Each year, about 100 tonnes of defunct satellites, uncontrolled spacecraft, spent upper stages and discarded items like instrument covers are dragged down by Earth’s upper atmosphere, ending their lives in flaming arcs across the sky. This news was reported in a communiqué issued by the European Space Agency on 30 March.

While still in orbit, these and many other objects are tracked by a US military radar network, which shares the data with ESA, since Europe has no such capability of its own.

It is the task of ESA’s Space Debris team to look at these data and issue updates to ESA Member States and partner civil authorities around the globe.

In the words of Holger Krag, head of ESA’s Space Debris Office: ‘With our current knowledge and state-of-the-art technology, we are not able to make very precise predictions. There will always be an uncertainty of a few hours in all predictions – even just days before the re-entry, the uncertainty window can be very large. The high speeds of returning satellites mean they can travel thousands of kilometres during that time window, and that makes it very hard to predict a precise location of re-entry.’