Arvidson's experience with NASA spans three decades, starting in 1974 and continuing today with the highly successful Mars Exploration Rover mission (MER), for which Arvidson has served as deputy principal scientist. Other WUSTL members of the MER team include Edward Guinness, Bradley Jolliff, Daniel Scholes, Susan Slavney, Thomas Stein, Alian Wang, Jennifer Ward and Sandra Wiseman.

MEPAG, comprising scientists and engineers, draws on the expertise of its members and other sources to provide analyses of plans and options to NASA on Mars exploration, including robotic exploration of Mars to search for evidence of life, to understand the history of the solar system and to prepare for future human exploration.

The committee also comments on plans for human expeditions to Mars, plans that will be in place once adequate knowledge is acquired about the planet using robotic missions and after successfully demonstrating sustained human exploration missions to the moon. Committee analyses will help guide program prioritization, budget formulation, facilities and human capital planning and technology investment.

At a Nov. 2-3 committee meeting, Arvidson oversaw 275 attendees, including scientists and representatives from seven of NASA's 10 field centers, NASA headquarters, delegations from 25 universities, aerospace industry, nonprofit research institutes, other government agencies and private research organizations. There was also substantial participation from the international community.

According to Arvidson, the Mars Exploration Program Plan, outlining Mars exploration over the next decade and beyond, was discussed at length. The plan's overall focus is to understand Mars as a global system and how the planet's climatic and tectonic processes have evolved with time.

There is an emphasis on whether the planet was or is habitable and if life developed and evolved. MEPAG concluded that the team wishes to continue to "follow the water," the evidence for which has been detected on Mars and to start focusing on the search for current and past habitable zones on the planet.