A two-tonne “Grandfather satellite” launched in 1995 is due to fall to Earth when it makes an uncontrolled descent through the atmosphere.
The satellite, known as European Remote Sensing 2 (ERS-2), was launched in 1995 as part of a plan to develop technology to monitor the Earth’s ozone layer, a new ability at the time. It was launched alongside a sister satellite that is still in orbit.
The European Space Agency has said that the satellite will most likely burn up as it descends, but that some parts may make it through. If they do, the agency has said the likelihood of them hitting populated areas is low.
Speaking to the BBC about the potential risk, the ESA’s Earth Observation Ground Segment Department Mirko Albani said: “None of the elements that might re-enter the atmosphere are radioactive or toxic.”
Dr Ralph Cordey added that ERS-2 and its sister satellite were the “grandfathers of observation in Europe” and that the ERS programme was “where it all started”.
While the destruction of ERS-2 will be uncontrolled and the location of any surviving debris uncertain, its ending has been planned well in advance.
In 2011, its final fuel reserves were used to lower it from an altitude of 487.5 miles (780km) down to 356.25 miles (570km) with engineers anticipating at the time that it would be dragged to Earth over a 15-year period.
When the spacecraft makes contact with the atmosphere, the component believed to have the highest chance of survival is the British-made carbon fibre antenna for the radar system.
ERS-2’s descent has highlighted another issue, the number of derelict or dead satellites in orbit around the Earth. In recent years, space agencies have been introducing rules recommending how long a spacecraft can stay in orbit.
Some private organisations are now deciding to clean up the skies themselves. Elon Musk’s SpaceX has said it will bring down around 100 of its 5,400 satellites because of a fault which could increase the probability of a failure in the future.
The Secure World Foundation released a statement calling for more action to be taken on derelict satellites in space. They said: “The accumulation of massive derelict objects in low Earth orbit (LEO) continues unabated; 28 percent of the current long-lived massive derelicts were left in orbit since the turn of the century.
“These clusters of uncontrollable mass pose the greatest debris-generating potential to the thousands of newly deployed satellites that are fuelling the global space economy.”
