Estimation for Ballistic Coefficient of a Nano-Satellite HAYATO (KSAT) from Trajectory Data

摘要

The ballistic coefficients of a nono-satellite at low altitude of less than 300 km are estimated from variations of satellite trajectories. The satellite analyzed is HAYATO (KSAT), which was developed by a collaboration of Kagoshima University and local venture companies and was launched on May 20, 2010 UT as a piggy-back satellite of H-IIA 17. After deployment at 300 km, the satellite rapidly decreased its altitude due to strong atmospheric drag and re-entered the atmosphere on mid July, 2010. A mean value of estimated ballistic coefficients is 3.22×10~(-2)m~2/kg with a maximum of 6.78×10~(-2) m~2/kg and a minimum of 1.12×10~(-2) m~2/kg during entire period from the deployment to the re-entry of the satellite. The mean value is relatively large comparing with a theoretical B value of 2.31×10~(-2)m~2/kg given with typical satellite parameters. We have analyzed the influence of the exospheric temperature and the space environment to the estimated ballistic coefficient, but found no clear relation.