China Captures First Close-Up Image of Earth's Rare Asteroid Minimoon
China's Tianwen-2 spacecraft has transmitted the first-ever close-up images of Kamo'oalewa, a rare asteroid known as a minimoon. The mission aims to collect samples for return to Earth.
The China National Space Administration (CNSA) has released the first close-up images of Kamoʻoalewa, an asteroid designated a 'minimoon,' captured by its Tianwen-2 spacecraft. This achievement follows a demanding 13-month journey spanning nearly one billion kilometers from Earth. Launched on May 29, 2025, Tianwen-2's primary objective is to collect asteroid samples and return them to our planet, marking a significant step in China's ambitious space exploration program.
Tianwen-2 first detected Kamoʻoalewa on June 6, 2026, and gradually maneuvered closer over the subsequent weeks. By July 2, the spacecraft had reached a distance of just 20 kilometers, enabling the acquisition of these unprecedented, detailed photographs. The images showcase the asteroid's irregular form and rugged surface, offering scientists an unparalleled view of this enigmatic celestial body.
Understanding Kamoʻoalewa's Unique Orbit
Despite its designation as a 'minimoon,' Kamoʻoalewa is not a natural satellite of Earth. Instead, it is classified as a quasi-satellite, a rare category of asteroid that orbits the Sun while maintaining a stable gravitational connection with Earth. This peculiar orbital dynamic causes it to remain in Earth's vicinity for extended periods, creating the illusion of orbiting our planet from our perspective. Kamoʻoalewa measures between 40 and 100 meters in diameter, positioning it among the smallest asteroids ever explored by human technology. Current astronomical surveys have identified only seven known quasi-satellites of Earth, underscoring the rarity of Kamoʻoalewa in our solar system.
Physicist Rongqiao Zhang of the Lunar Exploration and Space Engineering Center highlighted the significance of such objects in a paper published in Space Science Reviews. "Among the known near-Earth asteroids, 2016HO3 is an exceptionally rare Earth co-orbital object. As an Earth quasi-satellite, its orbital period is close to that of Earth, enabling low energy transfer, and it maintains a stable distance of about 0.1–0.3 AU from Earth, providing favorable conditions for tracking, control, and communication," Zhang noted.
The data gathered from the Tianwen-2 mission is expected to provide crucial insights into the origin and evolution of quasi-satellites. Previous telescopic observations have suggested a compelling theory: that Kamoʻoalewa might be a fragment of Earth's Moon, ejected into space by a colossal impact in the distant past. Analyzing the rock samples returned by Tianwen-2 could definitively prove or disprove this hypothesis. Furthermore, researchers anticipate that this mission will deepen our comprehension of how these unique objects form, how they persist in Earth's proximity for millions of years, and their potential implications for planetary science.
The successful capture of these images and the subsequent sample collection phase represent a major milestone for CNSA's asteroid exploration initiatives. The data will contribute significantly to the global scientific understanding of near-Earth objects and the early solar system.