Editing Apollo 16 (section)

===ALSEP and other surface equipment===
{{main|Apollo Lunar Surface Experiments Package}}
As on all lunar landing missions after Apollo 11, an [[Apollo Lunar Surface Experiments Package]] (ALSEP) was flown on Apollo 16. This was a suite of nuclear-powered experiments designed to keep functioning after the astronauts who set them up returned to Earth.<ref name = "astro">{{cite news|newspaper=[[Astronomy (magazine)|Astronomy]]|access-date=February 1, 2021|title=What did the Apollo astronauts leave behind?|date=June 21, 2019|last=Talcott|first=Richard|url=https://astronomy.com/news/2019/06/what-did-the-apollo-astronauts-leave-behind|archive-date=February 1, 2022|archive-url=https://web.archive.org/web/20220201050005/https://astronomy.com/news/2019/06/what-did-the-apollo-astronauts-leave-behind|url-status=live}}</ref> Apollo 16's ALSEP consisted of a Passive Seismic Experiment (PSE, a seismometer), an [[Active Seismic Experiment]] (ASE), a Lunar [[Heat Flow Experiment]] (HFE), and a [[Lunar Surface Magnetometer]] (LSM).{{sfn|Press Kit|p=48}} The ALSEP was powered by a [[SNAP-27]] [[radioisotope thermoelectric generator]], developed by the [[United States Atomic Energy Commission|Atomic Energy Commission]].{{sfn|Press Kit|p=66}}

[[File:Ap16 pse.jpg|thumb|upright=1.2|left|Apollo 16's [[Passive Seismic Experiment]]]]
The PSE added to the network of seismometers left by Apollo 12, 14 and 15.{{sfn|Preliminary Science Report|p=9–1}} NASA intended to calibrate the Apollo 16 PSE by crashing the LM's ascent stage near it after the astronauts were done with it, an object of known mass and velocity impacting at a known location.{{sfn|Press Kit|pp=48, 52}} However, NASA lost control of the ascent stage after jettison, and this did not occur.{{sfn|Orloff & Harland 2006|p=481}} The ASE, designed to return data about the Moon's geologic structure, consisted of two groups of explosives: one, a line of "thumpers" were to be deployed attached to three [[geophone]]s. The thumpers would be exploded during the ALSEP deployment. A second group was four [[Mortar (weapon)|mortar]]s of different sizes, to be set off remotely once the astronauts had returned to Earth. Apollo 14 had also carried an ASE, though its mortars were never set off for fear of affecting other experiments.<ref>{{cite news|date=February 12, 2018|last=Klemeti|first=Erik|title=That time Apollo Astronauts detonated explosives on the Moon|access-date=June 5, 2021|newspaper=[[Discover (magazine)|Discover]]|url=https://www.discovermagazine.com/the-sciences/that-time-apollo-astronauts-detonated-explosives-on-the-moon|archive-date=October 23, 2021|archive-url=https://web.archive.org/web/20211023153205/https://www.discovermagazine.com/the-sciences/that-time-apollo-astronauts-detonated-explosives-on-the-moon|url-status=live}}</ref>

The HFE involved the drilling of two {{convert|10|ft|order=flip|sp=us}} holes into the lunar surface and emplacement of thermometers which would measure how much heat was flowing from the lunar interior. This was the third attempt to emplace a HFE: the first flew on Apollo 13 and never reached the lunar surface, while on Apollo 15, problems with the drill meant the probes did not go as deep as planned. The Apollo 16 attempt would fail after Duke had successfully emplaced the first probe; Young, unable to see his feet in the bulky spacesuit, pulled out and severed the cable after it wrapped around his leg. NASA managers vetoed a repair attempt due to the amount of time it would take.{{sfn|Chaikin 1995|pp=467–469, 478}} A HFE flew, and was deployed, on Apollo 17.{{sfn|Chaikin 1995|p=513}}

[[File:ALSEP AS16-113-18374.jpg|thumb|upright=1.2|right|The Lunar Surface Magnetometer]]
The LSM was designed to measure the strength of the Moon's [[Magnetic field of the Moon|magnetic field]], which is only a small fraction of Earth's. Additional data would be returned by the use of the Lunar Portable Magnetometer (LPM), to be carried on the lunar rover and activated at several geology stops. Scientists also hoped to learn from an Apollo 12 sample, to be briefly returned to the Moon on Apollo 16, from which "soft" magnetism had been removed, to see if it had been restored on its journey.{{sfn|Press Kit|pp=50, 55–59}} Measurements after the mission found that "soft" magnetism had returned to the sample, although at a lower intensity than before.{{sfn|Preliminary Science Report|p=7–56}}

A [[Far Ultraviolet Camera/Spectrograph]] (UVC) was flown, the first astronomical observations taken from the Moon, seeking data on hydrogen sources in space without the masking effect of the Earth's corona.{{sfn|Press Kit|pp=71–74}} The instrument was placed in the LM's shadow and pointed at [[nebula]]e, other astronomical objects, the Earth itself, and any suspected volcanic vents seen on the lunar surface. The film was returned to Earth. When asked to summarize the results for a general audience, Dr. [[George Carruthers]] of the [[Naval Research Laboratory]] stated, "the most immediately obvious and spectacular results were really for the Earth observations, because this was the first time that the Earth had been photographed from a distance in [[ultraviolet]] (UV) light, so that you could see the full extent of the hydrogen atmosphere, the polar [[aurora|auroris]] and what we call the tropical airglow belt."<ref>{{cite web|publisher=[[NASA]]|access-date=September 21, 2021|url=https://www.nasa.gov/image-feature/looking-back-dr-george-carruthers-and-apollo-16-far-ultraviolet-cameraspectrograph|title=Looking Back: Dr. George Carruthers and Apollo 16 Far Ultraviolet Camera/Spectrograph|date=December 29, 2020|editor-last=Loff|editor-first=Sarah|archive-date=June 16, 2020|archive-url=https://web.archive.org/web/20200616135928/https://www.nasa.gov/image-feature/looking-back-dr-george-carruthers-and-apollo-16-far-ultraviolet-cameraspectrograph/|url-status=live}}</ref>

Four panels mounted on the LM's descent stage comprised the Cosmic Ray Detector, designed to record [[cosmic ray]] and [[solar wind]] particles. Three of the panels were left uncovered during the voyage to the Moon, with the fourth uncovered by the crew early in the EVA. The panels would be bagged for return to Earth. The free-standing [[Solar Wind Composition Experiment]] flew on Apollo 16, as it had on each of the lunar landings, for deployment on the lunar surface and return to Earth. Platinum foil was added to the aluminum of the previous experiments, to minimize contamination.{{sfn|Press Kit|pp=71–74}}