Exobiology in the Solar System & The Search for Life on Mars - ESA

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Table II.7.4/1. Recommended Instruments <strong>for</strong> <strong>Search</strong><strong>in</strong>g <strong>for</strong> Organics on Mars. Mass Power Volume Instrument Analysis (kg) (W) (m 3 ) Data Alpha/Proton/ Elemental analysis 0.5 0.4 300 16 kbit/ X-ray Spectrometer <strong>for</strong> all except H and He (1.3 peak) sample Mössbauer Fe-bear<strong>in</strong>g m<strong>in</strong>erals 0.5 1.6 600 1.2 Mbit/ Spectrometer Fe-oxidation state and ratios sample determ<strong>in</strong>ation of water, particularly as a function of depth. <strong>The</strong> depth profile of <strong>the</strong> abundance of oxidants <strong>in</strong> <strong>the</strong> regolith is ano<strong>the</strong>r obvious requirement. As yet, no organics have been found on Mars and <strong>the</strong>ir discovery and analysis would be of prime importance <strong>for</strong> exobiology. It will be necessary, however, to differentiate carefully between organics of an abiotic orig<strong>in</strong>, especially those of meteoritic orig<strong>in</strong>. On Earth, <strong>the</strong> primary biopolymers undergo a complex process of degradation and condensation follow<strong>in</strong>g <strong>the</strong> death of <strong>the</strong> organism. <strong>The</strong> result is a complex and chemically stable macromolecular material (kerogen). In addition, certa<strong>in</strong> stable lipid-rich biopolymers survive this degradation process, to contribute directly to <strong>the</strong> constitution of <strong>the</strong> kerogen. Sediments may also conta<strong>in</strong> o<strong>the</strong>r stable organic compounds that have survived, at least <strong>in</strong> part, <strong>the</strong> processes of alteration. Many can be classified as biomarkers on <strong>the</strong> basis of <strong>the</strong>ir structures and/or carbon isotopic compositions. Such biomarkers and kerogens of recognisable biological orig<strong>in</strong> have been found <strong>in</strong> sediments on Earth dat<strong>in</strong>g back at least 0.5 Gyr. It is <strong>the</strong>re<strong>for</strong>e conceivable that such materials might be detected on Mars, given appropriate sites. Tak<strong>in</strong>g <strong>in</strong>to account factors such as survivability, especially <strong>in</strong> an oxidis<strong>in</strong>g environment, has led to <strong>the</strong> follow<strong>in</strong>g recommended priority order <strong>in</strong> search<strong>in</strong>g <strong>for</strong> organics: 1. volatile low molecular weight compounds, <strong>in</strong>clud<strong>in</strong>g hydrocarbons (especially methane), alkanoic acids and peroxy acids; 2. medium molecular weight compounds, <strong>in</strong>clud<strong>in</strong>g hydrocarbons (straight- and branched-cha<strong>in</strong>, isoprenoids, terpenoids, steroids and aromatics); 3. macromolecular components, which would be kerogen-like components, oligoand polypeptides. Table II.7.4/1 lists <strong>the</strong> analysis <strong>in</strong>struments that have been identified as suitable, <strong>in</strong> total, to cover <strong>the</strong> range of determ<strong>in</strong>ations, elemental, isotopic, and molecular, outl<strong>in</strong>ed above. conclusions/II.7 Laser Raman Molecular analysis of organics 1.5 1.1 250 to be Spectrometer and m<strong>in</strong>erals (2.5 peak) determ<strong>in</strong>ed 200-3500 cm -1 & 8 cm -1 resolution Infrared Molecular analysis of m<strong>in</strong>erals 1.0 3.5 800 to be Spectrometer and organics determ<strong>in</strong>ed 0.8-10 µm. Spectral resolution 100. Spatial resolution 200 µm Pyrolytic Gas Analyse <strong>in</strong>organic/organic 4.0 8 2.5 Mbit max Chromatograph compounds; isotopic ratio (15 peak) 0.6 Mbit m<strong>in</strong> and Mass Spectrometer and chirality determ<strong>in</strong>ation 183
SP-1231 184 II.7.5 A Possible <strong>Exobiology</strong> Experiment Package and Operat<strong>in</strong>g Arrangement <strong>The</strong> previously described equipment could be distributed between a large Lander and a Rover on <strong>the</strong> follow<strong>in</strong>g basis: ROVER (option 1) – robotic position<strong>in</strong>g arm 2.0 kg – a rock surface gr<strong>in</strong>der 0.4 kg – low-power microscope 0.2 kg – APX spectrometer 0.5 kg – a small rock-cor<strong>in</strong>g drill 3.5 kg – core sample conta<strong>in</strong>ers 0.5 kg Total mass: 7.1 kg ROVER (option 2) – small robotic arm equipped to collect cm-sized surface rocks, place <strong>in</strong> transfer conta<strong>in</strong>ers, and subsequently pass to <strong>the</strong> Lander. (2 kg); – close-up colour camera (0.1 kg); – sample conta<strong>in</strong>ers <strong>for</strong> <strong>the</strong> collected small rock samples (0.5 kg). LANDER – subsurface drill system 6.5 kg – sample handl<strong>in</strong>g/distribution 4.0 kg – sample section<strong>in</strong>g 0.3 kg – sample gr<strong>in</strong>d<strong>in</strong>g 0.4 kg – low-resolution microscope 0.2 kg – optical microscope 0.3 kg – Atomic Force Microscope 1.5 kg – microscopy transfer stage 1.0 kg – Alpha/Proton/X-ray Spectrometer 0.5 kg – Mössbauer Spectrometer 0.5 kg – Laser Raman Spectrometer 1.5 kg – IR Microspectrometer 1.0 kg – Pyrolytic, Gas Chromatograph, Mass Spectrometer 5.5 kg – Oxidant detector 0.4 kg – Laser Ablation ICP mass spectrometer 2.5 kg Total mass: 26.1 kg In this configuration, <strong>the</strong> Lander is <strong>the</strong> centre <strong>for</strong> subsurface sampl<strong>in</strong>g and <strong>for</strong> <strong>the</strong> <strong>in</strong> situ sample preparation and analysis processes. <strong>The</strong> Rover <strong>the</strong>n provides a selection of rock samples from nearby locations ei<strong>the</strong>r as small core samples or as small (cmsize) rocks, <strong>for</strong> saw<strong>in</strong>g <strong>in</strong> <strong>the</strong> Lander. In <strong>the</strong> latter case, <strong>the</strong> Rover may be of small dimensions and be equipped with a camera and close-up imag<strong>in</strong>g system.
