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

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I.7.3 Organic Chemistry
Processes and
Microorganisms <strong>in</strong> Space
I.7.4 Laboratory-based
Studies
ORGANIC MOLECULES, represent<strong>in</strong>g potential build<strong>in</strong>g blocks of pre-biological
materials, may suffer degradation and racemisation under space conditions. It is
<strong>the</strong>re<strong>for</strong>e necessary to study <strong>the</strong> effects of space conditions on organics such as
am<strong>in</strong>o acids, sugars, lipids and nucleic acid bases. <strong>The</strong> potential protective
effects of association with m<strong>in</strong>eral dust particles will <strong>in</strong>dicate <strong>the</strong> <strong>in</strong>fluences of
<strong>the</strong> micrometeorite and cometary environments. Similar studies are also needed
on <strong>the</strong> polycyclic aromatic hydrocarbons (PAHs). Experiments of this type will
require access to <strong>the</strong> external environment of a space station or o<strong>the</strong>r vehicle
with dedicated facilities.
MICROORGANISMS subjected to <strong>the</strong> space environment, especially <strong>the</strong> UV
radiation and high-Z particle flux, will tend to be damaged progressively and
die. It is possible, however, <strong>for</strong> certa<strong>in</strong> types of organisms to survive <strong>in</strong> space
over long periods, especially if screened with<strong>in</strong> meteorite-like structures.
Cont<strong>in</strong>u<strong>in</strong>g experiments us<strong>in</strong>g space vehicles and eventually <strong>the</strong> International
Space Station will improve <strong>the</strong> understand<strong>in</strong>g of <strong>the</strong> underly<strong>in</strong>g damage
processes, <strong>the</strong> survivability of a range of organisms, and <strong>the</strong> possibility of life
be<strong>in</strong>g distributed among <strong>the</strong> <strong>Solar</strong> <strong>System</strong> by meteorite delivery.
LABORATORY SIMULATIONS can provide valuable <strong>in</strong><strong>for</strong>mation on <strong>the</strong> organic
chemistry processes <strong>in</strong> comets, on <strong>in</strong>terstellar gra<strong>in</strong>s and <strong>in</strong> meteorites. <strong>The</strong>y can
lead to a better understand<strong>in</strong>g of <strong>the</strong> processes occurr<strong>in</strong>g dur<strong>in</strong>g <strong>the</strong> trans<strong>for</strong>mation
of organic residues <strong>in</strong> sediments. Simulation of planetary environments
and <strong>the</strong> study of <strong>the</strong> effects on microorganisms will have both fundamental and
practical value.
LABORATORY STUDIES will cont<strong>in</strong>ue to provide <strong>the</strong> essential fundamental
experiments <strong>in</strong> <strong>the</strong> search to understand <strong>the</strong> earliest steps <strong>in</strong> <strong>the</strong> emergence of
life. Careful studies of <strong>the</strong> most ancient sedimentary rocks may yet yield fur<strong>the</strong>r
<strong>in</strong><strong>for</strong>mation on that process. In conjunction with <strong>in</strong> situ experiments <strong>in</strong> <strong>the</strong> field,
laboratory observations will cont<strong>in</strong>ue to make important contributions to <strong>the</strong>
knowledge of how life develops and survives under extreme conditions,
<strong>in</strong>clud<strong>in</strong>g deep subterranean life and its application to <strong>the</strong> search <strong>for</strong> life
elsewhere <strong>in</strong> <strong>the</strong> <strong>Solar</strong> <strong>System</strong>.