In September 2011, the GRAIL mission launched two unmanned spacecraft to the Moon, which entered into lunar orbit on December 31, 2011 and January 1, 2012. They orbited the Moon until December 17, 201
In September 2011, the GRAIL mission launched two unmanned spacecraft to the Moon, which entered into lunar orbit on December 31, 2011 and January 1, 2012. They orbited the Moon until December 17, 201
