He was born in Boulder, Colorado, on May 1, 1925, the son of research chemist Dr. M. Scott Carpenter and Florence Kelso Noxon Carpenter. He attended the University of Colorado from 1945 to 1949 and received a bachelor of science degree in Aeronautical Engineering.
Carpenter was commissioned in the U.S. Navy in 1949. He was given flight training at Pensacola, Florida and Corpus Christi, Texas and designated a Naval Aviator in April, 1951. During the Korean War he served with patrol Squadron Six, flying anti-submarine, ship surveillance, and aerial mining, and ferret missions in the Yellow Sea, South China Sea, and the Formosa Straits. He attended the Navy Test Pilot School at Patuxent River, Maryland, in 1954 and was subsequently assigned to the Electronics Test Division of the Naval Air Test Center, also at Patuxent. In that assignment he flew tests in every type of naval aircraft, including multi- and single-engine jet and propeller-driven fighters, attack planes, patrol bombers, transports, and seaplanes.
From 1957 to 1959 he attended the Navy General Line School and the Navy Air Intelligence School and was then assigned as Air Intelligence Officer to the Aircraft Carrier, USS Hornet. Carpenter was selected as one of the original seven Mercury Astronauts on April 9, 1959. He underwent intensive training with the National Aeronautics and Space Administration (NASA), specializing in communication and navigation. He served as backup pilot for John Glenn during the preparation for America’s first manned orbital space flight in February 1962.
Carpenter flew the second American manned orbital flight on May 24, 1962. He piloted his Aurora 7 spacecraft through three revolutions of the earth, reaching a maximum altitude of 164 miles. The spacecraft landed in the Atlantic Ocean about 1000 miles southeast of Cape Canaveral after 4 hours and 54 minutes of flight time.
On leave of absence from NASA, Carpenter participated in the Navy’s Man-in the-Sea Project as an Aquanaut in the SEALAB II program off the coast of La Jolla, California, in the summer of 1965. During the 45-day experiment, Carpenter spent 30 days living and working on the ocean floor. He was team leader for two of the three ten-man teams of Navy and civilian divers who conducted deep-sea diving activities in a seafloor habitat at a depth of 205 feet.