Gobbledegook messages from Mars probe test Nasa engineers

Those plucky individuals involved in the failed Beagle 2 mission could be forgiven a self-satisfied smirk. Nasa admitted last night that it had lost intelligent contact with its Mars rover.

Instead of sending back intelligent signals from the Red Planet, the United States space agency's Mars Exploration Rover, called Spirit, has transmitted nothing but nonsense since Wednesday night.

Engineers at Nasa's Jet Propulsion Laboratory in California are working round the clock to try to find a solution, hoping that it is a relatively straightforward glitch.

Pete Theisinger, Spirit's project manager, said Nasa was very worried. He said: "This is a serious problem. This is an extremely serious anomaly."

A Nasa spokesman said engineers were hoping that Spirit can still receive commands from Earth so that they can correct whatever has caused the malfunction in transmissions. He said: "It could just have gone into fault mode. It's not what we would have wanted to happen. Obviously we're concerned but it's too early to say what's happened."

Spirit's failure to transmit properly had temporarily ended its mobile exploration of the Red Planet and the search for evidence of water. Spirit is one half of a $820m (£455m) mission to Mars. Its twin rover, called Opportunity, is scheduled to land tomorrow.

Nasa's worst fear is that Spirit's mission could end in failure like two thirds of the missions to Mars over the past 40 years, including Britain's Beagle 2 space probe. This has given the planet a reputation for being the "Bermuda triangle" of the solar system.

Initially, Nasa thought the communications failure might have been due to a thunderstorm near the Tidbinbilla tracking station in Canberra, Australia, which was being used on Wednesday night to receive and transmit signals. The storm appeared to have weakened the signals which take nearly 10 minutes to travel the 56 million kilometres (35 million miles) to Mars.

Nasa last heard from Spirit as it prepared to continue its work examining its first rock, just a few metres from its lander. Since then, Spirit has transmitted just a few beeps to Earth in response to attempts to communicate with it. It has also skipped several scheduled communications opportunities, either directly with Earth or by way of two Nasa satellites in orbit around Mars.

When Spirit was hailed a success last week, President George Bush announced plans to take Americans back to the Moon. Mr Bush said the move represented a "new course for the American space programme". At that time Spirit's success contrasted sharply with Beagle 2, which landed on Mars on Christmas Day. The probe landed to much fanfare but controllers in Britain were unable to communicate with it.

Scientists postponed a search for Beagle 2 due to have started yesterday and said they would try to communicate with the craft this weekend. Controllers stopped trying to raise the British Mars lander on 12 January. It was hoped Beagle 2 would be forced into an emergency communication mode that ensured its transmitter was kept on for most of the Martian day. This would give its mother ship, the Mars Express orbiter, the best chance of making contact.

The original radio silence period ended yesterday, just before a fly-past by Mars Express but mission scientists decided not to hail the lander immediately.

A statement from the Beagle 2 team said: "We are erring on the side of caution as we cannot confidently predict the precise ending of the 10-day slot. This is because the absolute accuracy of the timer on Beagle 2 could have been affected by the temperature on Mars, making the clock run slightly faster or slower than predicted."