1. The search for life 2.0 in our Solar System Chris McKay NASA Ames Research Center chris.mckay@nasa.gov

2. The search for a second genesis of life? Aliens: not on our tree of life  comparative biochemistry (life 2.0)  life is common in the universe (yeah!)

3. Second Genesis: How will we get our second example of Biochemistry Make it in the laboratory Find it on another world Listen for them to call

4. Where to look? Mars: past liquid water, no/yes on organics, consumes organics Europa: has ocean, possibly organics Titan: liquid - not water, organics Enceladus: has icy jet, possibly liquid water, organics, nitrogen Increasing chance of life not related to Earth life

10. The Mars meteorites contain inclusions of martian air D. Bogart et al.

12. The next mission to Mars: Mars Science Laboratory Launched: Nov. 2011 Landing: 5 Aug 2012 10:15 pm PDT

13. APX instrument

16. SAM will wash the samples with two derivatization agents: N-Methyl-N-(Tert-Butyldimethylsilyl) trifluoroacetamide & tetramethylammonium hydroxide and this mode should be unaltered by perchlorate. There is a pyrolysis GCMS on the upcoming MSL mission Sample Analysis for Mars

19. Possible Ocean on Europa

20. 5 km

23. Surface material Liquid water reservoir Biology: H 2 + CO 2  CH 4 + H 2 O Thermal processing, T>500 o C: CH 4 +H 2 O  H 2 + CO 2 CH 4 H2H2 McKay et al. 2008

24. Europa’s surface If there is an ocean If the ocean has life Then these surface features may contain biogenic organic material

25. Europa Ice Clipper Sample Return Mission based on Stardust spacecraft flying through impact cloud

26. Jets of H 2 O on Enceladus

29. Stardust flys through the Plume of Enceladus for a Sample Return Mission & in-situ search for amino acids and chirality

31. Known composition of Titan’s Atmosphere Major gasesMinor gases N 2 95-99%C 2 H 6 20 ppm CH 4 1-5%C 3 H 8 5-20 ppm H 2 0.1%C 2 H 2 2 ppm Ar40 ppmC 2 H 4 400 ppb C 4 H 2 30 ppb C 6 H 6 0.4 ppb Surface pressure 1.5 atmCH 3 C 2 H30 ppb Surface temperature 95 K HCN20 ppm -180 o CHC 2 CN10-1000 ppb C 2 N 2 10-100 ppb CO 2 10 ppb CO60 ppm H 2 O8 ppb

33. 80 o N 78 o N Radar data from Cassini 100 km Lakes

34. Could there be methane life on Titan? McKay and Smith, Icarus, 2005

35. Iso-pentane Liquid ethane via iso-pentane Green = liquid ethane Tholin solubility in room temperature iso-pentane, less in liquid ethane via iso-pentane, and no detection in liquid ethane directly

36. Balloons Airplanes Lake Lander Future Titan Mission Concepts: Discovery and New Frontiers Class

37. If we find organic material on Mars, Europa, Enceladus, or Titan how can we tell if it was ever alive? If its like us then easy, less interesting If its alien then hard, but interesting

38. How do we recognize alien life? use a tricorder! we’ll know it when we see it!

39. Form of the sample Mars: dead microorganisms long frozen Europa: dead microorganisms on the surface, highly irradiated. Titan: alive in liquid methane Enceladus: dead microorganisms recently ejected into space

40. Two sources of non-biological organic materials: Meteorites and Miller-Urey synthesis experiments How do they differ from life? Two sources of non-biological organic materials: Life Miller-Urey Experiments Two sources of non-biological organic materials:

43. C=C=C H 2 O Ecological level (phototaxis, CO 2 uptake) Biochemical level (L amino acids, ATP) Atomic level

45. Abiotic distributions are smooth Biotic distributions are spiked McKay 2004 PLoS Biol 2(9)1260-12623

46. Abiotic distributions are smooth Biotic distributions are spiked McKay 2004 PLoS Biol 2(9)1260-12623 alien

47. A conceptual landscape of complexity in organic chemistry Minimum complexity for life

48. common ancestor What if we do find a second genesis on Mars?

49. Moral Status of Alien Microbes Now there are three sets: humans, life1, life2 Microscopic organisms which score low moral status based on pain, complex behavior & communication would have high moral status as being the sole representatives of the set life2

50. Immediate Recommendation: Biologically Reversible Exploration The robotic and human exploration of Mars should be done in a way that is biologically reversible. We must be able to undo (‘ctrl Z’) our contamination of Mars if we discover a second genesis of life.

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