Determination of nutation coefficients from lunar laser ranging

Abstract

It was just July 20, 1969 when the first retro-reflector for Lunar Laser Ranging (LLR) was deployed on the Moon by the Apollo 11 crew. From this day on, LLR is carried out to measure the distance between Earth and Moon. The complete set of observations is analysed and various parameters of the Earth-Moon system are determined by least-squares adjustment. Because of the long time span of data, long-term lunisolar nutation coefficients of the 18.6-year period (and the precession rate) can be determined well. But also other periods (182.62-day, 9.3-year, 365.26-day) can be fitted. The nutation coefficients were determined from LLR based on the models for precession and nutation according to the IAU Resolution 2006 and compared to the MHB2000 model of Mathews et al. (2002). In this paper, the corresponding preliminary results are discussed. © Springer-Verlag Berlin Heidelberg 2012.