Ellen Stofan is NASA chief scientist, serving as principal adviser to NASA Administrator Charles Bolden on the agency's science programs and science-related strategic planning and investments. Prior to her appointment, Stofan was vice president of Proxemy Research and honorary professor in the Department of Earth Sciences at the University College London in England. Her research has focused on the geology of Venus, Mars, Saturn's moon Titan, and Earth. Stofan is an associate member of the Cassini Mission to Saturn Radar Team and was a co-investigator on the Mars Express Mission's MARSIS sounder. She also was principal investigator on the Titan Mare Explorer, a proposed mission to send a floating lander to a sea on Titan. Previously, she held a number of senior scientist positions at NASA's Jet Propulsion Laboratory in Pasadena, Calif.. Stofan holds master’s and doctoral degrees in geological sciences from Brown University and a bachelor's degree from the College of William and Mary. Her many awards and honors include the Presidential Early Career Award for Scientists and Engineers.