INVITED: THE FUTURE OF MARS ASTROBIOLOGY

2004 was an unprecedented year in the history of Mars exploration, with two highly successful landed missions (NASA's Mars Exploration Rovers, Spirit and Opportunity) and three simultaneously operating orbiters, including the Mars Global Surveyor, the Odyssey Spacecraft and the European Space Agency's Mars Express mission. These spacecraft continue to deliver compelling new insights about the geological history of the Red Planet. Upon the heels of a highly successful robotic program came a new initiative to support the future human exploration of Mars, with a return to the Moon as a stepping-stone to prepare the way.

The long-term goals of Mars exploration will be shaped and refined by future missions. NASA's Mars Reconnaissance Orbiter (MRO) mission, to be launched later this year, will extend orbital mapping into the near-IR, with unprecedented high spatial and spectral resolution. The Phoenix (Mars Scout) mission, to launch in 2007, will deliver in situ investigations to a polar landing site to conduct detailed organic analyses of frozen soils and ices. Roving the Martian surface will become possible again with the Mars Science Laboratory (MSL), which will launch in 2009. MSL will carry a diverse payload to enable definitive mineralogy and geochemistry of Martian surface materials, coupled to advanced capabilities for the analysis of organic matter and fossil biomarkers in rocks, soils and ices.

Future exobiological investigations to explore for extant Martian life will be directed to the highest priority sites identified by previous missions (especially MRO, Mars Express and MSL). To further enable such missions, the major challenge to the astrobiological community will be to identify universal approaches to life detection that will be able to operate over a broad range of environmental extremes. These developments are still in their infancy. Another challenge will be deep drilling, which may provide the most compelling science driver for sending human to Mars. That said, the human exploration of Mars must be preceded by a satisfoctory mitigation of risks associated with planetary back-contamination. In this context, the systematic astrobiological exploration of Mars for extant life forms, assisted by targeted sample returns, will be of paramount importance in preparing the way for human exploration.