NASA Astronaut Group 5 was a group of nineteen astronauts selected by NASA in April 1966. Of the six Lunar Module Pilots that walked on the Moon, three came from Group 5. The group as a whole is roughly split between the half who flew to the Moon, and the half who flew Skylab and Space Shuttle, providing the core of Shuttle commanders early in that program. This group is also distinctive in being the only time when NASA hired a person into the astronaut corps who had already earned astronaut wings, X-15 pilot Joe Engle. John Young labeled the group the Original Nineteen in parody of the original Mercury Seven astronauts.

Joe Henry Engle is an American pilot, aeronautical engineer and former NASA astronaut. He was the commander of two Space Shuttle missions including STS-2 in 1981, the program's second orbital flight. He also flew two flights in the Shuttle program's 1977 Approach and Landing Tests. Engle is one of twelve pilots who flew the North American X-15, an experimental spaceplane jointly operated by the Air Force and NASA, and the last surviving test pilot of the aircraft. After Richard H. Truly died in 2024, Engle is now the last surviving crew member of STS-2.