Walter M. Schirra piloted this spacecraft, named Sigma 7, on October 3, 1962--the fifth manned flight of the first U.S. human spaceflight program, Project Mercury. He was the third American to go into orbit. His primary mission objective was to test methods of conserving attitude control fuel in order to extend flight; he allowed the spacecraft to drift for long periods. During the 9 hour 13 minute mission, Schirra orbited the Earth six times, solving overheating problems with his suit and deploying a 76 cm (30 in.) balloon on a 30 m (100 ft.) tether to experiment with atmospheric drag. Sigma 7 was the first of the Mercury capsules to splash down in the Pacific Ocean, northeast of Midway Island.

NASA transferred title of Sigma 7 (Mercury capsule # 16) to the Smithsonian in 1967 while the spacecraft was on exhibit at the NASA Marshall Space Flight Center.