Estimation and analysis of mars contamination

Since the beginning of the exploration of Mars, a little more than fourty years ago, more than thirty missions have been launched, including about fifty different space systems such as fly-by spacecrafts, orbiters, cruise modules, landing or penetrating systems. Taking into account failures at launch, about three missions out of four have been sucessfully sent toward the Red Planet. The fact today is that Mars orbital environment includes orbiters and maybe debris, and that its atmosphere and its surface are contaminated by terrestrial compounds and dormant microorganisms. According to the COSPAR planetary protection policy recommendations, Mars environment has to be preserved in order not to jeopardize the scientific investigations, and the level of contamination brought on and around Mars theoretically complies with this policy. After this number of Mars missions, it is now useful to assess Mars contamination, to evaluate what and how many materials, compounds and microorganisms are on Mars, to list what is in orbit and to identify where all these items are. Considering assumptions about material, spores and gas location and dispersion on Mars, average contamination levels can be estimated. Impact on scientific investigations can consequently be evaluated and ethical considerations may also be discussed.