In early April of 1972, NASA was preparing to launch the Apollo program's 10th manned mission, Apollo 16—the fifth to actually land on the Moon. This mission would be the penultimate trip in the Apollo program, carrying astronauts John Young, Charles Duke, and Ken Mattingly to the Moon, with Young and Duke headed to the lunar surface while Mattingly remained in orbit. Apollo 16 was the second expedition to bring a Lunar Roving Vehicle (LRV) along. The astronauts spent more than 20 hours exploring the surface of the Moon, driving 16.6 miles in their LRV, gathering 210 pounds of samples, and setting up a package of instruments and experiments. On April 27, 1972, the crew splashed down safely in the Pacific Ocean, after 12 days away from Earth.