Gerald Paul Carr was an American mechanical and aeronautical engineer, former United States Marine Corps officer, naval aviator, and former NASA astronaut. He was Commander of Skylab 4, the third and final manned visit to the Skylab Orbital Workshop, from November 16, 1973 to February 8, 1974.

Charles Moss "Charlie" Duke Jr. is an American former astronaut, retired U.S. Air Force officer and test pilot. As Lunar Module Pilot for Apollo 16 in 1972, he became the tenth and youngest person to walk on the Moon. Duke has logged 4,147 hours flying time, which includes 3,632 hours in jet aircraft; and 265 hours in space, plus 20 hours and 15 minutes of extravehicular activity. A resident of New Braunfels, Texas, he is currently chairman of the board of directors of the Astronaut Scholarship Foundation.

Joe Henry Engle is an American pilot who served in the United States Air Force, test pilot for the North American X-15 program, aeronautical engineer, and a former NASA astronaut. As of 2018, he is the last living pilot of the X-15 program. Engle test-flew the joint NASA-Air Force X-15 rocket airplane. During the course of testing, Engle earned his USAF Astronaut Wings, a Distinguished Flying Cross and other awards. Engle was selected by NASA in 1966 for the Apollo program, and was originally scheduled to land on the Moon as Lunar Module Pilot on Apollo 17, but was bumped when later flights were cancelled, so that geologist-astronaut Harrison H. Schmitt could fly. He subsequently became one of the first astronauts in the Space Shuttle program, having flight tested the Space Shuttle Enterprise in 1977. He was Commander of the second orbital test flight of the Space Shuttle Columbia in 1981.

Ronald Ellwin Evans Jr. was an American naval officer and aviator, electrical engineer, aeronautical engineer, and NASA astronaut, also one of only 24 people to have flown to the Moon. Evans was selected as an astronaut by NASA as part of Astronaut Group 5 in 1966 and made his first and only flight into space as Command Module Pilot aboard Apollo 17 in 1972, the last manned mission to the Moon to date, with Commander Eugene Cernan and Lunar Module Pilot Harrison Schmitt. During the flight, he orbited the Moon as his two crewmates descended to the surface. Consequently, he is the last person to orbit the Moon alone and holds the record for the most time spent in lunar orbit at 148 hours. In 1975 Evans served as backup Command Module Pilot for the Apollo-Soyuz Test Project mission.

Edward Galen "Ed" Givens Jr. was a United States Air Force officer, test pilot, and NASA astronaut. Selected by NASA in 1966 as a member of the fifth astronaut group, he died in an automobile accident before being assigned to a prime or backup spaceflight crew.

James Benson "Jim" Irwin was an American astronaut, aeronautical engineer, test pilot, and a United States Air Force pilot. He served as lunar module pilot for Apollo 15, the fourth human lunar landing. Following his retirement from NASA, he became a prominent born-again Christian. He was the eighth person to walk on the Moon and the first, and youngest, of those astronauts to die.

Don Leslie Lind, Ph.D. is an American scientist and a former naval officer and aviator, and NASA astronaut. He graduated from the University of Utah with an undergraduate degree in physics in 1953. Following his military service obligation, he earned a Ph.D. in high-energy nuclear physics from the University of California, Berkeley in 1964. Lind was a naval aviator and attained the rank of Commander in the United States Naval Reserve. He had active duty in San Diego and aboard the carrier USS Hancock. After completing his doctorate, Lind worked at NASA's Goddard Research Center from 1964 to 1966. During this period, he applied for the third group of astronauts but did not have enough flight hours. He applied for the fourth group, but was denied for being too old. The age restriction was raised for the fifth group, and he was selected with the Original Nineteen in 1966. Lind helped to develop the Apollo 11 EVA activities, and served as CAPCOM for the Apollo 11 and Apollo 12 missions. He was then assigned as backup Pilot for Skylab 3 and Skylab 4 and nearly flew on the proposed Skylab Rescue mission. Lind was the Payload Commander on his only flight, STS-51-B, launched April 29, 1985. He designed an experiment to capture the Earth's aurora. The payload experiments consisted primarily of microgravity research and atmospheric measurement. The Orbiter Challenger completed 110 orbits before landing at Edwards Air Force Base, California.

Jack Robert Lousma is an American aeronautical engineer, retired United States Marine Corps officer, former naval aviator, NASA astronaut, and politician. He was a member of the second manned crew on the Skylab space station in 1973. In 1982, he commanded STS-3, the third Space Shuttle mission.

Thomas Kenneth Mattingly II better known as Ken Mattingly, is a former American naval officer and aviator, aeronautical engineer, test pilot, Rear Admiral in the United States Navy and astronaut who flew on the Apollo 16, STS-4 and STS-51-C missions. He had been scheduled to fly on Apollo 13, but was held back due to concerns about a potential illness (which he did not contract). He later flew as Command Module Pilot for Apollo 16, making him one of only 24 people to have flown to the Moon.

Bruce McCandless II was a U.S. naval officer and aviator, electrical engineer, and NASA astronaut. In 1984, during the first of his two Space Shuttle missions, he made the first untethered free flight by using the Manned Maneuvering Unit.

Edgar Dean "Ed" Mitchell was a United States Navy officer and aviator, test pilot, aeronautical engineer, ufologist and NASA astronaut. As the Lunar Module Pilot of Apollo 14, he spent nine hours working on the lunar surface in the Fra Mauro Highlands region, making him the sixth person to walk on the Moon.

William Reid Pogue was an American astronaut, U.S. Air Force fighter pilot, and test pilot who was also an accomplished teacher, public speaker and author. Born and educated in Oklahoma, Pogue graduated from college and enlisted in the United States Air Force, in which he served for 24 years. He flew combat during the Korean War, and with the elite USAF Thunderbirds. He served as a flight instructor and mathematics professor, and was a versatile test pilot, including two years in an exchange with the RAF (UK). Colonel Pogue was an Air Force instructor when accepted into NASA in 1966. His astronaut career included one orbital mission, as pilot of the last crew of Skylab. The crew set a duration record (84 days) that was unbroken in NASA for over 20 years, and in orbit they conducted dozens of research experiments. The mission was also noted for a dispute with ground control over schedule management that news media named “The Skylab Mutiny”. Pogue retired from both the USAF and NASA a few months after he returned from Skylab. Over the next 30 plus years he taught, lectured, consulted, and wrote about aviation and aeronatics, in the US and abroad. He died in 2014, age 84, survived by three children, four stepsons, and his third wife.