HR: 17:45h
AN: P42C-08    [PDF]
TI: What are the best ways to look for extinct or extant life on mars? Thinking outside the box
AU: * Bada, J L
EM: jbada@ucsd.edu
AF: Scripps Institution of Oceanograph, Univ. Calif. at San Diego, La Jolla, CA 92093
AU: Grunthaner, F
EM: Frank.J.Grunthaner@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109
AU: Mathies, R
EM: Rich@zinc.cchem.berkeley.edu
AF: Dept. Chem., UC Berkeley, Berkeley, CA 94720
AB: Although the Viking missions a quarter century ago performed a series of life detection experiments, the question of whether life ever existed or even still exists on Mars remains unanswered. The finding that the Martian surface is highly oxidizing seemed to preclude the presence of a robust surface biology, but the subsurface may be more compatible with respect to the survival of both viable organisms (1) and organic compounds. Moreover, it is now also known that the Viking GCMS would not have detected refractory organic compounds (2) or amino acids associated with over a million bacterial cells in a gram of soil (3). The entire Mars community now faces a major challenge as to what we should do next in our search for evidence of life on Mars. The option that is presently favored is to fly "safe" missions focused on characterizing the mineral and elemental makeup of the surface with little emphasis on state-of-the-art analyses for important biomarkers. A second, or perhaps parallel, bolder approach would be to fly payloads made up of highly sensitive instruments designed to search for a wide variety of key organic compounds. Instrumentation available to detect trace levels of key biological compounds have improved dramatically since the Viking missions and many of these methods can be miniaturized so they can be accommodated into a spacecraft. The critical issue is what suite of instruments would provide the most definitive results in answering the life on Mars question. To rigorously address this question, we propose that various organic detection systems be extensively tested in situ using a common and well controlled set of samples in an environment that is known to have low levels of both microbes and organic compounds. One locality that would be a strong candidate is the Yungay Station site in the Atacama desert of Chile, one of the driest and harshest places on Earth. Only those instruments that are able to detect at high sensitivity organic biomarkers in a natural field situation such as this should be considered for components for a future Mars mission payload package. If an instrument can not detect the presence of life's organic signature here on Earth, there is no justification for flying this instrument in a payload to Mars! NIH and DOE embarked upon a similar critical competition to development the best methodology to sequence the human genome and this process was dramically successful. NASA's search for possible signs of life on Mars deserves at the same level of critical and competitive decision-making where scientific capability rather than other factors determine what is included in payloads. 1. B. P. Weiss et al, Proc. Natl Acad. Sci USA 97, 1395 (2000). 2. S. A. Benner et al, Proc. Natl Acad. Sci USA 97, 2425 (2000). 3. D. P. Glavin et al, Earth Planet. Sci. Lettrs. 185, 1 (2001).
DE: 1863 Snow and ice (1827)
DE: 5462 Polar regions
DE: 5499 General or miscellaneous
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting