The Last Captured Images before the Demise of Aeolus
Aeolus, a wind-profiling mission by the European Space Agency (ESA), recently made headlines as it completed its four-year, eleven-month, and six-day orbit around Earth. However, what captured the attention of scientists and space enthusiasts alike was the brief period when Aeolus became space debris. In its final three hours, the satellite began to tumble as it was buffeted by Earth’s atmosphere. This article delves into the details of Aeolus’s journey and its controlled reentry, highlighting the importance of space safety.
International regulations exist to mitigate the risks associated with space debris. Satellites are expected to be removed from orbit within 25 years once their mission is complete. For low-altitude missions like Aeolus, the process is expedited as they are assisted by Earth’s atmosphere, which quickly brings them back home. In July, Aeolus underwent a groundbreaking assisted reentry that not only reduced the risk of falling debris by a factor of 150 but also shortened the time it spent uncontrolled in orbit by a few weeks. This decrease in uncontrolled time minimizes the risk of collisions with other satellites in the crowded space environment.
The moment Aeolus transitioned into space debris came after the execution of its final command on July 28, 2023, at 17:43 CEST. From that point onward, the Flight Control Team lost all communication and control over the satellite. Months of preparation and critical operations led up to this moment, and the team had done everything they could to ensure a safe transition. The satellite was then passivated, or turned off, and handed over to ESA’s Space Debris Office, which precisely tracked its final descent.
The ground track of Aeolus’s reentry showcased the Fraunhofer Institute in Germany as an ideal location for observing the event. Utilizing their 34-m TIRA radar antenna, researchers tracked Aeolus for approximately four minutes at around 18:20 CEST. These observations confirmed that the final burn had gone as planned and that the now “dead” satellite had entered the expected elliptical orbit, with a minimum altitude of 120km. By analyzing the orbit information, a new estimate for Aeolus’s reentry time was calculated, aligning with the planned ground track.
The last images captured of Aeolus showed the satellite whole, just two hours away from disintegrating in Earth’s atmosphere over Antarctica, away from populated areas. At approximately 20:40 CEST, Aeolus transformed into a fireball, resembling a temporary shooting star in the atmosphere. Aeolus Mission Manager Tommaso Parrinello expressed his appreciation for the sustainable and responsible approach taken during the mission’s final stages. The team guided its return as much as possible, and these images serve as a farewell to a mission whose legacy will endure.
The safe disposal of satellites and the responsible management of space debris are crucial for the sustainability of space activities. Aeolus’s controlled reentry is an example of the ongoing efforts to ensure space safety. By adhering to international regulations and employing innovative techniques, missions like Aeolus can complete their objectives while minimizing the risks posed by space debris. As humanity continues to explore and utilize space, it’s imperative that we prioritize the responsible management of our orbital environment to safeguard future missions and preserve the vast potential of outer space.
