Michael Collins (born October 31, 1930) (Major General, USAF, Ret.) was an American former astronaut and test pilot. Selected as part of the third group of fourteen astronauts in 1963, he flew into space twice. His first spaceflight was on Gemini 10, in which he and Command Pilot John Young performed two rendezvous with different spacecraft and undertook two extra-vehicular activities (EVAs, also known as spacewalks). His second spaceflight was as the Command Module Pilot for Apollo 11. While he stayed in orbit around the Moon, Neil Armstrong and Buzz Aldrin left in the Lunar Module to make the first manned landing on its surface. He is one of 24 people to have flown to the Moon. Collins was the fourth person, and third American, to perform an EVA; and is the first person to have performed more than one EVA.

Richard Francis Gordon Jr. was an American naval officer and aviator, chemist, test pilot, and NASA astronaut. He was one of only 24 people to have flown to the Moon, as the Command Module Pilot for the Apollo 12 mission. He also flew in space in 1966 as the Pilot of the Gemini 11 mission.

Elliot McKay See Jr. was an American engineer, naval aviator, test pilot, and NASA astronaut. He was selected for NASA's second group of astronauts in 1962. See was chosen as the prime command pilot for what would have been his first space flight, Gemini 9. He was killed with Charles Bassett, his intended Gemini 9 crewmate, in a 1966 NASA trainer jet crash at the St. Louis, Missouri McDonnell Aircraft plant, where they were to take two weeks of space rendezvous simulator training.

William Alison "Bill" Anders is a retired United States Air Force Major general, former electrical engineer, nuclear engineer, NASA astronaut, and businessman. He is known for being one of the first three persons to leave low Earth orbit and travel to the Moon in Apollo 8 along with fellow astronauts Frank Borman and Jim Lovell as well as for photographing the iconic image, Earthrise. Apart from his professional and military careers, Anders was the U.S. Ambassador to Norway from 1976 to 1977 under President Gerald Ford.

Charles Arthur "Charlie" Bassett II, Major, USAF was an American electrical engineer and United States Air Force test pilot. He was selected as a NASA astronaut in 1963 and assigned to Gemini 9, but died in an airplane crash during training for his first spaceflight.

Alan LaVern Bean was an American naval officer and naval aviator, aeronautical engineer, test pilot, and NASA astronaut; he was the fourth person to walk on the Moon. He was selected to become an astronaut by NASA in 1963 as part of Astronaut Group 3. He made his first flight into space aboard Apollo 12, the second manned mission to land on the Moon, at age 37 in November 1969. He made his second and final flight into space on the Skylab 3 mission in 1973, the second manned mission to the Skylab space station. After retiring from the United States Navy in 1975 and NASA in 1981, he pursued his interest in painting, depicting various space-related scenes and documenting his own experiences in space as well as that of his fellow Apollo program astronauts. He was the last living crew member of Apollo 12.

Ronnie Walter Cunningham was an American astronaut. In 1968, he was a Lunar Module Pilot on the Apollo 7 mission. He was NASA's third civilian astronaut (after Neil Armstrong and Elliot See), and has also been a fighter pilot, physicist, entrepreneur, venture capitalist, and author of The All-American Boys.

Donn Fulton Eisele was a United States Air Force officer, test pilot, and later a NASA astronaut. He occupied the Command Module Pilot seat during the flight of Apollo 7 in 1968. After retiring from both NASA and the Air Force, he became the Peace Corps country director for Thailand, before moving into private business.

Theodore Cordy "Ted" Freeman was an American aeronautical engineer, U.S. Air Force officer, test pilot, and NASA astronaut. Selected in the third group of NASA astronauts in 1963, he was killed a year later in the crash of a T-38 jet, marking the first fatality among the NASA Astronaut Corps. At the time of his death, he held the rank of captain.

Russell Louis "Rusty" Schweickart is an American aeronautical engineer, and a former NASA astronaut, research scientist, U.S. Air Force fighter pilot, as well as a former business executive and government executive. Selected in 1963 for NASA's third astronaut group, he is best known as the Lunar Module Pilot on the 1969 Apollo 9 mission, the first manned flight test of the Lunar Module, on which he performed the first in-space test of the Portable Life Support System used by the Apollo astronauts who walked on the Moon. As backup Commander of the first manned Skylab mission in 1973, he was responsible for developing the hardware and procedures used by the first crew to perform critical in-flight repairs of the Skylab station. After Skylab, he served for a time as Director of User Affairs in NASA's Office of Applications. Schweickart left NASA in 1977 to serve for two years as California Governor Jerry Brown's assistant for science and technology, then was appointed by Brown to California's Energy Commission for five and a half years, serving as chairman for three. In 1984–85 he co-founded the Association of Space Explorers and later in 2002 co-founded the B612 Foundation, a non-profit organization dedicated to defending Earth from asteroid impacts, along with fellow former astronaut Ed Lu and two planetary scientists. He served for a period as its chair before becoming its chair emeritus.

Clifton Curtis "C.C." Williams Jr. was an American naval aviator, test pilot, mechanical engineer, major in the United States Marine Corps, and NASA astronaut, who was killed in a plane crash; he had never been to space. The crash was caused by a mechanical failure in a NASA T-38 jet trainer, which he was piloting to visit his parents in Mobile, Alabama. The failure caused the flight controls to stop responding, and although he activated the ejection seat, it did not save him. He was the fourth astronaut from NASA's Astronaut Group 3 to have died, the first two (Charles Bassett and Theodore Freeman) having been killed in separate T-38 flights, and the third (Roger B. Chaffee) in the Apollo 1 fire earlier that year. The aircraft crashed in Florida near Tallahassee within an hour of departing Patrick AFB. Although he was never on a spaceflight, he served as backup pilot for the mission Gemini 10, which took place in July 1966. Following this mission, he was selected to be the Lunar Module pilot for an Apollo mission to the Moon commanded by Pete Conrad. Following Williams' death, Alan Bean became Lunar Module pilot for Conrad's mission, which ended up being Apollo 12, the second lunar landing.

Fred Wallace Haise Jr. is an American former NASA astronaut, fighter pilot with the U.S. Marine Corps and the U.S. Air Force and test pilot. He is one of only 24 people to have flown to the Moon, having flown as Lunar Module Pilot on Apollo 13. He was to have been the sixth person to land and walk on the Moon, but the Apollo 13 mission was aborted before lunar landing. He went on to fly Space Shuttle Approach and Landing Tests in 1977, and retired from NASA in 1979.