Multiband photometric observations of GEO objects through Sloan filters

Abstract

With the precipitous growth of the population of objects in Earth's orbit, all major space agencies and companies have made space surveillance a priority to ensure the safety of space missions. With the application of the methods of space surveillance, this article aims to characterize the population of objects in the Geostationary Earth Orbit (GEO) using optical measurements across multiple spectral bands. The study takes place in a context in which the existence of space debris poses a continuous hazard to the operations of active satellites in GEO. Photometric observations of GEO objects using Sloan filters were obtained with SCUDO, a small-aperture telescope part of the Sapienza network. Observations are divided into categories, including 11 objects: rocket bodies (4), defunct satellites (3), and active satellites (4). The spectral response of these objects has been analyzed leading to the identification of a photometric signature which was repeated for two Eutelsat satellites observed under same conditions. All the observed targets resulted in a lower magnitude in the near-infrared. Color indexes also indicate that they are redder than the Sun. This is particularly evident for SL-12 rocket bodies, whose g’-z’ reaches 1.5.