Spectral Measurements of Geosynchronous Satellites During Glint Season

Anita N. Dunsmore, Joshua A. Key, Ryan M. Tucker, Evan M. Weld, Francis K. Chun, Roger D. Tippets
2017 Journal of Spacecraft and Rockets  
Operational communication geosynchronous satellites are typically large structures with long solar panels that maintain a stable attitude relative to the earth and sun. During the equinox periods of the year, the geometry of the satellite, sun and an earth observer is favorable for a condition to occur called a glint, or specular reflection. It is presumed that the glint is caused by the satellite solar panels and has been observed in the past using broadband photometry techniques. In this
more » ... , we present the first observations of a glint from two satellites, Wildblue-1 and DirecTV-12, as measured across the visible spectrum using slitless spectroscopy techniques. It is clear from the results that the wavelength where the glint maximum occurs can sometimes move toward the blue end of the spectrum relative to the time periods before and after the glint. This is consistent with the presumption that the solar panels are the main cause of the satellite glint. It is also clear from the spectral data that there is small-scale spatial and temporal structure associated with a glint that may not be seen in broadband photometry. We believe that these small-scale features can be exploited to discern satellite features such as solar panel orientation and secondary mechanical structures.
doi:10.2514/1.a33583 fatcat:26rh7jex3rhr3nsrwtkrf52pya