Delayed Launch of the Candle-wax Rocket

A test of nerves to the last: Due to unfavorable weather conditions and technical problems the “hot countdown” for launching the ZEpHyR had to be delayed three times. In face of these difficulties and with a minimum of red tape, the project sponsors in the space division of the German Center for Aerospace Research (German abbreviation DLR) spontaneously agreed to prolong the project. Finally, though, last Sunday saw a smooth start from the Esrange rocket launching site in Kiruna, Sweden. During test runs in Bremen, the hybrid rocket engine designed and built by students of the University of Bremen developed six megawatts of thermal output in 25 seconds – equating to about 8,100 horsepower. This is quite amazing as it only burns paraffin wax and liquid oxygen. The first launch propelled the rocket to an altitude of five thousand feet and showed it is fully functional.

Peter Rickmers, leader of the ZEpHyR project, is satisfied: "We are all very happy that the launch was successful. Five thousand feet is a little less than we had hoped for but this was probably because we were over-cautious and didn’t fill up enough oxygen. We’ll know more when the rocket is recovered. We were picking up GPS signals up to 1,500 feet before the rocket came down, so there is a good chance it will be found. We now have to analyze the data. This will hopefully reveal what we need to do to improve performance for the STERN 2 project."

The whole ZEpHyR team (“ZARM Experimental Hybrid Rocket”) around project leader Peter Rickmers flew to Kiruna on April 3, 2016, to witness the pioneer flight of their innovative concept. The trip to Sweden was the last stage of the STERN program for the Bremen students in the Faculty of Production Engineering. The idea behind the project supported by the German Center for Aerospace Research is to offer universities the opportunity to gather hands-on experience of aerospace research. In contrast to many other rocket launches where the research teams are merely spectators, ZARM involved active participation in all aspects – from building the rocket, through filling the fuel tanks, to the long-awaited moment when the start button was pressed. The Bremen team even supplied the launch adapter and then installed it themselves on the launching platform. The adapter ensured the ZEpHyR rocket was a good fit. The fact that ZERM’s environmentally friendly hybrid engine that only uses paraffin wax and liquid oxygen is a unicom in Europe and that the very first test of the concept had to be delayed so often did nothing to calm the nerves of members of the development team.

One hour before the actual launch, a siren goes off to warn people over a large area that a rocket is about to be launched. This is the sign for all the reindeer herders to seek refuge in their huts. The tension rises further 15 minutes before the launch when the final countdown begins. This was the fourth time following three postponements, and a real test of nerves.

When they saw the launch had been successful the relief was correspondingly great. Peter Rickmers: “Everybody was extremely tense following the three postponed launches and the success is now especially rewarding for the whole team. Despite the difficult conditions, we proved that our concept works. Moreover, all of us, including myself, have really learned a lot.” For the students, the week in Sweden was the highlight of their studies so far. Patrycja Kotarski, who is studying Production Engineering with a specialty in aerospace, joined the team six months ago says: “Working on the project has been really worthwhile for me: What more exciting way could there be to earn the credit points I need to graduate? And I gathered valuable practical experience into the bargain.”

Weitere Informationen:
Dr.-Ing. Peter Rickmers
Head of Space Propulsion and Energy Systems Group
ZARM - Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation
Universität Bremen
Tel. +49 421 218-57872
Mobil +49 172 5122120
peter.rickmersprotect me ?!zarm.uni-bremenprotect me ?!.de

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