Takao Endo, Mitsubishi Electric Corporation – Information Technology R&D Center, Hitomi Ono, Mitsubishi Electric Corporation – Information Technology R&D Center, Mana Hosokawa, Mitsubishi Electric Corporation – Information Technology R&D Center, Toshiyuki Ando, Mitsubishi Electric Corporation – Information Technology R&D Center, Takashi Takanezawa, Mitsubishi Electric Corporation – Communication Systems Center, Osamu Hashimoto, Gunma Astronomical Observatory
Keywords: Space Situational Awareness, GEO, Satellite, characterization, Non-resolved Object, Spectroscopy, Ground-base observation
Abstract:
The spectroscopic observation is potentially a powerful tool for understanding the Geostationary Earth Orbit (GEO) objects. We present here the results of an investigation of energy spectra of GEO satellites obtained from a groundbased optical telescope. The spectroscopic observations were made from April to June 2016 with the Gunma LOW resolution Spectrograph and imager (GLOWS) at the Gunma Astronomical Observatory (GAO) in JAPAN. The observation targets consist of eleven different satellites: two weather satellites, four communications satellites, and five broadcasting satellites. All the spectra of those GEO satellites are inferred to be solar-like. A number of well-known absorption features such as H-alpha, H-beta, Na-D,water vapor and oxygen molecules are clearly seen in thewavelength range of 4,000 – 8,000 Å. For comparison, we calculated the intensity ratio of the spectra of GEO satellites to that of the Moon which is the natural satellite of the earth. As a result, the following characteristics were obtained. 1) Some variations are seen in the strength of absorption features of water vapor and oxygen originated by the telluric atmosphere, but any other characteristic absorption features were not found. 2) For all observed satellites, the intensity ratio of the spectrum of GEO satellites decrease as a function of wavelength or to be flat. It means that the spectral reflectance of satellite materials is bluer than that of the Moon. 3) A characteristic dip at around 4,800 Å is found in all observed spectra of a weather satellite. Based on these observations, it is indicated that the characteristics of the spectrum are mainly derived from the solar panels because the apparent area of the solar cell is probably larger than that of the satellite body.
Date of Conference: September 19-22, 2017
Track: Poster