Slava+Turyshev

Analysis of Lunar Laser Ranging (LLR) data provides science results: gravitational physics and ephemeris information from the orbit, lunar science from rotation and solid-body tides, and Earth science. __Science from the orbit__: Sensitive tests of gravitational physics include the equivalence principle, limits on the time variation of the gravitational constant G, and geodetic precession. The equivalence principle test is used for an accurate determination of the parameterized post-Newtonian parameter beta. Lunar ephemerides are a product of the LLR analysis used by current and future spacecraft missions. The analysis is sensitive to astronomical parameters such as orbit, masses, and obliquity. The dissipation-caused acceleration in orbital longitude is -25.7 "/cent2, dominated by tides on Earth with a 1% lunar contribution. The soon to be operational Apache Point LLR observatory would provide for almost 50 times increase in range accuracy, reaching a mm level. With these advances LLR provides for a very sensitive test of general relativity. __Lunar science__: lunar rotational variation has sensitivity to interior structure, physical properties, and energy dissipation. The second-degree lunar Love numbers are detected; k2 has an accuracy of 11%. Lunar tidal dissipation is strong and its Q has a weak dependence on tidal frequency. A fluid core of about 20% the moon's radius is indicated by the dissipation data. Evidence for the oblateness of the lunar fluid-core/solid-mantle boundary is getting stronger. This would be independent evidence for a fluid lunar core. __Earth science__: Station positions and motion, Earth rotation variations, and precession are determined from analyses. APOLLO (the Apache Point Observatory Lunar Laser-ranging Operation) is a new effort in lunar laser ranging that uses the Apollo-landed retroreflector arrays to perform tests of gravitational physics. APOLLO achieved its first range return in October, 2005, and began its science campaign the following spring. The strong signal (>2500 photons in a ten minute period) translates to one-millimeter random range uncertainty, constituting at least an order-of-magnitude gain over previous stations. One-millimeter range precision will translate into order-of-magnitude gains in our ability to test the weak and strong equivalence principles, the time rate of change of Newton's gravitational constant, the phenomenon of gravitomagnetism, the inverse-square law, and the possible presence of extra dimensions.
 * Lunar Laser Ranging and Tests of General Relativity **
 * Slava G. Turyshev **
 * Jet Propulsion Laboratory, California Institute of Technology, **** Pasadena ****, CA 91109 **

This talk will emphasize the open frontier that exists in solar system tests of general relativity, briefly discussing technologies that can extend our knowledge of gravity by orders-of-magnitude. The work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration.