Image caption Russian scientists were hoping Phobos-Grunt would end a dreadful run of failure for Russia at Mars 8 Nov (GMT): The probe launched successfully on its Zenit rocket from the Baikonur Cosmodrome

It was dropped off 11 minutes later in an elliptical orbit some 345km (apogee) above the Earth

Two firings from the probe's hydrazine-fuelled cruise stage were planned over South America

The first, lasting 11.5 minutes, should have raised the orbit of Phobos-Grunt to 4,000km

A second burn, four hours into the mission, was to have sent the probe on a path to Mars

But Russian engineers later confirmed that neither burn took place

Controllers made only limited radio contact with the probe; mission recovery was not possible

Re-entry was predicted for mid-January; 20-30 fragments were expected to survive the descent

Orbital tracking reports suggest Russia's failed Mars probe, Phobos-Grunt, fell back to Earth on Sunday, to be destroyed over the Pacific.

Russian, US and European sources announced the demise of the craft within minutes of each other.

It brings to an end the sorry story of this mission, which promised to return rocky samples from Mars' biggest moon.

Instead, after its launch in November, Phobos-Grunt could not get more than 345km from Earth before stalling.

Once it became clear that controllers could not establish contact with the probe and diagnose its faults, a fiery dive back to Earth was inevitable.

The spacecraft's last orbit took it over Japan, and the Solomon Islands, and to the east of Australia and New Zealand. Conflicting reports then had the final re-entry point across a great swathe of the Southern Ocean. Certainly, it seems Phobos-Grunt was down and destroyed before it could have passed over South America.

The Russian space agency (Roscosmos) had estimated that no more than 200kg of the original 13-tonne launch mass of Phobos-Grunt would survive to the Earth's surface.

"According to information from mission control of the space forces, the fragments of Phobos-Grunt should have fallen into the Pacific Ocean at 1745 GMT," space forces spokesman Alexei Zolotukhin told the Interfax news agency.

The timing would have put the debris fall more than 1,000km west of Chile.

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.

With so much of the Earth's surface covered by water, there was every chance Phobos-Grunt would do the same.

The mission was built to land on Phobos, to scoop up rock and bring it back for study in Earth laboratories.

Such a venture would have yielded fascinating new insights into the origin of the 27km-wide object and the planet it circles.

Image caption The German Tira (Tracking and Imaging Radar) facility saw Phobos-Grunt during its last days

The mission was notable also because China's first Mars satellite, Yinghuo-1, was launched piggy-back on the main Russian spacecraft. It will have been destroyed along with Phobos-Grunt during the fall back to Earth.

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.

With their own opportunity to go to Mars now lost, the Russians may decide to put their future interplanetary efforts into joint ventures with the Americans and the Europeans. The Russians have an offer from the US and Europe to join the ExoMars missions to the Red Planet in 2016 and 2018.

Phobos-Grunt sat on the cruise stage that was supposed to take it to Mars. Attached also was the Yinghuo-1 satellite, China's first Red Planet mission

Most of this 2.5 tonnes of hardware would have burnt up in the atmosphere. The more-than-10-tonnes of fuel was expected to explode on re-entry

Phobos-Grunt's orbit around the Earth meant that it could only enter the atmosphere between the latitudes of 51.4 degrees North and South

Roughly one old satellite or rocket body falls to Earth every week, but at 13 tonnes Phobos-Grunt was one of the biggest, uncontrolled falls in years

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter