1971

Roving on the Moon

James B. Irwin (1930–1991), David R. Scott (b. 1932), Alfred M. Worden (b. 1932)

NASA’s first three Apollo Moon-landing missions were designed to be short, “plant the flag” kinds of visits, in which the main goal was to land accurately and safely, and then return home. The astronauts performed a limited amount of scientific activities, but they had strict limits on their mobility and time spent on the surface.

That changed for the last three missions in the Apollo lunar-landing program, however. For Apollo 15, 16, and 17, NASA configured the gigantic Saturn V launch rocket so that it could carry nearly twice the mass to the Moon, enabling the astronauts to bring more supplies for a longer stay, to set up more experiments, and to substantially increase their mobility on the surface by bringing along a lunar roving vehicle. The last three Apollo missions were thus much more focused on lunar science; in many ways they were the first—and last—great human exploration voyages in space.

Apollo 15 was the first of these extended voyages, sent to explore a rugged region in the Apennine Mountains between the Mare Serenitatis and Mare Tranquillitatis impact basins. Lunar geologists wanted astronauts David R. Scott and James B. Irwin to use the lunar rover to explore a 60-mile-long (100 kilometers) ancient collapsed lava tube known as Hadley Rille that snaked along the flat floor of one of the Apennine valleys. On July 30, 1971, Scott and Irwin undocked the lunar module Falcon from the command module Endeavor, bidding a temporary farewell to pilot Alfred M. Worden, and executed a pinpoint landing, avoiding the steep mountain peaks, setting down only about 0.6 miles (1 kilometer) from the edge of Hadley Rille.

The Apollo 15 mission was a great success. Scott and Irwin spent nearly three days on the Moon, almost 19 hours of which was spent driving the rover to different sample and vista sites and collecting nearly 170 pounds (77 kilograms) of precious lunar rocks and soils. The samples confirmed the volcanic origin of Hadley Rille and helped to reveal that the Moon was volcanically active—including with what must have been spectacular fire-fountaining volcanic eruptions—as “recently” as 3.3 billion years ago.

Astronaut Jim Irwin, photographed by fellow astronaut Dave Scott, loading up their lunar rover with equipment unpacked from the lunar module Falcon. Scott and Irwin drove the rover nearly 17.5 miles (28 kilometers) in their exploration of the Hadley Rille lava tube.