So today Mars Express lost its hitchhiker, and a large number of scientists felt a surge of relief. Beagle 2 is now falling to Mars, and Mars Express is free to change course and go into orbit. Had the separation not happened, Beagle 2 would have remained a dead weight attached to Mars Express; thus overburdened, Mars Express would have been unable to get into its proper orbit around Mars, and Colin Pillinger would have had to find somewhere a very very long way away to hide.
Happily, though, it all went off rather wonderfully. A couple of hundred people turned up to a "Wish me luck as you wave me goodbye" party at the Royal Geographical Society's headquarters, just next to the Albert Hall, to watch a live link from the Operations Centre at Darmstadt. A lot of hacks, a surprising number of TV crews (including a very nice one from BBC News 24 which recruited me as an enthusing expert for their reporter to talk to) and a large number of people who had actually worked on the project. Just before 11 in the morning we heard that it was "95% certain" that the Beagle's shackles were cut, that its spring had sprung and that it had pushed off on its own. About 20 minutes later we got the final confirmation -- the two spacecraft had separated just as they were supposed to. Applause all round -- specially for Steve Burnage and the rest of the very relieved team that had actually made the release system -- and then a couple of hours listening to speeches, eating vaguely oriental canapes and drinking mulled wine on the off chance that a monitoring camera on Mars Express might have managed to snap a picture of the Beagle as it left.
The Beagle team made sure that we had properly lowered expectations of this subject of the picture. In the end it turned out a triumph -- the little disk of the Beagle spinning away into a sparse starscape. Very rarely if ever do you actually get to see a planetary spacecraft do something. In fact I'm not sure a picture of a spacecraft in deep space has ever been taken before. It's a moving sight -- something little and human and magnificent, all on its own, moving beyond our ken. The high resolution camera on Mars Express will try to look for Beagle once it's landed (if it lands), as will Mike Malin's camera on Mars Global Surveyor. But it's only the size of a large barbeque, so even if all goes well and it sends back the best data imaginable, it may never be seen again. Once it's covered in dust it will be one lump in the desert among millions.
Among the guests is the MP Lembit Opik, grandson of a famous astronomer and campaigner for more government spending on protection against asteroids. I mention this mainly so that I can quote the wonderful song about him from Radio 4's "The Now Show":
He's lanky and myopic
And he wants to save the world.