15 was the fourth mission in which humans walked on the lunar surface.
15 launched on 26 July 1971 on a Saturn V from Pad 39A at Kennedy
30 July 1971 Commander David R. Scott and LM pilot James B. Irwin
landed in the Hadley Rille/Apennines region of the Moon while CM
pilot Alfred M. Worden continued in lunar orbit.
and Irwin made three moonwalk EVAs totaling 18 hours, 35 minutes.
During this time they covered 27.9 km, collected 76.8 kg of rock
and soil samples, took photographs, and set up the ALSEP and performed
other scientific experiments. This was the first mission which employed
the Lunar Roving Vehicle which was used to explore regions within
5 km of the LM landing site. After the final EVA Scott performed
a televised demonstration of a hammer and feather falling at the
same rate in the lunar vacuum.
LM took off from the Moon on 2 August and the astronauts returned
to Earth on 7 August.
of the spacecraft, the first of the Apollo J-series missions, was
excellent for most aspects of the mission. The primary mission goals
of exploration of the Hadley-Appenine region, deployment of the
ALSEP and other scientific experiments, collection of lunar samples,
surface photography, and photography and other scientific experiments
from orbit, and engineering evaluation of new Apollo equipment,
particularly the rover, were achieved.