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Astrobiological Pathways: From the Interstellar Medium, Through Planetary Systems, to the Emergence and Detection of Life

Unifying Intellectual Focus. The NASA Astrobiology Institute team led by the Carnegie Institution will be dedicated, over the coming five years, to the study of the gradual evolution of organic compounds from prebiotic molecular synthesis and organization to cellular evolution and diversification – processes central to the missions of the NAI. Our program attempts to integrate the sweeping narrative of life’s history through a combination of bottom-up and top-down studies. On the one hand, we study processes related to chemical and physical evolution in plausible prebiotic environments – the interstellar medium, circumstellar disks, extrasolar planetary systems, and the primitive Earth. Complementary to these bottom-up investigations of life’s origin, we will continue our field and experimental top-down efforts to document the nature of microbial life at extreme conditions, as well as the characterization of organic matter in ancient fossils. Both types of efforts inform our development of biotechnological approaches to life detection on other worlds. In the process, we will continue to serve as a resource center for all members of the NASA Astrobiology Institute.

Motivation and Rationale. The most compelling opportunities in astrobiology stem from new interdisciplinary approaches to fundamental questions about life’s origin and its distribution in the universe. We continue to be motivated by the importance of these questions and by our unusual interdisciplinary team approach to scientific research. The Carnegie Institution supports astrobiologists with backgrounds in astronomy, biology, geology, and chemistry on a single Washington, D.C., campus. We are motivated to make additional progress toward addressing these fundamental questions, while continuing to serve as a dynamic, interactive resource center for other NAI teams. The rationale for our proposal is guided by the visionary mission of NASA’s Astrobiology Program, as defined by the Astrobiology Roadmap. In particular, we address the nature and distribution of planets (Goal 1), past and present habitable environments (Goal 2), the chemical origin of life (Goal 3), past life on Earth (Goal 4), the environmental limits on life (Goal 5), and the identification and detection of biosignatures (Goal 7). Moreover, through our daily interactions we will continue to strive to integrate these separate goals into a fuller understanding of the continuous processes that characterize life’s origin, evolution, and distribution in the universe.

Proposed Research Plan. Our proposed research activities for the coming five years focus on life’s chemical and physical evolution, from the interstellar medium, through planetary systems, to the emergence and detection of life. We propose seven integrated areas of research:

1. We will continue to apply theory and observations to investigate chemical evolution in the interstellar medium, in circumstellar disks, during planetary formation, and on Solar System bodies.
2. We will conduct analytical research on extraterrestrial samples, including meteorites and interplanetary dust particles, with an emphasis on organic molecules and evidence for water.
3. We will study prebiotic chemical and isotopic evolution on Earth, with a new emphasis on the sulfur cycle and the role of sulfur in prebiotic organic synthesis.
4. We will investigate possible mechanisms of prebiotic molecular selection and macromolecular organization, including the self-organization of amphiphiles and the selective adsorption of organic molecules onto mineral surfaces.
5. We will continue to study life in extreme environments, with field studies of hydrothermal microbial communities and laboratory studies of stress adaptation of microbes in high-pressure and high-temperature environments.
6. We will examine ancient fossils and microbes fossilized in the laboratory with a variety of analytical techniques to assess preservation mechanisms of molecular biosignatures. We will study modern geothermal systems to investigate preservation of biosignatures during silicification in these environments.
7. We will apply our enhanced understanding of life’s chemical and physical evolution to develop new techniques in astrobiotechnology – procedures that will be applied to the design and testing of instruments for life detection, initially in terrestrial settings and eventually on spacecraft to be sent to other Solar System bodies.

Fuller understanding of life’s origin, evolution, and distribution requires major advances on all these topics, as well as the extensive challenge of integrating these topics. During the next five years of NAI support we anticipate significant progress in each of these seven areas, as well as considerable advances derived from integrating these theoretical, experimental, and field studies.

