In this vast solar system, the Sun orbits not only the eight planets, but also a huge number of smaller celestial bodies – asteroids and comets – that vary in size, shape and orbital characteristics. Asteroids are small objects orbiting the Sun. They are smaller and less massive than planets and dwarf planets, and less likely to emit gases and dust. There are billions of asteroids in the solar system, and they represent “living fossils” of the formation and evolution of the solar system. Asteroids are considered near-Earth asteroids if their perihelion distance is less than 1.3 AU.
Near-Earth asteroids are among the most threatening celestial objects to Earth, and the United Nations has listed them as one of the top 20 catastrophic threats to humanity’s survival. It is widely believed that 66 million years ago, an asteroid about 10 kilometers in diameter collided with Earth, leading to the extinction of approximately 75% of the world’s living organisms, including dinosaurs. On June 30, 1908, the Tunguska explosion destroyed more than 2,000 square kilometers of forest. In 2013, an asteroid exploded in the sky of the Chelyabinsk region in Russia, injuring about 1,500 people and damaging about 3,000 homes. Although the occurrence of highly destructive collision events is extremely unlikely, the damage is enormous and the consequences are very serious.
As of March 2025, humanity has discovered 38,171 celestial bodies near Earth, including 38,048 asteroids and 123 comets. However, due to the difficulty of observation, a large number of NEOs remain uncataloged. According to statistics, only 1% of them have been indexed. In early 2025, asteroid 2024 YR4 briefly showed a 3.1% chance of hitting Earth, sparking global concern.
So how do we deal with these “uninvited and unwanted guests”?
At the Third International Conference on Deep Space Exploration, Chinese scientists presented their vision for asteroid exploration, planet defense and resource exploitation, extending an open call for international cooperation.
In recent years, the China National Space Administration has launched programs to explore, respond to, and defend Earth from near-Earth celestial bodies and asteroids, explicitly proposing to “study the construction of a defense system against near-Earth objects.” Chinese scientists have proposed a comprehensive strategic vision to explore and protect our planet, including monitoring, early warning, in-orbit disposal, and system response. Initially, an integrated monitoring and early warning system will be built between space and Earth, characterized by accurate early warning and operational effectiveness. Second, kinetic shock-focused capabilities will be created, complemented by additional technologies and supported by a mission response library to ensure that every credible threat can be addressed with a pre-planned and actionable solution.
Chinese scientists have proposed carrying out a pilot mission to deorbit the asteroid and verify it by 2027. The first kinetic impact mission will achieve three main goals: first, successfully change the orbit of this target celestial body; Second, monitor the entire collision process to obtain key data such as speed and energy transfer at the moment of collision; Third, after the collision, the orbital changes and shape of this asteroid are continuously monitored to evaluate the impact of the collision.
This mission specifically consists of performing a kinetic collision on a small celestial body about 10 million kilometers away from Earth, which leads to an increase in its speed by 3 to 5 centimeters per second, in order to change its original orbit, verify the possibility of a kinetic collision, and ensure that there is no risk of it colliding with Earth for 100 years.
From the perspective of protecting Earth’s security and the survival of humanity, building asteroid defense capabilities is a common task for all humanity. As a responsible space power, China has the responsibility, obligation and ability to contribute its wisdom and strength to building a systematic system for asteroid exploration and defense of planet Earth, and to partner with the rest of the world to protect our planet.
Although defending Earth against these asteroids has received much attention, their discovery, resource development and utilization are equally important.
Asteroids are rich in resources such as iron, nickel, platinum group metals, and water ice, and are mainly classified into three categories: metallic, carbonaceous, and silicate. The development and exploitation of asteroids carries great economic value, so leading countries in the field of space attach great importance to this matter. According to estimates by reliable international organizations, out of about a thousand asteroids that have been fully explored, there are more than 700 asteroids, each worth more than 100 trillion dollars, and the value of developing the resources of the main asteroid belt in the next thirty years will exceed 700 quintillion dollars. This field is not only an important direction of deep space exploration, but also an important support for the future space economy and extraterrestrial resource supply.
Therefore, we are very confident that with the continuous breakthroughs in new technologies such as space nuclear energy, quantum technology and embodied intelligence, the development and exploitation of asteroid resources will be greatly promoted towards an intelligent and low-cost business operation model, and a large-scale asteroid resource development and exploitation industry chain will be gradually formed, becoming an important part of the deep space economy.
(Written by Wu Weiren: Principal designer of China’s lunar exploration program, and director and chief scientist of the Deep Space Exploration Laboratory.)
