Apollo 16

Fifty years ago, two spacecraft danced closely in formation high above a lunar landscape of grays and tans. On board were John Young (mission commander) and Charles M. Duke Jr (lunar module pilot), ready to undertake an epic journey across its rugged highlands and descend towards its surface.

Their objectives included exploring the descartes and Cayley formations to gain more insight into Moon history. One such discovery was House Rock – an enormous chunk of impact breccia material.

Mission objectives

Apollo 16’s main objectives included inspecting, surveying and collecting materials at a designated landing site in Descartes; emplacing surface experiments; conducting in-flight experiments from lunar orbit; as well as zero gravity experiments as well as engineering evaluation of spacecraft and equipment.

On April 16, 1972, from Pad 39-A at Kennedy Space Center on board a Saturn V, Apollo 14 was launched into space. Following its two-day journey to the Moon, its Command Module (CM) and Lunar Module (LM) separated at 20:28:37 UTC before being jettisoned from each other; crew then began an extended three-hour-and six-minute voyage towards its landing site.

John Young donned his spacesuit upon arrival at the Lunar Module (LM), then descended the ladder leading down to its surface. At Charles Duke’s side on the “porch” platform above the ladder was an equipment transfer bag which contained both a camera and television transmitting/receiving antenna – when Young collected this bag he received instructions from Duke on lowering it from above the LM platform.

The two began their EVA by driving their rover between Flag Crater and Spook Crater and collecting samples from Cayley Formation near Flag Crater and Spook Crater, as well as measuring its magnetic field with a portable magnetometer. Next they drove south toward Stone Mountain where there was little sign of volcanic activity except for one boulder called House Rock with bullet hole-like marks from micrometeroids fired from space – an anomaly which stands out.

Young and Duke spent one additional day exploring the Moon before returning to their spacecraft, collecting over 209 pounds (95.0 kg) in soil and rock samples; no igneous rocks suggested that its geology may have been more shaped by mass impact events rather than volcanoes.

Before returning to Earth, the crew retrieved a subsatellite from the LM and launched it into lunar orbit with instruments to measure plasma and particle environments near the Moon.

Launch

Apollo 16 spacecraft took off from Kennedy Space Center at 12:54 p.m. EST April 16, 1972 with three astronauts aboard: Commander John Young, Lunar Module Pilot Charles Duke and Command Module Pilot Ken Mattingly – heading towards lunar orbit and the surface. Their spacecraft included two command modules (CSMs) and one lunar module (LM). Two astronauts in each spacecraft traversed to lunar surface via lunar module while two others in CSMs remained orbiting lunar surface – these astronauts included Commander John Young, Lunar Module Pilot Charles Duke & Command Module Pilot Ken Mattingly among others.

Apollo 16’s flight duration totalled 74 hours and 28 minutes before communications with Mission Control were discontinued, as planned. After several hours had passed, however, astronauts fired their SPS engine for six minutes and 14 seconds to enter an elliptical orbit around the Moon using an SPS engine providing thrust and propulsion; an environmental control system provided recycled oxygen for astronauts and equipment as power was provided by silver-zinc batteries; navigation was accomplished using radar ranging, an inertial measurement unit (comprised of gyrscopes and accelerometers), and an Apollo Guidance Computer system.

After Apollo arrived in lunar orbit, Mattingly and the Lunar Module crew began preparations for their first of three lunar extravehicular activities (EVAs). Wearing spacesuits equipped with Apollo Scientific Experiment Packages, astronauts ventured beyond Lunar Module to explore Cinco Craters area; upon doing so they observed unique formation of rocks as well as collecting samples before returning back to Lunar Module for further EVAs.

Young and Duke were eager to return to Earth on their final day on the Moon. They had spent 20 hours and 14 minutes on EVAs outside the LM, collecting 96 kilograms of lunar samples while also deploying an ALSEP device. Young was delighted by his EVA experience, whooping and hooting as they bounced along on their lunar rover and repeatedly using “spectacular” to describe it – as were Duke.

