Tuesday May 12th 2009. Launch -2 days and Counting.


Just 2 days to go.


We are getting regular updates from Kourou. At present the weather is good and there is no threat to launch. There have been no storms so far this week, with the temperature a balmy 31C in the afternoon. With Herschel launching in the morning, local time in Kourou, the danger of a weather hold is greatly reduced as storms are most likely to occur in the afternoon. The news is that the Herschel cryostat is cold and tight. At 1.64K it is the coldest place in the Universe right now. The cryostat is full and being kept cold by an external helium tank, which must be disconnected finally when we roll out. From then on, an air conditioning unit inside the fairing will keep Herschel cool in the afternoon heat, reducing the warming of the telescope and cryostat to a minimum.


At the same time, we have the space weather forecast for launch. Yesterday a small, but non-zero probability of a solar flare was being reported. Today the prediction is for essentially zero solar activity. The solar disk is spotless and the probability of an important solar flare or storm is just about zero. In fact, there is no real danger to the spacecraft in a solar storm, but one could make the data from the instruments too noisy to be useful. We are still going through this remarkable, not to say surprising solar minimum, which has lasted far longer than anyone had predicted. The longer it lasts, the less likely it is that the next maximum will be big.


People here are nervous but resigned. We are in the hands of the experts at Mission Control and at Kourou. For the first few days our role is very limited anyway. The first data will start to come down on Thursday, but it will only be telemetry telling us that Herschel is alive and kicking. It wont be for more than a week that the controllers in Darmstadt will start to wake up the first instrument. Until then it is just a matter of checking out that the spacecraft has survived launch okay.


From tonight I have started making Twitter posts yes, Ive been asked to Tweet about Herschel. The aim is to make brief real-time posts as things happen over the next few days.


If you want to sign up for the alerts about new posts (limited to 140 characters), go to:




And sign up for ESAHerschel alerts. I will try to make them as regular as possible if there is any real news.