From defense to telecommunications and Earth observation to space exploration, cubesats have become a critical tool in expanding our horizons. But as the technical demands of the domain increase, power densities and subsequent temperatures are also on the rise. To help keep these temps in check, NLR and ISISpace have joined forces to keep the satellites, and their system engineers, cool.
Cubesats are a vital source for gathering information about the planet and its surrounding area. As satellite technologies continue to advance, these space-borne sensors have become more affordable and much more accessible. But as they get more popular, domain expectations are growing – demanding higher technical needs and larger payloads, resulting in increased power densities and rising temperatures of the onboard electronics. To keep the burgeoning technology from overheating, and its system engineers from breaking into a sweat, NLR is teaming up with Delft-based satellite integrator ISISpace on a mission to create new thermal modeling and dissipation concepts to cope with rising temperatures.
Through research and first-hand experience in the cubesat industry, NLR and ISIS have narrowed the thermal issues down to a few main gaps, or problems to solve. First is hardware design, which makes updating thermal controls difficult to implement and integrate. Next is knowledge, or the lack of insight and information on thermal properties like the transfer of heat through common elements of cubesats through conductive coupling or contact conductance. Finally, linked to this lack of information, is the verification and validation of systems with only basic modeling and testing.
To close the gaps in knowledge, collaborators turned to Esatan-TMS to build detailed thermal modeling concepts for improved accuracy of testing results and data. In doing so, researchers aim to cut the lead time of thermal analysis and the thermal modeling process. Additionally, with the new wealth of information, NLR and ISISpace can use the data to create a library of thermally validated and verified cubesat modules that can be used as building blocks for future satellites – accelerating the process even further for both current and potential customers.
Multi-parallel micro pump
While working to close the knowledge and validation gaps with more accurate data and standardization with the help of Esatan thermal modeling, project collaborators were also interested in how cubesat hardware could address the issue of rising or spiking temperatures. Compared to regular satellites, cubesats almost always have a higher energy density and subsequently higher temperatures than conventional satellites, due to advances in solar cell technology and miniaturized electrical components. The introduction of propulsion modules and high-power electronics are also contributing factors. To tackle this energy density issue, researchers narrowed their focus to a single-phase mechanically pumped fluid loop (MPFL).
At the heart of this NLR-patented design is the multi-parallel micro pump. This novel pump design utilizes a piezo-operated two-stroke system that transports heat through the use of a working fluid by heating it up at the heat source and then pumping that fluid to a heat sink or radiator where it’s then ejected into space. With their working prototype, NLR and ISISpace have realized 20 watts of heat transport at a mass flow of 500 mg per second with a pump power consumption of just 0.2 watts – suitable for today’s thermal dissipation needs.
The next step for collaborators, however, is to address future needs, which is why they’ve moved into the next phase of the project, which aims to scale the technology to transfer 100 watts of heat energy with a power consumption of less than 5 watts. Completion of this phase is expected by 2023. After completion, NLR, ISISpace and manufacturing partner Demcon Kryoz hope to continue development of the system with an in-orbit demonstration.
This article was written in close collaboration with NLR.