Apollo 15 (AS-510)

Exploration of Hadley-Apennine Region

Apollo 15 Liftoff

Earth (Apollo 15)

Apollo 15 was the fourth mission to land men on the Moon. This mission was the first flight of the Lunar Roving Vehicle which astronauts used to explore the geology of the Hadley Rille/Apennine region. The LRV allowed Apollo 15, 16 and 17 astronauts to venture further from the Lunar Module than in previous missions. Total surface traverses increased from hundreds of meters during earlier missions to tens of kilometers during Apollo 15 and 16 and just over 100 kilometers during Apollo 17.

Summary of Events

The successful Apollo 15 manned lunar landing mission was the first in a series of three advanced missions planned for the Apollo program. Its primary scientific objectives were to observe the lunar surface, survey and sample material and surface features in a preselected area of the Hadley-Apennine region, setup and activate surface experiments, and conduct inflight experiments and photographic tasks from lunar orbit.

Apollo 15 LaunchThe space vehicle with a crew of David R. Scott, commander; Alfred J. Worden, command module pilot; and James B. Irwin, lunar module (LM) pilot, was launched on schedule from the NASA Kennedy Space Center, Fla., at 9:34:00 a.m. EST on July 26, 1971.

At 22:04:09 GMT on July 30, the LM descent propulsion system was fired for powered-descent initiation. The LM landed approximately 12 minutes later with sufficient propellant remaining to provide an additional hover time of 103 seconds, had it been required.

During a lunar stay of 66 hr 54 min 53 sec, a 33-min standup extravehicular activity (EVA) and three periods of surface EVA totaling approximately 18.5 hr were performed.

The astronauts were able to collect samples from the low dark plains (maria), the Apennine highlands, and the area along Hadley Rille, a long, narrow winding valley.

Approximately 76 kg of lunar material including soil, rock, core-tube, and deep-core samples were returned to Earth.

Traverses during the three EVA periods were enhanced by use of a Lunar Roving Vehicle (LRV). An average speed of 9.6 km/hr was achieved, and speeds up to 12 km/hr were attained over level lunar terrain. The total distance traveled, was 27.9 km, corresponding to a map distance of approximately 25.3 km.

Liftoff of the LM ascent stage occurred at 17:11:23 GMT on August 2 and was monitored by the ground-command television assembly mounted on the LRV. Commanded from Earth, the television assembly was planned to provide coverage after liftoff of the lunar surface and of a lunar eclipse on August 6. Although the television assembly operated successfully during all three EVA periods, the elevation clutch began to slip during the second EVA, and operation deteriorated during the rest of the mission. When activated about 40 hr after LM liftoff, the unit operated satisfactorily for 13 minutes then failed.

Although entry was nominal and all three main parachutes deployed initially, one parachute collapsed before spashdown. However, the CM was landed safely at 20:45:53 GMT, August 7, 1971.

From NASA SP-289, Apollo 15 Preliminary Science Report.