system exploration both embraced astrobiology as a key component of their programs, with the questions encompassed by astrobiology serving as overarching themes for the programs as a whole.â â¢ âThe missions put forward in the solar system exploration survey are all key missions in astrobiology, whether they are labeled as such or not. And issues and missions related to astrobiology represent one of the key areas of interest identified in the astronomy and astrophysics communities.â â¢ âAstrobiology provides the intellectual connections between otherwise disparate enterprises.â The report continues by recognizing that: âNASAâs Astrobiology program creates an integrated whole and supports the basic interdisciplinary nature of the field. Further, the Vision [for Space Exploration] is, at its heart,
INTRODUCTION 15 70.0 ASTEP 60.0 NAI ASTID Exo/Evo 50.0 Millions of $ 40.0 30.0 20.0 10.0 0.0 FY96 FY97 FY98 FY99 FY00 FY01 FY02 FY03 FY04 FY05 FY06 FY07 (Plan) Fiscal Year FIGURE 1.1 The budgetary history of the four elements constituting NASAâs Astrobiology program. The program is currently operating on an annual budget of approximately $4 million more that the figure indicated for fiscal year 2007. Courtesy of John D. Rummel, NASA Science Mission Directorate. largely an astrobiology vision with regard to the science emphasis [footnote omitted]. In developing the future of the program, the missions actually feed forward from the basic science. Astrobiology is just beginning the type of synthesis and integration that will allow it to provide science input for future mission development. Without it, the science and the scientific personnel will not be in place to support the missions when they do fly.â 42 Despite favorable reviews by the NRC and almost a decadeâs worth of steady budget increases (Figure 1.1), the astrobiology community was shocked to learn that NASAâs proposed budget for Fiscal Year 2007 included a 50 percent cut for the Astrobiology program. The reason why the program was singled-out for a cut of 50 percent when other programs were only cut by 15 percent has never been explained satisfactorily. R01186 Some slight budgetary relief came in 2007 when approximately $4 million was added back to the program from Figure 1-1 SMD discretionary funds and a reallocation of resources within SMDâs Planetary Science Division. Nevertheless, the current expectation is that NASAâs Astrobiology budget will remain at approximately the FY2007-level with annual corrections for inflation. Thus, the Astrobiology program enters its second decade with a major disconnect between the resources allocated to its execution and the important role ascribed to the program in NASA and NRC strategic plans. NOTES â 1.â See, for example, S.J. Dick and J.E. Strick, The Living Universe: NASA and the Development of Astrobiology, Rutgers University Press, New Brunswick, New Jersey, 2004, pp. 205-213. â 2ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ Astrobiology 6: 735-813, 2006. .â L.J. Mix et al. (eds.), âThe Astrobiology Primer: An Outline of General KnowledgeâVersion 1, 2006,â ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ Available at http://www.liebertonline.com/doi/pdfplus/10.1089/ast.2006.6.735. â 3.â See, for example, http://www.nai.arc.nasa.gov/about/about_nai.cfm#overview. â 4.â L.J. Lafleur, âAstrobiology,â Astronomical Society of the Pacific Leaflets 3: 333-340, 1941. â 5.â See, for example, H. Sturghold, The Green and Red Planet, University of New Mexico Press, Albuquerque, New Mexico, 1953; O. Struve, âLife on Other Worlds,â Sky and Telescope 14: 137-146, 1955; or A.G. Wilson, âProblems Common to the Fields of Astronomy and Biology: A SymposiumâIntroduction,â Publications of the Astronomical Society of the Pacific 70: 41-43, 1958.
