Simulating space-based observations of orbital debris with PhotSat

Abstract

The growing population of artificial objects in Earth orbit has increased the need for effective Space Surveillance and Tracking (SST) capabilities. This work investigates the potential contribution of PhotSat, a 16U CubeSat designed for all-sky photometric monitoring of astrophysical sources, to SST applications as a secondary product of its nominal scientific operations. The artificial space objects expected to cross the PhotSat field of view were simulated over three day survey using a mission simulator developed at the Universitat de Barcelona and the Institut d’Estudis Espacials de Catalunya together with SST simulation software developed by GMV. The resulting observations were analysed according to their orbital and observational characteristics, and their detectability was reassessed using a signal-to-noise ratio (SNR) model that accounts for the apparent magnitude and angular velocity of each object. The results were also compared with simulations of the Telescopi Fabra-ROA Montsec (TFRM), a ground-based optical telescope, performed using the same SST software framework. During the simulated period, 13,721 catalogue objects crossed the PhotSat field of view, of which 12,053 satisfied the nominal SNR ≥ 3 detectability criterion, corresponding to 43.74% of the 27,555 catalogued space objects considered in the simulation. The detectable population was dominated by Low Earth Orbit (LEO) objects, although objects from all the considered orbital regimes were observed. While the most objects are detected only a few times during the three day survey, with a median of 2 detections and a mean of 3.11 detections per object, the results suggest that PhotSat could provide a substantial number of incidental observations of artificial space objects during its nominal survey. These observations could complement those obtained by ground-based SST sensors and potentially contribute to tasks such as observation correlation and orbit determination, although further work based on the analysis of actual PhotSat images will be required to assess their practical applicability.