Effect of Earth-Moon’s gravity on TianQin’s range acceleration noise

TianQin is a proposed space gravitational-wave detection mission using circular high Earth orbits. The geocentric concept has raised questions about the disturbing effect of nearby gravity field Earth-Moon system on highly-sensitive intersatellite ranging measurements. Here we examine issue through precision numerical orbit simulation with detailed gravity-field models. By evaluating range accelerations between distant free-falling test masses, study shows that majority Earth-Moon's disturbances are not in TianQin's frequency band above $10^{-4}$ Hz, and hence present no showstoppers to mission.