Japanese Lunar Exploration Program the LUNAR-A mission, and a small data relay satellite. SELENE-3 aims to return about 100 grams of samples from the Moon surface. It will be launched around 2020. However, due to financial issues JAXA is currently facing, this mission may be merged into the option-3 of SELENE-X. SELENE-X will be launched in the late 2010s, in view of Japan’s participation in Humans Lunar Activities foreseen. The SELENE-X may perform either of the following demonstrations: There are other options under study, and will be determined after the international exploration strategy has been clarified. MELOS (Mars Exploration with Lander-Orbiter Synergy) is a
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