APOLLO 15 (IRW PL)

APOLLO 15 (IRW PL) is classified as:

Space & Earth Science

NORAD ID: 5377

Int'l Code: 1971-063D

Launch date: July 26, 1971
Source: United States (US)
Launch site: AIR FORCE EASTERN TEST RANGE (AFETR)

The Apollo 15 subsatellite (PFS-1) was a small satellite released into lunar orbit from the Apollo 15 Service Module. Its main objectives were to study the plasma, particle, and magnetic field environment of the Moon and map the lunar gravity field. Specifically it measured plasma and energetic particle intensities and vector magnetic fields, and facilitated tracking of the satellite velocity to high precision. A basic requirement was that the satellite acquire fields and particle data everywhere on the orbit around the Moon. A virtually identical subsatellite was also deployed by Apollo 16. The Moon's roughly circular orbit about the Earth at ~380000 km (60 Earth radii) carried the subsatellite into both interplanetary space and various regions of the Earth's magnetosphere. The satellite orbited the Moon and returned data from 4 August 1971 until January 1973. The exact date and place of decay are unknown.