In the early hours of March 1, space scientists and governments across Europe heaved a collective sigh of relief as Europe's most ambitious - and expensive - satellite settled into a near perfect orbit 800km above the Earth.
The European Space Agency trusted the launch of its £1.4 billion Envisat satellite to an Ariane 5 , Europe's most powerful rocket. The rocket does not have a good record. Of the past ten launches, three malfunctioned - one exploded on its maiden launch and and one rendered a £500 million satellite useless by placing it in the wrong orbit in July. So when last-minute freak winds disconnected the rocket carrying Envisat from its tower, nerves were fraying. However, the launch from the coastal mangrove swamps of French Guyana was a success.
Planning for Envisat began life in 1991, and it is the offspring of the Canadian and 13 European Union governments and more than 100 European companies. It will circle the Earth once every 100 minutes, monitoring changes in the atmosphere, oceans, ice caps and vegetation. Each day it will generate enough data to fill the hard drives of 500 personal computers. At launch, the satellite was the size of an articulated lorry, 10m long, 4m wide and 4m deep, and weighed about 8.2 tonnes. With the solar panel deployed, its length has increased to 24.8m.
Envisat , which will be controlled from Germany, carries ten instruments to study the Earth's atmosphere and surface. Together they can measure sea surface temperature to within 0.3 degree Celsius, detect movements of the Earth's crust of only a few centimetres, measure the height of the Earth's surface to an accuracy of 4.5cm and identify the presence of more than 25 gases in the atmosphere. This data will be used to control industrial and natural pollution, monitor atmospheric changes and find out more about our oceans. Envisat will orbit the Earth for five years.