Fraunhofer FHRs radar tracking of ESAs ERS-2 satellite revealed essential structural changes before re-entry, improving understanding of satellite disintegration and assisting in more accurate future predictions. Credit: Fraunhofer FHRESAs ERS-2 satellite effectively reentered Earths environment after almost 30 years in orbit, with its final minutes tracked by Germanys Fraunhofer Institute. The unforeseen detachment of its solar range offered vital data for improving satellite reentry predictions.Following an extremely effective mission and almost 30 years in orbit, ESAs ERS-2 reentered Earths environment at approximately 18:17 CET (17:17 UTC) on February 21, 2024. Forecasting the specific time and area of ERS-2s natural reentry was made harder by the lack of brand-new observations of the satellite during its final transformations around Earth.Tracking ERS-2s Final MomentsThis GIF combines some of the last images of ERS-2 tumbling through the sky. They were captured by the Tracking and Imaging Radar (TIRA) at the Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR in Germany.TIRAs 34-m antenna tracked the satellite as it passed overhead for a few minutes on each of February 19, 20, and 21. The last session took place around 8:00 CET on February 21, still approximately 10 orbits before reentry.ERS-2 reentry– how and why is it occurring? Credit: ESAAnalyzing ERS-2s Solar Array DetachmentBy comparing the images from the 3 TIRA tracking sessions, we can see that ERS-2s solar array was currently coming loose and no longer strongly attached to the remainder of the satellite the day before re-entry. When predicting a satellites reentry trajectory, specialists treat it as one rigid object up until almost the very end. If ERS-2s solar selection was loose and moving separately a day early, it may have caused the satellite to engage with the environment in ways we did not expect.Experts are now evaluating the data. If the buckling of the solar variety is related to the reality that ERS-2s reentry took location a little later than predicted, this research study could help enhance our forecasts of future natural reentries.ESA thanks Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR for providing measurements of their area observation radar TIRA, in close collaboration with the German Space Situational Awareness Center, GSSAC.The color in these images represents radar echo intensity and not temperature level.
