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Last Updated: Friday, 22 July 2005, 15:28 GMT 16:28 UK
Ice mission almost set for launch
By Helen Briggs
BBC News science reporter

CryoSat (European Space Agency)
Mechanical tests are almost complete (Image: European Space Agency)
Engineers are carrying out final checks on the ice monitoring craft CryoSat, in preparation for an autumn launch.

The European Space Agency (Esa) satellite has gone through months of testing in Germany and will be transported to Russia's Plesetsk Cosmodrome next month.

The three-year mission will monitor how the world's ice sheets are changing.

Its main objective is to test the prediction that ice cover is diminishing due to global warming.

Data gathered by submarines suggests that Arctic sea ice is thinning rapidly.

The measurements carried out by the subs, in the 1960s and 1970s, and in the 1990s, by scientific vessels, suggest that Arctic sea ice has shrunk 40% in draught - the difference between the surface of the ocean and the bottom of the ice pack.

But scientists still do not have a full picture of how the polar caps as a whole are responding to climate change because of the paucity of data.

'On tenterhooks'

Dr Seymour Laxon, of the Centre for Polar Observation and Modelling at University College London, UK, said that Cryosat would provide a clear answer to this question.

CryoSat rendition (European Space Agency)
CryoSat will fly as close to the North Pole as possible (Image: European Space Agency)
"We are all on tenterhooks, waiting for CryoSat to give us the first view of what has been happening to the thickness of the sea ice around the North Pole since 1998, the last year for which submarine data are available," he told the BBC News website.

"Its amazing to think that something that was just an idea on paper 7 years ago will, in just a few months, actually be a satellite in orbit."

During the last 12 months the satellite has been put through a battery of mechanical and environmental tests at the Space Test Centre at IABG (Industrieanlagen-Betriebsgesellschaft mbH) in Ottobrunn, Germany.

These are nearly complete, and the spacecraft is due to be shipped to the launch site towards the end of August.

"We've still got a few major tests to do over the next couple of weeks. Once that is completed the spacecraft should be in good shape, from our point of view," said CryoSat spacecraft operations manager, Nic Mardle.

Earth Explorer

CryoSat is the first of Esa's Earth Explorer missions, which focus on specific aspects of the planet's environment, in this case polar ice.

Ice (European Space Agency)
Researchers have been carrying out ground studies ahead of launch (Image: European Space Agency)
Using a device known as a radar altimeter, it will measure fluctuations in land ice sheet height and sea-ice thickness to an accuracy that is only possible from space.

Principal Operations Engineer, Kate Adamson, said the radar altimeter on CryoSat would be the most accurate instrument of its type to fly.

"It's essentially a low-cost mission but has a very specialised instrument on it, the SIRAL radar altimeter, that can take very accurate measurements of the height of ice sheets and the sea ice, down to the centimetre level," she said.

A US space agency (Nasa) satellite, IceSat, launched in 2003, is already mapping the Antarctic and Greenland ice sheets, which cover 10% of the Earth's land area, using a laser instrument.

Data from both satellites should give scientists the clearest picture yet of what is happening to the world's total ice mass, and the consequences for climate, ocean currents and global sea levels.

Measuring the reality of climate change
21 May 05 |  From Our Own Correspondent
Antarctic buffers sea level rise
22 May 05 |  Science/Nature
Antarctic glaciers show retreat
21 Apr 05 |  Science/Nature
Climate 'threatens' Arctic lakes
01 Mar 05 |  Science/Nature
Arctic heads into warmer future
02 Nov 04 |  Science/Nature
Record ice loss in Arctic
09 Dec 02 |  Science/Nature

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