GRAIL: Gravity mapping the moon

The gravity recovery and interior laboratory (GRAIL) mission is the most recently selected NASA discovery mission. The GRAIL mission will utilize two spacecraft flying in tandem to provide a crust-to-core lunar gravity map. This lunar gravity map will provide important insight into the evolution of the Moon and other planetary bodies. The mission is currently in development with a September 2011 planned launch. The GRAIL mission concept is based on heritage from the GRACE instrument being used to map the gravity of the Earth. The spacecraft bus is based on a heritage system used successfully by lockheed-martin, the spacecraft contractor. This paper will discuss the science return expected from the GRAIL mission and provide an overview of the spacecraft system and mission design being developed to implement this exciting Discovery mission.