Apollo 15 was the ninth crewed flight of NASA's Apollo program. It was the fourth mission to land on the surface of the Moon and the first J-Type mission. Apollo 15 was launched on July 26, 1971. Alfred Worden stayed in orbit in the Command Module, Endeavour, while the Lunar Module, Falcon, landed at Hadley Base, with David Scott and James Irwin. The astronauts used the first Lunar Roving Vehicle to travel on the Moon. This vehicle was specially designed to work in a vacuum, with a wide range of temperatures across rough ground. They travelled a distance of on the Moon. They spent three days (66 hours, 55 minutes) on the Moon. They were able to collect a lot of rock samples, including a core sample from at least deep.