Apollo:. Next Generation Lunar Laser Ranging

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 (up to 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 test new regimes of gravity and/or Lorentz violation.