With Apollo 14 having put the program back on track, NASA decided to make the remaining Moon missions more ambitious, giving their crews longer on the lunar surface and providing transport in the form of the Lunar Roving Vehicle, or Moon buggy.
Apollo 15 blasted off from Florida on July 26, commanded by veteran astronaut David Scott, with first-timers Al Worden and Jim Irwin as pilots of the Command Module, Endeavour, and Lunar Module, Falcon, respectively.
Once in lunar orbit, there was a slight delay when Falcon, with Scott and Irwin aboard, failed to undock, but then Worden found a plug had come loose and reconnected it allowing the manoeuvre to take place. They landed on July 30 in the Mare Imbrium (Sea of Showers) at the foot of the Apennine mountains, close to a winding canyon called Hadley Rille.
Scott and Irwin spent 18 hours 37 minutes exploring their surroundings during three EVAs, including peering into the canyon, and drove more than 28 km in their buggy.
After setting up ALSEP, they collected more than 77 kg of rock and soil to take home, including a sample from 3 metres beneath the surface, and a stone dubbed the Genesis rock because it is nearly as old as the Solar System.
For the benefit of TV viewers, Scott dropped a hammer and feather at the same time to show how both would fall at the same rate in a vacuum, just as Galileo had suggested centuries before. He also franked a postage stamp.
After leaving a small sculpture on the lunar surface to commemorate fallen astronauts, Scott and Irwin lifted off and returned to Endeavour, before the lander was once more crashed into the Moon. They also launched a small satellite from the CSM into orbit around the Moon.
On the way back to Earth, Worden made the first ever spacewalk in deep space to collect film cassettes from mapping cameras at the rear of the Service Module.
Despite the failure of one of its three main parachutes, Endeavour splashed down safely, on August 7, in the Pacific where the USS Okinawa was waiting to greet them.