China is working on a space-ground integrated monitoring and early-warning network for asteroid defense under feasibility study, and Li Mingtao described it on International Asteroid Day. The plan pairs ground telescopes with a space-based constellation to track near-Earth asteroids with round-the-clock surveillance and no blind spots.
Li Mingtao on Asteroid Risk
Li, the chief scientist at the asteroid monitoring and early-warning research center under the China National Space Administration, said the system is meant to detect suspicious targets, calculate their orbits automatically and assess impact probability. He said that if a credible and urgent threat is identified, authorities will be notified immediately and the public will receive clear information about the risk and recommended actions.
He also said China has already made initial breakthroughs in risk assessment models and algorithms, and is developing an operational near-Earth asteroid early-warning system. More than 40,000 near-Earth asteroids have been discovered and cataloged worldwide.
China National Space Administration Plans
China will deploy multiple large-aperture optical telescopes at carefully chosen sites. Li said the ground network is intended to provide long-range, wide-coverage and precise night-sky surveys, while the space-based monitoring constellation would be free from atmospheric and day-night constraints.
The space segment is aimed at threats from the sunward direction, where ground telescopes are blinded by the sun's glare because of atmospheric scattering. Through coordinated ground-space operations, the system is designed to produce seamless day-and-night monitoring.
International Asteroid Day Warning
Li said on Tuesday, the International Asteroid Day designated by the United Nations, that no asteroid has so far been identified that will definitely collide with Earth in the foreseeable future, but many near-Earth asteroids remain undetected. He said the greatest risk comes from those hidden objects, which are numerous, faint and potentially approaching from the sun.
He added, "We must never let our guard down, but there is also no need for excessive anxiety."
Li said kinetic impact is the most viable countermeasure if an asteroid threatens Earth, while gravity tractors, ion beams and laser ablation exert very weak forces and would require over a decade of advance notice to work effectively. "That is why global scientists are racing to build monitoring and early-warning capabilities and catalog them," he said.
