The Guardian Unlimited
When a person is sick and the doctors do not know why, they send the
patient for a scan. When a planet is sick, they cannot.
From next Friday that will change with Europe's launch of the world's biggest and most expensive environmental monitoring satellite from Kourou spaceport in French Guiana.
Envisat, built for U.S. $2 billion, carries an orchestra of scientific instruments capable of simultaneously doing everything from taking Earth's temperature to counting the pulse of molten rock beating in its volcanic pores.
From its vantage point 500 miles (800 kilometers) above the planet's surface, the huge spacecraftweighing eight tonnes and as big as a double decker buswill sense the warmth of the oceans, the height of waves and the speed of the winds; count plankton, measure algae and see pollution; map forests and grassland, gauge snow and ice cover, and perhaps even warn of imminent volcanoes and earthquakes.
"In terms of what's going to affect people, predicting what's going to happen to the environment on Earth is the big scientific challenge," said Alan O'Neill, who will help coordinate Britain's use of the flood of data Envisat will generate.
"It isn't enough to look at, say, the atmosphere on its own to find out how the environment is going to change over 100 years. Envisat is going to give us a comprehensive picture of all the interactive elements."
O'Neill added: "You want to give the planet Earth a real health check, to diagnose its state of health and give a prognosis for the future. I liken Envisat to a body scanner."
Although Envisat builds on the work of two earlier European environmental satellites, in scale and scope there has never been anything like it.
It will not have a defence role, and although it will have limited commercial and emergency applications the bulk of its workload will be to understand global warming, what it is doing to the planet, and what it is likely to mean in the future.
The British firm Astrium was lead contractor for the satellite superstructure and for two of its 10 instruments. One of them, the Advanced Synthetic Aperture Radar, is capable of detecting tiny shifts in the ground.
There will be tension in the run-up to the launch, with such an expensive spacecraft riding into orbit on board the Ariane 5 booster, which has had problems on three out of 10 missions.
Copyright 2002 Guardian Newspapers Limited
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