Charles recently retired after 15 years as the director of the Jet Propulsion Laboratory and vice president of the California Institute of Technology. He joined JPL in 1970 and is a professor of electrical engineering and planetary science at Caltech. He has been a principal investigator on a number of research and development studies and flight projects sponsored by the National Aeronautics and Space Administration (NASA). These include the Shuttle Imaging Radar series (science team leader), the Magellan Imaging Radar (team member) and the Cassini Titan Radar (team leader). He is the author of more than 230 publications in the fields of active microwave remote sensing and electromagnetic theory, and he holds several patents in those fields. In 1989, Charles was elected to the National Academy of Engineering. In 2006, he was selected as one of America's Best Leaders by U.S. News & World Report and the Center for Public Leadership at Harvard University's Kennedy School of Government. He received his bachelor’s degree in physics from the University of Grenoble, France, the Diplome d'Ingenieur in Engineering from the Polytechnic Institute, Grenoble and his master’s and PhD degrees in electrical sciences from Caltech. He also has a master’s degree in geology from UCLA and an MBA from USC.