h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Nasa's latest probe to Mars is almost certainly lost.
Mission controllers say that the $125m spacecraft came too close to the planet when it tried to manoeuvre into orbit on Thursday and was probably destroyed.

Contact was lost with the Mars Climate Orbiter (MCO) shortly after it fired its main engine to reduce speed. This would have sent the spacecraft into a polar orbit with a temporary loss of radio contact as it flew behind the planet.

But communication was never re-established and mission controllers at the Jet Propulsion Laboratory (JPL) in Pasadena concede it is now highly unlikely it ever will.

When the JPL staff examined the navigation data, they discovered an error. It seems the MCO flew within 60 kilometres of the planet, 25 km below what was regarded as a safe distance.

One of the project managers, Richard Cook, told a news conference that the MCO - which took nine months to travel more than 400 million miles to Mars - would likely have started to break up at such a low altitude.

"We have formed a tiger team to evaluate what happened," he said. "Yesterday, MCO was approaching the planet to pass within 140km of the surface and all seemed okay. However, in the last six to eight hours before the approach we saw a 100km drop and we don't understand why."

The orbiter was designed to be the first interplanetary weather satellite, studying the ebb and flow of carbon dioxide frosts and giant dust storms over a whole Martian year.

Efforts will continue to find the MCO, said Mr Cook. However, If it remains lost, it will be a disaster. A few years ago another major spacecraft, the Mars Observer, was lost as it attempted to enter Martian orbit.

Dr Carl Pilcher from Nasa headquarters said: "We are facing a serious situation, possibly the loss of the mission. However, we went in to this with our eyes open, we knew the risks and we intend to persevere with our exciting Mars programme."