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

II.7 Conclusions
Three fundamental requirements were identified as need<strong>in</strong>g to be satisfied if a search
<strong>for</strong> evidence of life on Mars is to be conducted satisfactorily. <strong>The</strong>se are:
i. <strong>the</strong> land<strong>in</strong>g site must be selected as one of high exobiology potential. That has
not been <strong>the</strong> case so far. Sites associated with sedimentary deposits, <strong>in</strong> areas
relatively free from aeolian sand, would be prime targets.
ii. sampl<strong>in</strong>g that site must occur <strong>in</strong> several locations and should result <strong>in</strong> samples
free from <strong>the</strong> effects of <strong>the</strong> surface oxidation processes. Hence, mobility is
needed, toge<strong>the</strong>r with drill<strong>in</strong>g systems that can reach well <strong>in</strong>to <strong>the</strong> regolith and
<strong>the</strong> surface rocks.
iii. an <strong>in</strong>tegrated measurement set must be per<strong>for</strong>med on those samples such as to
reduce <strong>the</strong> potential <strong>for</strong> ambiguity. Hence, observational, spectroscopic and
analytical techniques should be used, which toge<strong>the</strong>r can provide a coherent
description of <strong>the</strong> petrology, m<strong>in</strong>eralogy and geochemistry of that site.
<strong>The</strong> preferred sites are generally located <strong>in</strong> large sedimentary terra<strong>in</strong>s with low
aeolian sand coverage. Hydro<strong>the</strong>rmal sites may provide an alternative. Higherresolution
imag<strong>in</strong>g of potential targets is needed, toge<strong>the</strong>r with confirm<strong>in</strong>g m<strong>in</strong>eralogical
mapp<strong>in</strong>g. It was agreed that <strong>the</strong> choice of sites would be narrowed down to
five, selected us<strong>in</strong>g <strong>the</strong> above criteria, among o<strong>the</strong>rs. Those currently identified are
listed <strong>in</strong> Table II.7.1/1. However, as new <strong>in</strong><strong>for</strong>mation becomes available <strong>the</strong>se may
change. <strong>The</strong> f<strong>in</strong>al site selection process obviously also has to take account of technical
and mission constra<strong>in</strong>ts.
Table II.7.1/1. Land<strong>in</strong>g Sites <strong>for</strong> <strong>Exobiology</strong>.
Exobiological
Name Location Potential General Remarks
Marca Crater 10.4ºS / 158.2ºW Good: lake beds Several craters with
lacustr<strong>in</strong>e deposits
Hydroates Chaos 0.02ºN / 33.94ºW Good: lacustr<strong>in</strong>e Complex bas<strong>in</strong>s
deposits rock debris
Apol<strong>in</strong>aris Patera 8.6ºS / 187.5ºW Good: hydro<strong>the</strong>rmal Volcano + rock debris
systems of various ages
Gusev Crater 14ºS / 184.5ºW Good: lake beds Lacustr<strong>in</strong>e bas<strong>in</strong>
+ large outflow channel
Capri Chasma 15ºS / 47ºW Good: probable Chaotic terra<strong>in</strong>/
water-laid deposits sediments
II.7.1 Land<strong>in</strong>g Sites <strong>for</strong>
<strong>Exobiology</strong>
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