PROPOSED HIGH-ACCURACY GYROSCOPE TEST OF GENERAL-RELATIVITY AND THE SEARCH FOR A MASSLESS SCALAR FIELD

A high-accuracy orbiting relativity experiment is described. A pure unsupported gyroscope in a spinning drag-free satellite at ambient temperatures with conventional optical instrumentation can measure relativity drifts with errors as low as 30.1 arc sec/yr, an improvement of 102103 over the current GP-B experiment. Recent theoretical work has suggested that the post-Newtonian parameter 1-1/BD might lie in the range 10-4 10-8, signaling the presence of a massless scalar field. The experiment described here could measure to an accuracy between 10-7 and 10-8; for the highest accuracies, the measurement depends critically on future microarcsecond astrometry or a two-gyro version of the experiment. © 1995 The American Physical Society.