Mission Summary
PFS-2 was the second Particles and Fields Subsatellite, released into lunar orbit by the Apollo 16 crew to keep measuring the Moon’s magnetic and particle environment after the astronauts left. Nearly identical to the satellite Apollo 15 had deployed the year before, it was ejected on April 24, 1972, shortly before the crew fired their engine for the journey home.
Trouble with the Apollo Command and Service Module’s main engine forced a change of plan. Rather than the intended higher orbit, the crew had to release PFS-2 into a low path only about 100 kilometers above the surface, where the Moon’s uneven gravity field would pull it down far sooner than planned.
The satellite circled the Moon for just 34 days, a fraction of its one-year design life, before crashing onto the surface on May 29, 1972. Even so, its low altitude let it gather valuable close-up measurements of the lunar environment that its higher-flying predecessor could not.
Sources and notes can be found on the Sources page.
