Chinese Military Scientists' Loofah Coating Could Hide Stealth Jets from Space Radar
- MM24 News Desk
- 2 days ago
- 3 min read
Chinese defence researchers have transformed the humble bath loofah into an advanced stealth material capable of absorbing 99.99 percent of radar waves, potentially making fighter jets nearly invisible to space-based radar systems. The breakthrough from China Aerospace Science and Industry Corporation (Casic) and People’s Liberation Army (PLA) scientists addresses a critical vulnerability in modern stealth technology.
For decades, stealth aircraft like America’s F-22 Raptor have relied on specialized shapes and coatings to minimize their radar signature when viewed from the front or sides. But the advent of space-based radar satellites has created a new challenge—they scan from directly above, where an aircraft’s flat back can reflect radar signals like a mirror. This causes the radar cross-section to balloon from the size of a bird to tens of square meters, making even the most advanced stealth jets detectable.
Led by defence scientist Chen Jun with Casic’s Guizhou Aerospace Metrology and Testing Technology Institute, the research team turned to an unlikely solution: the fibrous, porous structure of the loofah gourd. The team carbonized dried loofah at high temperatures, creating a lightweight, conductive scaffold, and then embedded it with magnetic nanoparticles of nickel cobalt oxide (NiCo₂O₄). The resulting composite, dubbed NCO-2, is just 4mm thick yet can reduce reflected radar signal intensity by nearly 700 times, according to their study published in High Power Laser and Particle Beams.
“When the test angle is zero degrees, which means the direction of the electromagnetic wave is perpendicular to the surface of the test plate, the RCS value decreases from 26.46 dBsm to −1.94 dBsm,” Chen’s team reported in the journal.
This dramatic reduction means a stealth aircraft with a vertical radar cross-section of 50 square meters could effectively shrink to less than 1 square meter when coated with the material. Such performance could fundamentally change how stealth aircraft evade detection from orbiting radar satellites, stated the research team.
The loofah’s effectiveness stems from its natural architecture. When carbonized, its intricate 3D network of interconnected cellulose fibers creates what resembles a microscopic jungle. Electromagnetic waves entering this maze bounce around endlessly in a process called multiple internal reflection, giving the material more opportunities to absorb energy. Meanwhile, the carbon network allows electrons to move freely, converting microwave energy into heat through conductive loss.
What makes this material particularly innovative is its dual-action mechanism. The magnetic nanoparticles create boundaries that change the polarization of radar waves while generating additional magnetic losses through natural and exchange resonance. Together, these effects achieve near-perfect impedance matching—allowing radar waves to enter easily while preventing them from escaping. This combination of mechanisms is rarely seen in traditional absorbers and represents a significant advancement in stealth technology, reported the research team.
The production process is relatively straightforward and scalable, which could make future implementation practical. Fresh loofah is cleaned, dried and baked at temperatures from 300 to 700 degrees Celsius in inert gas to form the porous carbon skeleton. The team then soaks it in a solution of nickel and cobalt nitrates with urea, allowing nanoparticle crystals to grow directly on the carbon fibers. This simple approach contrasts with more complex and expensive methods typically used to create advanced stealth materials.
This innovation represents a broader shift in Chinese scientific approach. Rather than looking solely to Western institutions for inspiration, Chinese researchers are increasingly turning to natural materials and ancient wisdom for solutions. From bamboo forests to silk and traditional blacksmith techniques, nature is providing templates for cutting-edge military technology. The loofah breakthrough demonstrates how seemingly ordinary biological structures can solve complex engineering challenges when viewed through a scientific lens.
However, the path from laboratory success to operational aircraft coating presents several challenges. The material must withstand the extreme conditions of flight—supersonic vibrations, moisture, and temperature fluctuations from freezing high-altitude cold to engine heat. Additionally, while the current design works exceptionally well in the critical Ku-band (12–18 GHz) used by many radar satellites, real-world combat requires broadband absorption across multiple frequency ranges. The researchers acknowledge that further tuning will be necessary to achieve this comprehensive protection.
As space-based radar networks become more sophisticated, the need for advanced stealth materials that work from all angles becomes increasingly urgent. This loofah-derived coating could provide a crucial advantage in the evolving cat-and-mouse game of electronic warfare. While more development is needed, the research demonstrates that sometimes the most advanced solutions can be found in the most unexpected places—even in Cleopatra's bath sponge.
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