section_path: Late 20th century–21st century uncrewed crash landings/GRAIL (U.S.)
section_name: GRAIL (U.S.)
paragraph_text: GRAIL (U.S.)
  
  The GRAIL mission consisted of two small spacecraft: GRAIL A (Ebb), and GRAIL B (Flow). They were launched on 10 September 2011 on board a Delta II rocket. GRAIL A separated from the rocket about nine minutes after launch, and GRAIL B followed about eight minutes later. The first probe entered orbit on 31 December 2011 and the second followed on 1 January 2012. The two spacecraft impacted the Lunar surface on 17 December 2012.