NASA’s twin GRAIL spacecraft were delivered by its builder Lockheed Martin (NYSE: LMT) to Kennedy Space Center, Fla., on May 20. The two vehicles will undergo four months of final testing and processing in preparation for launch from Cape Canaveral Air Force Station on a United Launch Alliance Delta II Heavy launch vehicle in early September.

The lunar orbiters will fly 30 miles (50 kilometers) above the surface of the moon in precision formation to determine the structure of the lunar interior from crust to core and to advance understanding of the thermal evolution of the moon.

“It has taken a great deal of dedication and hard work from the entire team to bring us to this moment,” said John Henk, GRAIL program manager at Lockheed Martin Space Systems Company. “Building two spacecraft simultaneously brought some challenges, but I’m proud that we are delivering them to the launch site on schedule and under budget.”

“It has taken a great deal of dedication and hard work from the entire team to build two spacecraft simultaneously and achieve this delivery milestone on schedule and under budget,” said John Henk, GRAIL program manager at Lockheed Martin Space Systems Company. “We look forward to preparing for launch and achieving total mission success on this important program.”

Both of the 440-pound (200 kilograms) spacecraft were transported on an Air Force C-17 transport plane in an environmentally controlled container. The plane departed from Buckley Air Force Base near Denver and touched down at 7:40 p.m. EDT at Kennedy Space Center’s Shuttle Landing Facility. The spacecraft were then transported to Astrotech Space Operations in Titusville, Fla., for final launch processing.

The Gravity Recovery And Interior Laboratory (GRAIL) mission will fly nearly-identical spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. The mission will also answer longstanding questions about Earth’s moon, and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the GRAIL mission. The Massachusetts Institute of Technology, Cambridge, is home to the mission’s principal investigator Dr. Maria Zuber.

The GRAIL mission is part of the Discovery Program managed at NASA’s Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA’s Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

Headquartered in Bethesda, Md., Lockheed Martin is a global security company that employs about 126,000 people worldwide and is principally engaged in the research, design, development, manufacture, integration and sustainment of advanced technology systems, products and services. The Corporation’s 2010 sales from continuing operations were $45.8 billion.

More information about the GRAIL mission can be found at: http://solarsystem.nasa.gov/grail and http://www.lockheedmartin.com/grail