Old Satellite to Burn Up Over Pacific in ‘Targeted’ Re-Entry First

AFP/APP

Paris: After 24 years of diligently studying Earth’s magnetic field, a satellite will mostly burn up over the Pacific Ocean on Sunday during a “targeted” re-entry into the atmosphere, a first for the European Space Agency (ESA) as it seeks to reduce space debris.

Since its launch in 2000, the Salsa satellite has played a key role in studying the magnetosphere, Earth’s magnetic shield that protects the planet from solar winds. Without this shield, life on Earth would be impossible.

According to the ESA, Salsa’s return marks the first-ever “targeted” re-entry for a satellite, meaning it will fall back to Earth at a precise time and place, though it will not be controlled as it re-enters the atmosphere.

Ground teams have performed a series of manoeuvres with the 550-kilogram (1,200-pound) satellite to ensure it burns up over a remote, uninhabited area of the South Pacific, off the coast of Chile.

This re-entry is possible due to Salsa’s unusual oval-shaped orbit, which ranges from 130,000 kilometres (80,000 miles) at its furthest point to just a few hundred kilometres from Earth at its closest. Bruno Sousa, head of the ESA’s inner solar system missions operations unit, explained that ensuring the satellite came within roughly 110 kilometres during its final orbits was crucial for the targeted descent.

“When a satellite starts entering the atmosphere at around 100 kilometres above sea level, intense friction with atmospheric particles causes it to disintegrate,” Sousa said. However, small fragments, about 10 percent of its original mass, may survive and fall to Earth.

Fear of ‘Cascading’ Space Junk

The ESA aims to pinpoint the re-entry location of Salsa, which is about the size of a small car, to within a few hundred meters. A plane will fly at an altitude of 10 kilometres to monitor the satellite’s burn-up and track any falling debris.

Salsa is one of four satellites from the ESA’s Cluster mission, which is concluding. The other three satellites are scheduled for re-entry in 2025 and 2026. The ESA hopes to use these re-entries to better understand which materials do not burn up during atmospheric re-entry, with the goal of designing future satellites that completely disintegrate.

Concerns about space debris have been growing as more dead satellites and mission fragments orbit the Earth. Last year, the ESA signed a “zero debris” charter for its missions starting in 2030.

Benjamin Bastida Virgili, the ESA’s space debris system engineer, highlighted two main risks: in-orbit collisions with space debris, which could trigger a “cascading” effect and create more debris, and the re-entry of old debris, which happens almost daily.

While the odds of space debris injuring someone on Earth are less than one in a hundred billion, the ESA is committed to designing satellites that fully burn up to eliminate any risk to the population. According to the ESA, the risk of being injured by space debris is 65,000 times lower than the chances of being struck by lightning.