Stratos III is a 8.2 meters high hybrid sounding rocket, aiming to break the European altitude record for student rocketry. Its 380 kNs engine propels the light-weight composite structure including scientific payloads during ascent, while the flight computer provides in-flight telemetry and video downlink. At apogee, the nosecone separates from the tank, and descends safely on a parachute. Discover more about this rocket below!
The nosecone contains the Flight Computer and the Stratos III Payload. The Flight Computer is the brain of the rocket which controls the engine, acquires sensor data and provides telemetry. It consists of custom-designed PCB’s that are programmed to send down flight data and even a live video feed through the antennas.The shell of the nosecone is designed to withstand the enormous loads and shockwaves while the rocket is accelerating to its maximum velocity of Mach 4, while producing as little drag as possible.
A large improvement to Stratos II+ is the use of a composite oxidizer tank able to store 174 kg of Nitrous Oxide at a pressure of 60 bar. While doubling the volume of the Stratos II+ tank, the empty mass stayed the same. The combination of a very thin aluminium liner wrapped with carbon fibre reduces the weight of the tank to 40 kg, allowing us to reach even higher altitudes.
The Hybrid engine powering Stratos III is similar to the Stratos II+ “Aurora” engine, but with its 380 kNs impulse and 21 kN peak thrust it is a lot more powerful. The design average thrust is 15 kN for 25 seconds, which is enough to lift an SUV. The fuel is an in-house developed mixture of Sorbitol, Paraffin and Aluminium. Initially, the engine nozzle was going to be manufactured with 3D printed titanium, however, due to unforeseen constraints the final design was produced in graphite. Are you wondering how this looks? Check out our engine tests on youtube.
After Stratos III has reached its apogee, the nosecone is separated from the tank and engine. When the nosecone has re-entered the thicker part of the atmosphere, it is decelerated by parachutes. The recovery system consists of a drogue parachute and the main parachute, used to stabilize and slow down the nosecone during descent. The drogue parachute is shot out of the rocket by means of a Cold Gas Deployment Device (CGDD), preventing entangling of the parachute wires with the rocket itself.
The Engine Bay contains the feed system, which controls the tank and the engine by means of multiple valves. It is able to remotely fill the tanks, ignite the engine and control the oxidizer flow during flight. Next to this, it houses the Flight Termination System, which is able to switch off the engine in case anything would go wrong during flight. This safety mechanism is controlled by an uplink from the ground stations.