Testing Newtonian gravity in space

We propose to measure the universal constant of gravity G in space by means of a small scale planetary system in geosynchronous orbit; test particle satellites of different nuclear composition and with different distances from the central mass would allow one to check possible variations with material and distance. With current technology G can be measured with a relative accuracy of 10⁻⁵ or better depending on the capability of controlling some perturbations which act at the level of 10⁻⁶ (i.e. ≈ 10⁻¹¹ cm s⁻²; however, particular dynamical configurations mutuated from celestial mechanics should allow detection of differential effects with composition and distance (if any) to at least 10⁻⁶. Distance variations will be detected only if acting on a distance scale of 10 m.