Nasa’s Gravity Recovery and Interior Laboratory (GRAIL) is planning its final launch preparations ahead of its 8 September 2011 launch onboard a Delta II rocket from Cape Canaveral Air Force Station in Florida, US.

The Gravity Recovery and Interior Laboratory twin spacecraft will go on a nine month mission to explore the structure of the lunar interior from crust to core and analyse the thermal evolution of the moon.

The twin spacecraft, GRAIL A and B, will fly a circuitous route to lunar orbit taking 3.5 months and covering approximately 2.6 million miles for GRAIL-A, and 2.7 million miles for GRAIL-B.

The spacecraft were built by Lockheed Martin Space Systems in Denver, US, and JPL will manage the GRAIL mission.

GRAIL’s launch period opens 8 September 2011 and extends until 19 October 2011.