Scientists at a laboratory near Didcot have celebrated the perfect lift-off of a rocket carrying two satellites on the other side of the globe.
More than 100 scientists at Rutherford Appleton Laboratory watched the launch of a Russian Soyuz rocket from Baikonur Cosmodrome in Kazakhstan, as it was relayed live on a large screen.
More Oxfordshire scientists and researchers, who will study data from the mission, watched the screens at the Royal Society in London.
The Cluster 2 mission is part of an international programme to find out more about how the Sun and Earth interact - often with dramatic effects on satellites and communications.
Trefor Edwards, the UK Cluster project officer at Rutherford Appleton Laboratory, spoke of their "enormous sense of relief and excitement" at the success of the launch.
He said there was also "the prospect of achieving science we have been dreaming of for the past 15 years".
Four satellites - including the first pair that were launched on July 16 - will join an armada of spacecraft from many countries. They are already studying the Sun and the solar wind - the high-speed stream of charged particles that it continually blasts into space.
The name Cluster was chosen because of the way four spacecraft will fly in a triangular formation around the Earth - enabling scientists to obtain a three-dimensional view of the solar weather.
Unfortunately, the first four Cluster spacecraft were destroyed when the Ariane-5 rocket spectacularly exploded during its launch in French Guyana in June 1996.
Ten years of work costing 380m was wiped out in less than a minute.
But the team refused to give up - and the result was the Cluster 2 mission, costing a further 200m, launched on two Soyuz rockets just over three weeks apart.
Staff at the Oxfordshire centre have been heavily involved in the design and construction of four of the 11 instruments on each spacecraft and will play a major part in handling and processing the data they send back.
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