NASA's Gravity Probe B mission, also known as GP-B, will use four ultra-precise gyroscopes to test Einstein's theory that space and time are distorted by the presence of massive objects. To accomplish this, the mission will measure two factors -- how space and time are warped by the presence of the Earth, and how the Earth's rotation drags space-time around with it.

Stanford University in Stanford, Calif., and Lockheed Martin performed the testing. Shipped by road transport, the vehicle arrived July 10 at Vandenberg for pre-launch operations in anticipation of a launch in late 2003.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the GP-B program. NASA's prime contractor for the mission, Stanford University, conceived the experiment and is responsible for the design and integration of the science instrument, as well as for mission operations and data analysis. Lockheed Martin, a major subcontractor, designed, integrated and tested the spacecraft and some of its major payload components.

The erection of the Boeing Delta II launch vehicle on Space Launch Complex 2 (SLC-2) at Vandenberg Air Force Base is currently scheduled to begin on September 15 with erection of the first stage. Attachment of the nine strap-on solid rocket boosters is scheduled to occur in sets of three on September 16 - 18. The second stage is planned for mating atop the first stage on September 19. Gravity Probe B will be transported from the spacecraft hangar to SLC-2 on October 29 and hoisted atop the second stage. The Delta II fairing will be installed around the spacecraft on November 5, part of final prelaunch preparations. The launch is the responsibility of NASA's John F. Kennedy Space Center in Florida.

NOTE TO EDITORS:

Low- and hi-resolution JPEG image files of Gravity Probe B can be found at: http://einstein.stanford.edu/gen_int/pict_gal/nav_map_image.html

For more information on the Gravity Probe B mission, see: http://einstein.stanford.edu/ and http://www.gravityprobeb.com/