The ESA/Roscosmos ExoMars rover will be launched in 2018. The primary aim of the mission will be to find evidence of extinct or extant life by extracting samples from the subsurface of Mars. The rover will incorporate a drill that is capable of extracting cores from depths of up to 2 m, a Sample Preparation and Distribution System (SPDS) that will crush the core into small grains and a suite of analytical instruments. A key component of the analytical suite will be the Raman Laser Spectrometer (RLS) that will be used to probe the molecular and mineralogical composition of the samples. In this work we consider the capability of the proposed Raman spectrometer to detect reduced carbon (possibly associated with evidence for extinct life) and to identify the level of thermal alteration/maturity. The Raman analysis of 21 natural samples of shale (originating from regions exhibiting different levels of thermal maturity) is described and it is shown that reduced carbon levels as low as 0.08% can be readily detected. It is also demonstrated that the Raman spectra obtained with the instrument can be used to distinguish between samples exhibiting high and low levels of thermal maturity and that reduced carbon can be detected in samples exposed to significant levels of oxidation (as expected on the surface of Mars).
HGME, IH, RI and LVH acknowledge the support of the STFC Research Council and the UK Space Agency in the UK ExoMars programme. Colin Taylor (University of Aberdeen) is thanked for skilled technical assistance. JJ׳s participation was supported by Grant no. P210/10/0467 from the Grant Agency of the Czech Republic and by institutional support MSM0021620855 from the Ministry of Education of the Czech Republic. CPM is supported by NSF Grant no. EAR-1053241.
- Carbonaceous matter
- Planetary exploration
- Raman spectroscopy