Editing Apollo 15 (section)

=== Lunar surface ===
{{main|Apollo 15 operations on the Lunar surface}}

==== Stand-up EVA and first EVA ====
{{quote box | align = right | width = 25em | salign = center
| quote = As I stand out here in the wonders of the unknown at Hadley, I sort of realize there's a fundamental truth to our nature. Man must explore. And this is exploration at its greatest.
| source = David Scott, upon setting foot on the Moon.<ref group=ALSJ name=deploying>{{cite web |url=https://history.nasa.gov/alsj/a15/a15.lrvdep.html |title=Deploying the Lunar Roving Vehicle |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=September 13, 2018 |archive-url=https://web.archive.org/web/20171225232151/https://history.nasa.gov/alsj/a15/a15.lrvdep.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref>}}

With ''Falcon'' due to remain on the lunar surface for almost three days, Scott deemed it important to maintain the [[circadian rhythm]] they were used to, and as they had landed in the late afternoon, Houston time, the two astronauts were to sleep before going onto the surface. But the time schedule allowed Scott to open the lander's top hatch (usually used for docking) and spend a half hour looking at their surroundings, describing them, and taking photographs. Lee Silver had taught him the importance of going to a high place to survey a new field site, and the top hatch served that purpose.{{sfn|Chaikin|pp=414–415}}<ref group=ALSJ name=landing>{{cite web |url=http://www.hq.nasa.gov/alsj/a15/a15.landing.html |title=Landing at Hadley |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=July 14, 2011 |archive-url=https://web.archive.org/web/20110628230652/http://www.hq.nasa.gov/alsj/a15/a15.landing.html |archive-date=June 28, 2011 |url-status=live |df=mdy-all }}</ref><ref group=ALSJ name=seva>{{cite web |title=Stand-Up EVA |url=http://www.hq.nasa.gov/alsj/a15/a15.seva.html |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=July 14, 2011 |archive-url=https://web.archive.org/web/20110628231634/http://www.hq.nasa.gov/alsj/a15/a15.seva.html |archive-date=June 28, 2011 |url-status=live |df=mdy-all }}</ref> Deke Slayton and other managers were initially opposed due to the oxygen that would be lost, but Scott got his way.{{sfn|Scott & Leonov|pp=294–295}} During the only stand-up [[extravehicular activity]] (EVA) ever performed through the LM's top hatch on the lunar surface, Scott was able to make plans for the following day's EVA.{{sfn|Beattie|p=231}} He offered Irwin a chance to look out as well, but this would have required rearranging the umbilicals connecting Irwin to ''Falcon''{{'s}} life support system, and he declined.{{sfn|Irwin|p=61}} After repressurizing the spacecraft, Scott and Irwin removed their space suits for sleep, becoming the first astronauts to doff their suits while on the Moon.{{sfn|Chaikin|p=415}}

[[File:Apollo 15 lunar rover EVA2.ogg|thumb|alt=Film taken aboard the lunar rover|Aboard the [[Lunar Roving Vehicle]]]]
Throughout the sleep period Mission Control in Houston monitored a slow but steady oxygen loss. Scott and Irwin eventually were awakened an hour early, and the source of the problem was found to be an open valve on the urine transfer device. In post-mission debriefing, Scott recommended that future crews be woken at once under similar circumstances. After the problem was solved, the crew began preparation for the first Moon walk.<ref group=ALSJ name=eva1wake>{{cite web |url=http://www.hq.nasa.gov/alsj/a15/a15.eva1wake.html |title=Wake-up for EVA-1 |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=September 9, 2018 |archive-url=https://web.archive.org/web/20161012014625/http://www.hq.nasa.gov/alsj/a15/a15.eva1wake.html |archive-date=October 12, 2016 |url-status=live |df=mdy-all }}</ref>

