China's Probe Reaches Tiny Asteroid That May Be Moon Chunk

China's Tianwen-2 spacecraft reached a mysterious asteroid this week that scientists think could be a long-lost chunk of Earth's moon, marking one of the most exciting deep space missions in recent years.

The probe arrived at Kamoʻoalewa on July 4 after more than a year of interplanetary travel. This tiny asteroid, measuring between 130 and 330 feet across, could become the smallest asteroid ever visited by a spacecraft.

Kamoʻoalewa has been dancing around Earth since long before we knew it existed. Discovered in 2016, it orbits the sun while staying in sync with our planet, making it what scientists call a "quasi-satellite."

Its Hawaiian name means "oscillating celestial object," and it's one of only seven known quasi-satellites sharing Earth's orbital neighborhood. While it's a constant companion in space, it's not technically a moon because it orbits the sun rather than Earth directly.

The really exciting part is what scientists hope to find. Evidence suggests this tiny world might be a missing piece of the moon, blasted into space during a major impact millions of years ago.

Over the next nine months, Tianwen-2 will map every inch of the asteroid's surface, searching for the perfect spot to collect samples. The spacecraft carries two collection systems: a touch-and-go sampler and an anchor-and-attach mechanism with drills.

Scientists are hoping to bring back at least 100 grams of material. The spacecraft will depart in April 2027, and if all goes well, those precious samples could land on Earth by November 2027.

The Ripple Effect

This mission represents more than just visiting a small asteroid. If Kamoʻoalewa really is lunar material, those samples could unlock secrets about the moon's violent history without the enormous cost of a lunar mission.

China's Tianwen program, meaning "Heavenly Questions," has been racking up impressive achievements. Tianwen-1 made China only the second nation to successfully land and operate a rover on Mars in 2021.

The program isn't stopping here. Tianwen-3 will attempt the first-ever Mars sample return mission in 2028, while Tianwen-4 aims to explore Jupiter's moon Callisto and fly past Uranus starting in 2030.

But Tianwen-2 has one more adventure after its 2027 Earth delivery. The spacecraft will use a gravity assist to slingshot toward comet 311P/PANSTARRS, where it's expected to arrive in 2035.

This mission shows how space exploration continues opening new frontiers, bringing pieces of our cosmic neighborhood home to tell their stories.