Scientists start last bid to find Mars probe

Scientists will today start a final all-out attempt to locate Britain’s Beagle 2 Mars probe.

They hope to communicate with the craft, which has been missing since Christmas Day, via its mother ship Mars Express.

The orbiter will today begin flying over Beagle 2’s landing site, providing its first opportunity to establish contact.

Until now the Beagle has had to rely on the American spacecraft Mars Odyssey to relay its messages to Earth.

But 11 Odyssey passes have failed to produce a signal. Attempts to contact Beagle 2 with the powerful Lovell radio telescope at Jodrell Bank in Cheshire have also been in vain.

Scientists now believe it unlikely that Beagle 2 cannot communicate because of a wrongly set clock or a tilted antenna.

The successful transmission of pictures from Nasa’s Spirit Mars rover, which landed on Sunday, also shows there is nothing wrong with Odyssey.

Controllers are certain Beagle 2 did not bounce off the Martian atmosphere, or burn-up during the descent.

Unless its parachutes or the gas bags designed to cushion the shock of landing failed, the probe should therefore be on the surface of Mars.

However, the landing site – a lowland basin near the equator called Isidis Planitia – is not nearly as safe as mission planners had expected.

A detailed picture taken by an American satellite just 20 minutes after Beagle 2 was due to land showed a deep crater right in the centre of the elliptical landing area.

The crater, a kilometre across and hundreds of metres deep, would be surrounded by large rocks and rubble thrown up by the asteroid or comet that gouged it out of the ground. Another smaller crater is situated close by.

In contrast Spirit’s landing site inside the Gusev Crater, a possible former lake, appears to be a flat stony plain free of hazardous boulders.

The Beagle team knows nothing can be done if the probe came to grief on a rock bed or down the side of a crater.

But the scientists have not yet abandoned hope. “We haven’t in any shape or form given up on Beagle 2,” the mission’s chief scientist Professor Colin Pillinger said on Sunday.

A further complication is that Mars Express has entered a different orbit from the one originally planned.

As a result Beagle 2 is ‘out of sync’ with the orbiter and cannot make contact with it using pre-programmed hailing signals.

But this should not matter if, as expected, the probe has gone into one of its back-up search modes.

The first of these, “communication search mode 1” causes Beagle 2 to prick up its ears and listen for a passing orbiter for 80 minutes during both the Martian day and night.

If no link is established by this method, ‘communication search mode 2’ is activated. In this mode the receiver is on for 59 minutes out of every hour throughout the day. A carrier signal is also transmitted five times in every daylight hour.

At night during search mode 2, the receiver is on for one minute out of every five, but there is no carrier signal.

Scientists believe if Beagle 2 is alive and well it should already have activated the first search mode. The earliest date by which search mode 2 could become operational was January 3.

Mars Express is due to fly over the landing site at 12.15 today, but the outcome may not be known until about three hours later.

Other passes will take place on Thursday, Friday and Saturday. However, all of these are only five to eight minutes long.

The best hope of making contact with Beagle 2 will be on January 12 and 14 when Mars Express is due to make potentially far longer passes.