After donning their suits and depressurizing the cabin,<ref group=ALSJ name=eva1prep>{{cite web |url=https://history.nasa.gov/alsj/a15/a15.eva1prep.html |title=Preparations for EVA-1 |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=September 13, 2018 |archive-url=https://web.archive.org/web/20171225232244/https://history.nasa.gov/alsj/a15/a15.eva1prep.html |archive-date=December 25, 2017 |url-status=live |df=mdy-all }}</ref> Scott and Irwin began their first full EVA, becoming the seventh and eighth humans, respectively, to walk on the Moon.{{sfn|Harland|pp=89–90, 358–359}} They began deploying the lunar rover, stored folded up in a compartment of ''Falcon''{{'s}} descent stage, but this proved troublesome due to the slant of the lander. The experts in Houston suggested lifting the front end of the rover as the astronauts pulled it out, and this worked.{{sfn|Harland|pp=90–93}} Scott began a system checkout. One of the batteries gave a zero voltage reading, but this was only an instrumentation problem. A greater concern was that the front wheel steering would not work. However, the rear wheel steering was sufficient to maneuver the vehicle.{{sfn|Harland|pp=93–94}} Completing his checkout, Scott said "Okay. Out of [[detent]]; we're moving", maneuvering the rover away from ''Falcon'' in mid-sentence. These were the first words uttered by a human while driving a vehicle on the Moon.<ref group=ALSJ name=deploying /> The rover carried a [[Apollo TV camera|television camera]], controlled remotely from Houston by NASA's Ed Fendell. The resolution was not high compared to the still photographs that would be taken, but the camera allowed the geologists on Earth to indirectly participate in Scott and Irwin's activities.{{sfn|Harland|pp=96–97}}

The rille was not visible from the landing site, but as Scott and Irwin drove over the rolling terrain, it came into view.{{sfn|Chaikin|pp=418–419}} They were able to see [[Elbow (lunar crater)|Elbow]] crater, and they began to drive in that direction.<ref group=ALSJ name=drivingtoelbow>{{cite web |url=https://www.hq.nasa.gov/alsj/a15/a15.elbowtrv.html |title=Driving to Elbow Crater |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=September 16, 2018 |archive-url=https://web.archive.org/web/20161012011146/http://www.hq.nasa.gov/alsj/a15/a15.elbowtrv.html |archive-date=October 12, 2016 |url-status=live |df=mdy-all }}</ref> Reaching Elbow, a known location, allowed Mission Control to backtrack and get closer to pinpointing the location of the lander. The astronauts took samples there,{{sfn|Harland|pp=106–107}} and then drove to another crater on the flank of [[Mons Hadley Delta]], where they took more. After concluding this stop, they returned to the lander to drop off their samples and prepare to set up the [[Apollo Lunar Surface Experiments Package]] (ALSEP), the scientific instruments that would remain when they left.{{sfn|Harland|pp=107–114, 315}} Scott had difficulty drilling the holes required for the [[Heat Flow Experiment|heat flow experiment]], and the work was not completed when they had to return to the lander.{{sfn|Harland|p=115}} The first EVA lasted 6{{nbsp}}hours and 32 minutes.{{sfn|Chaikin|p=598}}<ref name=summaryalsj group=ALSJ>{{cite web |url=http://www.hq.nasa.gov/alsj/a15/a15.summary.html |title=Mountains of the Moon |last=Jones |first=Eric M. |year=1995 |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=December 21, 2018 |archive-url=https://web.archive.org/web/20161011044716/http://www.hq.nasa.gov/alsj/a15/a15.summary.html |archive-date=October 11, 2016 |url-status=live |df=mdy-all }}</ref>

==== Second and third EVAs ====
[[File:Apollo 15 Genesis Rock.jpg|thumb|right|alt=A white rock, placed in a laboratory setting|The [[Genesis Rock]]]]

The rover's front steering, inoperative during the first EVA, worked during the second and third ones.{{sfn|Mission Report|p=101}} The target of the second EVA, on August 1, was the slope of Mons Hadley Delta, where the pair sampled boulders and craters along the [[Montes Apenninus|Apennine Front]]. They spent an hour at [[Spur (lunar crater)|Spur]] crater, during which the astronauts collected a sample dubbed the [[Genesis Rock]]. This rock, an [[anorthosite]], is believed to be part of the early lunar crust—the hope of finding such a specimen had been one reason the Hadley area had been chosen. Once back at the landing site, Scott continued to try to drill holes for experiments at the ALSEP site, with which he had struggled the day before. After conducting soil-mechanics experiments and raising the [[Lunar Flag Assembly|U.S. flag]], Scott and Irwin returned to the LM. EVA{{nbsp}}2 lasted 7{{nbsp}}hours and 12 minutes.{{sfn|Chaikin|p=598}}<ref name=summaryalsj group=ALSJ/>

