NASA's Twin GRAIL spacecraft lift off at 9:08 a.m. EDT on Saturday, September 10, 2011, on a mission to explore the moon in unprecedented detail.

The twin GRAIL Spacecraft finally lifted off today from Cape Canaveral at 13:08 UTC. The ultimate destination for the spacecraft - The Moon!

The Gravity Recovery and Interior Laboratory (GRAIL) is an American lunar science mission in NASA's Discovery Program, which will use high-quality gravitational field mapping of the Moon to determine its interior structure.

This is the launch of NASA's GRAIL spacecraft September 10, 2011 as seen from Jetty Park in Port Canaveral, 3 miles away.

Video shot from Press Site #1 at Cape Canaveral Air Force Station. NASA's twin lunar Gravity Recovery and Interior Laboratory (GRAIL) spacecraft lifted off from Cape Canaveral Air Force Station in Florida at 9:08 a.m. EDT Saturday to study the moon in unprecedented detail.

The spacecraft were launched aboard a United Launch Alliance Delta II rocket. GRAIL mission controllers acquired a signal from GRAIL-A at 10:29 a.m. GRAIL-B's signal was eight minutes later. The telemetry downlinked from both spacecraft indicates they have deployed their solar panels and are operating as expected.

GRAIL-A is scheduled to reach the moon on New Year's Eve 2011, while GRAIL-B will arrive New Year's Day 2012. The two solar-powered spacecraft will fly in tandem orbits around the moon to measure its gravity field. GRAIL will answer longstanding questions about the moon and give scientists a better understanding of how Earth and other rocky planets in the solar system formed.