The First Lunar Ranging Constraints on Gravity Sector SME Parameters

We present the first constraints on pure-gravity sector Standard-Model Extension (SME) parameters using Lunar Laser Ranging (LLR). LLR measures the round trip travel time of light between the Earth and the Moon. With 34+ years of LLR data, we have constrained six independent linear combinations of SME parameters at the level of $10^{-6}$ to $10^{-11}$. There is no evidence for Lorentz violation in the LLR dataset.