Chinese scientists detect ‘spy balloon’ as small as F-35 stealth fighter on radar

Despite the US military struggling to detect a balloon in its airspace, Chinese scientists have a simple method using common weather radar.

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US sailors recover a high-altitude surveillance balloon in South Carolina in February 2023. Photo: TNS

Published: 10:00pm, 26 Jun 2024Updated: 2:43am, 27 Jun 2024

While the US military struggles to detect spy balloons, Chinese scientists can offer a simple, efficient and low-cost solution.

According to recently declassified official information, the Chinese military conducted a field test of this unprecedented air-floating balloon detection technology in Wayao village, Neijiang, in the southwest province of Sichuan in January 2022.

The radar cross-section (RCS) of the balloon used in the test was only 16 square centimetres (2.48 square inches) . In comparison, the RCS of the F-35 stealth fighter is generally considered to be 15 square centimetres.

These balloons have a very low speed and are therefore more difficult to detect than aeroplanes. Under complex terrain and electromagnetic interference in the open environment, traditional radar detection methods cannot distinguish them from background noise.

The People’s Liberation Army (PLA) has launched 14 such balloons at various times and locations. With the help of the new radar technology, their probability of detecting and locking onto such targets soared from close to zero to 100 per cent.

“In military terms, air-floating balloons have functions such as creating false air situations, dropping lethal weapons, creating public opinion or psychological warfare, and intelligence reconnaissance,” wrote the project team led by Yin Jiapeng, an associate researcher on radar technology with the PLA National University of Defence Technology, in a peer-reviewed paper published in journal Acta Aeronautica et Astronautica Sinica on May 29.