Lieutenant Colonel Virgil Ivan "Gus" Grissom was one of the seven original National Aeronautics and Space Administration's Project Mercury astronauts, and the first of the Mercury Seven to die. He was also a Project Gemini and an Apollo program astronaut. Grissom was the second American to fly in space, and the first member of the NASA Astronaut Corps to fly in space twice. In addition, Grissom was a World War II and Korean War veteran, U.S. Air Force test pilot, and a mechanical engineer. He was a recipient of the Distinguished Flying Cross, and the Air Medal with an oak leaf cluster, a two-time recipient of the NASA Distinguished Service Medal, and, posthumously, the Congressional Space Medal of Honor.

Walter Marty Schirra Jr. was an American naval aviator and NASA astronaut. In 1959, he became one of the original seven astronauts chosen for Project Mercury, which was the United States' first effort to put human beings in space. On October 3, 1962, he flew the six-orbit, nine-hour, Mercury-Atlas 8 mission, in a spacecraft he nicknamed Sigma 7. At the time of his mission in Sigma 7, Schirra became the fifth American and ninth human to travel into space. In the two-man Gemini program, he achieved the first space rendezvous, station-keeping his Gemini 6A spacecraft within 1 foot (30 cm) of the sister Gemini 7 spacecraft in December 1965. In October 1968, he commanded Apollo 7, an 11-day low Earth orbit shakedown test of the three-man Apollo Command/Service Module and the first manned launch for the Apollo program.

James Alton "Jim" McDivitt was an American former test pilot, United States Air Force pilot, aeronautical engineer, and NASA astronaut who flew in the Gemini and Apollo programs. He commanded the Gemini 4 flight during which Ed White performed the first U.S. spacewalk, and later the Apollo 9 flight which was the first manned flight test of the Lunar Module and the complete set of Apollo flight hardware. He later became Manager of Lunar Landing Operations and was the Apollo Spacecraft Program Manager from 1969 to 1972.

Frank Frederick Borman II is a retired United States Air Force pilot, aeronautical engineer, test pilot, and NASA astronaut, best remembered as the Commander of Apollo 8, the first mission to fly around the Moon, making him, along with crew mates Jim Lovell and Bill Anders, the first of only 24 humans to do so. Before flying on Apollo, he set a fourteen-day spaceflight endurance record on Gemini 7, and also served on the NASA review board which investigated the Apollo 1 fire. After leaving NASA, he was the Chief Executive Officer (CEO) of Eastern Air Lines from 1975 to 1986. Borman is a recipient of the Congressional Space Medal of Honor. He is currently the oldest living former American astronaut, just eleven days older than fellow astronaut Jim Lovell.

Neil Alden Armstrong was an American astronaut and aeronautical engineer who was the first person to walk on the Moon. He was also a naval aviator, test pilot, and university professor.

Thomas Patten Stafford is an American former Air Force officer, test pilot, and NASA astronaut.

John Watts Young was an American astronaut, naval officer and aviator, test pilot, and aeronautical engineer. He became the ninth person to walk on the Moon as Commander of the Apollo 16 mission in 1972. Young enjoyed the longest career of any astronaut, becoming the first person to fly six space missions (with seven launches, counting his lunar liftoff) over the course of 42 years of active NASA service. He is the only person to have piloted, and been commander of, four different classes of spacecraft: Gemini, the Apollo Command/Service Module, the Apollo Lunar Module, and the Space Shuttle. In 1965, Young flew on the first manned Gemini mission, and commanded another Gemini mission the next year. In 1969 during Apollo 10, he became the first person to fly solo around the Moon. He drove the Lunar Roving Vehicle on the Moon's surface during Apollo 16, and is one of only three people to have flown to the Moon twice. He also commanded two Space Shuttle flights, including its first launch in 1981, and served as Chief of the Astronaut Office from 1974 to 1987. Young retired from NASA in 2004. He died on January 5, 2018.

Charles "Pete" Conrad Jr. was an American NASA astronaut, aeronautical engineer, naval officer and aviator, test pilot, and during the Apollo 12 mission became the third man to walk on the Moon. Conrad was selected in NASA's second astronaut class.

James Arthur Lovell Jr. is a former NASA astronaut, Naval Aviator, and retired Navy captain. Lovell is known for being the commander of the ill-fated Apollo 13 mission, which suffered a critical failure en route to the Moon but was brought back safely to Earth through the efforts of the crew and mission control. In addition to being part of the Apollo 13 crew, Lovell was the command module pilot of Apollo 8, the first Apollo mission to enter lunar orbit.

Edward Higgins White II was an American aeronautical engineer, U.S. Air Force officer, test pilot, and NASA astronaut. On June 3, 1965, he became the first American to walk in space. White died along with astronauts Virgil "Gus" Grissom and Roger B. Chaffee during prelaunch testing for the first manned Apollo mission at Cape Canaveral. He was awarded the NASA Distinguished Service Medal for his flight in Gemini 4 and was then awarded the Congressional Space Medal of Honor posthumously.

David Randolph Scott is an American engineer, former NASA astronaut, retired U.S. Air Force officer and former test pilot. He belonged to the third group of NASA astronauts, selected in October 1963. As an astronaut, Scott became the seventh person to walk on the Moon. Following the death of John Young in January 2018, Scott became the last living commander of a successful Apollo lunar landing mission and, as such, the only person currently alive who has flown a spacecraft to a landing on the Moon.

Eugene Andrew Cernan was an American astronaut, naval aviator, electrical engineer, aeronautical engineer, and fighter pilot. During the Apollo 17 mission, Cernan became the eleventh person to walk on the Moon. Since he re-entered the lunar module after Harrison Schmitt on their third and final lunar excursion, he is the last person to have walked on the Moon. Cernan traveled into space three times; as pilot of Gemini 9A in June 1966, as lunar module pilot of Apollo 10 in May 1969, and as commander of Apollo 17 in December 1972, the final Apollo lunar landing. Cernan was also a backup crew member of the Gemini 12, Apollo 7 and Apollo 14 space missions.