Training, Education, and Public Outreach. As members of the NASA Astrobiology Institute we will continue our firm commitment to a dynamic, sustained program of education, public outreach, and training at the K-12, undergraduate, graduate, and postgraduate levels. This effort is facilitated by our widely acknowledged programs, including the First Light Science School, the Carnegie Academy for Science Education (CASE), the Carnegie Institution Summer Intern Program, and the Capital Science Lecture Series. Our continuing NAI outreach programs will include the following:

• We will continue to introduce astrobiology themes to CASE, which will provide inservice training and summer workshops for more than 1,000 teachers in the District of Columbia Public School system.
• We will introduce astrobiology themes to our widely distributed educational product series, as well as our astrobiology web site.
• The Carnegie Institution will continue to sponsor general audience lectures by prominent astrobiologists through the successful Capital Science public lecture series at Carnegie’s headquarters in northwest Washington, D.C.
• We will initiate collaborative activities with the Minority Institution Astrobiology Collaborative, including research, internships, teacher training, and publications.
• We will develop an exhibition on astrobiology in the lobby of the Smithsonian Institution’s National Museum of Natural History, one of the most frequently visited museums in the world.
• We will support approximately 8 NAI summer interns per year as part of the Carnegie Institution’s program for undergraduate and high school students. This astrobiology program has already produced one Intel finalist and one Westinghouse finalist.
• We will support approximately 12-15 NAI Pre- and Postdoctoral Fellows per year.
• We will participate through teaching and research opportunities with the new Astrobiology Ph.D. program at George Mason University. The first Ph.D. candidate will be commencing research at Carnegie in the summer of 2003.

Management Plan. All investigators and collaborators have clearly defined roles and responsibilities. Team activities will be managed by an Executive Committee, consisting of representatives from the partner institutions and chaired by the Principal Investigator. Our plan for multi-institutional cooperation and coordination includes regular all-consortium symposia, frequent intersite lectures, regular visits of senior staff to partner institutions, and more extended exchanges of students, predoctoral scholars, and other staff. Through the use of the internet, the World Wide Web, and the next generation internet, we will continue to make extensive use of electronic communication. Beyond daily communications among individuals, we will continue to provide frequent Web-based news updates to all team members. We remain committed to the development of Web-based instructional and outreach materials, and we will continue our development of electronic communications to enable access to data archives and summaries of research activities.

Proposed Institutional Commitment. The Carnegie Institution will continue to make a substantial commitment of resources to astrobiology. Dr. Wesley Huntress, who initiated the Astrobiology Institute while at NASA’s Office of Space Science, was selected as Director of the Geophysical Laboratory in 1998. Subsequently, the institution has added six astrobiologists to the senior scientific staff (Paul Butler, Larry Nittler, James Scott, Sara Seager, Andrew Steele, and Alycia Weinberger). The institution will provide full salary support for all 16 members of the senior research staff who are investigators on this project, 50% of the stipends of all NAI-sponsored Postdoctoral Research Associates, support for half of the 8 college and high-school astrobiology summer interns, and full support of all NAI-related technicians and Information Technology staff. An array of laboratory instrumentation with an aggregate value in excess of $10 million will continue to be made freely available to research in support of NASA Astrobiology Institute objectives. The Carnegie Institution will continue as well its major financial commitment to programs in science education and outreach. Significant contributions of salary support and laboratory instrumentation and facilities will also be made by each of the partner institutions in our consortium.

Innovation and Distinguishing Features. Our NAI team is distinguished by several features:

• Scientific breadth: We integrate experimental, theoretical, observational, and field studies by experts in astronomy, biology, geochemistry, organic chemistry, mineralogy, planetary science, microbial ecology, and biotechnology in one laboratory.
• Scientific focus: We direct this broad expertise toward fundamental astrobiological questions regarding the origin and distribution of life in the universe.
• Shared resources: We provide important resources for the larger astrobiology community. During the first five years of the NAI we hosted more than 30 researchers from other NAI teams, NAI foreign associates, and other institutions with interests in astrobiology.
• E/PO: Our consortium is dedicated to training, education, and outreach programs that reach numerous students, teachers, and members of the general public.

Summary. The mission of the Carnegie Institution’s vibrant astrobiology program matches that of the NASA Astrobiology Institute itself – to explore the origins and distribution of life in the universe. Throughout the past five years the Carnegie team has played a significant and expanding role in shaping the context and text of NAI. Our dynamic and extensive research program, our acclaimed education and public outreach efforts, and our unswerving commitment to the future of astrobiology provide the primary motivations for this proposal. We look forward with enthusiasm to continued participation in this unique program.