China's Tianwen-2 Sends First Close-Up Image of Tiny Asteroid Kamo'oalewa

China's Tianwen-2 spacecraft has sent back the first close-up image of the asteroid Kamo'oalewa, a small, fast-spinning body that shares Earth's orbit around the Sun. The China National Space Administration released the picture on 6 July, showing an elongated grey object against black space with a 10-metre scale bar for reference. Tianwen-2 took the photo on 2 July from about 20 kilometres away, after covering roughly a billion kilometres over a 400-day journey since launching on a Long March 3B rocket on 29 May 2025.

That billion-kilometre distance was the length of the spacecraft's winding path, not a straight-line gap to the asteroid. Because both Tianwen-2 and Kamo'oalewa orbit the Sun, the probe had to reshape its own orbit and match the asteroid's path and speed rather than fly directly at it. It first detected Kamo'oalewa on 6 June, entered coplanar flight from 30,000 kilometres away on 7 June, and had closed to 2,000 kilometres by 19 June.

The image also revises how big Kamo'oalewa is thought to be. Earlier estimates, based on how much sunlight the asteroid reflects, put it anywhere between 40 and 100 metres across. A June preprint using James Webb Space Telescope data estimated a mean diameter of 18 plus or minus 2 metres, and found the object spins once every 27.9 minutes. Tianwen-2's image, with its visible elongation, is consistent with that smaller estimate, though the mission team describes it as an early navigation image rather than a finished measurement of the asteroid's shape.

Kamo'oalewa is often called a quasi-moon, but it is not gravitationally bound to Earth; it orbits the Sun in about the same time Earth does, which makes it appear to loop around the planet. It was discovered in 2016 by the Pan-STARRS 1 telescope in Hawai'i. Tianwen-2 carries 11 scientific instruments, including cameras, spectrometers, radar and a magnetometer, and CNSA says the spacecraft will keep mapping the asteroid's shape, composition and structure through a mix of hovering and close flybys.