|Gravity Recovery and Interior Laboratory|
|Launch vehicle||Delta II|
|Launch date|| 2011 September
The Gravity Recovery And Interior Laboratory (GRAIL) mission is a dual spacecraft effort designed to determine the structure of the lunar interior and to advance understanding of the thermal evolution of the Moon. The primary science objectives are to: map the structure of the crust and lithosphere; understand the Moon's asymmetric thermal evolution; determine the subsurface structure of impact basins and the origin of mascons, ascertain the temporal evolution of crustal brecciation and magmatism; constrain deep interior structure from tides; and place limits on the size of the possible inner core. The GRAIL mission was selected through the NASA Discovery Program.