became a test pilot at Naval Ordnance Test Station China Lake, California (NOTS). At China Lake, he tested various weapons systems, including becoming the first pilot to fly with and fire the Sidewinder missile. Schirra was assigned to Miramar Naval Air Station to test the newest Navy jet fighter, the F7U Cutlass. Schirra was subsequently assigned to NAS Moffett to begin transition training to the Cutlass, and subsequently the F3H Demon. After a deployment to Asia aboard the aircraft carrier and aviation safety training with the University of Southern California (USC), Schirra was accepted to the U.S. Naval Test Pilot School in 1958. Schirra was a member of Class 20 at the Naval Test Pilot School, along with future fellow astronauts Jim Lovell and Pete Conrad, where he learned to fly numerous aircraft, including the F4D Skyray, the F11F Tiger, and the F8U Crusader. After graduation, Schirra became a test pilot at Naval Air Station Patuxent River and learned to fly the F4H Phantom to determine if it could become a carrier-based aircraft. NASA career Project Mercury In February 1959, Schirra was one of 110 military test pilots selected by their commanding officers as candidates for the newly formed National Aeronautics and Space Administration's Project Mercury, the first U.S. crewed space flight program. Following several rounds of tests, Schirra became a member of the original seven astronauts selected for the program in April 1959. During the program's development, Schirra's areas of responsibility were the life-support systems and the pressurized flight suit. Additionally, Schirra worked alongside John Glenn in capsule design. Scott Carpenter and Schirra flew F-106 Delta Dart chase planes during Alan Shepard's Freedom 7 suborbital mission. Schirra was initially assigned as Deke Slayton's backup for the second orbital Mercury flight but was replaced with Carpenter when Slayton was grounded. Schirra was instead scheduled for the third orbital flight. At 7:15am on October 3, 1962, Schirra lifted off aboard his Mercury flight, named Sigma 7. After a minor trajectory deviation early in flight, Sigma 7 achieved orbit. Once in orbit, Schirra demonstrated manually positioning and maneuvering his spacecraft using a reaction control system. After the navigation issues during Carpenter's Aurora 7 mission, NASA and Schirra focused on the engineering and human factors in manually operating the capsule. Schirra reported rising suit temperatures, reaching a high of , before he was able to adjust his suit's cooling system manually. After completing