NASA is going to do this experiment based on Einstein's theory of relativity. For more information on the 'Gravity probe B' as it is known, please look here (not that it fills you in a great deal). The best bit I guess is this 1 paragraph out of three:
"The experiment will check, very precisely, tiny changes in the direction of spin of four gyroscopes contained in an Earth satellite orbiting at 400-mile altitude directly over the poles. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are warped by the presence of the Earth, and, more profoundly, how the Earth's rotation drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe."We wish them all the success.
- Art Neuro