China eyes asteroid defence system, comet mission

China will hold discussions on building a defense system against near-Earth asteroids, a senior space agency official said on Saturday, as the country steps up its longer term space ambitions.

Zhang Kejian, head of the China National Space Administration, did not provide further detail in his opening remarks at a ceremony for China’s Space Day in the eastern city of Nanjing.

The European Space Agency last year signed a deal worth 129 million euros (US$156 million) to build a spacecraft for a joint project with NASA examining how to deflect an asteroid heading for Earth.

China is also pushing forward its exploration of a near-Earth asteroid and a main-belt comet with one space probe, said a senior space expert.

The mission is to send a probe around an asteroid named 2016HO3 and then land on it to collect samples, said Ye Peijian, an academic of the Chinese Academy of Sciences, at the ongoing 2021 China Space Conference.

The probe will then fly back to Earth’s proximity and release a capsule to return the samples. After that, it will continue its journey. With the assistance of the gravity of Earth and Mars, it will finally arrive at the main asteroid belt and orbit comet 311P, Ye said, adding that the whole process will take about ten years.

Asteroid 2016HO3 has a close relationship with Earth. It has a diameter of about 40 to 100 meters, said Ye.

The second target, comet 311P, is one of the comets within the main asteroid belt. The diameter of its cometary nucleus is about 320 to 580 meters, he said.

Small celestial bodies preserve the original information of the formation and evolution of the solar system. They are considered living fossils for studying the origin of the solar system.

Probing small celestial bodies is a new frontier of space exploration, but with a high threshold. The main difficulties are the uncertainties and the unknown environment of the small bodies. It’s hard to learn about their shape, composition, structure, and other features through observation from Earth, Ye said.

China has designed multiple sampling methods in its mission, including touch, hovering, and landing.