Japanese Lunar Exploration Program km on opposite sides of the lunar body. The penetrators were to have been braked by a small rocket at an altitude of 25 km, then free fall to the surface. They were designed to withstand a collision speed of 330 meters per second to deeply penetrate the lunar regolith. Once the penetrators are deployed, the LUNAR-A spacecraft was mission-planned to maneuver to an orbital altitude of 200 km above the lunar surface. The craft was to have carried a monochromatic imaging camera with a resolution of 30 m. It was to be Japan's first large scale lunar probe. (Hiten
Lunar orbit to become the nominal circular when the LM made its return rendezvous with the CSM. But the effect was overestimated by a factor of two; at rendezvous the orbit was calculated to be by . Study of the mascons' effect on lunar spacecraft led to the discovery in 2001 of "frozen orbits" occurring at four orbital inclinations: 27°, 50°, 76°, and 86°, in which a spacecraft can stay in a low orbit indefinitely. The Apollo 15 subsatellite PFS-1 and the Apollo 16 subsatellite PFS-2, both small satellites released from the Apollo Service Module, contributed to this discovery. PFS-1 ended up