Japan Station: the Japanese Experiment Module (Kibo) was added to the station during Space Shuttle assembly flights in 2008. The space probe "Akatsuki" was launched May 20, 2010, and achieved orbit around Venus on December 9, 2015. Japan's plans in space exploration include: developing the "Mercury Magnetospheric Orbiter" to be launched in 2018; and building a moon base by 2030. On September 14, 2007, it launched lunar explorer SELENE (Selenological and Engineering Explorer) on a H-IIA (Model H2A2022) carrier rocket from Tanegashima Space Center. SELENE is also known as Kaguya, after the lunar princess of "The Tale of the Bamboo Cutter".
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