AGU member since 1977. Professor of Geological Sciences, Associate Director for Science in the Laboratory for Atmospheric and Space Physics, and Director of the Center for Astrobiology, University of Colorado. Scientific interests in Mars surface, atmosphere, climate history, and potential for life, and in societal and philosophical issues in science. Ph.D. in planetary sciences and geophysics from California Institute of Technology, 1982; postdoc, research associate, and professor at University of Colorado. 1982–present, member of AGU, AAAS, DPS, ISSOL; served on Icarus Editorial Board, 1989–1991; Local Arrangements Chair for 1993 DPS meeting; DPS Prize Committee, 1995–1997; COMPLEX, SSES, chair of MEPAG (2003-2005), co-chair of NRC COEL (2005–present). Authored 115 publications (including two books and one edited book), 52 in AGU journals. AGU service as Planetology Secretary (1988-1990), Guest Editor of JGR (1989–1990), Associate Editor of JGR (1990–1992), Meetings Committee (1990–1992), Publications Committee (1992–1994), Editor of JGR-Planets (1994–1998), and Committee on Public Affairs (2000–2002).