With only 15 days to go for the launch, the Stratos II team is getting both anxious and excited. This is the time for all the subsystems to integrate their subsystems. Throughout our journey we will keep you updated on all the activities and this article will be one of the many updates that will follow!
The clampband system has been put to test. After many weeks of designing the hardware it is time to actually test it. The design is based on a clamp that holds the nosecone and the rocket together. By cutting a wire that holds the clamp together, the clamp will open up that results in releasing the nosecone. After this event the parachutes will open up. Inside the clampband system there are two resistors. By running a current through the resistors they will heat up and consequently the wires will be cut. The cutting of the wire will be controlled by the electronic main stack designed by the Electronics Team of Stratos II. This design has been derived from a former design of the Cansat Rockets which have been produced by DARE itself.
What would all those hardware be without software? That’s why the Electronics Team of Stratos II is, in addition to producing the printed circuit board (PCBs), also tasked with writing the codes that will run on the electronics. The software will control the valving system of the hybrid propulsion system, the clampband system for releasing the parachutes and many more. For the engineers who are interested: the software will also contain a Kalman Filter, which will estimate the altitude of the rocket (the height that it has achieved) very accurately. Knowing the altitude is very important for the recovery phase of the mission, because without this information the deployement of the parachute will occur either too early or too late. The Kalman Filter will estimate the altitude of the rocket correctly ensuring an succesful parachute deployement and a safe touch-down of the rocket in the ocean.
In order to have a clear mission overview during the final minutes before the launch, software has been written to visualise all of the vital functions of the rocket. This will then be displayed on a big screen for the entire team.
Some final touches were made to the nozzle as well, before the nozzle is shipped to Spain together with all the other equipment and tools. The function of the nozzle is to accelerate the gases that are formed in the combustion chamber by burning the propellant which consists of sorbitol, aluminium powder and parafin wax. The nozzle itself is machined from a solid piece of graphite for its very high temperature resistance.