Making satellites smaller
Miniaturized spacecraft, such as satellites, are a hot topic. Both for engineers and scientists, because of the scientific and technological challenges involved. And also for society, as these smaller systems can be cheaper and more sustainable than traditional satellites. Silvana Radu MSc, Space Systems Engineer in the department of Space Systems Engineering (SSE), is working with her colleagues on the development of these miniaturized satellites.
With a mass of less than 1 kilogram, pico-satellites are lighter and cheaper than regular satellites. They can also be developed more quickly. Pico-satellites operate effectively in Low Earth Orbits, at a few hundred kilometres from the earth’s surface at most, reducing the overall cost of the missions. Also, the smaller a satellite is, the smaller the amount of energy is needed for its launch. After a life cycle lasting from just a few days to several months (rather than decades), these pico-satellites burn up in the atmosphere on their way back to Earth, leaving no trace of debris behind them.
You might think that miniaturising a satellite is simple: a linear back-calculation to a miniature format and it's done. Quite the contrary, explains Silvana: “Miniaturisation is not a question of simply downscaling the individual parts of a satellite. In fact, we need to completely reinvent the wheel and go through the entire design and qualification process all over again. Our aim is to define a new standard for smaller satellites and find applications that fit on these small platforms.”
“During the process of miniaturisation you get to encounter all kinds of things that do not yet exist. You will for example need to come up with a new way to connect the launch vehicle and the satellite.” This is a challenge that fits Silvana like a glove: “It forces you to think differently, which I really enjoy. One of Einstein's most well-known quotes is: ‘the important thing is to never stop questioning.’ I consider that to be my life motto: I'm inquisitive and always try to learn more. The brainstorming sessions in our team are the perfect time to do that. It's when the very best ideas emerge.”
Satellites the size of a chip are not an impossible dream. We have come far, but there is more to do.Silvana Radu
Silvana's interest in aerospace started at a very early age. “My father is a captain on a Boeing 737. He took me with him on his flights when I was still a toddler. In the cockpit, he taught me about navigation and avionics. My mother has a PhD in European Aviation Regulation, so most of the conversations at home were about aviation. Personally, I wanted to go a step further and discover space. I achieved this through my study programmes and work at the University Politechnica of Bucharest, the Romanian Institute of Space Science and at TU Delft.”
Thinking things through
Silvana's work started with CubeSat Subsystems: nanosatellites with standardised dimensions of 10 x 10 x 10 cm. She also worked on the famous ESA mission, Proba-3, involving two microsatellites aiming to research the Sun’s corona through difficult and precise manoeuvres of flying in formation. “Part of my research work at the Romanian Institute of Space Science and University Politechnica Bucharest on the Proba-3 mission was about detecting errors in the satellite and making sure that the onboard software automatically fixed them. This is a main engineering activity that starts with the design of the mission and ends with the satellite’s end of life. For this you need to think carefully throughout the entire process. And that is exactly why I find this subject so fascinating. You constantly have to think: “what can go wrong with this component, how do I prevent this from happening and if does, how can I solve it?
Just like everyone in space research, Silvana aims to help create a better world. “Scientists are trying to broaden their understanding of the solar system. At the same time, the business community is developing space applications such as satellite navigation to improve the quality of our lives. In order to make new progress in space travel, we need to improve our understanding of the universe. This is a question of striking the right balance and working constructively. But it is also about passing on our passion and inspiration to the next generation. I believe inspirational and original projects, plus the freedom to create, are essential for progress and for creating a more sustainable world.”
The focus in space industry and research is on making space vehicles both economically and environmentally sustainable. Examples of this include re-usable launchers (Falcon Heavy) and water-propellant for micro-propulsion. Also, satellites the size of a chip are not an impossible dream. Silvana: “We have come far, but there is more to do. The problem with miniaturization is that standards are not available, and it is difficult to find Launch Service Providers for pico-satellites.
It is even more difficult to find innovative space applications for these types of satellites, that are also relevant for research, science and the Earth. “We are currently implementing the micro-propulsion system developed by our colleague Angelo Cervone (link) and his team to measure how the satellite spins when the water-propellant thruster is not perfectly centred.”