page_title: Apollo 16
section_title: Lunar surface
hierarchical_section_title: Apollo 16 / Mission highlights / Lunar surface
caption_attribution_description: English: House Rock, on the moon.
context_page_description: Apollo 16 was the tenth crewed mission in the United States Apollo space program, the fifth and penultimate to land on the Moon, and the second to land in the lunar highlands. The second of Apollo's "J missions," it 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 April 16, 1972, the mission lasted 11 days, 1 hour, and 51 minutes, and concluded at 2:45 p.m. EST on April 27.
  Young and 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, the second produced and used on the Moon, for 26.7 kilometers. On the surface, Young and Duke collected 95.8 kilograms of lunar samples for return to Earth, while Command Module Pilot Ken Mattingly orbited in the command and service module above to perform observations. Mattingly, staying with the command module, spent 126 hours and 64 revolutions in lunar orbit.
context_section_description: The crew continued preparing for lunar module activation and undocking shortly after waking up to begin flight day five. The boom that extended the mass spectrometer out from the CSM's scientific instruments bay was stuck, semi-deployed. It was decided that Young and Duke would visually inspect the boom after undocking from the CSM in the LM. They entered the LM for activation and checkout of the spacecraft's systems. Despite entering the LM 40 minutes ahead of schedule, they completed preparations only 10 minutes early due to numerous delays in the process. With the preparations finished, they undocked in the LM Orion from Mattingly in the CSM Casper 96 hours, 13 minutes, 31 seconds into the mission. For the rest of the two crafts' passes over the near side of the Moon, Mattingly prepared to shift Casper to a circular orbit while Young and Duke prepared Orion for the descent to the lunar surface. At this point, during tests of the CSM's steerable rocket engine in preparation for the burn to modify the craft's orbit, a malfunction occurred in the engine's backup system. According to mission rules, Orion would have then re-docked with Casper, in case Mission Control decided to abort the landing and use the lunar module's engines for the return trip to Earth. After several hours of analysis, however, mission controllers determined that the malfunction could be worked around and Young and Duke could proceed with the landing. As a result of this, powered descent to the lunar surface began about six hours behind schedule. Because of the delay, Young and Duke began their descent to the surface at an altitude higher than that of any previous mission, at 20.1 kilometers (10.9 nmi). At an altitude of about 4,000 m (13,000 ft), Young was able to view the landing site in its entirety. Throttle-down of the LM's landing engine occurred on time and the spacecraft tilted forward to its landing orientation at an altitude of 2,200 m (7,200 ft). The LM landed 270 m (890 ft) north and 60 m (200 ft) west of the planned landing site at 104 hours, 29 minutes, and 35 seconds into the mission, at 2:23:35 UTC on April 21.
  After landing, Young and Duke began powering down some of the LM's systems to conserve battery power. Upon completing their initial adjustments, the pair configured Orion for their three-day stay on the lunar surface, removed their space suits and took initial geological observations of the immediate landing site. They then settled down for their first meal on the surface. After eating, they configured the cabin for their first sleep period on the Moon. The landing delay caused by the malfunction in the CSM's main engine necessitated significant modifications to the mission schedule. Apollo 16 would spend one less day in lunar orbit after surface exploration had been completed to afford the crew contingency time to compensate for any further problems and to conserve expendables. In order to improve Young's and Duke's sleep schedule, the third and final moonwalk of the mission was trimmed from seven hours to five.
  The next morning, flight day five, Young and Duke ate breakfast and began preparations for the first extra-vehicular activity (EVA), or moonwalk. After the pair donned and pressurized their space suits and depressurized the lunar module cabin, Young climbed out onto the "porch" of the LM, a small platform above the ladder. Duke handed Young a jettison bag full of trash to dispose of on the surface. Young then lowered the equipment transfer bag (ETB), containing equipment for use during the EVA, to the surface. Young descended the ladder and, upon setting foot on the lunar surface, became the ninth human to walk on the Moon. Upon stepping onto the surface, Young expressed his sentiments about being there: "There you are: Mysterious and Unknown Descartes. Highland plains. Apollo 16 is gonna change your image. I'm sure glad they got ol' Brer Rabbit, here, back in the briar patch where he belongs." Duke soon descended the ladder and joined Young on the surface, becoming the tenth and youngest human to walk on the Moon, at 
caption: House Rock
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