A 5,057-pound (2,294-kilogram) satellite, the European Space Agency’s (ESA) Earth-observing ERS-2, is anticipated to reenter Earth’s atmosphere on Wednesday morning, with a 15-hour window of uncertainty, according to the ESA’s Space Debris Office. The agency, in collaboration with an international surveillance network, is closely monitoring the satellite, providing live updates on its website.
The ERS-2 satellite, having depleted its fuel, is expected to break apart approximately 50 miles (80 kilometers) above Earth’s surface, with the majority of fragments burning up in the atmosphere. While some fragments may reach the planet’s surface, the ESA assures that they won’t contain harmful substances and are likely to fall into the ocean.
Solar activity, influenced by the sun’s 11-year cycle, known as solar maximum, introduces unpredictability to the exact timing of the satellite’s reentry. The increased solar activity has been accelerating reentries, as witnessed with the ESA’s Aeolus satellite in July 2023.
Launched on April 21, 1995, the ERS-2 satellite, alongside its twin ERS-1, was a groundbreaking Earth-observing satellite, collecting vital data on polar caps, oceans, land surfaces, and monitoring natural disasters. Despite its retirement in 2011, the data gathered by ERS-2 continues to be utilized today.
The ESA’s decision to deorbit the satellite in 2011 aimed to prevent adding to space junk in orbit. ERS-2 underwent 66 deorbiting maneuvers in July and August of that year, depleting its fuel and gradually spiraling closer to Earth. The controlled reentry is expected within 15 years of the satellite’s retirement.
Despite the uncertainty surrounding solar activity, the ESA emphasizes that the risk of an individual being injured by space debris is extremely low, with odds less than 1 in 100 billion per year. This statistic is about 1.5 million times lower than the risk of a person being killed in a home accident, providing reassurance amid the satellite’s imminent reentry.