Editing Apollo 16 (section)

===Solo activities===
[[File:Apollo 16 Command and Service Module Over the Moon (9457443889).jpg|thumb|''Casper'' above the Moon]]
After ''Orion'' was cleared for the landing attempt, ''Casper'' maneuvered away, and Mattingly performed a burn that took his spacecraft to an orbit of {{convert|53.1|by|67.8|nmi|order=flip|sp=us}} in preparation for his scientific work.<ref>{{cite web|title=Day Five Part Five – Clearance for PDI – Again – and Landing, Revs 15 and 16.|url=https://history.nasa.gov/afj/ap16fj/17_Day5_Pt5.html#103_21_44|publisher=[[NASA]]|access-date=June 13, 2021|work=Apollo 16 Flight Journal|date=February 11, 2020|editor-first=David|editor-last=Woods|editor2-first=Tim|editor2-last=Brandt|archive-date=February 24, 2013|archive-url=https://web.archive.org/web/20130224213429/http://history.nasa.gov/ap16fj/17_Day5_Pt5.htm#103_21_44|url-status=live}}</ref><ref name="timeline"/> The SM carried a suite of scientific instruments in its SIM bay,{{sfn|Press Kit|p=86}} similar to those carried on Apollo 15.{{sfn|Mission Report|p=5-1}} Mattingly had compiled a busy schedule operating the various SIM bay instruments, one that became even busier once Houston decided to bring Apollo 16 home a day early, as the flight directors sought to make up for lost time.{{sfn|Chaikin 1995|pp=484–485}}

His work was hampered by various malfunctions: when the Panoramic Camera was turned on, it appeared to take so much power from one of the CSM's electrical systems, that it initiated the spacecraft Master Alarm. It was immediately shut off, though later analysis indicated that the drain might have been from the spacecraft's heaters, which came on at the same time.<ref name="overvw">{{cite web|title=Apollo 16 Mission Overview|url=http://www.hq.nasa.gov/alsj/a16/a16ov.html|publisher=[[NASA]]|editor-first=Eric M.|editor-last=Jones|editor2-first=Ken|editor2-last=Glover|work=Apollo 16 Lunar Surface Journal|access-date=June 12, 2021|archive-date=July 21, 2019|archive-url=https://web.archive.org/web/20190721142640/https://www.hq.nasa.gov/alsj/a16/a16ov.html|url-status=live}}</ref> Its work was also hampered by the delay in the beginning of ''Casper''{{'}}s orbital scientific work and the early return to Earth, and by a malfunction resulting in the [[exposure (photography)|overexposure]] of many of the photographs. Nevertheless, it was able to take a photograph of the Descartes area in which ''Orion'' is visible.{{sfn|Mission Report|pp=5-7—5-8}} The Mass Spectrometer boom did not fully retract following its initial extension, as had happened on Apollo 15, though it retracted far enough to allow the SPS engine to be fired safely when ''Casper'' maneuvered away from ''Orion'' before the LM began its Moon landing attempt. Although the Mass Spectrometer was able to operate effectively, it stuck near its fully deployed position prior to the burn that preceded rendezvous, and had to be jettisoned. Scientists had hoped to supplement the lunar data gained with more on the trans-Earth coast, but Apollo 15 data could be used instead.<ref name = "overvw" />{{sfn|Mission Report|p=5-4}} The Mapping Camera also did not function perfectly; later analysis found it to have problems with its glare shield. The changes to the flight plan meant that some areas of the lunar surface that were supposed to be photographed could not be; also, a number of images were overexposed.<ref name = "overvw" />{{sfn|Mission Report|pp=5-10—5-11}} The Laser Altimeter, designed to accurately measure the spacecraft altitude, slowly lost accuracy due to reduced power, and finally failed just before it was due to be used for the last time.<ref name = "overvw" />{{sfn|Mission Report|pp=5-11—5-12}}