Steve Squyres is a Professor of Astronomy at Cornell University. Research for which he is best known includes study of the history and distribution of water on Mars, and of the possible existence of a liquid water ocean on Europa. He received his Ph.D. from Cornell in 1981 and spent 5 years as a postdoctoral associate and research scientist at NASA Ames Research Center before returning to Cornell as a faculty member. He was an associate of the Voyager imaging team for the encounters with Jupiter and Saturn, and a guest investigator on the Magellan mission to Venus.

Along with his work on the MARDI team, he is a member of the imaging team for the Cassini mission to Saturn, a member of the x-ray/gamma-ray spectrometer team for the Near Earth Asteroid Rendezvous mission, and a co-investigator on the Comet Nucleus Tour mission. He is also the Principal Investigator for the Athena Precursor Experiment (APEX) on the Mars Surveyor 2001 mission and the Athena Rover investigation on the Mars Sample Return mission in 2003. He is the chairman of NASA's Space Science Advisory Committee, and a member of the NASA Advisory Council. His awards include the American Astronomical Society's Harold Urey Prize for outstanding achievement by a young scientist.