[denphone]

http://www.bbc.co.uk/news/science-environment-16491457

The failed Russian Mars probe, Phobos-Grunt, continued its descent to Earth on Saturday, losing hundreds of metres in height every hour.

By 23:00 Saturday (GMT), the 13-tonne spacecraft was circling the planet at a mean altitude of 147km.

It is likely to impact the thicker parts of the atmosphere and burn up sometime late on Sunday, according to orbital tracking experts.

The Russian space agency says little of the probe will survive to the surface.

It calculates no more than 200kg in maybe 20-30 fragments.

Precisely where on the Earth's surface - and when - this material could impact is impossible to say, however. There are huge uncertainties in forecasting the final moments of a re-entry.

This is the third high-profile spacecraft re-entry in four months, following the return in September of the American UARS satellite and the German Rosat telescope in October. Both fell over the ocean.

The mission was supposed to be the most exciting Russian space science venture in decades - an audacious bid to scoop up rocky fragments from the Martian moon Phobos and bring them back for study in Earth laboratories.

The Russians have had a torrid run of space failures recently, leading the head of the country's space agency to wonder even if saboteurs were at work.

Western countries, which use Russian rockets to launch their satellites, are just worried though that some systematic failures have started to appear in what has traditionally been a highly regarded space industry.