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Last Updated: Tuesday, 16 September, 2003, 21:21 GMT 22:21 UK
Mars rocks Beagle team
By Helen Briggs
BBC News Online science reporter

The meteorite that revived hopes of finding life on Mars is to be analysed by scientists working on the British-led Beagle 2 mission.

Claims in 1996 that experts at the US space agency (Nasa) had found fossilised bugs inside a chunk of Mars rock remain highly contested.

Beagle 2 (European Space Agency)
Beagle 2 will land on Christmas Day
But the revelations helped inspire the current fleet of space craft heading to the Red Planet to search for water.

The meteorite is to be re-examined to help calibrate the "eyes" of Beagle 2 - the stereo camera system the Mars lander will use to view the strip of rock and soil where it bounces to a halt.

Geological samples from Earth and the Moon will also be tested to build up a database of the sorts of minerals the robotic probe might encounter on the Red Planet.

These experiments must be completed before Beagle is delivered to Mars in late December by the European Space Agency's Mars Express orbiter.

Call sign

Replica of stereocamera on Beagle 2
The stereo pair of cameras are mounted on Beagle's robotic arm
A third camera is contained within the microscope on the arm
The cameras contain 24 filters - for geology spectral work, determining rock structure, and looking at atmosphere and dust
Technology is similar to that used on Nasa's Pathfinder probe but significantly smaller and lighter
Unique features include a close-up lens and a torch for each camera to provide known illumination rather than the reddish scattered sunlight from the Martian sky
University College London's Mullard Space Science Laboratory (MSSL) leads the stereo camera team on Beagle 2.

"The reason for having two cameras is to get stereo images of the landing site," says lead scientist Dr Andrew Coates of MSSL.

"The operations for the whole mission depend on that. These things have got to work."

The stereo cameras mounted on Beagle's robotic arm will be the first of its "senses" to be deployed.

Shortly after touchdown, the probe's hard casing will spring open like a clam shell, exposing its inner workings and scientific instruments.

Solar panels will unfurl to capture sunlight to power the probe as its battery pack fades.

Then, earthlings should hear the craft's signature call sign - a track composed by the British rock band Blur - as a signal that all is well.

Isidis Planitia

The first image of Mars will be a wide-angle picture taken minutes after landing using a pop-up mirror on one of the cameras.

The data will be sent back to Earth via Nasa's Mars Odyssey orbiter, which should appear overhead a few hours later.

We plan to push the science we can do with the cameras beyond the digital elevation models, to study geology, water in the atmosphere and dust
Dr Andrew Coates
Only then will scientists know whether Beagle has survived the landing and what shape it is in.

The planned destination is a flattish basin - Isidis Planitia - in the northern hemisphere of Mars.

The target site measures 144 kilometres x 106 km so it is impossible to tell exactly where it will land.

The stereo camera system will scan the Martian terrain to capture the data needed to create a digital elevation model of the terrain.

Hallmarks of life

As well as sending back images of the landing site, 24 geological filters in the cameras will look at the spectrum of the sunlight reflected from Martian rocks to see what minerals are in them.

"We plan to push the science we can do with the cameras beyond the digital elevation models, to study geology, water in the atmosphere and dust," says Andrew Coates.

Martian meteorite ALH840001 (PA)
Meteorite ALH84001 is at the centre of the debate on Martian life
This information will be used in conjunction with data from other instruments on Beagle 2 to choose the sites where precious rock samples will be collected.

Fragments of Martian rock will be delivered to Beagle's mass spectrometer (the Gas Analysis Package, or Gap) to analyse samples for chemical signatures of biological processes.

The camera team says scientists are still developing their ideas to some extent about the chemical hallmarks of life.

"Certain minerals like carbonates are quite often found in association with organic molecules, possibly with life, so they'd be a good type of mineral to look for," says project manager Dr Andrew Griffiths. "Also iron minerals, as iron sulphides are often laid down by bacteria on Earth."

Space train

Mars Express and Beagle 2 are now more than halfway through their cruise to the Red Planet.

On 20 December, Mars Express will release Beagle 2 on to a collision path with the planet.

Nothing will be heard from the lander for five days but on Christmas Day, if all goes well, scientists should get a signal confirming that it has touched down safely.

The European probe is currently at the head of a crop of space craft heading to Mars.

Just behind are the US space agency's Spirit and Opportunity surface rovers, and the Japanese Nozomi satellite that will go into orbit around Mars.


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