In the Dark

With the launch of Planck and Herschel only two days away, excitement is reaching fever pitch. As the countdown inches slowly towards the moment of reckoning the tension mounts…

This post would have been a bit more exciting if all that had been true. Of course we now do have a definite launch window for Planck, 14th May 2009. The launch window opens at 14.12 BST and will remain open for about two hours. Let’s hope they manage to get the thing up in that time, otherwise there’ll be yet another substantial delay.

Planck will be launched with its sister-mission, Herschel.  They will both be carried by an Ariane 5 rocket from the European Space Agency’s launch site in Kourou, French Guyana. Within half an hour of launch, Planck and Herschel will separate and start on their journeys.  While both satellites are going to orbit the second Lagrangian Point (L2), they will have slightly different orbits.  It will take Planck around 6 weeks to get to L2, during which time it will start to cool down its cryogenic systems. Eventually it will be the coolest thing in space.

Of course that is all very exciting, but it would have been a lie to say that the excitement is mounting that much back here at home. Together with the fact that the undergraduate examination period is upon us, the department is extremely quiet and those that are most nervous have taken their jitters to South America. The fact is that most of the people directly involved with Planck or Herschel have actually been invited to the launch and have either already made their way there or have at least set out on their journeys to the jolly.

We do, however, plan to have a small function here to mark the  launch on Thursday with wine and nibbles and talks about the science. I hope it’s not tempting fate. I”m not exactly nervous myself, but probably will get butterflies as we watch the launch on the net. Still, there’ll be wine to steady our nerves…

I  remember very well the “launch”, in 1996, of a mission called Cluster which many of my colleagues at Queen Mary were heavily involved. This was the first flight of Ariane-5. Bugs in the software meant it lost control shortly after launch and the party very soon turned into a wake, although the resulting fireworks were quite spectacular.

Because the Ariane-5 vehicle was brand new, and somewhat untested, the European Space Agency had decided to take advantage of an offer to launch the mission without charge. This seemed like a good deal because the costs of putting an experiment in space are a sizeable fraction of the overall budget for such missions. It turned out, though, that the old expression was true. There’s no such thing as a free launch.

In fact, Cluster did eventually fly using flight spares and a launch on a Russian spacecraft. If Planck and Herschel go boom then there’s no way they can be replaced. It would be a terrible thing if this happened, for a large number of reasons, but Ariane-5 has launched many times since then, and I’m confident that both Planck and Herschel will soon be safely on their way to L2.

But don’t expect any science immediately, especially not from Planck. It will be years before the key science results emerge and, until then, the science team is sworn to secrecy….