The Search for Life's Origins Progress and Future Directions in Planetary Biology and Chemical Evolution (1990) / Chapter Skim
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7. Major Research Recommendations
7. Major Research Recommendations
Pages 123-129
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From page 123... ...
Within each group, lists have been priority ordered on the basis of a combination of near-term feasibility and scientific importance. In making recommendations involving space flight, it should be recognized that the principal impetus for these missions is most likely to stem from the astrophysical and planetary scientific communities and that the resources involved in performing exobiological studies thereon will typically be very much less than overall mission expenses.
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From page 124... ...
102-1031~. The committee therefore recommends studies to · conduct chemical, isotopic, mineralogical, sedimentological, and paleontological studies of Martian surface materials at sites where there is evidence of hydrologic activity in any early clement epoch, through in situ determinations and through analysis of returned samples; of primary interest are sites in the channel networks and outflow plains; highest priority is assigned to sites where there is evidence suggestive of water-lain sediments on the floors of canyons as in the Valles Marineris system, particularly Hebes and Candor chasmata; and · reconstruct the history of liquid water and its interactions with surface materials on Mars through photogeologic studies, space-based spectral reflectivity measurements, in situ measurements, and analysis of returned samples.
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From page 125... ...
Thus, investigations of these objects can be expected to shed much light on one model for the formation of life on the Earth, in which a reducing atmosphere has been invoked. The committee therefore recommends studies to · identify the compositions, and measure the abundances and distributions, of gaseous organic compounds and organic haze particles in Titan's atmosphere, using atmospheric entry probes and remote astronomical observations (see Chapter 3, pp.
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From page 126... ...
Accordingly, the committee recommends: · the reexamination of biological monomer synthesis under primitive Earthlike environments, as revealed in current models of the early Earth, and the synthesis and study of simple model systems for fundamental biological processes such as polynucleotide replication, sequestration of biomolecules, coenzyme functions, and elements of the translation system in protein syntheses (this recommendation is based on considerations discussed in Chapter 4 [pp. 80-903~; · the development of improved data on the biological and physical development of the Earth by modeling the geochemistry of the prebiotic and earliest biotic oceans to obtain their composition and their physical and chemical responses to large impacts, and by careful sedimentological, geochemical, and paleontological analysis of ancient sedimentary basins; local environments favorable for the origin of life should be identified and characterized geophysically and geochemically: geological research should be aimed not only at the elucidation of environmental evolution, but also at understanding the cosmic influences on terrestrial environments and evolution (see Chapters 3 [pp.
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From page 127... ...
The committee therefore recommends that . laboratory and theoretical model studies be carried out of photochemical and weathering processes on Mars that will determine the nature of inorganic carbon, nitrogen, sulfur, and iron-bearing phases in Martian surface soils; will indicate the geochemical cycles of these elements during an earlier aqueous epoch; and will characterize the nature of the oxidants revealed by the Viking experiments; and · scenarios be developed for chemical evolution and the origin of life on Mars, based on our knowledge of these processes on Earth, but bounded by existing data and theory on the accretionary, tectonic, geologic, and climatic history of Mars.
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From page 128... ...
simulations be carried out of organic synthesis resulting from the deposition of electrons, photons, and cosmic rays into Titan's atmosphere and that similar experiments, as well as computer simulations, be conducted that will yield predictions of the molecular compositions and abundances of organic matter produced by processes operating at various levels in the atmospheres of Jupiter and Saturn. Studies Related to the Interstellar Medium and Dust Data from laboratory investigations and from theoretical modeling are necessary to prepare for, understand, and extend the results obtained from space-borne experiments aimed at studying the interstellar medium and dust particles of interstellar and interplanetary origin.
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From page 129... ...
106-108, 109-112, and 1 13-1 171~; · commencement of a systematic ground-based search through the low end of the microwave window for evidence of signals from an extraterrestrial technology (see Chapter 6 [pp. 111-112 and 117-1223~; and · studies leading to the development of future technologies for these investigations, including large-scale optical, infrared, and submillimeter arrays or monoliths in orbit or on lunar farside for imaging extrasolar planets and protoplanetary nebulae; a dedicated SETI facility with RFI protection in high Earth orbit or lunar farside; advanced dataprocessing techniques; and substantive original or unconventional approaches to the detection of other technological civilizations (this topic is discussed in Chapter 6 [pp.
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