Lucy Zimmerman, US Air Force Academy; Sequoia Chun, US Air Force Academy; Marco Pirozzoli, United States Air Force; Michael Plummer, USAF Academy; Francis Chun, U.S. Air Force Academy; David Strong, USAFA/DFP;
Keywords: GEO Satellite Characterization, Non-Resolved Object Characterization, Data Fusion, Spectroscopy, Polarimetry
Abstract:
The Department of Physics at the United States Air Force Academy has been developing new methods of characterizing space objects using unresolved optical imagery. In the past, we have observed geosynchronous (GEO) communication satellites either photometrically, spectrally, or through polarized filters, but we have never observed these satellites in a near simultaneous fashion through more than one of those optical modes. For this research, we use two modes of analysis, polarimetry and spectroscopy, to characterize several GEO communications satellites which cannot be resolved with ground-based optical imagery due to their size and distance. Our observations are made using a 16-inch telescope outfitted with a 9-position filter wheel populated with broadband photometric filters (Johnson-Cousins B, V, and R; and a blue-blocking exoplanet filter), linear polarization filters (0 degrees, 45 degrees, 90 degrees, 135 degrees), and a 100 lines per millimeter diffraction grating. The spectral measurement is made using the diffraction grating, while the polarization measurement is made using the polarization filters. This research compares the spectra and polarization signatures collected from solar reflectance off of known GEO communication satellites during the Spring 2020 equinox. These observations were made both during a glint and outside of a glint period, and show very different signatures which presumably are due to reflectance from different spacecraft surfaces. More detailed analysis and correlation of a satellites spectral and polarization signatures are clearly warranted, and in the future should also be related to physical properties of the satellites.
Date of Conference: September 15-18, 2020
Track: Non-Resolved Object Characterization