Abstract

Laser pulses fired at retroreflectors on the Moon provide very accurate ranges. Analysis yields information on Earth, Moon, and orbit. The highly accurate retroreflector positions have uncertainties less than a meter. Tides on the Moon show strong dissipation, with Q = 33 ± 4 at a month and a weak dependence on period. Lunar rotation depends on interior properties; a fluid core is indicated with radius ∼20% that of the Moon. Tests of relativistic gravity verify the equivalence principle to ±1.4 × 10^-13, limit deviations from Einstein’s general relativity, and show no rate for the gravitational constant Ġ/G with uncertainty 9 × 10^-13/year.