Although Scott had eventually been successful at drilling the holes, he and Irwin had been unable to retrieve a core sample, and this was an early order of business during EVA 3, their third and final moonwalk. Time that could have been devoted to geology ticked away as Scott and Irwin attempted to pull it out. Once it had been retrieved, more time passed as they attempted to break the core into pieces for transport to Earth. Hampered by an incorrectly mounted vise on the rover, they eventually gave up on this—the core would be transported home with one segment longer than planned. Scott wondered if the core was worth the amount of time and effort invested, and the CAPCOM, Joe Allen, assured him it was. The core proved one of the most important items brought back from the Moon, revealing much about its history, but the expended time meant the planned visit to a group of hills known as the [[North Complex]] had to be scrubbed. Instead, the crew again ventured to the edge of Hadley Rille, this time to the northwest of the immediate landing site.<ref name=summaryalsj group=ALSJ />

[[File:Apollo 15 feather and hammer drop.ogv|thumb|alt=Video of an astronaut dropping a hammer and a feather while on the Moon|David Scott's hammer and feather experiment]]
Once the astronauts were beside the LM, Scott used a kit provided by the [[United States Postal Service|Postal Service]] to cancel a [[first day cover]] of two stamps being issued on August 2, the current date.<ref group=ALSJ name=hammer>{{cite web |url=https://history.nasa.gov/alsj/a15/a15.clsout3.html |title=The Hammer and the Feather |year=1996 |editor-last=Jones |editor-first=Eric M. |work=Apollo 15 Lunar Surface Journal |publisher=NASA |access-date=December 21, 2018 |archive-url=https://web.archive.org/web/20181230031714/https://history.nasa.gov/alsj/a15/a15.clsout3.html |archive-date=December 30, 2018 |url-status=live |df=mdy-all }}</ref><ref>{{cite web|title='Moon Mail' and Space Stamps Now on Display in World's Largest Postal Gallery|last=Pearlman|first=Robert Z.|date=September 24, 2013|url=https://www.space.com/22918-moon-mail-space-stamps-on-display.html|publisher=Space.com|access-date=December 21, 2018|archive-url=https://web.archive.org/web/20181221182858/https://www.space.com/22918-moon-mail-space-stamps-on-display.html|archive-date=December 21, 2018|url-status=live|df=mdy-all}}</ref> Scott then performed an experiment in view of the television camera, using a falcon feather and hammer to demonstrate [[Galileo]]'s theory that all objects in a given gravity field fall at the same rate, regardless of mass, in the absence of [[aerodynamic drag]]. He dropped the hammer and feather at the same time; because of the negligible lunar atmosphere, there was no drag on the feather, which hit the ground at the same time as the hammer. This was Joe Allen's idea (he also served as CAPCOM during it) and was part of an effort to find a memorable popular science experiment to do on the Moon along the lines of Shepard's hitting of golf balls. The feather was most likely from a female [[gyrfalcon]] (a type of falcon), a mascot at the [[United States Air Force Academy]].<ref group=ALSJ name=hammer />

[[File:Fallen Astronaut.jpg|thumb|left|alt=A small aluminum statue and a plaque on the lunar surface|The ''[[Fallen Astronaut]]'' memorial, near Hadley Rille, Moon]]
Scott then drove the rover to a position away from the LM, where the television camera could be used to observe the lunar liftoff. Near the rover, he left a small aluminum statuette called ''[[Fallen Astronaut]]'', along with a plaque bearing the names of 14 known American astronauts and Soviet cosmonauts who had died in the furtherance of space exploration. The memorial was left while the television camera was turned away; he told Mission Control he was doing some cleanup activities around the rover. Scott disclosed the memorial in a post-flight news conference. He also placed a Bible on the control panel of the rover before leaving it for the last time to enter the LM.<ref group=ALSJ name=hammer />

The EVA lasted 4 hours, 49 minutes and 50 seconds.{{sfn|Mission Report|p=16}} In total, the two astronauts spent 18{{frac|1|2}} hours outside the LM and collected approximately {{convert|77|kg|lb|abbr=on|order=flip}} of lunar samples.<ref name=summaryalsj group=ALSJ/>