By BBC News Online science editor Dr David Whitehouse

The mysterious faint signals thought to have come from the stricken Mars Polar Lander (MPL) spacecraft as it lay crippled on the frozen Martian soil were just man-made terrestrial interference.

That is the conclusion of scientists who have used the world's most sensitive radio telescopes to try to detect the signals from MPL.

They were following up work done by a team from the Stanford University who said they might have picked up faint beeps from the lander in December and January.

MPL was last heard from as it was descending to the Martian surface on 3 December. It failed to make contact after landing and scientists speculate that it may have crashed into a rock or fallen into a hole.

Radio scientists at Nasa's Jet Propulsion Laboratory have now completed their detailed analysis of data taken by Stanford's radio telescope on 4 January. They say that the suspect signal is more likely to be of terrestrial origin and not from Mars Polar Lander.

End of project

"We saw something in the 4 January data that had all the earmarks of a signal and we felt we had to check it out. In parallel, we started to perform analysis to determine if the signal came from Mars," said Richard Cook, project manager for Mars Polar Lander at JPL.

"Based on the latest results, it is unlikely that we will attempt to listen again."

Astronomers had long ago given up all hope that MPL would radio back to Earth scientific data.

But they had hoped that a few bits of information would be sent back to enable them to determine what had befallen MPL.

But now all hope is lost of ever contacting the spaceprobe. It will have run out of power and be frozen in the desolate tundra near the Martian south pole.