40 n SCIENTIFIC AND MEDICAL May 2025 www.drivesncontrols.com Flower-inspired satellite relies on tiny motors In the battle against climate change, it is crucial to minimise the heat escaping from buildings. Lost heat is expensive, so government agencies and businesses need to manage heat e ciency to control costs. The most e ective way to do this is by using a heat map, generated from satellite imagery. Until now, such a technology has not been widely available, but this is set to change with the launch next year of Hibiscus – a new satellite that will bring down the cost of thermal imaging, opening the benets of ultra-high resolution heat mapping to a wide range of applications. The satellite to due to be placed in orbit at the end of 2026 by a SpaceX rocket. Its uses could include: heat mapping of vehicles for security purposes; monitoring urban energy use for sustainability planning; and assessing the performance of irrigation schemes. The satellite, equipped with a highresolution camera, will capture thermal images to an accuracy of ±0.5ºC, in areas down to the size of a car. A key commercial advantage of Hibiscus, which is being developed by Cambridgebased Super-Sharp Space Systems – a team that originated in the city’s University – is its low size and weight, combined with a folding design. It will occupy a much smaller volume than existing thermal imaging satellites, resulting in a much lower manufacturing and launch costs, and making satellite thermal imagery commercially viable for a larger market. “With our telescopes, you will be able to get four times better resolution per unit cost, meaning that you can match the current state-of-the-art in thermal imaging from space using a satellite the size of a microwave,” explains SuperSharp’s CEO, Marco Gomez-Jenkins. “If our clients need higher image resolution, we can scale up to a larger platform with a larger version of our telescope to capture the sharpest thermal images available in the market.” Critical to Hibiscus’ success is nanometreprecision control of its mirrors which reect light from a target location towards the telescope’s sensors. An onboard metrology system measures the light, creating a feedback loop that automates the mirrors’ alignment. “When you’re operating in low-earth orbit, there are a lot of changes in the environment because of thermal cycling,” Gomez-Jenkins explains. “The feedback loop involving the onboard metrology system will enable Hibiscus to update position automatically every 10 seconds to enable the capture of extremely sharp images. That’s a huge advantage because you don’t need to rely on manual operation of the telescope, 24/7, to update the desired position of the mirrors.” Hibiscus gets its name from its ve unfolding mirror “petals”, similar to those of the ower of the same name. Deploying these petals is fundamental to telescope’s ability to capture thermal images. Once the satellite is in orbit, each petal will be driven by two maxon DCX motors with a high-e ciency GPX gearbox and an extended temperature encoder. Four more DCX motors will control robot arms that assist with the ne adjustment of the mirror conguration. Initially, the drive system will need to survive the extreme vibrations of launch. Once in space, the motors must operate in a vacuum, and withstand extremely low temperatures. The motors have been developed and tested to withstand the highest levels of shock and vibration. The motors’lubrication needs to prevent outgassing – the release of volatile substances trapped within lubrication when exposed to a vacuum. Outgassing can degrade the longterm performance of a drive, and cause condensation that can damage other components, so maxon has specied a vacuum-compatible grease. High solar radiation can also damage standard PVC insulation, so the motor and encoder use a PTFE alternative, with higher radiation resistance. Gomez-Jenkins says that one of the factors that inuenced the choice of the drive A UK-developed thermal imaging telescope due to be launched next year will open up new ways to combat global warming and increase building eciencies. A motor-driven unfolding mirror will reduce its size and boost its commercial viability for a variety of applications. When Hibiscus enters orbit at the end of next year, it will be the world’s rst closed-loop, unfolding thermal telescope.
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