UK Science Minister Lord David Sainsbury has saluted the project to build Europe's largest ever Earth-observation satellite.

The satellite, known as Envisat, is due to be launched from Kourou spaceport in French Guiana early next month.

The �1.4bn spacecraft carries 10 scientific instruments that will monitor the planet for signs of pollution and climate change.

Lord Sainsbury: "Envisat is no ordinary Earth-observation satellite"

Lord Sainsbury held a briefing on the project at the Department of the Trade and Industry Conference Centre in London.

He said: "Envisat is a milestone in the history of environmental science. It's the culmination of a decade of research and development but it's also [a] beginning.

"With the launch of Envisat, we will be in a position to understand much more about the environment we live in and our impact on it."

Health check

Britain has contributed about �300m towards the cost of constructing the 8.2-tonne satellite.

The information gathered by Envisat will be shared among the 14 participating countries - 13 members of the European Space Agency and Canada.

Two of the 10 instruments on board the spacecraft were built in the UK.

There have been extensive tests and we're confident that Ariane 5 is going to succeed

Dr Colin Hicks, British National Space Centre

The 10 instruments working together will provide vital information on the health of the Earth's land, oceans, ice caps and atmosphere.

The instruments are sensitive enough to detect subsidence in a city street of one millimetre a year from a height of 800 kilometres (500 miles) above the Earth.

Professor Alan O'Neill, director of the Data Assimilation Research Centre at the University of Reading, UK, compared the satellite to a medical body scanner used to check a patient's health.

"Planet Earth is going to be given a complete check-up by the Envisat satellite," he told the BBC.

He said the data would be used to decide how to protect the planet from climate change, ozone damage and other environmental problems.

Dr Stephen Briggs, head of the European Space Agency's (Esa) Earth Observation Applications department, said the information could answer important environmental questions.

"There is no doubt any longer that the planet is changing," he told BBC News Online. "We don't really understand how and why and to what extent it is likely to happen in the future.

"The data which we will get from Envisat will be very important in helping to answer those questions."

Launch fears

The satellite will be launched on the giant Ariane 5 rocket. This rocket has failed three times in its 10 launches.

But Dr Colin Hicks, director general of the British National Space Centre, said he was confident that technical problems had been resolved.

He said Ariane 5 had suffered complete failure only once and he believed the rocket had been modified to prevent it from happening again.

"There have been extensive tests and we're confident that Ariane 5 is going to succeed," he said. "We are confident as one can ever be at launch."

The satellite has been insured for 250m euros in the event of failure.