2007 in spaceflight 2007 in spaceflight The year 2007 contained several significant events in spaceflight, including a Chinese ASAT test, the launches of the US Phoenix and Dawn missions to study Mars and Asteroid belt respectively, Japan's Kaguya Lunar orbiter, and the first Chinese Lunar probe, Chang'e 1. The internationally accepted definition of a spaceflight is any flight which crosses the Kármán line, 100 kilometres above sea level. The first recorded spaceflight launch of the year occurred on 10 January, when a PSLV, launched from the Satish Dhawan Space Centre, placed four spacecraft into low Earth orbit. One of these spacecraft was SRE-1,
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