page_title: Apollo 16
section_title: Return to Earth
hierarchical_section_title: Apollo 16 / Mission highlights / Return to Earth
caption_attribution_description: English: The Apollo 16 Lunar Module (LM) "Orion" in early lunar liftoff phase is featured in this lunar scene at the Descartes landing site. The still picture is a reproduction taken from a color television transmission made by a TV camera mounted on the Lunar Roving Vehicle (LRV). While astronauts John W. Young, commander; and Charles M. Duke Jr., lunar module pilot; descended in the Apollo 16 LM to explore the Descartes highlands landing site on the moon, astronaut Thomas K. Mattingly II, command module pilot, remained with the Command and Service Modules (CSM) "Casper" in lunar orbit.
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: Eight minutes before departing the lunar surface, CAPCOM James Irwin notified Young and Duke from Mission Control that they were go for liftoff. Two minutes before launch, they activated the "Master Arm" switch and then the "Abort Stage" button, after which they awaited ignition of Orion's ascent stage engine. When the ascent stage ignited, small explosive charges severed the ascent stage from the descent stage and cables connecting the two were severed by a guillotine-like mechanism. Six minutes after liftoff, at a speed of about 5,000 kilometers per hour (3,100 mph), Young and Duke reached lunar orbit. Young and Duke successfully rendezvoused and re-docked with Mattingly in the CSM. To minimize the transfer of lunar dust from the LM cabin into the CSM, Young and Duke cleaned the cabin before opening the hatch separating the two spacecraft. After opening the hatch and reuniting with Mattingly, the crew transferred the samples Young and Duke had collected on the surface into the CSM for transfer to Earth. After transfers were completed, the crew would sleep before jettisoning the empty lunar module ascent stage the next day, when it was to be crashed intentionally into the lunar surface.
  The next day, after final checks were completed, the expended LM ascent stage was jettisoned. Because of a failure by the crew to activate a certain switch in the LM before sealing it off, it initially tumbled after separation and did not execute the rocket burn necessary for the craft's intentional de-orbit. The ascent stage eventually crashed into the lunar surface nearly a year after the mission. The crew's next task, after jettisoning the lunar module ascent stage, was to release a subsatellite into lunar orbit from the CSM's scientific instrument bay. The burn to alter the CSM's orbit to that desired for the subsatellite had been cancelled; as a result, the subsatellite lasted half of its anticipated lifetime. Just under five hours later, on the CSM's 65th orbit around the Moon, its service propulsion system main engine was reignited to propel the craft on a trajectory that would return it to Earth. The SPS engine performed the burn flawlessly despite the malfunction that had delayed their landing several days before.
  During the return to Earth, Mattingly performed an 83-minute EVA to retrieve film cassettes from the service module's scientific instrument module (SIM) bay, with assistance from Duke who remained at the command module's hatch.  At approximately 173,000 nautical miles (199,000 mi; 320,000 km) from Earth, it was the second "deep space" EVA in history, performed at great distance from any planetary body.  As of 2020, it remains one of only three such EVAs, all performed during Apollo's J-missions under similar circumstances.  Additionally, Mattingly set up a biological experiment, the Microbial Ecology Evaluation Device (MEED), an experiment unique to Apollo 16.  The crew carried out various housekeeping and maintenance tasks aboard the spacecraft and ate a meal before concluding the day.
  The penultimate day of the flight was largely spent performing experiments, aside from a twenty-minute press conference during the second half of the day. During the press conference, the astronauts answered questions pertaining to several technical and non-technical aspects of the mission prepared and listed by priority at the Manned Spacecraft Center in Houston by journalists covering the flight. In addition to numerous housekeeping tasks, the astronauts prepared the spacecraft for its atmospheric reentry the next day. At the end of the crew's final full day in space, the spacecraft was approximately 77,000 nautical miles (143,000 km) from Earth and closing at a rate of about 7,000 feet per second (2,100 m/s).
  When the wake-up call was issued to the crew for their final day in space by CAPCOM Tony England, it was about 45,000 nautical miles (83,000 km) out from Earth, traveling just over 9,000 ft/s (2,700 m/s). Just over three hours before splashdown in the Pacific Ocean, the crew performed a final course correction burn, changing the
caption: Launch of the ascent stage of the Apollo 16 Lunar Module Orion from the lunar surface
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