In response to the sharp rise in satellite deployments-now exceeding 9,850 globally-scientists are racing to protect these valuable assets from ground-based detection, particularly in the infrared spectrum. While visible and microwave detection have constraints, infrared sensors exploit low background radiation, making satellites highly vulnerable.
Addressing this issue, researchers led by by Riko Seibo
Tokyo, Japan (SPX) May 28, 2025
In response to the sharp rise in satellite deployments-now exceeding 9,850 globally-scientists are racing to protect these valuable assets from ground-based detection, particularly in the infrared spectrum. While visible and microwave detection have constraints, infrared sensors exploit low background radiation, making satellites highly vulnerable.
Addressing this issue, researchers led by Professor Qiang Li from Zhejiang University have proposed a groundbreaking infrared camouflage and thermal control strategy tailored for space environments. Their approach, detailed in Light: Science and Applications, targets four critical infrared detection bands-H, K, MWIR, and LWIR-for camouflage, while allocating the VLWIR band for efficient radiative cooling.
The core of their solution lies in a multilayer thin-film device-just 4.25 um thick-built from a ZnS/GST/HfO2/Ge/HfO2/Ni stack. It achieves high absorptivity in the H (0.839) and K (0.633) bands to reduce solar reflection, low emissivity in MWIR (0.132) and LWIR (0.142) to mask thermal signatures, and high emissivity (0.798) in the VLWIR band to promote heat dissipation.
Tests conducted on a satellite model showed the device significantly reduced radiative surface temperatures when viewed under MWIR and LWIR cameras. Camouflaged sections registered 30.5C and 21.0C, respectively-well below the unshielded areas at 42.2C and 45.5C-nearly matching sky background temperatures. Signal intensity also dropped by up to 36.9% in the H band and 24.2% in the K band compared to uncoated surfaces.
Simulated vacuum conditions mimicking space demonstrated that the device could lower thermal equilibrium temperature by 39.8C under a 1,200 W/m heat load. This confirms its suitability for managing heat in space, where radiative transfer is the only means of thermal control.
The researchers emphasized that this spectrally selective thin-film technology not only conceals satellites from infrared detection but also addresses their thermal stability needs. "This work holds significant prospects for augmenting our capabilities in space exploration and exploitation, thereby paving the way for humanity to venture into expanded realms of habitable space," the team stated.
Research Report:Space-to-ground infrared camouflage with radiative heat dissipation
Related Links
Changchun Institute of Optics
Space Technology News - Applications and Research