"It's crazy that you can study something like this: it’s usually the preserve of NASA!" That's what Sabine Klinkner thought when she came across the "Aerospace" folder at the Vocational and Information Center. Having good grades in maths and physics and following a few taster lectures, she began her engineering studies at the University of Stuttgart in 1996. "Even now", she says "I'm still thrilled about the fact that we always have to go to the limits in aerospace research and are continuously faced with new challenges." After all, satellites cannot be built using the modular design principle. A satellite is a highly complex system that has to get by on extremely limited resources both in terms of the construction materials and energy consumption whilst meeting some extremely demanding specifications. Above all, it has to be robust. Although the ground crew can upload software updates once the satellite is in orbit, for example in connection with the mission program, nobody can press the reset button. Klinkner always sees satellite research as an adventure.
Following her studies, she first worked for twelve years in a medium-sized systems aerospace products company, where she built scientific instruments and rover systems, such as robots that are used to explore the surface of planets, before committing to a career in science and also worked on her part-time doctoral degree studies. In 2015, she was invited to accept the University of Stuttgart's newly created Chair of Satellite Technology, which she ultimately accepted in order to have more freedom to pursue her scientific work. Klinkner introduced exploration robotics to the University and began to promote the development of small satellites, "which are not only needed in all aspects of spaceflight, but are also the perfect subject for teaching."
That is why she is a dedicated advocate of "a well founded, highly qualified and practice- oriented education." Power and communications systems, data management and thermal regulation, and the propulsion system are just some of the satellite's subsystems, whose interaction in orbit have to be orchestrated under difficult conditions. Klinkner involves her students in the development process as early as possible. "To understand these processes, you have to go through all the stages yourself," she explains. One example is the "Flying Laptop", which was launched into space from the Baikonur Cosmodrome on board a Soyuz-2 rocket in the summer of 2017 and was developed, built, and qualified for use in orbit almost exclusively by students and doctoral candidates. The fact that it is still orbiting 600 kilometers above the Earth is a success story for all involved.
Mission romeo: into space with innovative technology
As is the case for about 95 percent of small satellites, the "Flying Laptop" is traveling in a low Earth orbit (LEO). Klinkner's wants to reach medium earth orbit (MEO) in 2025 with her new "Research and Observation in Medium Earth Orbit" (ROMEO) mission. MEO extends to an altitude of 36,000 kilometers above the Earth and, until now, has been relatively underutilized: even getting there presents a challenge, as does operating a satellite in that zone. Currently, our knowledge about the environmental conditions in the MEO and their effects on materials and technology remains limited. That is why the new 60 kilogram "lightweight" research satellite will not only carry out Earth observations and space weather research, but will also take innovative technologies into space to be tested.
The research team wants to find out how they behave in a region of outer space, which is exposed to extreme radiation, and how they can be made fit for future MEO satellite missions. Alongside a green hydrogen propulsion system and a radiation-tolerant central computer, which the team is planning to assemble using "off-the-shelf" components for the first time, a compact and lightweight communications system with the lowest possible power requirements for data transmission in the amateur X-band will also be on board. "The most power-hungry component in a small satellite is the communications system," Klinkner explains. Signals transmitted between the satellite and the ground station are repeatedly disrupted due to various transmission losses. Until now, communication systems have been designed conventionally, i.e., to cater for the worst-case scenario, to ensure that they always function reliably, which, however, not only increases the energy requirement but also has a negative effect on the data transmission rate.
Research sattelite to reach an altitude of 2000 kilometers
The new system is expected to automatically adapt to the continuously changing conditions during a satellite overflight in order to save resources and optimize the use of bandwidth, an adaptive capacity, which Klinkner finds "particularly interesting" in view of the ROMEO mission because the plan is for the research satellite to spiral up from a low, circular orbit to a medium, elliptical orbit at an altitude of up to 2,000 kilometers after three months. If, rather than orbiting the Earth in a circle, a satellite takes an elliptical course, the environmental conditions become even more volatile, which significantly alters the requirements for a communications system that needs to be perfectly tuned. In view of this unique challenge, ROMEO is the ideal mission for testing an adaptive data transmission technology. The AI-controlled ground station will determine and transmit the optimal data transmission signal coding for each point in time in order to optimize the use of the entire overflight for data collection purposes.
What really fascinates me is to see the things I build fly.Prof. Dr. Sabine Klinkner
"That will enable us to get the most out of the mission," says Klinkner, who is expecting to increase data transmission rates by up to 100 percent. Her research projects place her at the interface of an expanding market in which the small satellite industry is being driven by both digital companies and the legacy economy. These smaller satellites have long been a "key component" for the Federation of German Industries (BDI) and the Association of German Engineers (VDI) and will account for 90 percent of the approximately 15,000 satellites to be launched by 2030 according to the two organizations. What is the role of the scientific community in light of this boom? "Our role is to explore new ideas without the pressure of commercial imperatives, which will later benefit everyone,"
Klinkner explains: "And we can also make significant contributions towards solving urgent problems such as the avoidance and removal of space debris." Trying to find ways of ensuring sustainability and safety in space given the growing volume of orbiting traffic is just one of the exciting challenges that space researchers are likely to face going forward. As Klinkner explains in summary: "We need to develop technologies that will keep the existing orbital zones clean even as we open up new ones.” Notwithstanding her thirst for adventure, the mother of two has not yet booked a ticket to space. "What really fascinates me," she says, "is to see the things I build fly. And that's by no means a given in the aerospace sector."
Author: Jutta Witte