Europe's largest and most expensive satellite was launched into space on Thursday on an Ariane 5 rocket from Kourou in French Guiana.

The successful launch signalled the start of a party. Many people have been working on the project since the late 1980s.

The blast-off could have been delayed. The rocket was rolled out only after engineers had managed to fix a technical glitch with a venting system that kept important components cool.

Envisat's 10 instruments will collect data from space for at least five years.

The whole project has cost �1.4bn to put together with the UK putting up �300m - the most Britain has ever spent on one satellite.

The Envisat flag, designed by a 12-year-old, sums up the satellite's mission to planet Earth.