China’s Tianwen-2 arrives at asteroid Kamoʻoalewa, returns first image
China’s Tianwen-2 spacecraft has arrived at the near-Earth asteroid 469219 Kamoʻoalewa and returned its first image of the target, revealing a small, elongated rocky body. The milestone marks the beginning of a survey campaign that will culminate in the collection of roughly 100 grams (3.5 ounces) of regolith for return to Earth.
The China National Space Administration (CNSA) released the first image on July 6, showing the asteroid from a distance of about 20 kilometers (12 miles). The probe reached this station-keeping point four days earlier, on July 2, after detecting Kamoʻoalewa from afar and gradually closing the gap.
The journey to the asteroid took just over 400 days. Tianwen-2 launched on May 29, 2025, from the Xichang Satellite Launch Center aboard a Long March 3B rocket, traveling roughly 1 billion kilometers (620 million miles) through the inner solar system before rendezvous.
What the image shows
The first image reveals a small, irregularly shaped body with a high geometric albedo, meaning it reflects a large fraction of the sunlight that strikes it. Ground-based observations had estimated Kamoʻoalewa’s diameter at 40 to 100 meters (130 to 330 feet), but the spacecraft’s image suggests it is just over 20 meters (66 feet) across, consistent with a recent study using the James Webb Space Telescope that estimated approximately 18 meters.
The high albedo is a significant finding. Kamoʻoalewa was previously thought to be a fragment of the Moon’s far side, blasted into space by an impact at Giordano Bruno Crater roughly 10 million years ago, because ground-based spectra showed lunar-like silicate material. However, the Moon’s surface has a low to moderate albedo, and the new data showing high reflectivity contradicts that hypothesis.
“The first image of Kamoʻoalewa at this early stage basically confirms the high geometric albedo, which is inconsistent with a lunar origin,” Mikael Granvik of the University of Helsinki told SpaceNews. “So it seems that Kamoʻoalewa is of asteroidal origin.”
Statistical models show that an asteroid on Kamoʻoalewa’s orbit is 10 times more likely to have come from the main asteroid belt than from the Moon.
A unique target
Kamoʻoalewa is one of only seven known quasi-satellites of Earth. Rather than orbiting Earth directly, it loops around the Sun in sync with our planet, making slow retrograde loops relative to Earth that remain stable for roughly 300 years. It rotates once every 28 minutes, roughly four times faster than typical small asteroids.
Tianwen-2 carries 11 scientific payloads, including cameras, laser ranging instruments, spectrometers, sounding radar, and particle analyzers. Italy contributed the DIANA dust analyzer. The spacecraft will spend the coming months mapping the asteroid from progressively lower altitudes, descending from 20 kilometers to 3 kilometers, then to 600 meters, and finally to 300 meters.
The team will study the asteroid’s surface morphology, material composition, and internal structure before selecting a sample collection site. The spacecraft carries three redundant sampling methods: a touch-and-go gas-driven head that brushes the surface, a hover sampling system using a robotic arm to scoop material while the spacecraft hovers, and an anchor-and-attach claw mechanism.
Sample return and beyond
Tianwen-2 is expected to depart Kamoʻoalewa in April 2027. The sample canister will return to Earth via a reentry capsule targeting Inner Mongolia in late November 2027.
After the sample delivery, the spacecraft will continue on an extended mission to comet 311P/PANSTARRS, with an expected arrival in January 2035.
Tianwen-2 is China’s second interplanetary mission following the successful Tianwen-1 Mars orbiter and rover. Future missions in the Tianwen series include Tianwen-3, a Mars sample return effort targeting a late 2028 launch, and Tianwen-4, a Jupiter system mission with plans for a Callisto landing.
Sources: SpaceNews (Andrew Jones), CNSA, Global Times, Scientific American, The Planetary Society