SELENE lunar exploration missions or lunar outpost construction on the Moon between 2018 and 2025. SELENE SELENE (; Selenological and Engineering Explorer), better known in Japan by its nickname , was the second Japanese lunar orbiter spacecraft following the Hiten probe. Produced by the Institute of Space and Astronautical Science (ISAS) and the National Space Development Agency (NASDA), the spacecraft was launched on September 14, 2007. After successfully orbiting the Moon for a year and eight months, the main orbiter was instructed to impact on the lunar surface near the crater Gill on June 10, 2009. The orbiter's nickname, Kaguya, was
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