ESA’s First “Targeted” Re-Entry Marks a Milestone in Space Debris Management
In a groundbreaking event for space exploration and debris management, a satellite that has spent 24 years studying Earth’s magnetic field will make a “targeted” re-entry into the atmosphere on Sunday. The European Space Agency (ESA) has meticulously planned for the satellite to mostly disintegrate over the remote South Pacific Ocean.
The Salsa satellite’s legacy
Launched in 2000, the Salsa satellite has been instrumental in deepening our understanding of Earth’s magnetosphere—the magnetic shield that protects our planet from solar winds, making it habitable. Salsa’s targeted re-entry will be a first for the ESA, representing a significant step toward reducing space debris.
“This mission has been crucial in studying the magnetosphere, and its targeted re-entry is a testament to our commitment to responsible space exploration,” said Bruno Sousa, head of the ESA’s inner solar system missions operations unit.
Planning the re-entry
The ESA has conducted a series of maneuvers to ensure the 550-kilogram (1,200-pound) satellite burns up over an uninhabited region of the South Pacific, off the coast of Chile. Salsa’s unique oval-shaped orbit, which ranges from 130,000 kilometers (80,000 miles) to just a few hundred kilometers, made this possible.
“It was crucial that Salsa came within roughly 110 kilometers during its last two orbits,” Sousa explained. “Then immediately on the next orbit, it would come down at 80 kilometers, where we have the highest chance for it to be fully captured and burned.”
The science behind the burn
As Salsa begins its re-entry around 100 kilometers above sea level, intense friction with atmospheric particles will cause it to disintegrate. However, some fragments may still make it back to Earth. The ESA aims to pinpoint the re-entry location to within a few hundred meters and will have a plane flying at an altitude of 10 kilometers to monitor the event.
The Future of space debris management
Salsa is one of four satellites in the ESA’s Cluster mission, with the remaining three scheduled for similar re-entries in 2025 and 2026. The ESA hopes to learn from these events to develop materials that completely burn up upon re-entry, reducing the risk of space debris.
“Understanding which materials do not burn up in the atmosphere will help us build future satellites that can be totally evaporated by this process,” Sousa noted.
The growing concern of space junk
The issue of space debris is becoming increasingly urgent. Last year, the ESA signed a “zero debris” charter for its missions from 2030. According to Benjamin Bastida Virgili, the ESA’s space debris system engineer, space junk poses two main risks.
“One is the risk of operational satellites colliding with space debris, creating a cascading effect that generates more debris,” Virgili said. “The second is when old debris re-enters the atmosphere, which happens almost daily.”
Designing satellites that completely burn up in the atmosphere will mitigate these risks, ensuring “no risk for the population,” Virgili emphasized. While the chance of space debris injuring someone on the ground is extremely low—less than one in a hundred billion—the ESA is committed to further reducing this risk.
As the ESA continues to innovate in space debris management, the successful targeted re-entry of the Salsa satellite marks a significant milestone. It sets the stage for a future where responsible space exploration and safety go hand in hand, ensuring the long-term sustainability of our activities in space.
