China plans to use its new China Compound Eye facility in Chongqing to observe asteroids and Earth-like planets hundreds of millions of kilometers away as part of its planetary defense work.

The Chongqing Innovation Center under the Beijing Institute of Technology, which designed and built the China Compound Eye, recently released its first 3D radar map of an area of moon craters taken by the high-definition deep-space observation facility.

Long Teng, an academician at the Chinese Academy of Engineering, said the facility consists of an array of radar antennas, which make it appear like the compound eye of an insect, with many tiny eyes to observe wide angles and ranges.

The 3D map of the moon craters was compiled using observation data from four radars built during the project's first phase. The mapping of the crater area was completed to verify the feasibility of the radar system.

The project's second phase will see the construction of 25 high-resolution radars, each with a diameter of 30 meters.

Although both are referred to as "eyes," the China Compound Eye in Chongqing is quite different from the "China Sky Eye," the FAST telescope in southwest China's Guizhou Province. FAST is a radio telescope that collects signals from stars but cannot detect asteroids as the small celestial bodies do not emit electromagnetic waves.

The facility in Chongqing shoots radio signals and records bounced signals to observe asteroids and terrestrial planets. "It's like we shine a beam of light through a flashlight in the darkness, illuminating our target and allowing us to take a look," said Xiang Yin, an associate researcher at the Chongqing Innovation Center.

Last April, Wu Yanhua, deputy director of the China National Space Administration, told Chinese media that the country would start to build Earth-based and space-based near-Earth asteroid monitoring and warning systems.

Xiang said the Chongqing facility is essential to the country's planetary defense system. Suppose a spacecraft is set to collide with an asteroid to deviate from its course -- it would be necessary to have accurate measurements of its original orbit as well as the orbital change following the impact and the distribution of the debris.

He said that after the completion of its third phase, the China Compound Eye is expected to have more than 100 radars to observe asteroids within 150 million kilometers of Earth.

It will be able to observe the trajectory of an asteroid the size of a soccer ball tens of thousands of kilometers away to determine if it could be hazardous to our planet, Xiang said.