Spectral Analysis of Borowiec SLR Data For Spin Determination Of Geodetic Satellite EGP

Borowiec 10 Hz Satellite Laser Ranging (SLR) station is capable to measure spin of the Japanese Experimental Geodetic Satellite (EGP). Spectral analysis of 391 passes measured from March 10, 1994 to November 27, 2009 gives frequency signal representing the 3^rd and the 6^th harmonics of the satellite spin rate. Analysis of this signal, corrected for the apparent effects, indicates en exponential slowing down of the satellite: the spin rate decreases according to the equation f = 671.115907 ・ exp(-4.08324 x 10^-5 ・ D) [mHz], where D is a day after launch. More than 15 years of the SLR measurements allowed investigating the initial spin rate of the satellite fini = 671.116, RMS = 0.203 [mHz] (initial spin period T_ini = 1.49006, RMS = 0.0007 [s]).