Apollo 16

Apollo 16 was the tenth manned mission in the United States Apollo space program, the fifth and penultimate to land on the Moon and the first to land in the lunar highlands. The second of the so-called J-missions, 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 at 12:54 PM EST on 16 April 1972, the mission lasted eleven days, one hour, and fifty-one minutes, and concluded at 2:45 PM EST on 27 April.

John Young and Charles Duke spent 71 hours—just under three days—on the lunar surface, during which they conducted three extra-vehicular activities, or moonwalks, totaling 20 hours and 14 minutes. The pair drove the Lunar Roving Vehicle (LRV), the second ever produced and used on the Moon, a cumulative distance of 26.7 kilometres (16.6 mi). On the surface, Young and Duke collected 95.8 kilograms (211 lb) of lunar samples for return to Earth, while Command Module Pilot Ken Mattingly orbited in the Command/Service Module above to perform observations. Mattingly spent a total of 126 hours and 64 revolutions in lunar orbit. After Young and Duke rejoined Mattingly in lunar orbit, the crew released a sub-satellite from the Service Module. On the return trip to Earth, Mattingly performed a one-hour spacewalk to retrieve several film cassettes from the exterior of the Service Module.

The decision to target the Apollo 16 lunar landing for the highlands region of the Moon was made to obtain samples of the Descartes Formation and the Cayley Formation. Geologists believed prior to the mission that both of these formations were volcanic in origin; however, samples returned from the lunar surface have since proven this hypothesis is incorrect. Three of the first four landings in the Apollo program landed in the lunar maria; the fourth was in the vicinity of Mare Imbrium. Accordingly, highest priority was given to a highlands site that would allow the astronauts to sample material older than the impact that formed the Imbrium basin.