Radar images reveal damage on Europe's doomed ERS-2 satellite during final orbits

The European Space Agency has released images showing some of the final orbits experienced by a European satellite before its fiery reintroduction to Earth's atmosphere.

The school-bus-sized European Remote Sensing (ERS-2) satellite reentered our planet's atmosphere over the Pacific Ocean on Feb. 21, almost 29 years after its launch in April 1995.

The Tracking and Imaging Radar (TIRA) at the Fraunhofer Institute for High Frequency Physics and Radar Techniques FHR in Germany observed the spacecraft in the days and hours ahead of its demise.

Related: Big, doomed satellite seen from space as it tumbles towards a fiery reentry on Feb. 21 (photos)

Space debris is becoming a bigger and more visible issue as time goes on. The combined radar images from TIRA — in which the color represents radar echo intensity, not temperature — notably show the buckling and bending of one of ERS-2's solar arrays occuring earlier than expected. This could have implications in terms of understanding how spacecraft behave as they reenter the atmosphere.

"When predicting a satellite's reentry trajectory, experts treat it as one rigid object until almost the very end. If ERS-2's solar array was loose and moving independently a day early, it may have caused the satellite to interact with the atmosphere in ways we did not expect," said an ESA statement.

Precise data regarding the reentry is now being assessed. Of particular interest is whether the buckling of the array was related to the slightly-later-than-predicted reentry sequence. The outcome could help improve forecasts of future natural reentries, according to ESA.

ERS-2 made a "natural," or uncontrolled, atmospheric reentry. Its fuel and batteries were depleted to lower the risk of debris-creating explosions in orbit; it was, rather, left to be pulled back to Earth by gravity and atmospheric influence. Space agencies and companies are now moving to controlled reentries, whereby operators deliberately deorbit a spacecraft over sparsely populated areas of Earth such as the South Pacific Ocean.