NASA Astrobiology Roadmap April 8, 2002 Draft
Goals and Objectives
GOAL 1: Understand how life originates from cosmic and planetary precursors. Perform observational, experimental, and theoretical investigations to understand the physical and chemical principles underlying the origin of life, both on the Early Earth and on other planetary bodies.
Objective 1.1 – Sources of prebiotic materials and catalysts. Characterize the cosmic and planetary sources of matter (organic and inorganic) for potentially habitable environments in the Solar System and in other planetary and protoplanetary systems.
Objective 1.2 – Origins of functional biopolymers. Identify multiple plausible pathways for the condensation of prebiotic monomers into polymers with the potential for catalytic and genetic functions, and mechanisms for their assembly into more complex molecular systems having specific properties of the living state.
Objective 1.3 – Origins of energy transduction. Identify prebiotic mechanism by which available energy can be captured by molecular systems and used to drive primitive metabolism and polymerization reactions.
Objective 1.4 – Origins and early consequences of cellularity. Investigate both the origin of membranous boundaries on the early Earth and the associated properties of energy transduction, transport of nutrients, growth, and division. Investigate primitive processes leading to heterogeneous populations of cells.
GOAL 2: Understand the interactions between life on Earth and its planetary and Solar System environment. Investigate the historical relationship between Earth and its biota by integrating evidence from Earth history, organisms, and modern environments.
Objective 2.1 – Earth’s earliest biosphere. Investigate key biological processes and their environmental consequences during the early history of Earth through molecular, stratigraphic, geochemical, and paleontological studies.
Objective 2.2 – Dawn of multicellular life. Study the origin and early evolution of complex, multicellular life (plants, animals, and fungi) and its planetary context to understand better the transition to multicellularity and the initial steps leading eventually to intelligence.
Objective 2.3 – Extraterrestrial effects on biospheres. Examine the response of Earth’s biosphere (both the habitable environment and biota) to extraterrestrial events.
GOAL 3: Understand how life evolves on the molecular, organismal, and ecosystem levels. Identify general, perhaps universal, features of evolution. From the molecule to the ecosphere, to understand better how life might have evolved on planets other than Earth, and how life might respond to novel environments in the future.
Objective 3.1 – Molecular evolution. Examine the behavior of artificial chemical systems, both terrean and non-terrean, that model processes of natural selection to understand better the intimate interaction between chemistry and evolution.
Objective 3.2 – Ecosystem adaptation and evolution. Examine the responses of microbes and microbial communities to environmental factors, challenges, and changes, to understand how they adapt and evolve.
GOAL 4: Explore the Physical and chemical limits to which life has adapted as a guide for searching for life on other worlds. Characterize the biota that live under conditions relevant to the search for life elsewhere in the solar system. Characterize the fundamental molecular adaptations that allow biota to thrive or at least survive under these conditions.
Objective 4.1 – Explore for life surviving or thriving under the most extreme conditions on Earth. Examine the combined impact of factors such as high temperature and low pH, or ionizing radiation and low nutrients, or extreme cold and desiccation and high salt, and most importantly, the impact of duration of exposure to any condition. These all contribute to defining limits for life that are relevant to Astrobiology.
Objective 4.2 – Characterize and elucidate the biochemical adaptations that define the limits for the individual, the species, and for life itself. Investigate the intrinsic stabilities of biomolecules (e.g. proteins, nucleic acids, lipids, carbohydrates) in isolation and in the complexity of living cells to understand the limit for living systems. Explore the biochemical strategies that cells have evolved to push the limits by reinforcing, replacing, or repairing, or repairing cricitical biomolecules (e.g. spore formation, resting stages, membrane stabilization, protein replacement rates, or DNA repair).
Objective 4.3 – Evolution of life beyond its planet of origin. Explore the survival of life under novel environmental conditions, particularly space and other planets.
