Chinese Tianwen-2 spacecraft reaches Earth quasi-moon Kamo’oalewa

The Chinese Tianwen-2 spacecraft has reached Kamo’oalewa, a mysterious quasi-moon orbiting the sun alongside Earth, marking a significant milestone in space exploration. Launched on May 28, 2025, the probe traveled 620 million miles over 400 days before arriving at the asteroid, according to state-run Xinhua. Now circling the object at a distance of 12.5 miles, Tianwen-2 has captured the first clear image of Kamo’oalewa, revealing a rocky, fast-spinning body that could hold clues to the moon’s origins and the solar system’s history.

Identified in 2016 by a Hawaiian telescope, Kamo’oalewa is one of seven quasi-moons—objects that temporarily orbit the sun in tandem with Earth but are never gravitationally bound to it. Measuring between 130 and 330 feet in diameter, the asteroid rotates once every 30 minutes, creating a challenging target for the nearly two-ton Tianwen-2. Its fragile, rubble-pile composition, confirmed by the spacecraft’s initial scans, complicates sample collection, as experts had hoped for a solid surface to test the probe’s "anchor-and-attach" drilling method. Instead, mission planners now face the risk of an unstable landing, with few flat areas to safely touch down.

"Kamo’oalewa is the smallest object that humans have visited with a spacecraft," said Cristina Thomas, a planetary scientist at Northern Arizona University, highlighting the technical precision required for the mission. The probe’s primary goal is to gather 100 grams of regolith, which could be returned to Earth in November 2027. If successful, China would join Japan and the United States as the third nation to return asteroid samples, though the method remains untested. The samples may resolve a longstanding debate: whether Kamo’oalewa is a fragment of the moon, ejected by an ancient impact, or a main-belt asteroid that merely resembles lunar material.

Researchers have long theorized a lunar connection. Observations from 2021 showed Kamo’oalewa reflects light similarly to the moon, and a 2024 study narrowed its potential origin to the Giordano Bruno crater on the moon’s far side. Marco Fenucci, a mathematician at the European Space Agency, called the mission "definite" in settling this question. "We’ll only obtain definitive answers after completing our exploration," said Li Chunlai, chief commander of Tianwen-2’s ground application system, in a state-sanctioned video.

The mission’s challenges extend beyond sampling. Kamo’oalewa’s orbit, which has kept it near Earth for at least a century, is expected to last another 300 years before it drifts away. Its proximity to our planet also raises questions about its potential as a resource. If water can be extracted from such objects, they might serve as refueling stations for deep-space missions, a concept explored by planetary scientists like Richard Binzel of MIT. "These objects could become stepping stones for human missions to Mars," he said.

Tianwen-2’s journey is not without precedent. The probe’s arrival follows a 400-day voyage that included a flyby of Earth and a series of orbital adjustments. Its decagonal solar panels, visible in the first released image, suggest a design optimized for long-duration missions. The spacecraft will spend months mapping Kamo’oalewa’s surface before attempting a sample collection, likely using a "touch-and-go" approach if the asteroid proves too unstable for anchoring.

Beyond Kamo’oalewa, Tianwen-2’s secondary mission targets 311P/PanSTARRS, a comet-asteroid hybrid beyond Mars, which it aims to study in 2035. This dual-purpose design underscores China’s growing ambition in space exploration, a trend reflected in its secretive Shenlong space plane, which has deployed nine unexplained payloads since 2022. While the Shenlong’s purpose remains unclear, its repeated missions highlight China’s focus on advancing orbital capabilities.

As Tianwen-2 prepares for its next phase, the world watches to see if it can overcome the hurdles of a fragile, spinning target. Success would not only advance scientific understanding but also solidify China’s role as a leader in space exploration. For now, the probe’s images of Kamo’oalewa offer a glimpse into the mysteries of our cosmic neighborhood, where even the smallest objects hold the potential to reshape our knowledge of the universe.