On Thursday the 3th of May 2012, the hybrid propulsion team of the Stratos II project (named Dawn) successfully tested their flight engine. This hybrid rocket engine has been developed based on the research they have done during the whole span of the project. Now finally they are ready to go for the first attempt in the history of DARE to launch a hybrid rocket engine.

The team has kept to their original design of an engine with a sorbitol fuel grain and a nitrous oxide oxidizer. To store the oxidizer the tank concept developed during the Spacecraft Engineering Minor this year was used. This tank has been integrated together with the combustion chamber, the feed system and the fill valves into one sleek looking rocket body. This whole setup was tested during the static ground test of this Thursday.

The group had performed a similar test a few weeks before, however that test was unfortunately not a success. There the servo mechanism that opens the main valve did not function properly and so it was not able to open the valve at the correct speed. This time however there was no apparent problem what so ever with this system. The servo had been replaced by a new one, the bracket attached to the valve was made to fit tighter and the actual flight electronics were implemented and integrated into the rocket. This all together made that the whole system behaved like it was designed to. The valve opened correctly, which can be seen from the very steep increase in thrust at the start of the burn. This is a good property of the system as a high thrust at the beginning means that a rocket equipped with the engine will quickly accelerate to exit its launch tower with enough speed to be sufficiently stabilized by its fins.

The attempt at the first launch of a hybrid rocket engine of DARE will take place during the 19th and 20th of May on a launch day near Leipzig, Germany. The team will now work further on the preparations for this launch day to make sure that they can conduct this launch successfully as well.