China has launched an ambitious mission to bring asteroid samples back to Earth – part of broader efforts to explore the solar system and make advances in planetary science, resource utilisation and defence.
The Tianwen-2 spacecraft lifted off aboard a Long March 3B rocket from the Xichang Satellite Launch Centre in southwest China at 1.31am Beijing time on Thursday, according to the China National Space Administration.
“About 18 minutes after lift-off, the rocket placed the spacecraft into a transfer orbit from Earth to asteroid 2016 HO3. The spacecraft’s solar panels deployed successfully, marking the complete success of the launch mission,” the agency said on its website.
The spacecraft’s first planned visit is asteroid 469219 Kamo’oalewa (2016 HO3) – a small quasi-satellite of Earth which scientists believe may be a fragment of the moon. Tianwen-2 is expected to collect samples from its fast-spinning surface and return them to Earth in late 2027 via a re-entry capsule.
After that, the main spacecraft will use the Earth’s gravity for a slingshot manoeuvre and begin a seven-year journey to comet 311P/PANSTARRS – an object in the solar system’s asteroid belt, known for shedding dust in multiple tails.
Tianwen-2 will investigate the comet’s orbit, shape, rotation, surface composition and dust activity.
If successful, the mission will make China the third country – after Japan and the United States – to return samples from an asteroid.
While China has previously returned moon samples during two Chang’e missions, an asteroid poses different challenges.
Given its microgravity environment, landing on 2016 HO3 would be more like approaching and docking – an operation that demands entirely distinct engineering capabilities, said planetary scientist Dante Lauretta of the University of Arizona.
Lauretta is leading an international team of about 200 researchers studying samples returned by Nasa’s OSIRIS-REx mission from asteroid Bennu, which landed back on Earth in September 2023.
He said Tianwen-2 would also need to ensure that pristine material was securely collected and returned.
When Lauretta’s team discovered that Bennu’s surface was extremely porous and fragile, they had to adapt their sampling approach in real time.
“If 2016 HO3 has a more consolidated or cohesive surface, it may present a different set of challenges in anchoring or in ensuring material is adequately captured and retained,” he said.
He added that Tianwen-2’s two-phase mission would bring more challenges. “Operating a spacecraft for years beyond its primary mission is no small feat,” he said. “It requires not only durable hardware but sustained organisational commitment.”
Lauretta noted the scientific uniqueness of Tianwen-2’s target. He said that unlike the Japanese and US missions that focused on carbon-rich asteroids to study early solar system chemistry, Tianwen-2 could shed light on the early impact history of the Earth – moon system and lunar evolution if 2016 HO3 turned out to be a fragment of the moon.
Qian Yuqi, a planetary geologist at the University of Hong Kong, said he was most curious about the origin of the asteroid.
If 2016 HO3 is indeed a chunk of the moon, he would like to find out which part of the moon it belonged to, and how it got ejected and eventually entered the current orbit.
But if it proves to be an S-type asteroid, it would be the second most abundant type of asteroid in the solar system. “In this case, the samples could help us understand the origin of asteroid families and the formation of planets such as the Earth,” he said.
Lauretta said he would be keen to take part in analysing the samples returned by Tianwen-2, if such access were possible.
“The science is compelling, and I believe international collaboration – when conducted with transparency and mutual respect – can benefit everyone.”
Yang Wei, a planetary geologist from the Institute of Geology and Geophysics in Beijing, said international collaboration was key to future asteroid sampling.
He said there were more than 20 different types of asteroids, based on their composition, and it would take multiple countries working together to collect samples from all of them.
“To make that possible, missions need to be smaller, more standardised, and more affordable,” he added.
Tianwen-2 is the second mission in China’s Tianwen, or “Questions to Heaven”, planetary exploration programme. The first, Tianwen-1, successfully placed an orbiter around Mars and landed a rover on its surface in 2021.
The next mission, Tianwen-3, aims to bring back the first Martian rock samples by 2031, while Tianwen-4 is scheduled to launch around 2030 to explore the Jupiter system and conduct a Uranus fly-by. - South China Morning Post
Already a subscriber? Log in
Get 20% OFF The Star Digital Access
Cancel anytime. Ad-free. Unlimited access with perks.
