The Gravity Recovery and Interior Laboratory (GRAIL) mission, conducted by NASA, aimed to study the Moon's gravitational field with the goal of understanding its internal structure and history. The first GRAIL satellite was successfully placed into lunar orbit on December 31, 2011, marking a key achievement for NASA's lunar exploration efforts. The mission consisted of two spacecraft, named Ebb and Flow, which utilized precision measurements of the Moon's gravitational pull to detect variations in gravity as they orbited around it.

The launch took place from Cape Canaveral Air Force Station in Florida on September 10, 2011, with the primary objective of sending the twin satellites into a series of orbits around the Moon. Upon reaching lunar orbit, the satellites were to gather data that would reveal the thickness of the Moon's crust and mantle as well as other critical information about its composition. These insights contribute to our overall understanding of the Moon's formation, including the processes that shaped the early solar system.

The GRAIL mission, part of NASA's Discovery Program, followed previous lunar missions aimed at both robotic exploration and human landing. The data collected from the GRAIL spacecraft provided essential clues about the Moon's geological history, suggesting that it had a more complex interior than initially thought. By mapping the gravitational anomalies on the lunar surface, the mission offered researchers unique opportunities to piece together the Moon's evolution since its formation billions of years ago.