China has begun worki on the construction of the second phase of their planetary defense radar array, known as the "China Compound Eye" or Fuyan project.

The China Compound Eye project involves the creation of a network of radar antennae, which will use radar signals to track and image asteroids, and determine whether they pose a threat to Earth.

The first phase of the project, which consisted of four 54-foot-diameter radars located near Chongqing, was completed in December of last year. Scientists used this initial phase to ping signals off the moon and test the feasibility of the system's key technologies.

The second phase of the project involves the construction of 25 radar antennas, each with a diameter of 98 feet, and is expected to be completed by 2025. This expansion will allow researchers to observe asteroids as small as dozens of meters in diameter from a distance of 10 million kilometers away. With this improved observation capability, researchers will be able to determine an asteroid's composition, rotation speed, and changes in orbit after being hit.

Following the completion of the second phase, a third phase will be initiated to expand Fuyan's detection range to 90 million miles using multiple smaller arrays. This system will simulate a larger aperture to allow for deep-space detection.

In April of last year, the China National Space Administration announced plans to launch a planetary defense plan, which includes tracking near-Earth objects and launching an asteroid-deflection test similar to NASA's DART mission in the coming years.