China’s space agency wants to send a craft to a rock that loops around Earth.Credit: Xinhua/eyevine

China has set its sights on deep space. The China National Space Administration (CNSA) is planning a robotic mission that would return samples from an asteroid and visit a comet — and it has invited international researchers to take part.

The ten-year mission, which has yet to be formally approved by the government, could launch from 2024, CNSA’s international cooperation manager Yang Ruihong told Nature.

Japan and the United States both currently have spacecraft orbiting asteroids and, in 2010, Japan’s Hayabusa mission became the first to bring samples of asteroid material back to Earth.

The CNSA wants to encourage foreign research institutions to propose scientific payloads that could fly on its mission — either developed independently or in collaboration with Chinese partners, according to details published by the agency on 19 April.

The asteroid mission would put a probe on the rock 2016 HO3, and would later return to Earth’s orbit and drop a sample-containing capsule back to the ground. The small asteroid — also known as Kamo‘oalewa, a Hawaiian name that refers to an oscillating celestial object — is thought to be less than 100 metres across and was discovered in 2016. It is classed as a quasi-satellite: it loops constantly around Earth, but is too far away to be considered a normal satellite (see ‘Earth’s pet rock’)﻿. The maximum distance from Earth to HO3 is around 100 times the distance to the Moon.

After visiting HO3, the Chinese craft would undertake a seven-year journey beyond Mars, to the Solar System’s asteroid belt. There, it would study the comet 133P/Elst–Pizarro, which is sometimes also classified as an asteroid because of its location. However, like a comet, 133P releases dust and gas to create a ‘tail’.

The mission aims to find clues about the formation and evolution of small bodies in the Solar System and their interaction with the solar wind. It also intends to compare their compositions with those of material on Earth, to illuminate the origins of life on our planet, says the CNSA.

In February, Japanese spacecraft Hayabusa2 touched down on the surface of asteroid Ryugu to collect a sample that it hopes to return next year. Meanwhile, NASA’s OSIRIS-REx is making a detailed study of a smaller target, the asteroid Bennu, before attempting to collect a sample in 2020.