Evaluation of a proposed test of the Weak Equivalence Principle using Earth-orbiting bodies in high-speed co-rotation

The proposed space mission Galileo Galilei (GG) utilizes Earth-orbiting test masses in high-speed co-rotation to test the Weak Equivalence Principle (EP). This paper presents the results of a technical evaluation of the proposal, as it was presented in September 1996. Investigation of the dynamics and control aspects reveals that the experiment is limited by the imperfections inherent in the practical implementation of the required drag-free control and stabilizing servo forces. The net consequence is a degradation of the EP measurement sensitivity by many orders of magnitude compared with the proposers' expectations.