16 ASSESSMENT OF THE NASA ASTROBIOLOGY INSTITUTE â 6.â See, for example, S.J. Dick and J.E. Strick, The Living Universe: NASA and the Development of Astrobiology, Rutgers University Press, New Brunswick, New Jersey, 2004, pp. 204-205. â 7.â J.E. Strick, âCreating a Cosmic Discipline: The Crystallization and Consolidation of Exobiology, 1957-1973,â Journal of the History of Biology 37: 131-180, 2004. â 8.â V.V. Levin and P.A. Straat, âRecent Results from the Viking Labeled Release Experiment on Mars,â Journal of Geophysical Research 82: 4663-4667, 1977. â 9.â N.H. Horowitz, G.L. Hobby, and J.S. Hubbard, âViking on Mars: The Carbon Assimilation Experiments,â Journal of Geophysical Research 82: 4659-4662, 1977. 10.â V.I. Oyama and B.J. Berdahl, âThe Viking Gas Exchange Experiment Results from Chryse and Utopia Surface Samples,â Journal of Geophysical Research 82: 4669-4676, 1977. 11.â K. Biemann, J. Oro, P. Toulmin III, L.E. Orgel, A.O. Nier, D.M. Anderson, D. Flory, A.V. Diaz, D.R. Rushneck, and P.G. Simmonds, âThe Search for Organic Substances and Inorganic Volatile Compounds in the Surface of Mars,â Journal of Geophysical Research 82: 4641- 4662, 1977. 12.â N.H. Horowitz, To Utopia and Back: The Search for Life in the Solar System, Freeman, New York, New York, 1986, pp. 134-136 and 137-138. 13.â See, for example, S.J. Dick and J.E. Strick, The Living Universe: NASA and the Development of Astrobiology, Rutgers University Press, New Brunswick, New Jersey, 2004. 14.â See, for example, S.J. Dick and J.E. Strick, The Living Universe: NASA and the Development of Astrobiology, Rutgers University Press, New Brunswick, New Jersey, 2004, pp. 204-205. 15.â D.S. McKay, E.K. Gibson, Jr., K.L. Thomas-Keprt, H. Vali, C.S. Romanek, S.J. Clemett, X.D.F. Chillier, C.R. Maechling, and R.N. Zare, âSearch for Past Life on Mars: Possible Relic Biogenic Activity in Martian Meteorite ALH 84001,â Science 273: 924-930, 1996. 16.â See, for example, D.H. Smith, âAstrobiology in the United States: A Policy Perspective,â in Astrobiology: Future Perspectives, P. Ehrenfreund et al. (eds.), Kluwer, Dordrecht, The Netherlands, 2004. 17.â Letter from J.H. Gibbons, Assistant to the President for Science and Technology, to D.S. Goldin, Administrator, NASA, September 25, 1996. 18.â C.R. Canizares, A.I. Sargent, et al., The Search for Origins: Findings of a Space Science Workshop, National Aeronautics and Space Administration, Washington, D.C., 1996. 19.â For more information concerning the Astrobiology Roadmap see http://nai.arc.nasa.gov/roadmap/. 20.â For more information about the NAI Director see http://nai.arc.nasa.gov/about/about_nai.cfm#director. 21.â For more information about NAI Central see http://nai.nasa.gov/team/index_nai.cfm. 22.â For more information about cooperative agreements see http://nai.nasa.gov/tools/handbook/3.cfm#CAN. 23.â For more information about the NAI Handbook see http://nai.nasa.gov/tools/handbook/. 24.â For more information about the Executive Council see http://nai.nasa.gov/ec/index.cfm. 25.â For more information about the Directorâs Seminar Series see http://nai.nasa.gov/seminars/index.cfm#1. 26.â For more information about the focus groups see http://nai.nasa.gov/about/focus_groups.cfm. 27.â For more information about the annual report see http://nai.arc.nasa.gov/team/execsumms.cfm. 28.â For more information about the Research Archive see http://nai.nasa.gov/news_stories/news_archive.cfm?member. 29.â For more information about the NAI Newsletter see http://nai.nasa.gov/newsletter/index.cfm. 30.â For more information about the Astrobiology Roadmap see http://nai.nasa.gov/funding/PostDocList.cfm. 31.â For more information about the Lewis and Clark Fund see http://nai.nasa.gov/funding/index.cfm#lc. 32.â For more information about the Strategic Impact Workshop see http://nai.nasa.gov/ec/siw.cfm. 33.â For more information about the Directorâs Discretionary Fund see http://nai.arc.nasa.gov/ddf_2007/index.cfm. 34.â National Research Council, Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology, The National Academies Press, Washington, D.C., 2003, p. 7. 35.â National Research Council, Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology, The National Academies Press, Washington, D.C., 2003, p. 1. 36.â National Research Council, Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology, The National Academies Press, Washington, D.C., 2003, p. 1. 37.â National Research Council, Astronomy and Astrophysics in the New Millennium, National Academy Press, Washington, D.C., 2001. 38.â National Research Council, New Frontiers in the Solar System: An Integrated Exploration Strategy, The National Academies Press, Washington, D.C., 2003. 39.â G.W. Bush, âA Renewed Spirit of Discovery: The Presidentâs Vision for U.S. Space Exploration,â in The Vision for Space Exploration, NP-2004-01-334-HQ, NASA, Washington, D.C., 2004. 40.â See, for example, National Aeronautics and Space Administration, Science Plan For NASAâs Science Mission Directorate 2006-2016, NP-2007-03-461-HQ, NASA, Washington, D.C., 2007, pp. 31-32. 41.â National Research Council, An Assessment of Balance in NASAâs Science Programs, The National Academies Press, Washington, D.C., 2006. 42.â National Research Council, An Assessment of Balance in NASAâs Science Programs, The National Academies Press, Washington, D.C., 2003, p. 20.