Nieuwe inzichten over het leven op Mars
door Christian Muller (BIRA)

The space exploration of Mars began with Mariner 4 in 1964 that showed a dry and cold planet closer to the moon than to earth and Venus. The VIKING lander of 1976 showed however unexplained and ambiguous results that were at the time thought to be incompatible with life. It was then almost certain that Mars was sterile and that astronauts could walk safely on it without fear of encountering any "second" life which they would not have brought with them. The situation changed in the late eighties where extremophiles were discovered at several locations on the earth pushing the envelope of life to much wider limits. In particular, this new knowledge led in 1996 to interpret a meteorite of Martian origin as containing a microfossil of 3.9 billion years of age. The controversy over this discovery is still raging. Even more incredibly, an isolated measurement from the Russian 1989 PHOBOS mission seems to show formaldehyde in the Mars atmosphere while repeated observations of Mars-Express and ground telescopes show now methane. The discovery of perchlorates by the PHOENIX lander in the Martian northern cap could also be related to life processes. These different observations will be shortly described with the possible Martian habitats. The new ESA-NASA EXOMARS mission will verify these results and look for both contemporary and extinct life beginning in 2016, the future of the programme and its consequences on the future Mars sample return missions and manned flight will be described.