Jiri Silha, Comenius University Bratislava; Daniela Bartková, Comenius University Bratislava; Juraj Toth, Comenius University Bratislava; Tomáš Paulech, Comenius University Bratislava; Matej Zigo, Astros Solutions s.r.o.; Tobias Lips, Hyperschall Technologie Göttingen GmbH; Patrik Kärräng, Hyperschall Technologie Göttingen GmbH; Stefan Loehle, Institute for Space Systems, University of Stuttgart; Clemens Müller, Institute for Space Systems, University of Stuttgart; Fabian Zander, University of Southern Queensland; Byrenn Birch, University of Southern Queensland; Ranjith Ravichandran, University of Southern Queensland; Gerard Armstrong, University of Southern Queensland; Beatriz Jilete, GMV for ESA (Space Safety Programme/Space Debris Office); Stijn Lemmens, ESA/ESOC Space Debris Office
Keywords: re-entry, airborn, observation, modeling
Abstract:
Airborne observation campaigns are currently the main means to monitor spacecraft, cargo ships, upper stages, or other compact space objects as they demise during re-entry [1]. The main objective is to investigate the physics of the disintegration and fragmentation processes that accompany these objects during the final stages of their lifecycle. While re-entries are becoming an increasingly common phenomena, the processes related to them—such as parent body breakup, ablation, fragment cloud formation, and, consequently, the survivability of the fragments and their impact locations—are still not well understood. One way to improve our knowledge is to collect data on such events using various methods, including direct imaging, spectroscopy, and narrow-band photometry. A daylight airborne campaign organized by European Space Agency was conducted on September 8, 2024, to observe the re-entry of the Salsa satellite, one of four satellites from the former ESA space weather Cluster mission. Salsa, with its highly eccentric orbit, was a suitable observation target because a sufficiently precise prediction of its entry location was possible, allowing for an airborne observation. Furthermore, the Cluster satellite re-entered at high speed, making it one of only a few of such entries being observed from an airborne campaign, e.g., WT1190F entry in 2015.
This target selection also provides an opportunity for repeated experiments, focusing on the re-entry of the remaining three Cluster satellites in October 2025 and in August/September 2026. A team of nine researchers from four institutions across three countries deployed 26 scientific instruments on board to detect the event. In this work, we focus on the reconstruction of the re-entry event, crucial event timestamps, and object dynamics based on measurements acquired by the Comenius University instrument DMK 33UX183 20 MP with Sony IMX183 1” CMOS sensor equipped with Tamron C-Mount,1.1″, F1.8, 16 mm lens and M55 K filter (770 nm) selected to isolate the potassium (K) radiative emission. A total of 15 seconds of footage was recorded, when the object is visible on the recording, during which several bright flashes were identified. These flashes could potentially be linked to high-energy events, such as fragmentation. Furthermore, we reduced data using available calibration measurements to extract the position of the satellite in the sky, as well as its brightness. The Moon was used as a reference object as it was present in the field of view of the camera during data acquisition. We reconstruct the dynamics of the object and, consequently, the potential fragment cloud using the available footage, along with the plane’s pointing direction and telemetry data. The extracted data were then compared to high-fidelity simulations conducted using the ESA SCARAB model.
Date of Conference: September 16-19, 2025
Track: Space Domain Awareness