Approximately one year ago, the PoGOLite team deployed to the Esrange Space Centre located outside of Kiruna in Northern Sweden. The result of that ill-fated flight attempt is well known to readers of this blog. Time flies (which is more than can be said for our balloon) and the last year has passed quickly. Now we find ourselves back at Esrange with some 6 weeks until PoGOLite is due to be airborne once more. It is a little bizarre to be commuting back-and-forth to 67 degrees N. Just as summer finally seems to be coming to the Stockholm region, there is still snow and chilly days up North.
The past year has by no means been a quiet one for the PoGOLite team. During the Autumn, the result of an investigation into the cause of the flight failure was published. The investigation showed that a sudden change of wind speed and wind direction just as the balloon was released was primarily to blame. After licking our wounds, we started the painstaking task of completely disassembling our X-ray polarimeter, repairing damage, reassembling and testing. Much of this work was completed around the start of 2012 and since then we’ve been based in a drafty hangar at Linköping airport for tests together with the attitude control system (which keeps the polarimeter accurately aligned with observation targets), developed with DST Control AB. The team’s obsession with checking weather forecasts in order to pinpoint clear nights for tests of our star trackers lead to colleagues commenting that some of us had truly made the transition from our particle physics pasts.
On July 1st, the PoGOLite launch window will open. We stand to benefit from a 15 day long flight with corresponding multiple observations of our scientific targets – The Crab and Cygnus X-1. This is very exciting, but we’ll also be somewhat nervous… such a large balloon has never made such a circumpolar traverse before. The balloon will be carried in a Westerly direction by stratospheric winds, flying over Norway, Greenland, Canada and Russia before returning to Scandinavia where the flight will be terminated and our telescope returned to ground by parachute.
More news from PoGOLite as the launch date approaches. In the meantime, if you want to know more why not come to Merlin Kole’s licentiate seminar on May 31st: “PoGoLite: 2011 flight results and 2012 pre-flight predictions“? Although we were aloft for a short time during the 2011 flight, it was still possible to squeeze some very useful information from the data we collected and Merlin will reveal all.
While we’re on the subject of thesis presentations, I would also like to alert you to two PAMELA Ph.D. thesis presentations in the near future. Juan Wu will present her thesis, “Measurements of cosmic ray antiprotons with PAMELA and studies of propagation models“, on Friday June 1st with Fiorenza Donato from Turn University as opponent. Juan has worked closely with Antje Putze, giving this work a true OKC flavour. Laura Rossetto presents her thesis, “PAMELA measurements of high energy cosmic ray positrons“, on May 11th with Tatsuya Nakada as opponent. The particle physicists amongst you may know him as a past Spokesperson for LHCb – you may not know that he is also leading a balloon-borne positron mission called PEBS (cosmic-ray positron measurements up to the TeV scale – something for OKC, maybe?). These will be the final two PAMELA Ph.D. students at KTH. The end of an era! Of course, we’re all waiting with bated-breath for first results from PAMELA’s larger sibling, AMS. I am particularly curious to see their positron results. Now that the PAMELA rise in the positron fraction has been confirmed by an inventive use of the Fermi Gamma-ray Space Telescope, that AMS also sees the rise will not come as much of a surprise. What will be interesting, however, is the maximum energy at which AMS can reliably resolve positrons from the large background of cosmic-ray protons. The Twittersphere was recently awash with congratulatory messages as AMS passed 17 billion triggers – so far, so good. Rumour has it that something ‘interesting’ will be shown at the summer conferences. Stay tuned…