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SP-1231 Exobiology
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Cover Fossil coccoid bacteria, 1 µ
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4 I.5 Potential Non-Martian Sites <
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6 6.2 Imaging of F
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The Exobio
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pyrolysis, or similar techniques, f
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Ignasi Casanova, Institute
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I AN EXOBIOLOGICAL VIEW OF THE SOLA
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SP-1231 18 surface pressure of CO 2
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SP-1231 20 10 bar befor</st
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SP-1231 22 kilometres in</s
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SP-1231 24 Laboratory Investigation
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I.3 Limits of Life
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temperatures of 95-106ºC. This sug
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(mainly found <str
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cannot exclude fin
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Responses to Cosmic Radiation <stro
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acid to identify the</stron
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Horneck, G. (1993). Responses of Ba
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SP-1231 Fig. I.4.2.2/1. Size distri
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SP-1231 Fig. I.4.2.2/4. Evaporite w
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SP-1231 Fig. I.4.2.3/1A (left). Net
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SP-1231 48 A detailed chemical anal
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SP-1231 Fig. I.4.3.1.1/1. Scheme of
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SP-1231 Fig. I.4.3.1.2/1. A: Compar
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SP-1231 54 I.4.3.2.1 Sedimentary Or
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SP-1231 56 The iso
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SP-1231 Fig. I.4.3.2.3/1. Cholester
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SP-1231 60 References regard to non
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SP-1231 62 Klein,
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SP-1231 64 ities in</strong
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SP-1231 Fig. I.5.1.1/1. A 34×42 km
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SP-1231 Fig. I.5.2.1/1. Titan’s a
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SP-1231 Fig. I.5.2.2/2. Modelled Ti
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SP-1231 72 Galileo: images availabl
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SP-1231 74 TABLE I.6.2/1 EVIDENCE O
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SP-1231 I.6.3 What to Searc
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SP-1231 78 I.7.3 Organic Chemistry
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II.1 Introduction The</stro
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II.2 The Planet Ma
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cover the range 4.
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The depletion of c
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valley networks (Fig. II.2.5/2) are
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plate tectonic evidence has been ob
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Table II.2.7.4/1. Potential Mars <s
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II.3 The Martian M
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principal atmosphe
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Lines of evidence
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indicated by carbo
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quest for
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Anders, E. (1989). Prebiotic organi
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Urey, H.C. (1968). Origin</
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SP-1231 Fig. II.4.1.1/1. A Gilbert-
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SP-1231 Fig. II.4.1.3/1. Th
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SP-1231 114 Sinuou
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SP-1231 Fig. II.4.3/1. Ages of seve
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SP-1231 118 orbital characteristics
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SP-1231 120 II.4.5 The</str
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SP-1231 122 II.4.6 Rovers and Drill
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SP-1231 124 Site 2: Apolin<
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SP-1231 126 Site 4: Chasma area, ea
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SP-1231 128 Sharp, M., Parkes, J.,
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Page 161 and 162: SCIENTIFIC METHOD AND REQUIREMENTS
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Exobiology in the Solar System & The Search for Life on Mars - ESA

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