In the framework of the Space Studies Programme 2011 of the International Space University (ISU) the seventh take off of Passepartout took place on Saturday, 13th of August. This was the first time the new “Sherpa” configuration was used. Planning started the day before, with some last discussions about the weather forecast we obtained from the Austrian Armed Forces. Cloud cover was predicted between 4 and 8 km hight with some rain on the afternoon. Based on these predictions, we calculated the track of the balloon and its most likely landing spot – assuming, that the balloon would explode again at 37km hight and that the air flows don’t change.

At 7 AM members of the Forum met at the Observatory “Lustbuehl”, from where the balloon would take off. Nearly everything was laready prepared by the core team, who have arrived several days in advance. The last thing left to do was to put up some beachflags and prepare the filling station – and already we could fill the balloon with Helium. The time it took to fill up the balloon was surprisingly short, which worried the team who had filled Passepartout as an overfill would mean less final hight.

Filling of Passepartout at the Observatory “Lustbuehel”

After the balloon was full with Helium, it got secured and tied down, before the telemetric and payload capsule was attached to it. The payload has been developed by ISU students and contained 4 different experiments: HD camera, algae, temperature sensor and a VLC (very low frequency) receiver.
Since this weekend was also the alumni weekend of ISU, there were 30 alumni attending the take off in adition to the Forum members – at 100 people present altogether, the roof of the observatory got pretty “cosy”!
After a last photo session of the balloon and its payload, we could finally releave Sherpa. The take off was filmed by a camera attached on a remote controlled helicopter. In order not to damage the balloon, the helicopter did not stay close to it for long.
After take off MCC (Mission Mission Control Center) gave me a small tablet PC which received the slightly time delayed APRS packages from the internet. This also enabled me to have a look at all the sensor data.

Visitors witness the take off at the “Lustbuehel” in Graz

In the meanwhile we had already sent the recovery team on its way, and onlookers started to leave the observatory.
The balloon was taking to the skies quite smoothly and was already over Hungary. First results could already be collected from the scientific experiments. At 12 o clock I was just sitting at a computer watching the tracking softwares different diagrams and tables. The balloon was close to break 33km, when the software reported the balloon as falling. The recovery team got warned and it did get hectic again in the MCC, while the further track of Sherpa got closely monitored. Would the balloon land on a field? Would it land the right way up, would the parachute work? That last point did not seem to work, as the whole fall only took Passepartout 22 minutes, which is very short for 33 150 m.
After the balloon had landed, we waited another 10 minutes to obtain the balloon’s position via Globalstar-Tracking. The advantage of this system is, that it can find objects even when they are on the ground, with the disadvantage that it does not work in great heights. Globalstar positioned the capsule south of Fehring in Austria. The data suggested that it was somewhere in a tree next to a cornfield – which got confirmed very soon afterwards by the recovery team: They had found the capsule, hanging about 15m above ground in a tree.
Trying to climb that tree did not proof succesfull, so members of the MCC called the voluntary firebrigade of Fehring. We were lucky – a member of the brigade was just in the area, and he was a trained tree climber! After another hour, the capsule had been recovered. With that message, tidying up everything else finally started.
It was a very eventful and succesful day: Passepartout Sherpa reached a hight of 33 150m. After a short discussion over the mission and lessons learnt, the day was over. What is waiting now is the scientific data analysis.

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