On 14th May two giant telescopes on top of an Ariane 5 rocket were launched into space from Kourou in French Guiana. From Cardiff I am leading two of the surveys that one of the telescopes is carrying out. This is my account of the days leading up to launch.
Launch -6 days. I am a chronic worrier, but it is disconcerting to see my normally level-headed colleagues join me in the fog of anxiety. The conversation at coffee every day this week has been about Herschel and Planck, the two telescopes that, if successfully rocketed into space, could help to answer questions about how the stars and galaxies were formed, and why the universe expanded so rapidly in the first split second after the big bang.
This week, though, we haven't mentioned any of this. Instead the conversation has been about things that could go wrong. If anything does, it will be something daft. The first launch of Ariane 5 in 1996 failed because the software wasn't updated from the less powerful Ariane 4. When the rocket measured the higher acceleration, it thought it was heading towards Earth and blew itself up. Possible daft things that we thought of this morning include Herschel and Planck getting stuck together and ending up just observing each other, or the cover not coming off Herschel's mirror, leaving a billion-euro camera with its lens cap on hanging uselessly in space.
Launch -5 days. At coffee yesterday we tried to estimate the probability of failure, but couldn't remember how many Ariane 5s had blown up; our estimates ranged between 5 and 20 per cent. Neither number seems reassuring.
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Launch -3 days. A silver lining—if anything does go wrong this means no more telecons. A telecon is a telephone conference call—the glue that keeps big international projects going. There are 110 scientists from 15 countries on the Herschel team I'm working with. They never all get on the phone at the same time, but leading a discussion between even 20 disembodied voices is a nightmare. This is my second telecon of the day, but I'm not running it, which means I can write this diary entry.
Launch -23 hours. We are now just about ready for the launch event. Matt Griffin, who led the team that built one of the cameras for Herschel, and several others are at the launch site in French Guiana. The rest of us are going to watch it on a big screen in our Cardiff conference room. We've invited the local media and politicians. A few of us will talk about what Herschel and Planck will do, we'll watch the launch and then we'll have a lot of wine.
Launch -8 hours 45 minutes: I managed to sleep until 4.15am. I now feel rather fatalistic; if there's going to be a problem it must already be present in the machinery sitting on the launchpad. The only thing I'm not really ready for is what to say if the mission fails. It will be up to me to say some consoling words to the younger scientists whose careers depend on this.
Launch -2 hours 30 minutes: I planned to do some research this morning, but I couldn't concentrate so I've just been downstairs to the conference room. There's nobody there yet but the satellite feed is now working and I could see the rocket on the launchpad. It is dawn in Kourou.
Launch -20 minutes: The room is packed and I'm about to give my talk. I'm so nervous now that I'm afraid I'll disgrace myself. Someone has just heard from Kourou: it's sunny and there's no wind. All systems go, if that's what they still say.
Launch +10 minutes: For some reason we didn't see the countdown, and then I saw steam and the Ariane 5 lift off the ground. It rose smoothly into the sky, nothing like the shudder of the Apollo launches I saw as a kid. There was no cheering because there is a sequence of things that have to go right, although there has been a gradual release of tension as one after another the elements of the mission plan have clicked into place. The only bad moment was eight minutes ago when I saw flames on the screen. I thought it was the boosters dropping away, which is supposed to happen, but I wasn't sure and there were a few other white faces. Someone on the screen has just said the mission parameters are nominal, space-speak for everything is going fine. The last remaining hurdle is when Herschel and Planck separate from the launcher in about 20 minutes.
Launch +20 minutes: Rhodri Morgan, the first minister of Wales, has arrived. We replay the launch for him, which means we will miss the separation from the launcher, but at least this time we see the countdown. Rhodri says some nice words and seems to understand some of the science. From somewhere the word rustles through the room: both spacecraft have successfully separated. We are on our way to L2.
Follow my diary after the launch at First Drafts, Prospect's blog.
