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For release: 11-08-04
Release #: 04-275  

Testing Einstein's Theory: Aurora native plays role in NASA Gravity Probe B mission

Photo description: Carter

As a major NASA mission begins science operations, Aurora, Mo., native Dr. James M. Carter can make a rare claim — that he helped test Albert Einstein's General Theory of Relativity.

Photo: Carter (NASA/MSFC)

Carter, an Aurora native and 1962 graduate of Aurora Junior-Senior High School, is a member of NASA's Gravity Probe B team. Also known as GP-B, the experiment will test Einstein's theory that space and time are slightly distorted by the presence of massive objects such as planets and stars.

Specializing in optical physics at NASA's Marshall Space Flight Center in Huntsville, Ala., Carter monitored the performance of the science telescope used for pointing the space vehicle at its guide star -- a process critical to the program's acquisition of science data.

Gravity Probe B launched April 20 from Vandenberg Air Force Base, Calif., aboard a Boeing Delta II launch vehicle. Orbiting 400 miles above Earth, the Gravity Probe B space vehicle circles the globe every 90 minutes, crossing over both poles.

The experiment will measure, very precisely, tiny changes in the direction of spin of four gyroscopes contained in the spacecraft satellite. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system.

These measurements will enable scientists to track two effects -- how space and time are very slightly warped by the presence of the Earth, and how the Earth's rotation very slightly drags space-time around with it.

Einstein proposed the General Theory of Relativity in 1916, approximately 80 years before the advent of technology capable of testing this aspect of his theory.

Gravity Probe B's 12-month science-data acquisition period will be followed by a month post-science period for calibrations. By 2005 the Gravity Probe B mission will be complete, and a one-year period is planned for scientific analysis of the data.

Carter has a bachelor's degree in electrical engineering and a master's and doctorate in physics from the University of Missouri-Rolla. NASA's Gravity Probe B program is managed at the Marshall Space Flight Center.

NASA's prime contractor for the mission, Stanford University in Stanford, Calif., conceived the experiment and is responsible for the design of the science instrument, as well as for mission operations and data analysis. A major subcontractor, Lockheed Martin of Sunnyvale, Calif., designed and built the spacecraft as well as portions of the science instrument.

More information about the Gravity Probe B mission is available at:


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