ENGLAND: In a landmark endeavor, scientists at the European Space Agency (ESA) are preparing for a “first-of-its-kind” operation to guide a dead satellite safely back to Earth through a controlled re-entry.
The satellite in question is the renowned Aeolus spacecraft, a wind-monitoring marvel that has revolutionized meteorology. At a press conference held on Wednesday (July 19), ESA scientists unveiled their ambitious plan to guide Aeolus’ return to Earth, with the operation scheduled to take place on Friday, July 28.
ESA’s ambitious plan
Described as the “impossible mission” due to its unique challenges and cutting-edge technological requirements, the Aeolus satellite achieved a historic feat in 2018 as the first spacecraft to measure Earth’s winds from space.
For five remarkable years, it contributed invaluable data to Europe’s leading meteorology centers, significantly improving global weather forecasts. However, its operational life came to an end in April this year, and the satellite was finally powered off in early July.
Since then, Aeolus has been descending toward Earth at an accelerating pace, falling from an altitude of 200 miles (320 kilometers) at a rate of approximately 0.62 miles (1 kilometer) per day. This freefall presented a unique opportunity for scientists to attempt a guided re-entry, an unprecedented feat in the history of spaceflight.
Aeolus’ original design did not include provisions for a guided re-entry, and under normal circumstances, the satellite would have naturally returned to Earth.
However, utilizing the remaining fuel onboard, ESA scientists at the Space Operations Centre in Germany will execute a series of maneuvers to steer Aeolus to the optimal point for re-entry.
The guided return operation commences on Monday, July 24, as the satellite reaches an altitude of 174 miles (280 kilometers) above Earth. Initial maneuvers will lower Aeolus to 155 miles (250 km), placing it in an elliptical orbit around the planet.
Three days later, further maneuvers will be performed to reduce its altitude even more, to approximately 93 miles (150 km). The final critical maneuver is scheduled for Friday, July 28, when Aeolus’ altitude will be further decreased to about 62 miles (100 km) above Earth’s surface.
Within five hours of this final maneuver, the guided re-entry of Aeolus will occur, ensuring precise control over its descent. During its descent, Aeolus will be continuously tracked by ground-based radar systems, enabling ESA experts to monitor and guide its trajectory.
The satellite is expected to re-enter over the Atlantic Ocean. However, despite the meticulous planning, not all parts of Aeolus will survive the re-entry process.
Holger Krage, head of ESA’s Space Debris Office, revealed that only around 20% of the satellite is expected to survive re-entry, with the remaining 80% burning up in Earth’s atmosphere.
As Aeolus disintegrates around 50 miles (80 kilometers) above Earth, any surviving debris will be scattered across a vast area of the ocean. You might wonder about the purpose of this guided re-entry operation if there are no plans to recover the surviving components of Aeolus.
The significance lies in its role in developing controlled re-entry maneuvers for satellites, especially in an era with an increasing number of spacecraft in space.
With such a significant amount of human-made space debris, about 100 tons of it returning to Earth each year, controlled re-entry becomes essential to ensure the safety of space operations and activities.
Although the likelihood of damage or injury from falling debris is currently low, future spacecraft must be designed with controlled re-entry in mind, adhering to new rules for space.
The groundbreaking guided return to Earth of Aeolus serves as a pioneering initiative to establish protocols for controlled re-entry of spacecraft, contributing to a safer and more sustainable approach to space exploration.