page_title: Apollo 15 operations on the Lunar surface
section_title: EVA-1
hierarchical_section_title: Apollo 15 operations on the Lunar surface / EVA-1
context_page_description: Apollo 15 lunar surface operations were conducted from July 30 to August 2, 1971, by Apollo 15 Commander David Scott and Apollo Lunar Module Pilot James Irwin, who used the first Lunar Roving Vehicle to make three exploratory trips away from their landing site at the base of the Apennine Mountains, near Hadley Rille.
  They collected a total of 77 kg of lunar surface material during 18½ hours outside the Lunar Module Falcon.
context_section_description: Throughout the astronauts' sleep period, Mission Control had watched with some concern as the pressure inside descent stage oxygen tanks of the LM slowly dropped. To conserve power during the night, the LM was run on a low-data-rate telemetry stream, so Mission Control could not tell the exact cause. Unwilling to wake the crew they decided to wait until they had woken up.
  In the end, Flight Director Peter Frank chose to wake the crewmen an hour early and got them to turn back on the high-data-rate telemetry. With this they saw that the valve of the Urine Transfer Device was open even though the receptacle was capped. A total of about 8 out of 95 pounds (3.6 out of 43 kg) of oxygen had been lost. About half of the total amount was reserve. Scott and Irwin would state in the post-flight Technical Debrief that Mission Control should have awakened them as soon as the leak was detected.
  Once they were awake, it was decided to start their preparations for the first lunar EVA of their mission. As with everything in Apollo, it was an involved procedure. Not only did they have to prepare Falcon, but had to don their space suits. Apollo 15 was the first crew that got to sleep in long johns rather than having to stay in their space suits. It would not be until four hours after waking up that Mission Control gave the Go to depressurize the LM.
  As Scott became the seventh man to step onto the lunar surface, he said:
  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.
  After inspecting the LM, Scott began to unpack the Modularised Equipment Stowage Assembly (MESA), which was attached to the side of the LM and carried the Apollo TV camera, sample bags, batteries, CO₂ scrubbers for the space suits, and other equipment needed while the astronauts were outside the spacecraft. About seven minutes after Scott stepped outside Irwin is on the surface.
  Irwin's first task was to collect a contingency sample of lunar rock. This was collected in case of an emergency, i.e., suddenly having to leave the lunar surface within the first few minutes. In such an event having a contingency sample meant that the crew would not return to Earth empty-handed. However, the contingency sample was not of much value because the ground surrounding the landing site had been disturbed by the LM descent engine.
  After Scott positioned the TV camera on a tripod so Mission Control could see the deployment of the Lunar Rover, he and Irwin began the process by pulling on two lanyards. These released the Rover and let it swing down on hinges. As it did, it began to unfold. They experienced some problems at first due to the angle the LM was sitting on, but within minutes it was on the ground almost ready to go.
  Scott had the honor of the first test drive, taking it around the LM. The Rover had both front and back steering, but Scott found that only the rear-wheel steering was working (mysteriously the front steering would be working at the start of the second EVA). Other difficulties came from how their space suits did not bend very much when they sat down. When training on Earth, their body weight had forced the suits down, but on the Moon, they ended up reclining in the seats. Apart from the steering there were no other problems and the crew set about loading up the Rover for their first geological traverse.  During lunar surface operations, Commander Scott always drove the rover, while Lunar Module Pilot Irwin was a passenger who assisted with navigation.  This division of responsibilities between the two crew positions was used consistently throughout Apollo's J missions.
  The astronauts could not travel any farther than the distance they could walk with the remaining oxygen in their Portable Life Support Systems (PLSS). So the earlier they set out, the farther they could travel. They would travel to the farthest point of the traverse and then work their way back. On EVA-1 they would travel to the base of Hadley Delta via the Rille. Their first
caption: Taken at the double-core site by Irwin. It shows the view up the rille toward the northwest. Scott is at the Rover and the gnomon is on the ground at his right foot. Scan by Kipp Teague.
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