A Swiss student project is shooting for the stars: As part of the student association for space, the team of project EULER is building the first supersonic rocket of Switzerland. For their construction, the students also make use 3D printing technologies such as Selective Laser Sintering (SLS).
A STUDENT ASSOCIATION FOR AEROSPACE AND AVIATION
The “Akademische Raumfahrt Initiative Schweiz” – ARIS for short – is a student association that pushes for more aerospace topics in Swiss academia. According to ARIS, this field is often underrepresented in the curricula of the universities. That is why the association offers more than 120 students from the German speaking part of Switzerland the unique opportunity to develop, design and test rockets and rocket engines. However, ARIS by no means limits itself to the natural sciences: students from various disciplines such as mechanical engineering, electrical engineering or even management are brought together to form interdisciplinary teams. In the future, the goal is to become one of the Swiss main players in the field of aerospace, both technically and scientifically.
REACHING SUPERSONIC WITH PROJECT EULE
One specific goal of ARIS is to win the annual Spaceport America Cup (SPAC). Every year, this competition attracts several hundred student teams from all over the world to the desert of New Mexico where their rockets compete against one another in various categories. For 2020 the corresponding rocket project of ARIS is named EULER – after the Swiss mathematician and astronomer Leonhard Euler – and is under the technical lead of physics student Michael Kerschbaum.
"The aim of the project is to develop ARIS’ first supersonic rocket and fly it to an altitude of almost 10,000 meters" Michael states. And even though the Cup could not be held this year due to the COVID-19 pandemic, Michael’s team of 35 motivated students is still committed to this endeavor.
MORE FLEXIBILITY THANKS TO 3D PRINTING
Developing a supersonic rocket is not an easy undertaking. For a student project, the situation is further complicated by a limited access to industrial production methods and the lack of financial resources. As a result, the students at ARIS often rely on cost-effective 3D printing technologies to construct their prototypes – both with in-house Fused Deposition Modeling (“FDM”) printers and sponsored selective laser sintered (“SLS”) parts. For the team, the main advantage of additive manufacturing lies in the great flexibility during the design phase. "3D printing allows us to be very creative when coming up with ideas and to quickly integrate new features," Michael Kerschbaum explains. For example, a mount for a new on-board computer was quickly designed, 3D printed and installed in the rocket just days before a test run.
SINTRATEC SPONSORS LASER-SINTERED COMPONENT
In the case of ARIS, 3D printed parts are usually located inside of the rockets, where material requirements are comparatively low. Components on the outside of the rocket on the other hand need to be aerodynamically optimized, as they affect the drag, while being robust enough to withstand the extreme forces during lift-off. FDM printers quickly reach their limits in such applications, which is why Team EULER looked for sponsors in the field of selective laser sintering. As the only Swiss manufacturer of SLS 3D printers, Sintratec was quickly found to be the right partner to produce the required work pieces on the Sintratec S2 system free of charge. The parts sintered with durable nylon powder (Sintratec PA12) are so-called Launch Lugs (see below). "This is a very crucial part for the rocket’s flight – if the launch lug does not hold in the first few moments, the rocket cannot lift off the launch rail safely," emphasizes Michael Kerschbaum.
About the Launch Lug
The launch lug is designed to guide the rocket safely from the launch pad when taking off alongside the launch rail. You can think of the launch rail as a track in which the launch lug is guided. The heavy forces during lift-off (the launch lug slides along the rail at speeds of up to 200km/h) require a high degree of robustness of the used material. By means of SLS 3D printing the launch lug of team EULER was aerodynamically optimized and perfectly adapted to the launch rail.
FIRST SUPERSONIC – THEN ORBIT?
After more than 9 months of development, manufacturing and testing, the EULER team was ready for the maiden flight in July 2020. In the Swiss mountains near Lucerne, the rocket with the Sintratec parts had to prove itself – with success: The launch proceeded without any errors and the launch lugs had no problem withstanding the forces. Michael Kerschbaum was convinced by the material properties of the SLS components: "The Sintratec technology allows for a high degree of flexibility in manufacturing while at the same time keeping weight down – both of which are important advantages for the aerospace sector. I can imagine many applications where such parts could be used in the production of rockets or rocket engines." For the first supersonic flight of their rocket, the students now have to find a more suitable location with a greater amount of free airspace than small Switzerland. But even if ARIS will have to wait until the sound barrier is broken, the ambitions remain high: "By 2029, we also hope to be the first student team to send something into the Earth’s orbit (rocket, satellite, rover…)," emphasizes Michael.
Sintratec is wishing the team all the best – and who knows, maybe then we will not only be able to admire the first Swiss rocket, but also the first Swiss SLS parts in orbit.