Apollo 15

Roving in the shadow of mountains

Apollo 15 was the beginning of an end—the first of the final three crewed missions to the Moon in the 20th century. These final three were effectively Apollo 2.0, featuring hardware upgrades that extended both their duration and scientific return. The service module was now laden with scientific instrumentation; a beefier lunar module doubled the total time spent on the surface. NASA also debuted the motorized lunar rover, which extended the exploration range of its astronauts by a factor of five.

Lightning strikes behind Apollo 15's Saturn rocket
Lightning strikes behind Apollo 15's Saturn rocket Despite the weather's dramatic flourish, the mission launched without incident the following day.Image: NASA

Originally envisioned to send 10 initial sorties to the surface and then establish a more permanent presence, America’s lunar ambitions were severely curtailed by the launch of Apollo 15. Three missions had already been canceled and increasing budgetary pressure from the Nixon White House called into question the futures of Apollos 16 and 17. For a brief period in the summer of 1971, Apollo 15 could have been the final mission to the Moon.

Political uncertainty did not trickle down to the mission itself. Apollo 15 was the most ambitious mission to the Moon yet, representing a new level of program maturity and operational confidence by NASA. It was the first of the “J-class” missions, which featured upgraded spacecraft that enabled longer stays at the Moon with greater scientific return.

The mission began on July 26, 1971 with the liftoff of the Saturn V rocket carrying Commander Dave Scott, Command Module Pilot Al Worden, and Lunar Module Pilot Jim Irwin. The rocket had been modified to loft thousands of additional kilograms (more than 4,000 pounds) of materials and supplies to the Moon, which included a full suite of scientific instruments on the service module, additional life support materials to support a three-day stay on the lunar surface, and, of course, the Lunar Roving Vehicle.

Apollo Landing Sites
Apollo Landing Sites Project Apollo landed 6 missions on the Moon, all on the near-side facing the Earth. This image displays the location of each mission as recorded by NASA's Lunar Reconnaissance Orbiter spacecraft.Image: NASA/Ernie Wright/Casey Dreier

The landing site was a study in extremes. Dave Scott and Jim Irwin landed near a massive chasm in the lunar surface — Hadley Rille — created by ancient lava flows. Bounding them to the south were the Apennines, a soaring mountain chain towering upwards of 5 kilometers (16,000 feet) above the diminutive lunar module. The mountains and rille provided opportunities to collect samples from deep in the lunar bedrock and to study new types of geologic formations. It was also the most breathtaking lunar landing site to date. In the debate about where to land his mission, Dave Scott broke a tie in favor of the Apennine mountains, believing that all else being equal, exploration should favor beauty.

The Lunar Module "Falcon" at the foot of the Apennine mountain range
The Lunar Module "Falcon" at the foot of the Apennine mountain range Note the tilt of the LM on the uneven terrain. The light spherical object at the top is a reflection in the lens of the camera. This image has been modified to remove the crosshair pattern used to calibrate Apollo surface imagery.Image: NASA

Scott and Irwin spent three days on the Moon and made three long scientific excursions, using the lunar rover to drive nearly 28 kilometers (17.4 miles). They climbed the foothills of the Apennines, flirted with the edge of the rille, and collected 77 kilograms (about 170 pounds) of lunar rocks and soil samples, including the so-called "Genesis rock" dated at more than 4 billion years old. The lunar roving vehicle — designed, tested, and engineered in a mere 17 months — performed well for its first outing. Its additional capacity supported an independent direct-to-Earth antenna which provided a live color television feed of their progress.

Jim Irwin with Apollo 15's Lunar Roving Vehicle
Jim Irwin with Apollo 15's Lunar Roving Vehicle Developed in a breakneck 17 months, the LRV greatly extended the exploration range of final three Apollo missions. Note: this image was slightly modified to remove the cross-hair pattern common to Apollo imagery.Image: NASA/The Planetary Society

Not to be outdone, Command Module Pilot Al Worden performed complex measurements of the lunar environment from orbit. Using the upgraded suite of science instruments on the service module, he gathered detailed data on the Moon's topography, radiation environment and exosphere. Worden even released the first micro-satellite at the Moon to measure its magnetic field.

After spending three days on the Moon, astronauts Scott and Irwin blasted off from the surface to rejoin their fellow astronaut in orbit. The remaining flight home was uneventful, though Worder did perform a spacewalk in trans-lunar space in order to retrieve film from one of the service module’s scientific instruments.

The crew splashed down in the pacific ocean on August 7th, 1971, 13 days after their departure. It was the longest-duration Apollo mission to that point.

Apollo 15 Timeline

EventTime (UTC)Date
Liftoff13:34:0026 Jul 1971
Earth orbit insertion13:45:4426 Jul 1971
Trans-lunar injection16:30:0326 Jul 1971
Lunar Orbit Injection Burn20:05:4629 Jul 1971
CSM/LM undocking18:13:1630 Jul 1971
LM lunar landing22:16:2830 Jul 1971
1st EVA started13:13:1731 Jul 1971
1st EVA ended19:45:5931 Jul 1971
2nd EVA started11:48:4801 Aug 1971
2nd EVA ended19:01:0201 Aug 1971
3rd EVA started08:52:1402 Aug 1971
3rd EVA ended13:54:0002 Aug 1971
LM lunar liftoff17:11:2302 Aug 1971
CSM/LM docked19:10:2502 Aug 1971
Transearth injection ignition21:22:4504 Aug 1971
Transearth EVA start (Worden)15:31:1205 Aug 1971
Transearth EVA end16:10:1905 Aug 1971
Entry20:32:5407 Aug 1971
Splashdown20:45:5307 Aug 1971

Apollo 15 Cost

NASA estimated the following marginal costs for Apollo 15. Full costs of the Apollo program can be found on the "How Much Did the Apollo Program Cost?" page.

original $inflation adjusted $
Command & Service Module$65 million$450 million
Lunar Module$50 million$345 million
Saturn V Launch Vehicle$185 million$1.3 billion
Science Experiements & Lunar Roving Vehicle$40 million$276 million
Operations$105 million$726 million
Total$445 million$3.7 billion


Project Apollo

Starting with Apollo 7 in 1968 and culminating with Apollo 17 in 1972, NASA launched 33 astronauts on 11 Apollo missions. Twelve humans walked on the Moon.

Astronaut Dave Scott in the Lunar Receiving Lab
Astronaut Dave Scott in the Lunar Receiving Lab Dave Scott visits the Genesis Rock in the Lunar Receiving Laboratory on Earth. This piece of anorthosite is one of the oldest rocks ever studied by scientists, who dated it at over 4 billion years old. Scott and Jim Irwin collected it on the flank of Hadley Delta mountain during the Apollo 15 mission.Image: NASA