Mercury was the first United States project to send humans into space. It lasted from 1958 to 1963. The National Aeronautics and Space Administration (NASA) ran the project. It launched a total of six rockets, each carrying one astronaut in a small capsule. Mercury helped prove that humans could survive temporary weightless conditions. It also helped prove that astronauts could operate complex flight machinery in the vacuum above Earth’s atmosphere. In addition, NASA scientists gained valuable experience in quickly recovering the astronauts and spacecraft after landing.
The seven astronauts selected for the project were United States Air Force and Navy test pilots. Their military training included keeping an untested aircraft in the air, monitoring its performance in different flight conditions, and reacting calmly to potentially deadly problems. NASA selected the astronauts based on these skills and for intelligence and overall physical health.
The first two Mercury flights were suborbital flights, quick up-and-down shots that did not orbit (circle) Earth. The first American astronaut in space was Navy pilot Alan B. Shepard, Jr. His flight was on May 5, 1961. The second astronaut, Air Force pilot Virgil I. (Gus) Grissom, flew on July 21, 1961. Each astronaut was carried into space by a United States Army Redstone rocket. After roughly 15 minutes, both flights quickly returned to Earth. They landed in the Atlantic Ocean east of the launch site in Cape Canaveral, Florida.
The third astronaut to be launched was Marine Corps pilot John H. Glenn, Jr. Glenn flew aboard an Atlas rocket on Feb. 20, 1962, becoming the first American to orbit Earth. His capsule orbited three times before splashing down safely in the Atlantic Ocean.
Three more Mercury missions followed Glenn’s flight. The astronauts M. Scott Carpenter, Walter M. (Wally) Schirra, Jr., and Gordon Cooper each flew the same number or more orbits than the previous flight. They also tried new maneuvers with the space capsule. NASA grounded Mercury astronaut, Donald K. (Deke) Slayton, because of a minor heart ailment.
