ERS-1 and Envisat both suffered major failures that left them drifting uncontrolled through LEO.

BBC: 'Urgent need' to remove space debris

The measurements were recorded via a radar altimeter onboard the European Space Agency's (Esa) Envisat satellite.

BBC: Arctic ice thickness 'plummets'

The agency's Envisat satellite shows part of the Larsen Ice Shelf, which lies on a peninsula south of Chile, has decreased from 3, 463 square kilometers (1, 337 square miles) in March 2002 to 1, 670 square kilometers (645 square miles) today, a change the European Space Agency blames on warmer temperatures.

CNN: Satellite documents thinning ice shelf