Editing Apollo 15 (section)

=== Launch and outbound trip ===
[[File:Apollo 15 launch.ogg|thumb|right|alt=Film of a rocket lifting off|Apollo 15 launches on July 26, 1971]]
{{main|Journey of Apollo 15 to the Moon}}

Apollo 15 was launched on July 26, 1971, at 9:34{{nbsp}}am [[Eastern time|EDT]] from the [[Kennedy Space Center]] at [[Merritt Island]], Florida. The time of launch was at the very start of the two-hour, 37-minute launch window, which would allow Apollo 15 to arrive at the Moon with the proper lighting conditions at Hadley Rille; had the mission been postponed beyond another window on July 27, it could not have been rescheduled until late August. The astronauts had been awakened five and a quarter hours before launch by Slayton, and after breakfast and suiting up, had been taken to Pad 39A, launch site of all seven attempts at crewed lunar landing, and entered the spacecraft about three hours before launch. There were no unplanned delays in the countdown.<ref group=ALFJ name=launch>{{cite web |url=https://history.nasa.gov/afj/ap15fj/01launch_to_earth_orbit.html |title=Launch and Reaching Earth Orbit |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233954/https://history.nasa.gov/afj/ap15fj/01launch_to_earth_orbit.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>

At 000:11:36 into the mission, the [[S-IVB]] engine shut down, leaving Apollo 15 in its planned parking orbit in [[low Earth orbit]]. The mission remained there for 2{{nbsp}}hours and 40 minutes, allowing the crew (and Houston, via telemetry) to check the spacecraft's systems. At 002:50.02.6 into the mission, the S-IVB was restarted for [[trans-lunar injection]] (TLI), placing the craft on a path to the Moon.<ref group=ALFJ name=launch /><ref group=ALFJ name=earthorbit>{{cite web |url=https://history.nasa.gov/afj/ap15fj/02earth_orbit_tli.html |title=Earth Orbit and Translunar Injection |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225234000/https://history.nasa.gov/afj/ap15fj/02earth_orbit_tli.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref> Before TLI, the craft had completed 1.5 orbits around the Earth.{{sfn|Orloff & Harland|p=430}}

[[File:Apollo 15 TandD.ogv|thumb|left|alt=Video showing the final stages of spacecraft docking with lunar module|Astronaut Al Worden maneuvers the CSM to a docking with the Lunar Module ''Falcon'']]
The command and service module (CSM) and the Lunar Module remained attached to the nearly-exhausted S-IVB booster. Once trans-lunar injection had been achieved, placing the spacecraft on a trajectory towards the Moon, [[Detonating cord|explosive cords]] separated the CSM from the booster as Worden operated the CSM's thrusters to push it away. Worden then maneuvered the CSM to dock with the LM (mounted on the end of the S-IVB), and the combined craft was then separated from the S-IVB by explosives. After Apollo 15 separated from the booster, the S-IVB maneuvered away, and, as planned, impacted the Moon about an hour after the crewed spacecraft entered lunar orbit, though due to an error the impact was {{convert|146|km|nmi|sp=us|order=flip}} away from the intended target.<ref group=ALFJ name=translunar>{{cite web |url=https://history.nasa.gov/afj/ap15fj/03tde.html |title=Transposition, Docking and Extraction |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233953/https://history.nasa.gov/afj/ap15fj/03tde.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref> The booster's impact was detected by the [[seismometer]]s left on the Moon by Apollo 12 and Apollo 14, providing useful scientific data.{{sfn|Mission Report|p=1}}

There was a malfunctioning light on the craft's [[service propulsion system]] (SPS); after considerable troubleshooting, the astronauts did a test burn of the system that also served as a midcourse correction. This occurred about 028:40:00 into the mission. Fearing that the light meant the SPS might unexpectedly fire, the astronauts avoided using the control bank with the faulty light, bringing it online only for major burns, and controlling it manually. After the mission returned, the malfunction proved to be caused by a tiny bit of wire trapped within the switch.<ref group=ALFJ name=sps>{{cite web |url=https://history.nasa.gov/afj/ap15fj/05day2_checking_sps.html |title=Day 2: Checking the SPS |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233956/https://history.nasa.gov/afj/ap15fj/05day2_checking_sps.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref><ref group=ALFJ name=summary />

