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THE ICEBREAKER MISSION TO SEARCH FOR LIFE ON MARS C. Stoker1, C. McKay1, W. Brinckerhoff2, A. Davila3 V. Parro4, R. Quinn3 ,1NASA Ames Research Center, CA, USA, 2NASA Goddard Space Flight Center, 3SETI Institute, CA, USA, 4Centro de Astrobiología Madrid, Spain Introduction: The search for evidence of life on Mars (SOLID) [Parro et al., 2011] for biomolecular analysis, is the ultimate motivation for its scientific exploration. Laser Desorption Mass Spectrometer (LDMS) [??? The results from the Phoenix mission indicate that the 2015]) for broad spectrum organic analysis, and Wet high N. latitude ice-rich regolith at low elevations is Chemistry Laboratory (WCL) [Hecht et al., 2009] for likely to be a recently habitable place on Mars [Stoker detecting soluble species of nutrients and reactive oxi- et al., 2010]. The near-surface ice likely provided ade- dants. The Icebreaker payload fits on the Phoenix quate water activity during periods of high obliquity, 3 spacecraft and can land at the well-characterized Phoe- to 10 Myr ago. Carbon dioxide and nitrogen are pre- nix landing site in 2020 in a Discovery-class mission. sent in the atmosphere, and nitrates may be present in Habitable Conditions at the Phoenix Landing Site the soil. Together with iron in basaltic rocks and per- on Mars: The Phoenix landing site on Mars is argua- chlorate in the soil they provide carbon and energy bly the most likely site to support life during recent sources, and oxidative power to drive metabolism. periods of high obliquity, 3 to 10 Myr ago: 1. Pressure Furthermore, the presence of organics is possible, as above the triple point of water; 2. Ice near the surface thermally reactive perchlorate would have prevented as a source of liquid water; 3. High summer insolation o o their detection by Viking and Phoenix. at orbital tilts >35 (present 25 ), equivalent to levels The Mars Icebreaker Life mission [McKay et al., of summer sunlight in Earth’s polar regions at the pre- 2013] focuses on the following science goals: (1) sent time. Terrestrial permafrost communities are an example of Search for biomolecular evidence of life; (2) Search possible life in the ice-rich regolith. Studies in perma- for organic matter from either exogeneous or endoge- frost have shown that microorganisms can function in neous sources using methods that are not effected by ice-soil mixtures at temperatures as low as -20°C, liv- the presence of perchlorate; (3) Characterize oxidative ing in the thin films of interfacial water. In addition, it species that produced reactivity of soils seen by Vi- is well established that ground ice preserves living king; and 4) Assess the habitability of the ice bearing cells, biological material, and organic compounds for soils. The Icebreaker Life payload (Figure 1) includes long periods of time, and living microorganisms have a 1-m rotary percussive drill that brings cuttings sam- been preserved under frozen conditions for thousands ples to the surface where they are delivered to three and sometimes millions of years . Smilar biomolecular instruments (Fig. 1), the Signs of Life Detector evidence of life could have accumulated in the ice-rich regolith on Mars. References: Stoker et al. (2010) J.G.R. XXXX; McKay et al. (2013) Astrobiology, 13, 334-353. Parro et al. (2011) Astrobiology 11: 15-28. Hecht et al. 2009 XXXX; LDMS ; Gilichinsky et al. (1992) Adv. Space Res. 12, 255-263 Figure 1. Artist concept of the Icebreaker lander sam- pling the martian subsurface .