Apollo 16

Apollo 16 was the tenth crewed mission in the United States Apollo space program, administered by NASA. It was the fifth and penultimate mission to land on the Moon. Apollo 16 was launched on April 16, 1972, from the Kennedy Space Center in Florida. The mission was crewed by Commander John Young, Lunar Module Pilot Charles Duke, and Command Module Pilot Ken Mattingly.

The astronauts faced some small problems on their way to the Moon, including a delay with the spacecraft's main engine. After landing on the Moon on April 21, Young and Duke spent nearly three days exploring the lunar surface. They drove a special vehicle called the Lunar Roving Vehicle for over 26 kilometers and collected many rocks and samples, including a very large one called Big Muley. Meanwhile, Mattingly orbited the Moon in the command and service module, taking photos and running experiments. The crew returned safely to Earth on April 27, 1972.

Crew and key Mission Control personnel

John Young was the mission commander for Apollo 16. He was 41 years old and a captain in the Navy. He had flown in space three times before and became the second American to fly in space four times. Thomas Kenneth "Ken" Mattingly was the command module pilot and had trained for earlier missions. Charles Duke was the lunar module pilot and, at 36 years old, was the youngest astronaut to walk on the Moon during the Apollo missions.

The backup crew included Fred W. Haise Jr., Stuart A. Roosa, and Edgar D. Mitchell. Support crew members helped prepare the mission rules and checklists. The flight directors and capsule communicators played important roles in ensuring the safety and success of the mission.

Mission insignia and call signs

The Apollo 16 mission patch shows an American eagle and a red, white, and blue shield, standing for the people of the United States, on a gray background that represents the Moon. Over the shield is a gold design of NASA orbiting the Moon. Along the border are 16 stars for the mission number and the crew members’ names: Young, Mattingly, and Duke. The crew created the design with help from Barbara Matelski at the Manned Spacecraft Center in Houston.

The Lunar Module was named “Orion” by Young and Duke because it is a bright group of stars they could see during their trip. Mattingly named the command module “Casper” after Casper the Friendly Ghost, choosing a fun name to balance the serious work of the mission.

Planning and training

Apollo 16 was the second of the Apollo program's "J missions," which meant it had more time on the Moon for science and used a special vehicle called the Lunar Roving Vehicle. Scientists wanted to learn more about the Moon's early history by studying its ancient surfaces. They chose a place called the Descartes Highlands to land because some thought it might have been formed by old volcanic activity, though this turned out not to be true.

The team preparing for Apollo 16 trained very hard. They studied rocks and landforms to know what they might find on the Moon. They visited places on Earth that look like parts of the Moon, such as the Sudbury Basin in Canada, which has a big crater made long ago by a meteorite. This helped them learn about impacts, which the Moon has many of. The astronauts also practiced wearing their space suits, moving in low gravity, collecting samples, and driving the Lunar Roving Vehicle. They spent a lot of time learning so they could do their job well when they landed on the Moon.

Equipment

Apollo 16 used a Saturn V rocket to travel to the Moon. This rocket, called AS-511, was almost the same as the one used for Apollo 15. One small change was adding back four special rockets to the bottom part of the rocket to prevent it from hitting the main rocket after it was thrown away.

Apollo 16 carried special science tools to the Moon to keep working after the astronauts left. These tools studied the Moon's surface and inside. They included machines to measure earthquakes on the Moon, heat coming from inside the Moon, and the Moon's magnetic field. There was also a special camera to take pictures of space without Earth's light getting in the way. These tools helped scientists learn more about our Moon and space.

Mission events

Elements of the spacecraft and launch vehicle began arriving at Kennedy Space Center in July 1970, and all had arrived by September 1971. Apollo 16 was originally scheduled to launch on March 17, 1972. One of the bladders for the CM's reaction control system burst during testing. This issue, in combination with concerns that one of the explosive cords that would jettison the LM from the CSM after the astronauts returned from the lunar surface would not work properly, and a problem with Duke's spacesuit, made it desirable to slip the launch to the next launch window. Thus, Apollo 16 was postponed to April 16. The launch vehicle stack, which had been rolled out from the Vehicle Assembly Building on December 13, 1971, was returned thereto on January 27, 1972. It was rolled out again to Launch Complex 39A on February 9.

The Apollo 16 mission launched from the Kennedy Space Center in Florida at 12:54 pm EST on April 16, 1972. The launch was smooth; the crew experienced vibration similar to that on previous missions. The spacecraft entered orbit around Earth just under 12 minutes after lift-off.

After reaching orbit, the crew spent time adapting to the zero-gravity environment and preparing the spacecraft for trans-lunar injection (TLI), the burn of the third-stage rocket that would propel them to the Moon. In Earth orbit, the crew faced minor technical issues, but eventually resolved or compensated for them as they prepared to depart towards the Moon.

By the time Mission Control issued the wake-up call to the crew for flight day two, the spacecraft was about 112,220 miles or 181,000 kilometers away from the Earth, traveling at about 1.622 km/s. As it was not due to arrive in lunar orbit until flight day four, flight days two and three were largely preparatory, consisting of spacecraft maintenance and scientific research.

The crew continued preparing for Lunar Module activation and undocking shortly after waking up to begin flight day five. Powered descent to the lunar surface began about six hours behind schedule. The LM landed north and 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. They then settled down for their first meal on the surface.

After waking up on April 21, Young and Duke ate breakfast and began preparations for the first extravehicular activity (EVA), or moonwalk. 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. Duke soon descended the ladder and joined Young on the surface, becoming the tenth person to walk on the Moon.

