Europe’s largest satellite prepares for lift-off
After months of delay, the largest Earth observation satellite ever built in Europe is due to be launched this week.
Fourteen countries including Switzerland have cooperated on the €2.3 billion (SFr3.4 billion) project. The eight-tonne satellite, known as Envisat, is the size of an articulated lorry. It has 10 instruments on board that will monitor environmental changes.
During its five-year life, the satellite will circle the earth every 100 minutes, gathering data on global changes such as depletion of the ozone layer, ocean levels, the state of polar ice and plankton currents in the world’s seas.
“Envisat is the most powerful tool for monitoring the state of our planet and the impact of our activities on our world that has ever been created,” Professor Daniel Nüsch, who works at Zurich University’s remote sensing laboratories, told swissinfo.
“Hundreds of scientists from all over the world from many different fields are today very keen to get data from space to be able to give answers to burning questions such as ‘Can we slow down global warming?’ ‘How badly damaged is the ozone layer?’ ‘What causes El Nino?’ ‘What is happening to the world’s forests?’ ‘Why are our sea levels rising or not?’ ‘What are the effects of atmospheric pollution?’ ‘Are natural disasters becoming more frequent?'”
Switzerland has contributed about SFr127 million towards the cost of constructing the satellite. Some 86 Swiss firms from 17 cantons have furnished parts and components.
Map of the world
As Envisat circles the globe 14 times a day, information will be relayed to ground stations worldwide for analysis. The satellite will return in a 35-day cycle to the same orbit and after three days draw a complete map of the world.
The instruments are sensitive enough to detect subsidence in a city street of one millimetre a year, from a height of 800 kilometres above the Earth.
The scientists admit it is a risk, packing so much technology into one satellite, but say it is essential to have a comprehensive understanding of the environment and climatic processes.
“It is very difficult to see interactions in the climate between land, ocean and atmosphere with smaller satellites,” said Michael Rast, a scientist in ESA’s directorate for earth observation. “They fly at different times and they observe different spots.”
“You have to observe atmosphere, ocean and land contemporaneously to really understand what sort of processes are happening in our environment.
“Only when we’ve understood the processes can we make reasonably accurate predictions and assumptions about our climate development.”
An Ariane-5 rocket is due to launch Envisat from the European Spaceport in French Guyana on March 1. It was scheduled to lift off last October but a malfunction in the launcher caused a six month delay.
by Vincent Landon
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