First Close-Up Photo of Kamoʻoalewa Opens Opportunities to Uncover Moon's Origins

For years, astronomers could only observe the small object dubbed Earth’s ‘mini-moon’ from afar. Now, for the first time, the mysterious object has been photographed up close by China’s Tianwen-2 spacecraft. This achievement marks an important step in asteroid research as it opens up opportunities to uncover the origins of one of the most unique celestial bodies near Earth. The object in question is Kamoʻoalewa, an asteroid with a very close orbital relationship with Earth. Although often called a ‘mini-moon’, this celestial body is not actually a natural satellite like the Moon that has been orbiting our planet. Kamoʻoalewa belongs to the category of quasi-satellite. This means the asteroid orbits the Sun, not Earth. However, its trajectory is almost identical to Earth’s orbit, so from our planet’s perspective, Kamoʻoalewa appears to remain near Earth for many years. The asteroid, first discovered in 2016, is estimated to have a diameter of about 40 to 100 metres. Because of its stable and relatively close orbit, scientists consider it a natural laboratory for studying the early history of the solar system. The latest photo sent by Tianwen-2 shows Kamoʻoalewa has an irregular shape with a surface covered in boulders. The image was taken when the spacecraft was about 20 kilometres from the asteroid. The mission does not only aim to photograph the object. Tianwen-2 will also map its surface characteristics before attempting to land and collect rock samples. If successful, the samples are scheduled to return to Earth in 2027 for analysis by scientists. The mission’s success could help answer a major question in astronomy: whether Kamoʻoalewa is a fragment of the Moon ejected by a massive impact millions of years ago, or whether it originates from another asteroid group in the solar system. Analysis of the returned samples is expected to reveal the asteroid’s detailed mineral composition. This information will provide a clearer picture of the Moon’s formation process, the evolution of near-Earth asteroids, and the early history of the solar system. The first photo of Kamoʻoalewa represents an important milestone in space exploration. Beyond proving the technological capability of the Tianwen-2 mission, this achievement also opens a new chapter in humanity’s efforts to understand the small bodies residing in the cosmic environment closest to Earth.