[[File:Apollo 15 Earth1.jpg|thumb|upright|alt=Picture of Earth taken from space|Image of Earth taken during the translunar coast]]
After purging and renewing the LM's atmosphere to eliminate any contamination, the astronauts entered the LM about 34 hours into the mission, needing to check the condition of its equipment and move in items that would be required on the Moon. Much of this work was televised back to Earth, the camera operated by Worden. The crew discovered a broken outer cover on the Range/Range Rate tapemeter. This was a concern not only because an important piece of equipment, providing information on distance and rate of approach, might not work properly, but because bits of the glass cover were floating around ''Falcon''{{'s}} interior. The tapemeter was supposed to be in a helium atmosphere,<ref group=ALFJ name=entry>{{cite web |url=https://history.nasa.gov/afj/ap15fj/06day2_enter_lm.html |title=Day 2: Entering the LM |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233955/https://history.nasa.gov/afj/ap15fj/06day2_enter_lm.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref> but due to the breakage, it was in the LM's oxygen atmosphere.{{sfn|Mission Report|p=153}} Testing on the ground verified the tapemeter would still work properly, and the crew removed most of the glass using a vacuum cleaner and adhesive tape.<ref group=ALFJ name=entry />{{sfn|Orloff & Harland|p=431}}

As yet, there had been only minor problems, but at about 61:15:00 mission time (the evening of July 28 in Houston), Scott discovered a leak in the water system while preparing to chlorinate the water supply. The crew could not tell where it was coming from, and the issue had the potential to become serious. The experts in Houston found a solution, which was successfully implemented by the crew. The water was mopped up with towels, which were then put out to dry in the tunnel between the command module (CM) and Lunar Module—Scott stated it looked like someone's laundry.<ref group=ALFJ name=laundry>{{cite web |url=https://history.nasa.gov/afj/ap15fj/08day3_leak_hilltop.html |title=Day 3: Leaking Water and the Top of the Hill |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233959/https://history.nasa.gov/afj/ap15fj/08day3_leak_hilltop.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>

At 073:31:14 into the mission, a second midcourse correction, with less than a second of burn, was made. Although there were four opportunities to make midcourse corrections following TLI, only two were needed. Apollo 15 approached the Moon on July 29, and the lunar orbit insertion (LOI) burn had to be made using the SPS, on the [[far side of the Moon]], out of radio contact with Earth. If no burn occurred, Apollo 15 would emerge from the lunar shadow and come back in radio contact faster than expected; the continued lack of communication allowed [[Christopher C. Kraft Jr. Mission Control Center|Mission Control]] to conclude that the burn had taken place. When contact resumed, Scott did not immediately give the particulars of the burn, but spoke admiringly of the beauty of the Moon, causing [[Alan Shepard]], the Apollo 14 commander, who was awaiting a television interview, to grumble, "To hell with that shit, give us details of the burn."<ref group=ALFJ name=encounter>{{cite web |url=https://history.nasa.gov/afj/ap15fj/09day4_lunar_encounter.html |title=Day 4: Lunar Encounter |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=September 5, 2018 |archive-url=https://web.archive.org/web/20171225233956/https://history.nasa.gov/afj/ap15fj/09day4_lunar_encounter.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref> The 398.36-second burn took place at 078:31:46.7 into the mission at an altitude of {{convert|86.7|nmi|km|sp=us}} above the Moon, and placed Apollo 15 in an elliptical lunar orbit of {{convert|170.1|by|57.7|nmi|km}}.{{sfn|Orloff & Harland|p=431}}