Mars Science Laboratory Search for Organics: Potential Contribution from Infall of Meteorites

Introduction: A major goal of the Mars Science Laboratory (MSL) mission is to search for past and present habitable environments at Gale crater [1]. To achieve this goal MSL has, in particular, the capability to detect complex organic molecules in rocks and soils using the Sample Analysis at Mars instrument (SAM). A primary goal of the SAM investigation is to carry out a search for organic compounds and to measure the isotopic composition of carbonaceous material [2]. As stated in [2], sources of organic compounds that SAM might detect could be indigenous (that is the desired target of the mission), exogenous (which we touch on in this paper), and terrestrial contamination (which will hopefully not be the case). The authors of [2] consider as exogenous sources the organic compounds which are derived from the in-fall of meteorites, interplanetary dust particles, and larger volatile-rich impactors such as comets or carbonaceous asteroids. Meteorites observed by MERs: In this work we briefly consider the issue of organic compounds brought by in-fall of meteorites. The atmosphere of Mars with its 17 g of mass per cm 2 of its surface and significantly lower (comparing to Earth) velocity of entry of meteoroids into atmosphere of Mars, seem to provide favorable conditions for entry and recovery for meteorites of centimeters to decimeters in diameter either through direct deccelleration at highly oblique entrees, or fragmentation of larger impactors [3, 4]. This suggestion is supported by the observations of the two Mars Explorations Rovers (MER). The latter, during the 42 km cumulative traverse identified 17 meteorites candidates: 10 irons and 7 stones (Fig. 1) [5, 6].