The pair's first task of the moonwalk was to offload the Lunar Roving Vehicle, the Far Ultraviolet Camera/Spectrograph, and other equipment. This was done without problems. On first driving the lunar rover, Young discovered that the rear steering was not working. He alerted Mission Control to the problem before setting up the television camera, after which Duke erected the United States flag.

The day's next task was to deploy the ALSEP; while they were parking the lunar rover, on which the TV camera was mounted, to observe the deployment, the rear steering began functioning. After ALSEP deployment, they collected samples in the vicinity.

The next stop of the day was Buster Crater, a small crater located north of the larger Spook Crater. There, Duke took pictures of Stone Mountain and South Ray Crater, while Young deployed the LPM. By this point, scientists were beginning to reconsider their pre-mission hypothesis that Descartes had been the setting of ancient volcanic activity, as the two astronauts had yet to find any volcanic material.

After waking up three and a half minutes earlier than planned, they discussed the day's timeline of events with Houston. The second lunar excursion's primary objective was to visit Stone Mountain to climb up the slope of about 20 degrees to reach a cluster of five craters known as "Cinco craters". They drove there in the LRV, traveling 3.8 km from the LM. At 152 m above the valley floor, the pair were at the highest elevation above the LM of any Apollo mission. They marveled at the view from the side of Stone Mountain, then gathered samples in the vicinity.

During the third and final lunar excursion, they were to explore North Ray crater, the largest of any of the craters any Apollo expedition had visited. After exiting Orion, the pair drove to North Ray crater. Upon arriving at the rim of North Ray crater, they were 4.4 km away from the LM. After their arrival, the duo took photographs of the wide and deep crater. They visited a large boulder, taller than a four-story building, which became known as 'House Rock'. Samples obtained from this boulder delivered the final blow to the pre-mission volcanic hypothesis, proving it incorrect.

After Orion was cleared for the landing attempt, Casper maneuvered away, and Mattingly performed a burn that took his spacecraft to an orbit of 98.3 by 125.6 kilometers in preparation for his scientific work.

Eight minutes before the planned departure from 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, causing small explosive charges to sever the ascent stage from the descent stage. At the pre-programmed moment, there was liftoff and the ascent stage blasted away from the Moon. Six minutes after liftoff, at a speed of about 5,000 kilometers per hour, Young and Duke reached lunar orbit. Young and Duke rendezvoused and re-docked with Mattingly in the CSM.

The next day, after final checks were completed, the expended LM ascent stage was jettisoned. 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.

During the return to Earth, Mattingly performed an 83-minute EVA to retrieve film cassettes from the cameras in the SIM bay, with assistance from Duke who remained at the command module's hatch.

When the wake-up call was issued to the crew for their final day in space by CAPCOM England, the CSM was about 45,000 nautical miles from Earth, traveling just over 2.7 km/s. Just over three hours before splashdown in the Pacific Ocean, the crew performed a final course correction burn. Approximately ten minutes before reentry into Earth's atmosphere, the cone-shaped command module containing the three crewmembers separated from the service module. At 265 hours and 37 minutes into the mission, at a velocity of about 11 km/s, Apollo 16 began atmospheric reentry. After parachute deployment and less than 14 minutes after reentry began, the command module splashed down in the Pacific Ocean southeast of the island of Kiritimati. The spacecraft and its crew was retrieved by the aircraft carrier USS Ticonderoga. The astronauts were safely aboard the Ticonderoga 37 minutes after splashdown.

Scientific results and aftermath

When scientists studied the rocks brought back from the Moon, they found that the Cayley Formation was not made by volcanic activity. They were also unsure about the Descartes Formation because they couldn’t tell if any of the rocks came from there. They found no proof that Stone Mountain was volcanic. One reason Descartes was chosen for the landing was because it looked different from other Apollo landing spots, but the rocks there were very similar to those found at the Fra Mauro Formation, where Apollo 14 landed.

Scientists realized they had been too sure that Cayley was volcanic and didn’t consider other ideas. They also learned that the Moon doesn’t have much of the same geologic history as Earth, so comparing it to Earth wasn’t a good way to understand the Moon. They concluded that there are very few, if any, volcanic mountains on the Moon. These discoveries were helped by observations from Mattingly, the first crew member to use binoculars while looking at the Moon from orbit. He saw that the Descartes Formation didn’t look special from the Moon’s orbit—it fit in with the Mare Imbrium area.

Other important findings from Apollo 16 included the discovery of two new auroral belts around Earth. After the mission, Young and Duke helped prepare for Apollo 17. Duke left NASA in December 1975. Both Young and Mattingly later flew on the Space Shuttle. Young commanded the first Shuttle mission, STS-1, in 1981 and another mission, STS-9, in 1983. He retired from NASA in 2004. Mattingly also commanded two Shuttle missions, STS-4 in 1982 and STS-51-C in 1985, before leaving NASA in 1985.

Locations of spacecraft and other equipment

The Ticonderoga brought the Apollo 16 command module to the North Island Naval Air Station near San Diego, California, on May 5, 1972.

The Apollo 16 command module Casper is displayed at the U.S. Space & Rocket Center in Huntsville, Alabama. The Lunar Module’s top part separated from the spacecraft on April 24, 1972, and orbited the Moon for about a year. Its crash site is still not known for sure.

Duke left two special items on the Moon. One was a photo of his family, and the other was a medal to honor the United States Air Force’s 25th anniversary.

In 2006, after a hurricane, a young boy named Kevin Schanze found a piece of metal on his beach in Bath, North Carolina. It turned out to be part of the rocket that launched Apollo 16. Kevin returned it to NASA, and his family got a special tour of the Kennedy Space Center and watched the last Space Shuttle launch together.