The Apollo 15 spacecraft was modified to carry out a greater range of lunar orbital science activities than any previous mission. Other modifications were included to increase lunar surface stay time and accommodate a larger scientific payload. The biggest change to the CSM was the addition of the Scientific Instruments Module (SIM) to the service module. Various handrails, handholds, and a foot restraint were also added to the CSM to assist the astronauts during their EVA to retrieve film cassettes from the SIM. On the LM, a number of structural changes were made to increase storage capacity for more consumables, a heavier load of scientific experiments, and the Lunar Roving Vehicle (LRV), which is described below.

The spacecraft consisted of three modules: a lunar module (LM), command module (CM), and a service module (CSM). After the spacecraft orbited the moon, the LM and CSM separated. Two astronaunts in the LM landed on the lunar surface, while the CM pilot remained in lunar orbit in the command module.

The lunar module was a two-stage vehicle designed for space operations near and on the Moon. The lunar module stood 7 meters high and was 9.4 meters wide (diagonally across the landing gear). The ascent and descent stages of the LM operated as a unit until staging, when the ascent stage functioned as a single spacecraft for rendezvous and docking with the command module (CM). The on-orbit dry mass weight of the LM was 4240 kilograms.

The lunar roving vehicle, used for the first time on Apollo 15, was a four-wheeled, manually controlled, electrically powered vehicle that carried the crew and their equipment over the lunar surface. The increased mobility and ease of the travel made possible by this vehicle permitted the crew to travel much greater distances than on previous lunar landing missions. The vehicle was designed to carry the two crewmen and a science payload at a maximum velocity of about 16 kilomenters per hour (8.6 mph) on a smooth, level surface and at reduced veolocities on slopes up to 25 degrees. It could be operated from either crewman's positions, as the control and display console was located on the vehicle centerline. The deployed vehicle was appoximately 10 feet long, 7 feet wide, and 45 inches high. Its chassis was hinged such that the forward and aft sections folded back over the center potion, and each of the wheel suspension systems rotated so that the folded vehicle would fit in quadrant I of the lunar module. The gross operational weight was approximately 1535 pounds, of which 455 pounds was the weight of the vehicle itself. The remainder was the weight of the crew, their equipment, communications equipment, and the science payload.

David R. Scott, Mission Commander, was born on June 6, 1932, in San Antonio, Texas. He received a B.S. from the U.S. Military Academy in 1954 and an M.S. in Aeronautics and Astronautics from the Massachusetts Institute of Technology in 1962. He was chosen with the third group of astronauts in 1963. He was the pilot of Gemini 8, command module pilot on Apollo 9, and backup commander of Apollo 12. He was the seventh man to walk on the Moon. In July 1972 he became Special Assistant for Mission Operations for the Apollo-Soyuz Test Project and in April 1975 was appointed director of the NASA Dryden Flight Research Center. He resigned from NASA on October 30, 1977.

Alfred M. Worden, Command Module Pilot, was born on February 7, 1932, in Jackson, Michigan. He earned a B.S. at the U.S. Military Academy in 1955 and an M.S. in both Astronautical and Aeronautical Engineering and Instrumentation Engineering at the University of Michigan (1963). Worden was chosen in the fifth group of astronauts in 1966. He was backup command module pilot for Apollo 12. In September 1972 he was assigned to the NASA Ames Research Center as Director of Advanced Research and Technology. He resigned from NASA and the Air Force on September 1, 1975.