China declassifies tech of world's first high orbit radar satellite, worrying US

South China Morning Post

27-02-2025

After 18 months of eye-in-the-sky secrecy, Chinese scientists have revealed the revolutionary technology behind the world's first
geosynchronous orbit synthetic aperture radar (SAR) satellite , giving China a permanent view of one-third of the Earth's surface.
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Ludi Tance 4-01 – or Ludi – which was
launched in August 2023 , is the highest flying surveillance satellite ever launched. It continuously monitors the Asia-Pacific region from an altitude of 36,000km (22,370 miles), far above US remote-sensing radar satellites that are positioned in low Earth orbit, according to the project team, led by senior engineer Ni Chong, with the China Academy of Space Technology (CAST).
The satellite is equipped with a 'space power combination' system that merges multiple microwave beams in mid-space, between two objects. The feat – reminiscent of the Death Star in the Star Wars films – allows it to achieve high, stable radar emissions that can penetrate cloud cover and darkness while maintaining relatively high resolution, Ni said in an article published in the latest issue of Chinese Space Science and Technology, a peer-reviewed journal run by the academy.
Beijing has said that Ludi is intended for civilian purposes, such as weather observations and earthquake monitoring, to improve
disaster prevention and responses. It can also be used to help researchers in oceanography, meteorology, agriculture and forestry.
However, the United States military remains wary about Beijing's advancing satellite capabilities.
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Ludi can be coordinated with other powerful Chinese surveillance satellites to make a 'qualitative leap' in tracking and targeting capabilities, according to Chief Master Sargeant Ronald Lerch, an intelligence specialist at the Space Systems Command under the United States Space Force, who was quoted by US Space News in January last year.