A team of engineering students at Rice University in Houston, Texas, has designed and built a safer, low-cost propulsion module for small satellites – a breakthrough that won them the top prize at the 2025 Huff OEDK Showcase and competition, the signature event of the Oshman Engineering Design Kitchen.
The project prompt came from Stellar Exploration, a California-based aerospace technology company looking for a student team that would ‘really dig into the R&D and document their work’, said Chance Bisquera, a design engineer at the company who mentored the team.
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‘This is an all-encompassing project that covers a lot of the aspects of what we were looking for in a new system, both from a design perspective and an R&D perspective,’ Bisquera said. ‘Throughout the year, I’ve seen the attention to detail they put in with everything ⎯ that was definitely something that our company had asked for throughout the process, and I think the team definitely delivered and more.’
The team designed, fabricated and tested a warm gas propulsion system for small satellites featuring a custom cylindrical pressure vessel, optimised supersonic nozzles and a compact thruster array small enough to fit within four CubeSat units. Their design uses ‘warm gas’ technology to propel small satellites in orbit without relying on conventional hypergolic propellants typically used in spaceflight.
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‘This is something that is just starting to make its way into the industry. It’s a type of propulsion system that is still pretty underutilised,’ said Warren Rose, a mechanical engineering student.
Conventional propulsion systems are difficult to scale down for small satellites. Cold-gas-based systems have low energy density, requiring larger volumes of gas to fuel the satellite for sufficient durations. Meanwhile, combustible propellants have much higher energy efficiencies, but they are toxic and difficult to work with, raising regulatory hurdles for testing such as specialized hazmat crews and isolated testing sites.
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The new system uses an off-the-shelf, chemically inert automotive refrigerant stored as a liquid and vaporised with heat to generate thrust. ‘What this system can provide a massive discount on is that sunken cost in the testing and development phases,’ Rose said, adding that the team opted for the most environmentally friendly propellant. ‘We can test it right here at the OEDK around other students.’
Daniel Stulski, a mechanical engineering senior, emphasised the challenge of the scale of the system the team was tasked to develop. ‘Our nozzles are tiny. The throat diameter is 0.2 millimetres, so it requires a different level of precision than most other applications,’ he said.
To measure thrust at the scale of their system, the team built a custom vacuum chamber test setup capable of detecting forces smaller than the weight of two pennies. Anish Chitnis, who has an aerodynamics internship lined up at Lockheed Martin, explained that this served to emulate the conditions under which the thruster would have to operate, outside the Earth’s atmosphere. ‘This was a way for us to actually validate our models and make sure the whole design could reach performance targets,’ he said.
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In addition to the technical challenges, the project also entailed handling complex logistics. The team adopted a real-world management system where each student took end-to-end responsibility for a major component, mirroring practices at top aerospace firms.
The students credit their time at Rice and the environment at the OEDK ⎯ a 2,000-square-metre facility supporting more than 1,200 students this year ⎯ with preparing them for the demands of high-impact engineering work.
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Sam Sarver, who worked on packaging the system into a compact satellite-compatible form factor, said his time at Rice and the capstone project experience helped him grow both in terms of engineering but also teamwork and leadership skills. ‘My time at Rice has shaped how I approach problems and collaborate with others,’ he said. ‘This project brought it all together — engineering under real constraints, working across disciplines and learning how to lead and adapt as part of a close-knit team.’