Space probe 'broke in two'

Scientists say this image suggests the probe is done for

A missing $159m Nasa space probe may have broken in two when its rocket engine malfunctioned, according to the mission's chief scientist.

The loss of the Contour, which was supposed to leave Earth's orbit on Thursday to rendezvous with two comets over the next four years, is a blow to the US space agency.

While the spacecraft's fate is still unconfirmed, scientists said an image captured by an Arizona telescope suggests it could have broken into two pieces after it fired its engines on Thursday.

The Contour probe was supposed to spy on comets

"I'll be real honest, I'm not very optimistic," said mission director Robert Farquhar from the Johns Hopkins University laboratory that is running the mission for Nasa.

The probe was supposed to begin its 48 million-kilometre journey on Thursday after firing its engine to leave Earth's orbit.

But it never sent out the radio signals it was supposed to afterwards, leaving mission control in the dark about where the probe was.

On Friday, a University of Arizona telescope picked up what appeared to be two "parallel trails" near where the probe should have been, suggesting it had broken apart.

"The team will look over weekend with some radar and radio and telescope images and determine what it might be. It was located pretty close to where Contour might be. So we are definitely not encouraged by that news," mission spokesman Mike Buckley told Reuters news agency.

Solar system's origins

Contour was supposed to probe secrets of two comets - Comet Encke in 2003 and Comet Schwassmann-Wachmann 3 in 2006.

Scientists working with Nasa on the project hoped to find out more about the origins of the solar system from the comets.

The spacecraft, or what was left of it, was believed to be about 460,000 kilometres away from Earth - a little more than the distance to the Moon - when it was sighted.

Scientists had hoped that the probe would tell them about the frozen nucleus of each comet, which is believed to be as much as 4.6 billion years old.

The age of the comets' cores means they may hold information about the early stages of the solar system's development.

Mr Buckley said the mission would have another chance to re-establish contact with the probe - if it is still functioning - on Monday.