GOAL 5: Determine how to recognize signatures of life on other worlds and on early Earth. Define and learn how to measure biosignatures that can infer the existence of past or present life in earthly and extraterrestrial samples, including remotely measured planetary atmospheres and surfaces, samples measured in situ, and returned samples studied on Earth.
Objective 5.1 – identify biosignatures to be sought in Solar System materials. Learn how to recognize and interpret biosignatures which, if identified in samples from ancient rocks on Earth or from other planets, can help to detect and/or characterize the former presence of ancient and/or extant life.
Objective 5.2 – Identify biosignatures to be sought in nearby planetary systems. Learn how to measure biosignatures that can reveal the existence of past or present life through remote observations of distant planetary atmospheres and surfaces.
GOAL 6: Explore for past or present potentially habitable environments, prebiotic chemistry and life that might exist elsewhere in our Solar System. Characterize ancient climates, any extinct life and potential habitats in the outer Solar System.
Objective 6.1 – Mars exploration. Through orbital and surface missions, explore Mars for potentially habitable ancient environment, as evidenced by water or aqueous minerals. Study Martian meteorites to guide future Mars exploration. Develop the methods and supporting technologies for the in situ characterization of aqueous minerals, carbon chemistry and/or life.
Objective 6.2 – Outer Solar System exploration. Conduct basic research, develop instrumentation to support astrobiological exploration and provide scientific guidance for outer Solar System missions. Such missions should explore the Galilean moons of Jupiter-Europa, Ganymede, and Callisto, for habitable environments where liquid water could have supported prebiotic chemical evolution, or life. Saturn’s moon, Titan, should be explored for environments favorable for complex prebiotic synthesis or life.
Goal 7: Understand habitable planets in the Universe. Determine the potential for habitable planets in the Universe, and characterize those that are not observable.
Objective 7.1 – Develop models of habitable planet formation and evolution. Investigate how planets acquire liquid water, and how planetary system processes affect their environment and thereby sustain habitable conditions. Use theoretical and observational studies of the formation and evolution of planetary systems to predict where water-dependent life is likely to be found in such systems.
Objective 7.2 – Improve indirect and direct astronomical observations of extrasolar habitable planets. Support planning for indirect and direct detection of habitable planets by obtaining environmental and biomarker spectroscopic information.
Goal 8: Understand the principles that govern changes in ecosystems on Earth and shape their future biosphere. Elucidate the mechanisms and effects associated with changes in ecosystems and their environment, as a basis for assessing future changes on time scales ranging from decades to millions of years.
Objective 8.1 – Develop a comprehensive biogeochemical model. Develop a predictive model that integrates biogeochemical cycles of multiple elements as well as the effects of environmental changes and biological evolution.
Objective 8.2 – Conduct an observational program. Conduct an observational program to quantify kinetic equations that define how biological and environmental changes affect the chemical transformations of key elements (e.g. C, N, S, O, Fe, Mn, and Mo) and their exchange between the biota, environment and crust.
Astrobiology Roadmap Team Members
Alan P. Boss, Carengie Institution of Washington
David Deamer, university of California, Santa Cruz
Paul Falkowski, Rutgers University
S. Blair Hedges, Penn State University
Andrew Knoll, Harvard University
Victoria Meadows, Jet Propulsin Laboratory
Alfred Spormann, Stanford University
William Turner, NASA headquarters
Harold Yorke, Jet Propulsion Laboratory
Carl Pilcher, NASA Headquarters (ex officio)
John Cronin, Arizona State University
David Des Marais, Chair, NASA Ames Research Center
Jack Farmer, Arizona State University
Bruce M. Jakosky, University of Colorado
David Liskowsky, NASA Headquarters
Kenenth Nealson, Jet Propulsion Laboratory
Jonathan Trent, NASA Ames Research Center
Neville Woolf, University of Arizona
Michael Meyer, NASA headquarters (ex officio)
Astrobiology
