Apollo 15 operations on the Lunar surface  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 of lunar surface material during 18½ hours outside the Lunar Module "Falcon". At 104 hours, 30 minutes and 12 seconds GET the descent engine of "Falcon" ignited. Burning at about 10% for the first 26 seconds so that the guidance computer could gimbal the engine to direct the thrust through the center of gravity of the LM, it then thrust up to 100%. Irwin confirmed that the Abort Guidance System (AGS) agreed with the Primary Guidance and Navigation System (PGNS) on their height and rate of descent. At three minutes the computer rolled the spacecraft so that they were now on their back, with the windows facing away from the lunar surface. This was so the landing radar could acquire the surface. Scott then announced the altitude and velocity lights, indicating the computer was getting acceptable data from the radar. Six minutes into the burn they were 30,000 feet (9000 m) above the surface. In Mission Control, the Flight Director learned that tracking data indicated they were going to land 3000 feet (900 m) south of the targeted landing site. Although at first he decided not to tell the crew, Ed Mitchell, the CapCom, convinced him otherwise. During this time Scott was trying to see the ground through his window. He thought they were going to land as long as he could see Mount Hadley Delta. He was unable to see the Rille, something that had been possible in the simulators. Nine minutes and ten seconds into the burn, Program 64 started on the computer and the LM pitched forward and the crew could see the ground. Using scribe marks on the window and angles read to him by Irwin, Scott found where the computer was predicting the landing site to be and then used a hand controller to move the predicted location. He did this 18 times during the landing, moving the target site a total of 338 meters (1110 feet) uprange and 409 meters (1341 feet) north. Scott's main problem was that there was very little detail on the surface. The best images of the site only had 66 ft (20 m) resolution and photoanalysers had overenhanced the images.