European Space Agency's Satellite Concludes Its Three-Decade-Long Mission

The European Space Agency's ERS-2 satellite gracefully concluded its three-decade-long mission with a natural atmospheric reentry over the North Pacific Ocean on Wednesday, February 21, as per the ESA. Launched on April 21, 1995, ERS-2, alongside its sibling ERS-1, has been a game-changer in Earth observation, providing vital data on land surfaces, ocean temperatures, the ozone layer, and polar ice extent.

Despite being originally planned for only three years, the ERS satellites far exceeded expectations. However, concerns about orbital debris led ESA to decide on ERS-2's controlled deorbiting in 2011. Over the years, the satellite's altitude gradually decreased, reaching a critical point of about 80 km on February 21, 2024, triggering its natural reentry.

ESA's Director of Earth Observation Programmes, Simonetta Cheli said, “The ERS satellites have provided a stream of data which has changed our view of the world in which we live. They have provided us with new insights on our planet, the chemistry of our atmosphere, the behaviour of our oceans, and the effects of mankind's activity on our environment – creating new opportunities for scientific research and applications.”

An international collaboration, including the Inter-Agency Space Debris Coordination Committee and ESA's Space Debris Office, diligently monitored this process. Tim Flohrer, Head of ESA's Space Debris Office, explained that uncontrolled atmospheric reentry is a standard method for retiring space objects, with similar-sized objects reentering the atmosphere multiple times each year.

“In the 67 years of spaceflight, thousands of tons of artificial space objects have reentered the atmosphere. Pieces that make it to the surface have only very rarely caused any damage and there has never been a confirmed report of a human injury,” Mr Flohrer said.

ERS-2's reentry was labelled “natural” because all its fuel was depleted during deorbiting in 2011, ensuring it couldn't be controlled during its descent. The atmospheric drag became the guiding force, leading to a safe re-entry over the North Pacific Ocean, without any reported damage to property.

While natural reentries have been common, ESA is now embracing a more sustainable approach with the 'ESA Zero Debris' initiative. The agency aims to minimise space debris and encourage safer reentry methods. Controlled reentries, directing satellites to less populated areas, are now standard practice.

ERS-2's legacy is significant, having provided valuable data for over 15 years. ESA is committed to environmentally friendly disposal methods for ageing satellites, aligning with its broader vision for sustainable space activities. The mission has laid the groundwork for subsequent Earth observation missions, contributing to weather forecasting, climate monitoring, and enhancing our understanding of our planet.