NASA's GRAIL spacecraft successfully launched from Cape Canaveral Air Force Station, Florida, at 9:08 EDT on September 10, 2011. As depicted in the artist's concept on the right, the twin spacecraft, GRAIL-A and GRAIL-B, will work in tandem to study the lunar interior from crust to core, and to advance understanding of the thermal evolution of the Moon. Credit: NASA/JPL-Caltech/Thom Baur, United Launch Alliance