By BBC News Online's Helen Briggs in Kourou, French Guiana

There were smiles, handshakes and clapping in the Jupiter Control Room, when news came through that the Envisat Earth-observation spacecraft had successfully separated from the last section of its launch rocket.

Although it would still be some time before mission controllers were sure that the spacecraft was safe, the speeches began.

"Bravo Europe, congratulations," said Jean-Marie Luton, the chairman and CEO of Arianespace, the company that runs the Ariane launcher programme.

"We can celebrate the success of European space," he said.

Nervous wait

But Jose Achache, Director of Earth Observation at the European Space Agency (Esa), said he would not relax until he had heard that the spacecraft's solar panels had been successfully deployed.

"First of all, we need energy on board and for that we need the solar panel on board," he told BBC News Online.

As he spoke, a big screen at the front of the control room showed an animated reconstruction of the satellite's solar panels unfurling. There were more claps, cheers and smiles when news came through that the real thing had been successful.

Michael Rickett of Astrium, who has been working on the satellite since 1989, said the launch was fantastic.

'Our children's future'

"In a sense it is only the start as far as the spacecraft is concerned," he added. The next crucial stage, he said, was the release of the satellite's main antenna three days after launch.

Dr Colin Hicks, director general of the British National Space Centre, said it had been a perfect start for the satellite.

"Following this perfect launch, the work has got to go on deploying the instruments and testing the satellite," he told BBC News Online. "But everything so far has been perfect."

"One of the awe-inspiring things is the vision of the scientists who developed these instruments 10 years ago and whose work is going to provide us with answers to questions which will affect our children's future."