The National Aeronautics and Space Administration (NASA) has decided to proceed with one of the most sophisticated attempts yet to test Einstein's gravitational theory. The proposed Gravity Probe B instrumented spacecraft program has been included in the agency's Fiscal Year 1985 budget request, but only after considerable in-depth evaluation, both scientific and financial. Budgeted at $1.8 million for study in fiscal year 1984, it has been proposed at $ 3–5 million in fiscal year 1985 under the Physics and Astronomy Research and Analysis section of NASA's budget.
The idea of Gravity Probe B is to test the general theory of relativity by examining in fine detail changes of the precision parameters of an earth orbiting gyroscope (Science, 223, 30, 1984). The gyroscope will be a cryogenically cooled, highly sensitive instrument specifically designed for the measurements. The engineering concepts have been under development for decades, and although the effects being sought are subtle, the experiment is considered to be within the realm of feasibility.