China has begun building the world’s largest fully rotating radio telescope – the antenna diameter will be 120 m

Until now, the largest fully rotating radio telescopes in the world were the German Effelsberg radio telescope and the American Green Bank with 100-meter dishes. China intends to bypass these instruments by starting to build a monster with a 120-meter fully steerable antenna. The telescope will monitor the planets and asteroids of the solar system. The fully rotating design will allow you to do this at any point in the sky above the horizon at any time of the day.

Full rotation antennas of the VLA radio telescope array in the USA. Image source: wikipedia.org

Planetary defense will receive impressive reinforcements in the form of a radio telescope in Huadian in northeast China (Jilin Province). Since the collapse of the 300-m Arecibo radio telescope in Puerto Rico, which also served as a planetary radar, there are not many radio telescopes left to monitor near-Earth asteroids.

Today, the largest solid dish is the Chinese radio telescope FAST, whose diameter reaches 500 m. But it is created in the form of a so-called earthen bowl – in a natural depression in the ground and is limited in pointing at objects and tracking them. Such an antenna does not rotate itself; this happens by adjusting the phases of the radio signal. A rotating telescope in this regard is the height of flexibility, but its cost is prohibitive, since mechanisms and counterweights are needed to provide all degrees of freedom of movement for a giant antenna.

The site for the construction of the telescope has been selected in May 2024. To date, the foundation of the structure has already been partially poured. The radio telescope is expected to be commissioned in 2028. The work is supervised by the Chinese Academy of Sciences (CAS).