By Helen Briggs BBC News science reporter

The rocket launched from the Plesetsk Cosmodrome in Russia

Russian space officials have identified the rocket fault that led to the loss of Europe's Cryosat satellite.

A problem with the onboard flight-control system of the newly built upper stage of the rocket was to blame.

The Russian state commission report clears the launcher for future use.

It was grounded on 8 October when the mission to map the Earth's ice sheets fell into the ocean shortly after lift-off from Plesetsk in Russia.

The �90m (135m euro) satellite was riding atop a Rockot launch vehicle, a former military rocket modified by the addition of a newly manufactured third stage.

1- 1502 GMT: Cryosat launches from Plesetsk, northern Russia 2 -1504: First stage separation 3 - 1508: Second stage separation due - but scientists believe that a software error meant this did not happen. The rocket plunged back to Earth when its fuel ran out.

The Russian Failure Investigation State Commission says a set of measures is being implemented to prevent a recurrence of the incident.

"We confirm from the information we have from the State Commission that there was a problem with the software flight-control system in the Breeze upper stage of the launcher," European Space Agency spokesperson, Simonetta Cheli, told the BBC News website.

"This problem led to a failure of the Breeze upper stage to generate the command to shut down the second stage engine."

The error meant that separation of the rocket's second and third stages did not occur, denying the satellite the final boost it needed to reach orbit and causing it to nosedive into the sea.

A board set up by the rocket operator, Eurockot, is to review the findings of the State Commission next week.

The British scientist who proposed the mission, Prof Duncan Wingham, is calling for the spacecraft to be re-built.