Satellite Laser-Ranging as a Probe of Fundamental Phys

Satellite laser-ranging is successfully used in space geodesy, geodynamics and Earth sciences; and
to test fundamental physics and specific features of General Relativity. We present a confirmation to
approximately one part in a billion of the fundamental weak equivalence principle (“uniqueness of
free fall”) in the Earth’s gravitational field, obtained with three laser-ranged satellites, at previously
untested range and with previously untested materials. The weak equivalence principle is at the
foundation of General Relativity and of most gravitational theories.