In the last blog post, we discussed the update of three of the four teams working on the Aether project. In this post, we would like to update you on the remaining teams: the Solid Propulsion Team and the Structures & Recovery Team.
ASIMOV Project: In the beginning of 2016, a few months after the mission statement of Project Aether, the solid six joined Aether by taking the challenge to work on the engine for the supersonic technology demonstrator – the Aether launcher – by building the biggest solid engine ever built in DARE. After a complete team change, S6 put all effort to be able to launch Aether in around a year time. The first engine test, based on the previous solids team’s Leonidas engine family was successfully tested in March 2016 and included a 5.0-kilogramme Potassium Nitrate/Sorbitol (KNSB) single grain motor (SGM). Up until the September launch day an extensive analysis was performed mainly to gain knowledge in the field of lightweight structures and to enhance engine start-up behaviour. Since it would become the biggest solid engine of DARE, the engine was dubbed as DXS Asimov, the start of a new project. The next steps were the SGM test of September, the basket igniter test in November, the SGM test in December, the FSM test in February and the FSM test in March. The root cause for the anomalies during one of the single grain test (SGM2) and both full-scale tests (FSM2 and FSM3) was that the propellant either contained cracks in the grain or was delaminated from its liner. The result of this was that the engines did not perform and exposed unintended behaviour. Therefore, the Asimov project was delayed in March 2017 due to these unanticipated propellant issues. Which meant that the whole mission would have a delay. Although no complete engine could be presented and delivered to the Aether launcher, some key developments and revival of production methods have arisen from the Asimov development:
- Lightweight ablative composite nozzle, a composite design containing elements of glass fibre reinforced pertinax with a graphite insert which is retained by an aluminium ring, the total weighing around 200 grams;
- Knowledge to couple and improve glass fibre laminating methods and GFRP engine casing lay-up designs;
- Basket igniter, a 3d printed igniter which is fitted inside the top propellant grain to allow a wide particle spread during ignition.
IKAROS Project: Continuing from June, the solids have been contemplating a new approach. This time it would be much more driven on the internal ballistics of the engine (i.e. the propellant) and take time to execute the intermediate goals which were partially neglected during the course of the year due to the project’s time-pressure. As ambitious the Solid Six is, it was decided to do a complete propellant research, to primarily tackling the propellant quality issues with a focus on the propellant production methods of KNSB. This in practice means to make a device which enables propellant characterisation tests to yield a burn-rate to pressure curve for different formulations – the device is called a strand burner, in other words, an engine with transferable propellant strands and with a changeable nozzle throat. When the tests will be successful the Solid Six are able to make more potent propellant grains which will be a big step towards building the 2-2.5 meter long engine to provide the Aether launcher with a reliable propulsion system.
The Aether crew hopes that with the future accomplishment of the project, we will get closer to the stars.
Structures and Recovery Team update:
Several months ago it became clear that the launch of project Aether would be delayed. This meant that the team would have more time to focus on improving the existing system. At the start of this academic year, a large number of new members joined. However, with most of the hardware already produced, it is time to develop new systems.
Structures department: The team has welcomed 7 new members in the structures department. Whose focus is to test and improve the existing hardware of Aether and to work on the development of new systems for the future. The testing of the existing hardware is done in steps on both the test sample and the actual hardware. A few weeks ago the nosecone was transported to the aircraft hall of the Aerospace facility for visual inspection. Because the nosecone is made out of glass fibre, it is relatively see-through and could be inspected with the use of a bright light inside it. This inspection revealed a few minor imperfections, but nothing that could compromise the mission. Furthermore, non-destructive testing of the nosecone will be carried out in the coming few weeks; this to improve our knowledge and trust in the flight hardware. Moreover, once the non-destructive tests are done, several destructive tests will be carried out on sample pieces with identical material properties to the nosecone. This will ensure that the flight hardware has the proper strength to sustain the launch and flight of Aether.
Recovery department: The recovery team has also gained a few new members at the start of this new year. Last year, a lot of research and tests were conducted in the Open Jet Facility of the TU Delft. This year, that trend is continued and the team has been provided with 5 days of full access to the wind tunnel. The first test series will be in the 3rd week of December, in which multiple new parachutes and configurations will be tested. Over the past years, DARE has had the same standard parachute, the cross parachute. Although easy to manufacture, this parachute does not have the best properties in terms of drag and stability. Therefore the recovery department has decided that, in addition to test more cross parachutes, an annular parachute will be produced and tested. An annular parachute can be best described as a half donut. This donut would be cut throughout its length, so the hole in the middle is still there. In theory, this parachute has a better drag coefficient, which means it can be made smaller for the same sized rocket. Results of this new research will be announced once the testing has been completed later this year
SIC ITUR AD ASTRA.