Bill Stone has organized the exploration of some of our planet’s deepest underwater caves. During the past 35 years, Dr. Stone has led 51 caving expeditions, spent more than seven years in the field, and logged 403 days below ground. In his spare time, Dr. Stone pioneered the development of computer-controlled diving apparatus, diver propulsion vehicles, 3D underwater and dry cave mapping equipment, spacecraft reaction control systems, next-generation laser radar systems for unmanned ground vehicles, and novel re-entry vehicles. In April of 2004 Dr. Stone was selected as Principal Investigator to lead the NASA project to develop the Europa lander third stage prototype – the “hydrobot” that will explore the hypothesized subsurface ocean on that Jovian moon and to autonomously search for life.