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

Table II.5.9.4/1. New PYR-GC-MS Developments <strong>for</strong> Space Applications.
Experiment MS type Mass Power Requirement
MODULUS Ion Trap 3.5 kg
COSAC Time-of-Flight 4.5 kg 8-16 W
carrier gas to transfer <strong>the</strong> result<strong>in</strong>g gases to <strong>the</strong> GC-MS <strong>for</strong> analysis. Such a system
has sensitivity and resolution capabilities of one to several orders of magnitude higher
than Vik<strong>in</strong>g’s PYR-GC-MS, with less mass and volume.
New <strong>in</strong>strumentation <strong>in</strong>volv<strong>in</strong>g PYR-GC-MS techniques and us<strong>in</strong>g <strong>the</strong> heritage of
Huygens is under development <strong>for</strong> space application, <strong>in</strong> particular <strong>for</strong> <strong>in</strong> situ analysis
of cometary nuclei.
<strong>The</strong> COSAC and MODULUS <strong>in</strong>struments, <strong>the</strong> two GC-based experiments on <strong>the</strong>
Rosetta lander, use pyrolysis oven GC techniques with several columns and a
coupl<strong>in</strong>g to mass spectrometry. COSAC uses a new concept of time-of-flight MS,
based on a specific geometry of <strong>the</strong> MS. MODULUS uses a ion-trap MS; mass is 10-
20 g (exclud<strong>in</strong>g power supplies).
Pyrolysis ovens with load<strong>in</strong>g mechanisms will be available <strong>for</strong> <strong>the</strong> COSAC and
MODULUS experiments. Some ovens will have <strong>the</strong> facility <strong>for</strong> optically view<strong>in</strong>g <strong>the</strong>
sample be<strong>for</strong>e <strong>the</strong> heat<strong>in</strong>g process starts. O<strong>the</strong>r types, which have excit<strong>in</strong>g potential
<strong>for</strong> studies at predeterm<strong>in</strong>ed temperatures, without us<strong>in</strong>g circuitry <strong>for</strong> control, are hot
wire and curie po<strong>in</strong>t pyrolysis units. Here, <strong>the</strong> properties of <strong>the</strong> material, ra<strong>the</strong>r than
feedback loops, decide <strong>the</strong> temperatures to which <strong>the</strong> sample is heated. Although not
yet tested <strong>in</strong> space, such methods should be easily adaptable.
PYR-GC-MS <strong>in</strong>strumentation on <strong>the</strong> exobiology package will be able to analyse:
• <strong>in</strong>organics: HO, CO 2, NO 2, N xO y, SO 2, SO 3, H2S, ...
– volatiles adsorbed <strong>in</strong> <strong>the</strong> soil and released by light heat<strong>in</strong>g
– or chemically bound <strong>in</strong> m<strong>in</strong>erals and released by pyrolysis.
Only <strong>the</strong> analysis of H 2O 2 may be a problem and specific analytical techniques
have to be found <strong>for</strong> this compound.
• organics:
– low molecular weight organics (RH, RCO 2H, RCO 3H, ...) can be analysed
by GC-MS and MS
– higher molecular weight organics:
hydrocarbons, <strong>in</strong>clud<strong>in</strong>g PAHs can be analysed by GC-MS and MS
am<strong>in</strong>o-acids and pur<strong>in</strong>es by PYR-GC-MS/PYR-MS
– macromolecular compounds:
kerogens and oligopeptides can be analysed by PYR-GC-MS and PYR-MS.
An <strong>in</strong>strument based on <strong>the</strong> COSAC and MODULUS concepts seems a good
solution:
• small furnace pyrolysis;
• multi-GC columns system sets of 2-4 columns <strong>in</strong> parallel;
• ion-trap MS.
By extrapolation from <strong>the</strong> Rosetta <strong>in</strong>strumentation, <strong>the</strong> expected mass is 4 kg.
II.5.9.5 Laser Ablation-Inductive Coupled Plasma-MS (LA-ICP-MS)
Major and trace element determ<strong>in</strong>ations of organic and <strong>in</strong>organic phases could be
team II: <strong>the</strong> search <strong>for</strong> chemical <strong>in</strong>dicators of life/II.5
149