Gravity Recovery and Interior Laboratory

United States space mission

Also known as: GRAIL

Written by

Erik Gregersen

Fact-checked by

Britannica Editors

History

Gravity Recovery and Interior Laboratory (GRAIL), U.S. space mission that consisted of two spacecraft, Ebb and Flow, designed to map the Moon’s gravitational field. GRAIL was launched from Cape Canaveral, Florida, on September 10, 2011. To conserve fuel, the spacecraft traveled very slowly, taking three and a half months to travel to the Moon. (Most other missions to the Moon took only a few days and thus burned fuel much faster.) Beginning on March 6,...