China’s Tianwen-2 mission has (probably) arrived at a quasi-moon of Earth

The Tianwen-2 mission, operated by the China National Space Administration, appears to have successfully rendezvoused with the asteroid Kamo’oalewa on June 7, 2026. This asteroid is known as a quasi-moon of Earth, a rare and recently discovered category of worlds. 

Andrew Jones, a contributing editor for The Planetary Society and a freelance space journalist covering China's accelerating space exploration program, joined Planetary Radio host Sarah Al-Ahmed to discuss what we know about the rendezvous so far, when we can expect images, and what the future of the mission has in store. You can listen to the full interview on Planetary Radio.

The following transcript has been edited for length and clarity.

Sarah Al-Ahmed:

This mission is going to two separate bodies. One's an asteroid, and one's a comet. How did they come up with this mission, and why did they pick these targets?

Andrew Jones:

Kamo'oalewa is one of seven known quasi-moons of Earth, so it’s in a kind of resonance orbit. These [worlds] have been discovered relatively recently. It’s maybe opportunistic, in the sense that we've got something which is relatively low energy to get to and come back. [But Kamo’oalewa] might even be a chunk of the Moon. It gives us an opportunity to do some serious science and head off and do something else in a deeper part of space as well. I think it checks off a lot of boxes.

Sarah Al-Ahmed:

Around what time should we expect these pictures to start flowing in?

Andrew Jones:

June 7 was what we expected to be the rendezvous with Kamo'oalewa. The China National Space Administration hasn't officially confirmed that this rendezvous maneuver has taken place, but AMSAT-DL, which is a nonprofit, used their telescopes in Bochum in Germany, and Dwingeloo in the Netherlands, and they pretty much confirmed that this maneuver took place. It seems that everything went well.

Looking at the mission papers that have been put out there, what I'm expecting is that the spacecraft is about 2,000 kilometers out from the asteroid at the moment, and that over the next few weeks, it's going to begin its approach to the asteroid. It's going to move from a couple of thousand kilometers out down to around about 20 kilometers.

Hopefully then around July 4, we get the confirmation that, “Yes, Tianwen-2 is in its desired orbit, here's an image.” 

From there, they're going to spend until April 2027 mapping the asteroid using LiDAR, cameras, and sounding radar. They're going to find out as much as they can about the surface, about the topography, and try to find some landing points for sampling using three different sampling techniques — well, at least two. And then, if possible, they'll try to anchor and attach to the asteroid depending on what the surface turns out to be.

All being well, they will depart from the asteroid on the 24th of April 2027, which also happens to be China's National Space Day. So in a year and a half, the reentry capsules should come through the atmosphere and land safely. And then we'll have a fourth set of samples from an asteroid.

Sarah Al-Ahmed:

What can we learn about this that'll give us some clue into, say, Solar System formation? Why is this an interesting object?

Andrew Jones:

[Kamo’oalewa’s origin] is of keen interest in the science community. One idea is that it was sent into orbit by an impact that hit the Moon in the last 10 million years, hitting the far side and creating the Giordano Bruno crater, according to some models. On the other hand, there are some saying that it's more likely that this came from a particular family of main-belt asteroids and migrated inwards.

If it turns out that this is a chunk of the Moon, that would tell us something about how different bodies can end up in a similar orbit to the Earth. And then conversely, it would tell us lots about the evolution of the Solar System and its impacts.

Sarah Al-Ahmed:

It feels like just yesterday we were talking about Tianwen-1 and its rover landing on Mars, and that being a huge moment for that space agency, and now we're looking at a whole timeline of upcoming missions in this Tianwen series. Can you talk a little bit about where Tianwen-2 fits into China's broader goal with this set of missions?

Andrew Jones:

Tianwen-2 is very much an engineering-led mission. They want to demonstrate particular capabilities and technologies, building toward different missions. I think that Tianwen-2 is relevant for the Mars sample return mission, Tianwen-3, which they plan to launch in late 2028, in the sense that this would be their first sample-return at the second cosmic velocity — hitting the atmosphere at 12 kilometers per second. They've already done this twice with their Chang'e 5 and Chang'e 6 missions, but that was at a slightly slower speed of like 11.2 kilometers per second.

That change in velocity is another challenge which they have to overcome. And the other thing is that they're using ion propulsion and [attempting] long-term operation in deep space. That's relevant for the Jupiter mission, Tianwen-4, which is scheduled for around 2030, and that would be an orbiter to go to the Jupiter system and then eventually go into orbits around the Galilean moon Callisto and possibly land or use an impactor.

Sarah Al-Ahmed:

It's interesting that they're trying multiple sampling techniques. We've seen previous missions try to do a kind of tag maneuver, and you mentioned the anchor and attach, but what's the third sampling method they're going to be trying to use on this?

Andrew Jones:

That would be a hover approach, where they match the rotation of the asteroid. And it is spinning really fast, by the way. It spins once every 28 minutes. And there's an idea of a “spin barrier,” that if there's something spinning faster than, say, two, two and a half hours, then it can't be a rubble pile. It's probably something monolithic.

So, they would try to match the rotation of the asteroid and then descend and use a robotic arm to try and take some samples. That's very challenging, to match this rapidly rotating body and then try to deal with reaction forces. This is kind of a pioneering approach. 

The idea is that Tianwen-2 went equipped with three different sample techniques as a redundancy, in the sense that we don't know what the surface of this asteroid is like. If we have different options, then there's a greater chance of getting samples. The other view would be that this is more of an engineering demonstration: they want to try different things rather than being overly concerned with how many samples they're getting. 

It's going to be very interesting to see if they can make these techniques work. And the other reason that they'd want to do this is because China has an interest, going forward, in small bodies in the Solar System. Potentially, what they learned from this mission could also be applicable for, say, resource mining in the future.

Sarah Al-Ahmed:

Can you talk a little bit about the second target for this mission?

Andrew Jones:

The target for that is 311P, which is a main-belt comet. When Tianwen-2 returns to Earth in November 2027, it will use its rendezvous with Earth for a gravitational slingshot to send it on its path towards this comet. It's going to be in deep space for eight years by itself after that. That sounds kind of boring, but it's verifying that China can do long-term deep space missions and building towards even more ambitious missions in the future.

Sarah Al-Ahmed:

They're not actually going to be trying to sample the comet, right? They're only doing the sampling on the asteroid side?

Andrew Jones:

They haven't said so. The way that they describe it in the mission papers is that the goal is to rendezvous with the comet and perform studies of it. Once they've done the global study of 311P, if they want to experiment with the sampling, I mean, why not? Maybe as an extended part of that mission, we might see something like that.