John Young (astronaut) in the context of "United States Naval Test Pilot School"

The surface gravity, g, of an astronomical object is the gravitational acceleration experienced at its surface at the equator, including the effects of rotation. The surface gravity may be thought of as the acceleration due to gravity experienced by a hypothetical test particle which is very close to the object's surface and which, in order not to disturb the system, has negligible mass. For objects where the surface is deep in the atmosphere and the radius not known, the surface gravity is given at the 1 bar pressure level in the atmosphere.

Surface gravity is measured in units of acceleration, which, in the SI system, are meters per second squared. It may also be expressed as a multiple of the Earth's standard surface gravity, which is equal to

Apollo 10 (May 18–26, 1969) was the fourth human spaceflight in the United States' Apollo program and the second to orbit the Moon. NASA, the mission's operator, described it as a "dress rehearsal" for the first Moon landing (Apollo 11, two months later). It was designated an "F" mission, intended to test all spacecraft components and procedures short of actual descent and landing.

After the spacecraft reached lunar orbit, astronaut John Young remained in the Command and Service Module (CSM) while astronauts Thomas Stafford and Gene Cernan flew the Apollo Lunar Module (LM) to within 14.4 kilometers (7.8 nautical miles; 9 miles) of the lunar surface, the point at which powered descent for landing would begin on a landing mission. After four orbits they rejoined Young in the CSM and, after the CSM completed its 31st orbit of the Moon, they returned safely to Earth.

STS-1 (Space Transportation System-1) was the first orbital spaceflight of NASA's Space Shuttle program. The first orbiter, Columbia, launched on April 12, 1981, and returned on April 14, 1981, 54.5 hours later, having orbited the Earth 37 times. Columbia carried a crew of two—commander John W. Young and pilot Robert L. Crippen. It was the first American crewed space flight since the Apollo–Soyuz Test Project (ASTP) in 1975. STS-1 was also the maiden test flight of a new American spacecraft to carry a crew, though it was preceded by atmospheric testing (ALT) of the orbiter and ground testing of the Space Shuttle system.

The launch occurred on the 20th anniversary of Vostok 1, the first human spaceflight, performed by Yuri Gagarin for the USSR. This was a coincidence rather than a celebration of the anniversary; a technical problem had prevented STS-1 from launching two days earlier, as was planned.

Apollo 16 (April 16–27, 1972) was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's "J missions", with an extended stay on the lunar surface, a focus on science, and the use of the Lunar Roving Vehicle (LRV). The landing and exploration were in the Descartes Highlands, a site chosen because some scientists expected it to be an area formed by volcanic action, though this proved not to be the case.

The mission was crewed by Commander John Young, Lunar Module Pilot Charles Duke and Command Module Pilot Ken Mattingly. Launched from the Kennedy Space Center in Florida on April 16, 1972, Apollo 16 experienced a number of minor glitches en route to the Moon. These culminated with a problem with the spacecraft's main engine that resulted in a six-hour delay in the Moon landing as NASA managers contemplated having the astronauts abort the mission and return to Earth, before deciding the problem could be overcome. Although they permitted the lunar landing, NASA had the astronauts return from the mission one day earlier than planned.