China’s Tianwen-2 Space Probe Has Rendezvoused With Earth’s Quasi-Moon
China’s Tianwen-2 Space Probe Has Rendezvoused With Earth’s Quasi-Moon
中国“天问二号”探测器已与地球准卫星“会合”
The China National Space Administration’s asteroid probe Tianwen-2 successfully reached the asteroid Kamo’oalewa, which orbits the sun in a path nearly identical to Earth’s. 中国国家航天局的小行星探测器“天问二号”已成功抵达小行星“卡莫奥瓦”（Kamo’oalewa），该小行星绕太阳运行的轨道与地球几乎完全一致。
After undergoing multiple orbital adjustments in deep space, it first detected Kamo’oalewa on June 6, 2026. On July 2, it successfully captured the first-ever images of Kamo’oalewa from a distance of about 20 kilometers. This achievement comes at the end of a 400-day journey covering a distance of roughly 1 billion kilometers. 在深空经过多次轨道调整后，探测器于2026年6月6日首次探测到卡莫奥瓦。7月2日，它在约20公里的距离上成功拍摄了卡莫奥瓦的首批图像。这一成就标志着其历时400天、航程约10亿公里的旅程取得了阶段性成果。
Kamo’oalewa is the most stable of Earth’s known quasi-satellites, and because it orbits the sun in near-synchronous motion with Earth, it is considered a relatively accessible celestial body. 卡莫奥瓦是目前已知地球准卫星中最稳定的一颗，由于它与地球近乎同步地绕太阳运行，因此被认为是一个相对容易接近的天体。
But landing on the asteroid—let alone gathering samples—will be a challenge. Kamo’oalewa has an average diameter of only about 41 meters and rotates at high speed. This means the spacecraft must achieve stable contact and collect samples within a limited time frame. If it manages to gather samples, it will then release them in a capsule during an Earth flyby in November 2027. 但要在该小行星上着陆，更不用说采集样本，将是一项巨大的挑战。卡莫奥瓦的平均直径仅约41米，且处于高速旋转状态。这意味着探测器必须在有限的时间窗口内实现稳定接触并完成采样。如果采样成功，它将在2027年11月飞掠地球时释放返回舱。
Tianwen-2 is equipped with multiple cameras with different focal lengths. In addition to switching between a narrow-field-of-view camera and a wide-field-of-view camera depending on the situation, it also features a detachable camera that will be used during sample collection. Since the probe’s orientation must be finely adjusted when capturing images, seizing these limited windows of opportunity is an extremely difficult task. Tianwen-2 plans to conduct more detailed scientific observations of Kamo’oalewa’s shape, material composition, and internal structure. “天问二号”配备了多台不同焦距的相机。除了根据情况在窄视场相机和宽视场相机之间切换外，它还配备了一台可在采样过程中使用的可拆卸相机。由于在拍摄图像时必须对探测器的姿态进行精细调整，抓住这些有限的机会窗口是一项极具难度的任务。“天问二号”计划对卡莫奥瓦的形状、物质成分和内部结构进行更详细的科学观测。
If this mission is successful, it will mark another achievement in asteroid sample return, following Japan’s Hayabusa and Hayabusa2 missions—the first to return asteroid samples to Earth—and NASA’s OSIRIS-REx mission. Material from small celestial bodies orbiting near Earth could provide clues to understanding the formation of the solar system, including Kamo’oalewa. 如果此次任务成功，它将继日本“隼鸟号”和“隼鸟2号”（首次将小行星样本带回地球）以及美国国家航空航天局（NASA）的“奥西里斯-REx”任务之后，成为小行星采样返回领域的又一里程碑。来自地球附近轨道小天体的物质，可能为理解太阳系的形成提供线索，卡莫奥瓦也不例外。
“It is highly likely to contain primordial information from the early days of the solar system’s formation, and it holds great scientific value for studying early material composition, formation processes, and evolutionary history,” explains Han Siyuan, deputy director of the Lunar and Space Exploration Engineering Center and spokesperson for the Tianwen-2 mission. “它极有可能包含太阳系形成初期的原始信息，对于研究早期物质成分、形成过程和演化历史具有极高的科学价值，”探月与航天工程中心副主任、“天问二号”任务发言人韩思远解释道。
Researchers have previously theorized that Kamo’oalewa is a fragment of the moon blown away by an asteroid impact millions of years ago, and that explanation has been widely accepted until recently. This is because the spectrum of reflected light closely resembles that of silicate minerals found on the moon’s surface. Simulations also backed up the theory. 研究人员此前曾推测，卡莫奥瓦是数百万年前因小行星撞击而从月球上剥离的碎片，这一解释直到最近都被广泛接受。这是因为其反射光谱与月球表面发现的硅酸盐矿物非常相似，模拟实验也支持这一理论。
In May, though, an international research team—including the Chinese Academy of Sciences—published a paper that casts doubt on this leading hypothesis. A reanalysis of available data found that the central wavelength of the absorption band—the point where light weakens at a specific wavelength—matched the characteristics of LL chondrites (a type of meteorite with low iron and metal content). 然而，今年5月，包括中国科学院在内的一个国际研究团队发表了一篇论文，对这一主流假说提出了质疑。对现有数据的重新分析发现，其吸收带的中心波长（即光在特定波长下减弱的点）与LL型球粒陨石（一种铁和金属含量较低的陨石）的特征相符。
The research team conducted an experiment in which they irradiated LL chondrite meteorite powder with a laser to simulate space weathering caused by solar wind and micrometeorites. The results closely matched observational data of Kamo’oalewa. The researchers posit that Kamo’oalewa likely migrated to the Earth’s vicinity from the Flora family—a group of celestial bodies in the asteroid belt. 研究团队进行了一项实验，用激光照射LL型球粒陨石粉末，以模拟太阳风和微陨石造成的空间风化。结果与卡莫奥瓦的观测数据高度吻合。研究人员推测，卡莫奥瓦很可能是从位于小行星带的“花神星族”（Flora family）迁移到地球附近的。
If Tianwen-2 successfully completes its mission to take samples and return to Earth, it will likely help answer questions about Kamo’oalewa’s origins. But first, it has to reach the asteroid’s surface. 如果“天问二号”能成功完成采样并返回地球，将有望解答关于卡莫奥瓦起源的疑问。但首先，它必须成功抵达这颗小行星的表面。