The past month the propulsion team has been working hard to prepare for the full scale propulsion tests, currently planned for the second week of June. During this test campaign, conducted at the Prins Maurits Lab of TNO, the propulsion team will validate the performance of the DHX-200 Aurora engine. If the initial tests are successful and time permits, the propulsion team will also attempt to increase the performance of the engine by tweaking the mixer design and increasing the oxidizer tank pressure.
In total four tests are planned, and hence four solid fuel grains are required. The DHX-200 Aurora engine is loaded with a cylindrical fuel grain consisting out of sorbitol, paraffin and aluminum, weighing in total 23 kg. In order to assure that these solid grains are in top notch state, all of the grains where analyzed using the CT scanner at the faculty of Civil Engineering at the TU Delft. These scans showed that none of the grains suffered from production defects such as cracks or cavities and hence on the fuel front, all is good.
Another major effort was the development of the measurement and control system. Since this year, DARE partnered up with National Instruments, who kindly supported DARE with a compact RIO system for measurement and actuation. The cRIO system is used to acquire the signals from all four pressure sensors, two loadcells and the thermocouples. Furthermore it will actuate all valves, heaters and ignitor. The whole system is operated via a laptop using the LABVIEW front end. The cRIO is kept safe from the extreme conditions during motor operations by a steel enclosure provided by ELDON.
The feedsystem also underwent a revision. The addition of a dump valve will allow the propulsion team to quickly dispose oxidizer from the run tanks away from the engine in case of an anomaly. Furthermore all feed system parts underwent a rigorous cleaning session in order to ensure safe usage in combination with nitrous oxide.
On the 8th of June, the test equipment will be transferred to TNO in Rijswijk. After the whole system is setup, the propulsion team can finally get down to business. The exact date of the tests will be depended on the weather. When Mother Nature permits, the tanks of the DHX-200 Aurora motor will be loaded with 80 kg of Nitrous Oxide, generously provided by Airliquide. Once the countdown reaches zero, this Nitrous Oxide will be injected over the fuel grain, produced an awesome force of 10 kilonewton, enough to lift a small car in the air, and to propel the Stratos II rocket to supersonic velocities.
The propulsion tests will provide more insight in the performance of the engine and will yield the required input data for the in house developed trajectory simulation tool. As such the propulsion test campaign serves as an invaluable milestone in our quest to travel half way into Space.