NASA astronaut Josh Cassada retired Oct. 1, after 11 years of service to the agency across multiple programs, including 157 days in space and three spacewalks. Cassada also is a retired United States Navy captain and naval aviator with more than two decades of service. Before his selection by NASA in 2013 as a member of NASA's 21st Class, Cassada earned his doctorate in High Energy Particle Physics from the University of Rochester, New York and was a U.S. Navy pilot, instructor pilot, test pilot, and instructor test pilot.