A novel infrared camouflage capability could help valuable satellites evade detection in the increasingly crowded orbital space around Earth, offering a new stealth defense against satellite detection tools.
The camouflage technology, developed by researchers at Zhejiang University, is the brainchild of Professor Qiang Li’s team from Zhejiang’s State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering. The new technique takes on the greatest threat to identifying any satellite, anywhere, at any time.
Orbital Expansion
Satellite launches continue to accelerate, with estimates placing the number of active satellites at 11,701 as of May 12—up from 9,850 at the end of 2023. This growth is part of an expanding space economy, which the World Economic Forum predicts will rise from $630 billion in 2023 to $1.8 trillion by 2035—nearly double the projected growth rate of the global GDP. Protecting high-value space assets like military and intelligence satellites has remained a complex and unresolved issue.
Satellites in orbit are primarily vulnerable to three types of detection: visual, microwave, and infrared. The first two have notable limitations. The bright sky masks satellites during daylight, making visual detection extremely difficult. While microwave sensors can offer 24-hour tracking, they are most effective for identifying objects in low Earth orbit. This makes infrared detection the most reliable method for locating satellites at any time and altitude.
Reconceptualizing Infrared Camouflage
The extreme space environment has long hindered the development of effective infrared camouflage. Earlier attempts rarely accounted for the solar radiation spectrum, and existing radiative heat dissipation methods are largely ineffective in space, where heat can only be lost via thermal radiation. In addition to reducing infrared visibility, any workable camouflage must also minimize weight to support launch logistics and maintain durability against the harsh conditions of space.
Li’s team examined the infrared energy distribution across various wavelength bands to develop a potential solution. They identified ways to obscure signatures in the H, K, MWIR, and LWIR bands while dissipating heat using the VLWIR band. The researchers translated this theoretical concept into a physical device composed of layered materials: ZnS/GST/HfO₂/Ge/HfO₂/Ni. The system minimizes reflected solar radiation in the H and K bands, suppresses thermal radiation in the MWIR and LWIR bands, and allows high thermal emission in the VLWIR band to reduce heat buildup and maintain operational temperatures.
Testing a Stealth Satellite
The team conducted outdoor experiments to evaluate their technology by attaching the camouflage to a model satellite. The difference between exposed and camouflaged surfaces was clear when observed against the sky using infrared cameras. MWIR and LWIR cameras recorded exposed surfaces at 42.2°C and 45.5°C, while the camouflaged areas matched the sky’s background temperatures more closely, at 30.5°C and 21.0°C, respectively. In the H and K bands, reflectivity decreased by 36.9% and 24.2% in the camouflaged areas compared to the uncoated model.
In laboratory conditions, the researchers tested the material’s ability to dissipate heat in a vacuum chamber replicating space. Inside the chamber—pressurized to 0.15 Pa and cooled with liquid nitrogen to simulate deep space’s 3K background temperature—an electric heating plate mimicked thermal energy collected during satellite operation. Compared to a metal film used as a control, the new camouflage reduced the device’s temperature by 39.8°C.
“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 predicts.
The paper “Space-to-ground Infrared Camouflage with Radiative Heat Dissipation” appeared on May 27, 2025, in Light Science & Applications.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.