'The feeling is one of great shock and disbelief and a lot of despair'

Four celebration cakes in honour of the four Cluster satellites lay uncut at the Rutherford Appleton Laboratory's launch party in Oxford on Tuesday. The 200 guests had watched a live screening of the launch - and then disintegration - of their beloved satellites. They did not feel like cake and left the champagne unopenned.

"Instead I had coffee and a doughnut," said Peter Vaughan, head of the coordinated data handling facility at RAL, whose pivotal work processing the deluge of data from Cluster's 44 instruments was to have begun that afternoon.

"I've not watched many launches before. The vehicle lifted off and everybody was very pleased. Then it seemed to veer and there was a little explosion. I sat there thinking 'that's a bit early for the boosters to come off'. It didn't dawn on me that anything was drastically wrong. Then the red blob seemed to get bigger and it slowly dawned on us that there was a major malfunction. Here was all our work and investment over 10 years, lost. The feeling is still one of great shock and disbelief and a lot of despair. We had all our eggs in one basket."

Nick Flowers, of the Mullard Space Science Laboratory, also at the RAL party, was looking down at his notebook when Cluster exploded. "It cleared the tower, which was one of the riskiest parts. There was whooping and relief. Then after about 40 seconds it exploded. There was a tangible feeling of loss. No one quite knew what to say."

Dr Vaughan said: "I had never thought about it going wrong. You get so caught up in the project that it is part of your world and it would almost be counterproductive to think such a thing."

As for the cakes, "they've gone to the four winds", an RAL spokesperson said.