How can lubricant be prevented from evaporating in the vacuum of space and damaging sensitive satellite components? Josef Pouzar explored this question during his doctoral studies at FME. He focused on so-called labyrinth seals—unobtrusive yet crucial components of space mechanisms. His dissertation was prepared in cooperation with the European Space Agency (ESA), and its results are set to be tested directly in orbit.
Space is fascinating, but also an extremely hostile environment—not only for humans, but also for space technology. It is a vacuum, with intense radiation, and atomic oxygen also causes problems by disrupting the structure of materials. In space applications, labyrinth seals are used to keep liquid lubricants in place while preventing contamination of surrounding subsystems. In a vacuum, lubricants gradually evaporate, which can compromise both device functionality and sensitive optical components. And that is not the only issue.
“In space, there is no atmosphere, and therefore no layers of adsorbed molecules to keep surfaces apart. When two clean metal surfaces are next to each other, they have no reason to ‘think’ they are not one and the same—and so they can weld together. This is known as cold welding, and it has happened before, for example during the Galileo mission. It is a problem we are trying to prevent. That is why lubricants are one of the key topics space engineers deal with,” explains Josef Pouzar of the Institute of Machine and Industrial Design, who has recently earned his PhD.
The inaccuracies in predicting lubricant evaporation were precisely what inspired his research. The topic proved so compelling that it was also supported by the European Space Agency (ESA) through its Co-funded Research programme within the Discovery initiative, under which the agency co-finances part of the costs of doctoral projects and provides ongoing expert consultations. The support is difficult to obtain, with a success rate of around seven percent.
“If you succeed, ESA supports your research by covering half of the costs throughout your doctoral studies. I also had the opportunity to consult regularly with ESA experts. René Seiler was responsible for my project on the agency’s side—a person who has worked at ESA for twenty-five years and has been involved in most of its scientific missions,” says Pouzar, describing the support as his gateway into the world of space technologies.
In parallel with his fundamental research, ESA also commissioned a consortium of companies to address a similar problem by developing computational software for more accurate predictions of lubricant leakage. “Their development is still ongoing. ESA would like to have one comprehensive output from both projects in the end, so we are now discussing how my results could contribute to the development of the software,” adds Pouzar, who is looking forward to continuing work on the topic for the agency.
| Interested in learning more? Read the article on the ESA website. |
These are not the only plans he has for the results of his research. Last year, at the International Engineering Fair in Brno, he and his colleague David Košťál presented an experiment they plan to send into orbit next year aboard the BRNOsat experimental satellite. “We will compare a traditional seal with our optimized version directly in microgravity. At the same time, we are developing new measurement methods, because collecting data directly in orbit is technically very challenging,” says Pouzar.
The research also has potential beyond space applications. The principles of molecular flow and contamination in vacuum are important, for example, in semiconductor manufacturing and other technologies operating in vacuum environments. According to Pouzar, the results could also be applied through cooperation with industry.
“One of the options currently being prepared is to build on this research through a spin-off company focused on consulting, simulations, experimental validation, and optimization of labyrinth seals for vacuum applications. My long-term goal, however, remains further professional development in the field of space mechanisms and cooperation with ESA,” concludes Pouzar.
| Labyrinth Seals in Space
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