Testing Einstein's theory: Camden, Ala., native plays role in NASA Gravity Probe B mission
Marshall Space Flight Center, Huntsville, Ala.
News release: 05-008
Camden, Ala., native Reginald Cobb can make a rare claim -- that he helped test Albert Einstein's General Theory of Relativity.
Cobb, a 1977 graduate of Wilcox County High School in Camden, 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.
As the Engineering Directorate liaison for the Science Directorate at NASA's Marshall Space Flight Center in Huntsville, Ala, Cobb coordinated engineering manpower and resources to support the Gravity Probe B program.
Gravity Probe B launched April 20, 2004, 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.
Gravity Probe B's four ultra-precise gyroscopes monitors their alignment changes in relation to the mission's guide star, IM Pegasus. One of the anticipated changes is only 42 milliarcseconds after one year, an angle so small that if someone climbed a slope of 42 milliarcseconds for 100 miles, their altitude would be only one inch higher than when they started.
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.
Considered among the most profound enigmas of physics, these factors have far-reaching implications for the nature of matter and the structure of the universe. Einstein proposed the General Theory of Relativity in 1916, approximately 80 years before the advent of technology capable of testing his theory.
Gravity Probe B's 12-month science-data acquisition period will be followed by a two-month post-science period for calibrations. A one-year period is planned for scientific analysis of the data.
Cobb has a bachelor's degree in mechanical engineering from the University of Alabama in Tuscaloosa.
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: