Editing Apollo 15 (section)

=== Command module activities ===
{{main|Solo operations of Apollo 15}}

After the departure of ''Falcon'', Worden in ''Endeavour'' executed a burn to take the CSM to a higher orbit.<ref group=ALFJ name=preparations /> While ''Falcon'' was on the Moon, the mission effectively split, Worden and the CSM being assigned their own CAPCOM and flight support team.<ref group=ALFJ name=solo1>{{cite web |url=https://history.nasa.gov/afj/ap15fj/13solo_ops1.html |title=Solo Orbital Operations-1 |year=1998 |editor-last=Woods |editor-first=W. David |editor-last2=O'Brien |editor-first2=Frank |work=Apollo 15 Flight Journal |publisher=NASA |access-date=December 15, 2018 |archive-url=https://web.archive.org/web/20171225233953/https://history.nasa.gov/afj/ap15fj/13solo_ops1.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>

[[File:Apollo 15 CSM (14412950693).jpg|thumb|upright=1.3|left|alt=A spacecraft seen with the Moon in background|''Endeavour'', with the SIM bay exposed, as seen from the Lunar Module ''Falcon'']]
Worden got busy with the tasks that were to occupy him for much of the time he spent in space alone: photography and operating the instruments in the SIM bay.<ref group=ALFJ name=solo1 /> The door to the SIM bay had been explosively jettisoned during the translunar coast. Filling previously unused space in the service module, the SIM bay contained a gamma-ray spectrometer, mounted on the end of a boom, an X-ray spectrometer and a laser altimeter, which failed part way through the mission. Two cameras, a stellar camera and a metric camera, together comprised the mapping camera, which was complemented by a panoramic camera, derived from [[Corona (satellite)|spy technology]]. The altimeter and cameras permitted the exact time and location from which pictures were taken to be determined. Also present were an alpha particle spectrometer, which could be used to detect evidence of lunar volcanism, and a mass spectrometer, also on a boom in the hope it would be unaffected by contamination from the ship. The boom would prove troublesome, as Worden would not always be able to get it to retract.<ref group=ALFJ name=summary>{{cite web|url=https://history.nasa.gov/afj/ap15fj/a15summary.html|title=Apollo 15 Flight Summary|year=1998|last=Woods|first=W. David|publisher=NASA|access-date=February 19, 2019|archive-url=https://web.archive.org/web/20171225233958/https://history.nasa.gov/afj/ap15fj/a15summary.html|archive-date=December 25, 2017|url-status=live|df=mdy-all}}</ref>

[[File:Apollo 15 Hadley Rille.jpg|thumb|alt=Part of the lunar surface|The landing area is shown in an image taken by the mapping camera]]
''Endeavour'' was slated to pass over the landing site at the moment of planned landing,<ref group=ALFJ name=preparations /> but Worden could not see ''Falcon''<ref group=ALSJ name=landing /> and did not spot it until a subsequent orbit. He also exercised to avoid muscle atrophy, and Houston kept him up to date on Scott and Irwin's activities on the lunar surface. The panoramic camera did not operate perfectly, but provided enough images that no special adjustment was made. Worden took many photographs through the command module's windows, often with shots taken at regular intervals. His task was complicated by the lack of a working mission timer in the Lower Equipment Bay of the command module, as its circuit breaker had popped en route to the Moon.<ref group=ALFJ name=solo1 /> Worden's observations and photographs would inform the decision to send [[Apollo 17]] to [[Taurus-Littrow]] to search for evidence of volcanic activity. There was a communications blackout when the CSM passed over the far side of the Moon from Earth; Worden greeted each resumption of contact with the words, "Hello, Earth. Greetings from ''Endeavour''", expressed in different languages. Worden and El-Baz had come up with the idea, and the geology instructor had aided the astronaut in accumulating translations.<ref group=ALFJ name=solo2>{{cite web |url=https://history.nasa.gov/afj/ap15fj/14solo_ops2.html |title=Solo Orbital Operations-2 |year=1998 |editor-last=Woods |editor-first=W. David |editor-last2=O'Brien |editor-first2=Frank |work=Apollo 15 Flight Journal |publisher=NASA |access-date=December 16, 2018 |archive-url=https://web.archive.org/web/20171225233957/https://history.nasa.gov/afj/ap15fj/14solo_ops2.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>

Results from the SIM bay experiments would include the conclusion, from data gathered by the X-ray spectrometer, that there was greater fluorescent X-ray flux than anticipated, and that the lunar highlands were richer in aluminum than were the mares.{{sfn|Mission Report|p=37}} ''Endeavour'' was in a more inclined orbit than previous crewed missions, and Worden saw features that were not known previously, supplementing photographs with thorough descriptions.<ref name = "moon mountain" />

By the time Scott and Irwin were ready to take off from the lunar surface and return to ''Endeavour'', the CSM's orbit had drifted due to the rotation of the Moon, and a plane change burn was required to ensure that the CSM's orbit would be in the same plane as that of the LM once it took off from the Moon. Worden accomplished the 18-second burn with the SPS.<ref group=ALFJ name=solo4>{{cite web |url=https://history.nasa.gov/afj/ap15fj/16solo_ops4.html |title=Solo Orbital Operations-4 |year=1998 |editor-last=Woods |editor-first=W. David |editor-last2=O'Brien |editor-first2=Frank |work=Apollo 15 Flight Journal |publisher=NASA |access-date=December 16, 2018 |archive-url=https://web.archive.org/web/20171225233958/https://history.nasa.gov/afj/ap15fj/16solo_ops4.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>