China's Tianwen-2 Captures First Image of 60-Foot Quasi-Moon Kamoʻoalewa

Q: As the asteroid spins every 28 minutes, how will China's robotic probe grab a sample from its craggy surface?

China’s Tianwen-2 is expected to collect the sample by briefly synchronizing with Kamoʻoalewa’s fast 28-minute spin and then using one of several short-contact sampling modes, rather than trying to land and stay put for long. The main plan described by mission reporting is a hover approach. The spacecraft will map the asteroid closely, match its motion as precisely as possible, descend toward the surface, and use a robotic arm to scoop up grains from a suitable spot. That is difficult because Kamoʻoalewa is tiny, irregular and rotating quickly, so the probe must control its position and reaction forces with high precision. Tianwen-2 also carries backup options in case the surface proves different from expectations. One is a touch-and-go method, in which the probe makes only a brief contact and uses a gas-driven collection head to sweep material into a chamber before backing away. Another is an anchor-and-attach approach, using a claw-and-spike style mechanism to secure itself long enough to sample if the surface is solid enough. Scientists say the asteroid’s rapid spin suggests it may be a coherent rock rather than a loose rubble pile, which could affect which method is safest. The mission is designed with multiple techniques because Kamoʻoalewa’s craggy, unusual shape and uncertain surface properties make a single sampling strategy too risky. China hopes to return at least 100 grams of material to Earth in 2027.

3 articles · Updated · The New York Times · Jul 9

Tianwen-2 photographed 469219 Kamoʻoalewa for the first time after closing to 12.5 miles from the asteroid, capping a 400-day chase since its May 2025 launch.
The image shows a pointy, asymmetric body about 60 feet long, unlike the rounder, rubble-pile asteroids visited by recent robotic missions.
Scientists said the craggy shape could point to a violent past, possibly leaving Kamoʻoalewa as debris from a catastrophic collision.
Kamoʻoalewa is a quasi-moon that moves in step with Earth while orbiting the sun, making it a useful target for studying how near-Earth asteroids arrive close to the planet.