Mission Summary
GRAIL, short for Gravity Recovery and Interior Laboratory, was a NASA mission that used twin spacecraft, named Ebb and Flow, to reveal the hidden structure of the Moon. Launched on September 10, 2011, the two spacecraft flew together around the Moon, precisely measuring tiny changes in the distance between them caused by variations in lunar gravity.
By mapping these gravitational differences, the Gravity Recovery and Interior Laboratory mission created the most detailed gravity map of the Moon ever made. This allowed scientists to look beneath the lunar surface and study the Moon’s crust, deep interior, and formation history.
GRAIL helped determine the thickness of the lunar crust and showed that the Moon’s interior was more fractured than previously believed. After completing their science mission, Ebb and Flow were deliberately crashed into the lunar surface on December 17, 2012.
Sources and notes can be found on the Sources page.