As they returned to the LM, astronauts took this picture of Earth from its surface on the Moon. Canada and oceans can be seen, while much of United States remains obscured by clouds. Soon after taking this image, Casper the CSM, named for its chimpanzee simulator, separated.

Docking

As Apollo 16 launched on April 16, 1972, exploration of the Moon seemed more like a legacy project than an active path forward. NASA’s space program had become stagnant amid an uncertain political environment, while John Young led an exploration team composed of Charles Duke for Lunar Module pilot duties and Thomas Mattingly for Command Module pilot duties to test out and push boundaries of system capabilities while showing that lessons still remained to be gained from exploration.

After an initial brief delay due to a docking ring jettison issue, both spacecraft reestablished communications and rendezvoused in lunar orbit. The LM, named Casper after its astronaut crew’s dog; and CSM “Columbia”, named for Mattingly’s family pet; docked successfully on lunar surface as planned during EVA 2 of 3.

The crew transferred samples from the LM to Columbia, including double core samples from North Ray area of crater North Ray, as well as conducting several penetrometer tests to better understand lunar soil composition. At the conclusion of their second moonwalk, they returned back into CSM for cleaning of cabin and rest before tomorrow’s excursion.

On the third day, Young and Duke took part in a longer moonwalk to the area surrounding Crater Descartes where they set up the Apollo Lunar Surface Experiments Package (ALSEP) and collected additional scientific data. While on EVA Duke nearly lost his wedding ring due to lunar dust; additionally the crew noticed that its exterior surfaces were covered in small flakes of rock material that covered its surfaces.

Black Team controllers were waiting eagerly for news of Eagle-Columbia rendezvous at 125 hours and 21 minutes Ground Elapsed Time, knowing there would only be 10 minutes between acquisition and TPI (Terminal Phase Initiate). Their crew planned a CDH maneuver involving radial burns that changed Eagle’s orbit to match Columbia’s with less than one minute remaining before initiating TPI – it proved successful!

Landing

Apollo 16 launched from Launch Complex 39 at Kennedy Space Center on April 16, 1972 with Commander John Young, Command Module Pilot Thomas “Ken” Mattingly II and Lunar Module Pilot Charles Duke aboard. Although several problems arose during its three week mission duration and two lunar surface excursions were attempted, all objectives were accomplished successfully and safely back home.

As soon as Young and Duke disembarked from Casper, a six-hour delay ensued due to a fault with the control circuit for Service Module Propulsion System (SMP). Vibrations during testing caused alarm as this component is responsible for propelling Lunar Module (LM) into lunar orbit and could not be repaired on-the-fly. After ascertaining oscillations did not hinder SMP steering capabilities, lunar orbital maneuvering resumed without incident and preparations began for their return home.

On April 21, 1972, astronauts conducted their inaugural moonwalk – a seven-hour and 11-minute excursion at the Apollo Lunar Surface Experiments Package site in Descartes highlands northwest of Mare Nectaris – at ALSEP site ALSEP site of Descartes highlands northwest of Mare Nectaris. While at this location they deployed solar wind composition experiment, dug double cores, performed penetrometer tests, took panoramic and 500mm telephotography photography and collected 209 pounds in samples while driving 166.6 miles while collecting 209 pounds worth of samples!

Young and Duke traveled south of the outbound track at Spook Crater before conducting further experiments at ALSEP, including magnetic field studies. Young demonstrated driving the rover while Duke recorded footage using his 16 mm movie camera.

At Station 9, the astronauts collected breccias in an area thought to be free from South Ray Crater ejecta. Additionally, they dug and examined another core. After finishing their work at ALSEP site, the astronauts began an easy ascent up Stone Mountain to view Buster Crater and its blocky crater with radiating rays of ejecta ringed with rays of ejecta rimmed by rays of ejecta rimmed with radiating rays of ejecta rimmed by blocky crater rimmed by rays of ejecta ringed by blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky blocky crater with its blocky shape and blocky shape with its many layers of rays of ejecta-rimmed blocky shape and its various stages.

Prior to entering the Lunar Module (LM), astronauts deposited an equipment transfer bag and jettison canister into its bay, then descended the ladder towards Earth – becoming only nine humans ever to land on the Moon.