Thursday May 14^th 2009. Launch Day.

What a day! Everything went perfectly. Absolutely perfectly.

The party line is that things went so well that it was almost boring. Well you could have fooled us. The VIP room was full to the rafters, despite the fact that entrance was carefully limited. Well before the doors opened formally the room was filling up and 15 minutes before the start very few spaces were left and excitement was mounting. There were a series of presentations about Herschel and Planck before connecting to the satellite feed from Kourou.

To be honest, by 20 minutes before launch people just wanted to see the action from Kourou, even though the talks were excellent. The countdown had absolutely no drama. All through I was posting as fast as I could on Twitter, with the tiny inconvenience that the lights were out and I could barely see the keyboard. Through the launch increasing numbers of people were joining the group at a healthy rate. However, the last minute people hardly dared breathe. As the French Controller intoned 10… 9… 8… our newer colleague noted that people stopped breathing completely. He was only partly right: those last 10 seconds it was not my breathing, but my heart that stopped!

As the rocket accelerated off the launch pad at a barely believable rate the applause rang out and we started high fives. As each landmark passed the routine repeated.

The upper stage burn lasts 12 minutes and, for the first part of the burn the rocket dips slightly downwards, trading altitude for velocity in a shallow dive. It came down around 50km before pulling out of the dive and shooting up at great speed. At 1200km the tension rose again as the moment arrived for Herschel separation. More loud applause. And two minutes later, Planck separated too and the room broke into bedlam.

One last crunch point remained, which was the acquisition of signal from Herschel and Planck. Herschel might be en route to L2 but, if it wasn’t speaking to us…

Word came first over the Twitter and, within a few minutes, Mission Control showed us the clear signal over the satellite connection. That was the cue for the assembly to break up and to crowd outside to drink a toast and enjoy an excellent assortment of food. There were plenty of toasts to Herschel and plenty of Cava to toast with (mind you, I drank Fanta after one small glass of Cava).

Finally, some of us enjoyed a relaxing stroll down to the river and back to clear our minds.

I was exhausted by the time that I left al 18:45 and find the ride home hard work. In fact, I fell asleep rapidly in the chair when I got home.

What a day!

What emotions!

And things look very promising. The helium tank had only risen in temperature from 1.64K to 1.81K between fairing closure and launch. This means that very little helium was wasted in the launch pad and that promises a long lifetime for the helium in the dewar.