DARE – Stratos V

The Stratos V team of Delft Aerospace Rocket Engineering (DARE) has been hard at work the past months on the design of Stratos V’s Engine Control Unit (ECU). The ECU is a stack of PCBs which cooperate to control and monitor the engine and feed system of the rocket. The stack will be mounted within a sealed box such that it is protected from possible water ingress into the rocket when it splashes down in the sea. The design of the boards has been decreased in size while maintaining their required functionalities. Having smaller boards also means that the sealed box will take up less mass and volume, which not only allows for the feed system around it to be more easily integrated, but also for the rocket to reach greater heights.

During the past half a year, three out of the ECU’s four PCBs have been designed. Let’s go through a brief overview:

• The actuation board is on its second version. Each actuation board can interface with up to six solenoids, which will control the pneumatic system that the valves work on, effectively controlling the valves. By actuating the solenoids with the right timings, the flow of pressurant gas into the tanks and liquid propellants to the engine’s combustion chamber can be controlled. Adding a spark to the equation is the final step to start combustion of the propellants and reach for the skies.
• The thermocouple board is on its first version. It works exactly as planned and has been providing us with real-time temperature readings of up to eight connected thermocouples. Thanks to Eurocircuits’ fast service, we were able to go from start of schematic design to having temperature readings all within three weeks.
• The pressure sensor board is on its first version, but the second version will soon be ready to be ordered from Eurocircuits. It will interface with up to six 4-20mA current loops, allowing us to connect not only pressure sensors to it, but also a capacitive fill level sensor which will measure the fill level of our fuel tank.

The team has performed a successful hot fire campaign in early June where we have fired both the DLX150-A and DLX150-B version of our 3D-printed rocket engine. The propulsion department has been hard at work developing our in-house manufactured flight valves and designing the next iteration of our Firebolt engine. The tanks of the rocket have been designed and are entering the manufacturing stage now. Next to the tanks, the structures team has designed the thrust structure, which carries the thrust force of the engine into the rest of the rocket. They have tested the thrust structure, where it overperformed. The recovery department has tested a prototype of our ballute, which is a hybrid of a balloon and a parachute, to get reference data on its performance. The experience gained in the manufacturing and testing of this first prototype will help them in further designing and manufacturing the next prototypes.

We are incredibly grateful to Eurocircuits for providing us with the opportunity to iterate so rapidly on the designs of our PCBs. Their swift manufacturing and delivery allow us to make fast progress where usually delays would be expected. Stratos V is looking forward to working together with Eurocircuits throughout the coming years to achieve our mission of launching a reusable liquid bi-propellant rocket.