China to carry out asteroid defense system test in near future: chief scientist

Wu Weiren, chief designer of China’s lunar exploration program and newly elected president of the International Deep Space Exploration Association (IDSEA), delivers a keynote report at the third International Deep Space Exploration Conference held in Hefei, East China’s Anhui Province on September 4, 2025. Photo: Courtesy of DSEL

China has recently unveiled its plan to initiate an experimental verification project to demonstrate and test the effectiveness of its asteroid defense system, and Wu Weiren, one of the country’s top space scientists, stressed the necessity of such project to the Global Times on Sunday, saying that from the perspective of safeguarding the Earth’s safety and the continuation of humanity, building asteroid defense capabilities is a shared task for all humankind, while calling on further international collaborative efforts against the threats posed by asteroid impact. 

“As a responsible spacefaring nation, China has the responsibility, obligation, and capability to contribute Chinese wisdom, leverage Chinese strength, and systematically develop an asteroid detection and defense system, working together with the world to protect our planetary home,” Wu said. Wu is the chief designer of China’s lunar exploration program and director and chief scientist of the country’s Deep Space Exploration Laboratory (DSEL).

Wu outlined China’s asteroid exploration and defense system in detail for the first time at the third International Deep Space Exploration Conference, and during the event held from Thursday to Friday in Hefei, East China’s Anhui Province, Wu revealed that in the near future, China will conduct a kinetic impact demonstration and verification mission on an asteroid posing a potential threat to Earth. 

“We will launch an observer and an impactor. The observer will arrive first to perform close-range observations of the target asteroid, obtaining detailed characteristic parameters. Then, the impactor will carry out a high-speed collision with the asteroid. The entire impact process will be monitored through a combined space-ground approach, observing changes in the asteroid’s orbit, morphology, and ejecta, to accurately assess the impact’s effectiveness,” Wu said.

Asteroids are small celestial bodies that orbit the Sun, with smaller volume and mass than planets and dwarf planets, and they rarely release gas or dust. They are primarily composed of rock and metal. The solar system contains billions of asteroids, categorized by proximity to the Sun into groups such as near-Earth asteroids, main-belt asteroids, Trojans, Centaurs, Kuiper Belt asteroids, and more, the DSEL said in a statement to the Global Times on Sunday. 

Asteroids are considered “living fossils” of the solar system’s formation and evolution. However, Near-Earth asteroids are among the most potentially damaging celestial bodies in the solar system. The scientific community widely believes that 66 million years ago, an asteroid approximately 10 km in diameter struck Earth, wiping out around 75 percent of species, including dinosaurs. High-impact events are extremely rare but carry immense destructive power, and the United Nations lists asteroid impacts as the top disaster threat to human survival, according to the lab.

But our understanding of asteroids is still limited, the lab noted. As of March 2025, humanity has identified 38,171 near-Earth objects, including 38,048 near-Earth asteroids and 123 near-Earth comets. Because asteroid monitoring is difficult, many near-Earth asteroids remain uncatalogued, with estimates suggesting that only about 1 percent have been fully recorded. For instance, in early 2025, the asteroid 2024YR4 had a collision probability that rose to 3.1 percent, causing global concern.

Pang Zhihao, a senior space expert, told the Global Times on Sunday that such an asteroid defense experiment is highly challenging, with the main difficulties lying in “precision” and “uncertainty.”

“It’s like hitting a fly from tens of millions of kilometers away,” he said, “with both the asteroid and Earth moving at high speeds.” The experimental spacecraft must travel through space for months or even years, constantly adjusting its trajectory to precisely strike an asteroid only a few hundred meters in diameter, with an error margin of just a few dozen meters. This is far more challenging than long-range shooting on Earth, Pang elaborated.

Also, we are not sure how hard the asteroid is, especially its internal structure. It could be solid rock or a loose rubble pile, Pang said, noting that the inability to definitively determine the asteroid’s “hardness” before the experiment makes it difficult to accurately predict the orbit deflection effect.

The China National Space Administration (CNSA) launched the “Near-Earth Object Exploration Program” in 2006. In 2021, it began a feasibility study on an asteroid defense project, and in the same year, the white paper on China’s Space Program explicitly proposed studying and building a near-Earth object defense system, Wu said when asked to explain on China’s progress and planning on the asteroid defense issue. 

On May 29, 2025, China successfully launched the Tianwen-2 probe, which aims to return samples from the near-Earth asteroid 2016HO3 and later conduct flyby observations of the main-belt comet 311P, Wu added. 

Wu said, in terms of ground-based monitoring and early warning, China has established routine sky-survey capabilities. The country has built the 1-meter dedicated telescope at Purple Mountain Observatory, a 2.5-meter large-field survey telescope at Lenghu, the 2.16-meter telescope at Xinglong, and the 2.4-meter and 1.8-meter telescopes at Lijiang. The “China Compound Eye” project plans to construct 25 radars with 30-meter apertures, which will allow detection and high-precision imaging of asteroids tens of millions of kilometers away once completed. 

China has preliminarily established a ground-based monitoring network with multi-caliber coordination, multifunctional integration, and efficient collaboration, the DSEL chief scientist said. 

He explained that when a near-Earth asteroid posing a potential threat to Earth is identified, in accordance with the requirements of the United Nations Committee on the Peaceful Uses of Outer Space, if the warning level reaches a certain threshold, in-orbit mitigation measures must be carried out. At present, China is exploring kinetic impact mitigation solutions and researching long-term mitigation methods such as laser ablation and attachment-based deflection.

Looking ahead, China plans to establish a comprehensive near-Earth asteroid detection and defense system. It will deploy observation spacecraft at optimally selected stable orbital positions, forming a multi-orbit, multi-method, integrated space-based monitoring network capable of efficient coordination with the ground-based monitoring network. For near-Earth asteroid impact risks of varying sizes and mitigation requirements, China will refine multiple mitigation methods, including instantaneous and long-term approaches, develop various mitigation spacecraft and in-orbit evaluation spacecraft, and establish a mission library for near-Earth asteroid defense. For asteroids of different sizes and impact risks, pre-formulated mitigation plans will ensure that “a plan is ready upon discovery, and risks can be addressed immediately.”

Near-Earth asteroid defense is a shared responsibility for all humanity, and the international community attaches great importance on it. Since 2009, the United Nations Committee on the Peaceful Uses of Outer Space has convened the International Planetary Defense Conference on a regular basis. 

In 2014, the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG) were formally established under the UN framework.

“We warmly welcome global partners to cooperate in areas such as joint ground-based monitoring, collaborative development and payload integration, and data and research sharing,” Wu said. 

China also called on stronger international cooperation and coordination in joint ground-based monitoring, collaborative development and payload integration, facilitated through the Space Mission Planning Advisory Group and broader data and results sharing.