Did you know that the Earth has a «minimoon»? It is known as asteroid 2016HO3, or Kamoʻoalewa.
The probe sent for the Tianwen-2 mission of the China National Space Administration (CNSA) has just sent your first image of the quasi-satellite, whose name comes from a Hawaiian song that designates an oscillating object in the sky.
The probe is the first CNSA mission to bring back samples from an asteroid, and was launched on May 29, 2025 from the Xichang Satellite Launch Center, reports Science Alert.
Now, after 13 months of traveling through approximately 1 billion kilometers of space, Tianwen-2 has reached its main destination, according to the agency.
Since July 2, the probe has been hovering about 20 kilometers from Kamoʻoalewa, where it took this photo of the «minimoon.»
Kamoʻoalewa is too far away to be considered a proper Earth satellite, and its primary orbit is around the Sun. But because it circles our planet in an elliptical orbit every 45 years, it qualifies for the rare «quasi-satellite» status, being one of only seven known to orbit Earth, it says. Science Alert.
It belongs to the class of asteroids known as Apollo asteroids, which more or less share the Earth’s orbit around the Sun. However, as a quasi-satellite, Kamoʻoalewa stays close to Earth for long periods and throughout multiple orbits.
What we know so far about Kamoʻoalewa is scant, based on observations from a distance. It has approximately between 40 and 100 meters in diametermeaning it could be the smallest asteroid ever visited by a human spacecraft.
Following its long journey from Earth, Tianwen-2 made its first optical detection of Kamoʻoalewa on June 6, and by June 19 it had come within 2,000 km, it says. Science Alert.
By July 2, it was just 20 km from the asteroid: close enough to capture the image above.
As part of its mission, Tianwen-2 will conduct observations of rock in orbit and collect samples to bring back to Earth, as described in a paper published in Space Science Reviews in January.
They want to know everything about the mini moon
Scientists want to know if it is a pile of rubble or a monolithic body; whether there are traces of water and what else it is composed of; how its orbit evolved; And if the solar wind has anything to do with it, reports Science Alert.
The researchers noted that its unusual orbit, enigmatic origin, and unresolved questions about its physical properties «make it a compelling candidate to address fundamental questions about the origins of Earth’s quasi-satellites and the dynamical evolution of their orbits.»
The samples you send back to Earth will help confirm whether Kamoʻoalewa is really a fragment of the Moonas scientists have deduced from telescopic observations.
After this approximately nine-month stop at Kamoʻoalewa, Tianwen-2 will continue its journey toward the main belt comet 311P, which lies beyond Mars. But not before depositing its capsule with samples of the quasi-moon during a flyby of the Earth, it indicates. Science Alert.
311P stands out for its strange six-pointed dust tail, and we’re still not sure of its shape, so researchers are keen to investigate these questions closely.
Additionally, the comet coincides with the trajectory of the Tianwen-2 return mission, making it a convenient target for a flyby of the main asteroid belt.
GML
