Not only did the students develop the rocket themselves, but also the fuel. It is a mixture of paraffin wax, aluminium powder and sugar substitute sorbitol. The oxygen that is needed for combustion is supplied in the form of nitrous oxide (N2O, also known as laughing gas). When all the fuel is burned, a small amount of residual N2O remains in the tank. If this was to get into the combustion chamber, the propulsion unit could be destroyed and the rocket damaged. The supply line is therefore closed by a valve immediately after combustion has taken place. This drive consists of a series 4490 … BS brushless DC-Servomotor from FAULHABER, equipped with an analogue Hall sensor K1155, a 38A gearhead and an MCBL3006 S RS controller.
"We have very little space in the rocket, meaning that the drive must be as small and light as possible, but also very powerful and completely reliable. It must also withstand the intense vibration at the launch, after having opened the valve in less than a half second" explained Jesse Hummel, Team Manager of Stratos III. "We have intensively examined the motors that were available for this task. The model from FAULHABER was the only one that fit and delivered sufficient torque." The diameter of the 8.2 meter long rocket is a mere 28 centimetres.
DARE fired its Stratos II+ rocket to a height of 21.5 kilometres in October 2015, setting a new European altitude record for amateur space travel. However, this record has been broken by a rocket from the University of Stuttgart, and now stands at 32.3 kilometres. Stratos III should be able to go much higher than this. At the same time, the record attempt will be used to collect data for atmospheric research using different instruments on board the rocket capsule. The capsule should fall into the sea braked by parachutes, and recovered from there.