Adam W. Masters, US Air Force Academy; Kody A. Wilson, United States Air Force Academy; Francis K. Chun, United States Air Force Academy; David M. Strong, Strong EO Imaging, Inc.; Casey P. Schuetz-Christy, Millennium Engineering & Integration Co
Keywords: Falcon Telescope Network, Photometry, GEO Satellites, Space Situational Awareness, Space Domain Awareness, DirecTV 10
Abstract:
With the vast amount of space objects currently in orbit, the future of Space Domain Awareness (SDA) depends on the ability to quickly identify unknown space objects. One way to identify geosynchronous satellites is by comparing their photometric light curves for a given night to known light curves for many satellites. Before this method can be used, effects on the light curve such as satellite degradation of the satellite must be considered. The Falcon Telescope Network (FTN) includes 0.5-meter telescopes in geographically diverse locations. These locations are Colorado (6), Pennsylvania (1), Chile (1), Germany (1), and Australia (2). These identical telescope systems are designed to be operated both manually and automatically with Johnson-Cousin photometric filters (B, V, R) in a filter wheel. The USAFA-16 telescope is a 0.4-meter telescope located in USAF Academy, CO. This telescope is designed to be operated manually with photometric filters (B, V, R).
Data was analyzed from the 2013 AFRL/RV GOLDS I and II campaigns as well as data collected from the USAFA-16 telescope and Falcon Telescope Network (FTN) in 2021-2022. Both datasets include observations of DirecTV 10 that were taken during the 2021-2022 glints seasons. The data from the GOLDS I and II campaigns consisted of over 15,000 processed images with each giving the satellites time of observation, longitudinal phase angle (LPA), and an estimate of its instrument magnitude. The GOLDS data uses only the red and blue filter. The USAFA-16 and FTN data taken in 2021-2022 includes approximately 2600 process images of DirecTV 10 taken in the red and blue filters. The FTN locations used were Durango, CO (FLC), La Junta, CO (OJC), Sterling, CO (NJC), and Grand Junction, CO (CMU). The FTN images were processed to build a light curve consisting of the instrument magnitude and LPA. The image processing was accomplished using a modified version of a previously created cadet program. The program modifications found the object centroid for each raw image with minimal user input by using centroids found in previous images. This program also determines a reliability parameter for each individual satellite images instrument magnitude by comparing the total pixel area of that satellites images to the average area through the night. By doing this, uneven distribution patterns such as a star streak going through the object or ice buildup on the lens can be accounted for in the result. This will provide a better sense as to why some data points may deviate significantly when compared to the others.
Using the processed information from 2013 and 2021-2022, features were identified for DirecTV 10 that are consistent with both datasets and are not due to nightly variations as well as identified features that appeared to change between the two datasets. If distinguishing features that occur on a nightly basis in 2013 do not occur in 2021-2022 this would preclude the use of these features as a basis for comparison when attempting to identify an unknown satellite today.
Date of Conference: September 27-20, 2022
Track: Non-Resolved Object Characterization