NASA's two lunar-bound spacecraft, vacuum-packed

As seen in the photo, taken April 29, technicians installed lifting brackets prior to hoisting the 200-kilogram (440- pound) Grail-A spacecraft out of a vacuum chamber at Lockheed Martin Space Systems, Denver. Along with its twin Grail-B, the Grail-A spacecraft underwent an 11-day-long test that simulated many of the flight activities they will perform during the mission, all while being exposed to the vacuum and extreme hot and cold that simulate space.

The Grail mission is scheduled for launch late this summer. The Grail-A and Grail-B spacecraft will fly in tandem orbits around Earth's moon for several months to measure its gravity field in unprecedented detail. The mission will also answer longstanding questions about the moon and provide scientists with a better understanding of how Earth and other rocky planets in the solar system formed.

Provided by JPL/NASA