中国于5月28日成功发射天问二号任务，目标是近地小行星469219 Kamoʻoalewa。任务计划于2026年7月抵达该小行星，利用11种仪器进行近距离研究，并尝试收集约100克样本。采集方式包括悬停取样、机械臂取样和“触碰即走”方式。样本将被储存在返回舱中，预计于2027年11月返回地球。如果成功，中国将成为继美国和日本之后第三个成功取回小行星样本的国家。任务的第二阶段将利用地球引力弹弓效应，前往另一目标——311P/PanSTARRS彗星进行观测。

🚀 天问二号任务于5月28日凌晨从中国西昌卫星发射中心发射，使用长征二号丁运载火箭，标志着中国首次小行星采样返回任务的开始。

🎯 天问二号的目标小行星是469219 Kamoʻoalewa，它是一颗直径在40-100米之间的近地小行星，被称为地球的“准卫星”，距离地球1500万至3900万公里。

⛏️ 任务计划通过三种方式采集小行星样本：悬停近距离采样、使用机械臂采集样本，以及“触碰即走”方式，即轻轻降落在小行星上，使用钻头获取物质，目标是收集约100克样本。

🛰️ 天问二号的后续任务，将利用地球的引力辅助，花费六年时间前往另一个目标——311P/PanSTARRS彗星，该彗星位于火星和木星之间的小行星带，距离地球约1.4亿公里，任务将使用仪器从远处研究这颗“活跃小行星”。

China has launched its first mission to retrieve samples from an asteroid. The Tianwen-2 mission launched at 01:31 a.m. local time on 28 May from the Xichang satellite launch center, southwest China, aboard a Long March B rocket.

Tianwen-2’s target is a small near-Earth asteroid called 469219 Kamoʻoalewa, which is between 15-39 million km away and is known as a “quasi-satellite” of Earth.

The mission is set to reach the body, which is between 40-100 m wide, in July 2026 where it will first study it up close using a suite of 11 instruments including cameras, spectrometers and radar, before aiming to collect about 100 g of material.

This will be achieved via three possible methods. One is via hovering close to the asteroid, the other is using a robotic arm to collect samples from the body while a third is dubbed “touch and go”, which involves gently landing on the asteroid and using drills at the end of each leg to retrieve material.

The collected samples will then be stored in a module that is released and returned to Earth in November 2027. If successful, it will make China the third nation to retrieve asteroid material behind the US and Japan.

Next steps

The second part of the 10-year mission involves using Earth for a gravitational swing-by to spend six year travelling to another target — 311P/PanSTARRS. The body lies in the main asteroid belt between Mars and Jupiter and at its closest distance is about 140 million km away from Earth.

The 480 m-wide object, which was discovered in 2013, has six dust tails and has characteristics of both asteroids and comets. Tianwen-2 will not land on 311P/PanSTARRS but instead use its instruments to study the “active asteroid” from a distance.

Tianwen-2’s predecessor, Tianwen-1, was China’s first mission to Mars, successfully landing on Utopia Planitia — a largely flat impact basin but scientifically interesting with potential water-ice underneath – following a six-month journey.

China’s third interplanetary mission, Tianwen-3, will aim to retrieve sample from Mars and could launch as soon as 2028. If successful, it would make China the first country to achieve the feat.

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