Follow this link to skip to                                      the main content


Text Size

Einstein's Theory of Relativity to be Tested
Albert EinsteinNASA is preparing to put Albert Einstein's Theory of General Relativity to the test. The Gravity Probe B (GP-B) spacecraft will use four ultra-precise gyroscopes to determine whether space and time are distorted by the presence of massive objects.

Albert Einstein conceived the Theory of General Relativity.

In order to carry out the mission, GP-B 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.

At Stanford University, ideas for Gravity Probe B began to take shape in 1960. A physics-engineering team was formed, led since 1962 by Francis Everitt, now GP-B principal investigator. So began a long process of design, analysis, and exploratory research funded by NASA and supported technically by NASA's Marshall Space Flight Center in Huntsville, Ala. The GP-B spacecraft was designed, integrated and tested by Lockheed Martin.

Computer-designed artist rendering of the Gravity Probe B space vehicleThe GP-B spacecraft arrived at Vandenberg Air Force Base July 10 from the Lockheed Martin Space Systems Facility in Sunnyvale, Calif. Launch is set for late 2003 aboard a Boeing Delta II launch vehicle.

Computer-designed artist rendering of the Gravity Probe B space vehicle

Low- and high-resolution JPEG image files of Gravity Probe B can be found at:

For more information on the Gravity Probe B mission, see: and
NASA's Marshall Space Flight Center and John F. Kennedy Space Center