China Launches Tianwen-2: A Decade-Long Mission to Kamoʻoalewa and 311P/Pan-STARRS

On May 29, 2025, China successfully launched the Tianwen-2 mission, marking a significant advancement in the country’s space exploration ambitions. The mission, initiated by the China National Space Administration (CNSA), aims to collect samples from the near-Earth asteroid 469219 Kamoʻoalewa and study the main-belt comet 311P/Pan-STARRS over a ten-year period. The launch took place at the Xichang Satellite Launch Center in Sichuan Province, utilizing a Long March-3B rocket, which made history by sending a payload beyond Earth’s orbit for the first time.

According to a report by Xinhua, the launch occurred at 1:31 a.m. Beijing time. Approximately 18 minutes after liftoff, the Tianwen-2 probe successfully entered a transfer orbit, an achievement that required not only breaking free from Earth’s gravitational pull but also achieving precise trajectory calculations. The CNSA emphasized that a deviation of merely one meter per second during launch could lead to a positional error of up to 100 million kilometers, underscoring the mission's complexity.

"Achieving such trajectory precision is akin to shooting a basketball from Shanghai to hit a hoop in Beijing," stated the China Aerospace Science and Technology Corporation (CASC) in an article quoted by Xinhua.

The Tianwen-2 mission is remarkable not only for its technical achievements but also for its ambitious scientific goals. Kamoʻoalewa, the mission's primary target, is estimated to be between 40 to 100 meters in diameter, making it the smallest asteroid ever targeted for exploration. It is thought to be a fragment of the Moon, based on its optical characteristics. This hypothesis presents an opportunity for scientists to understand more about lunar impacts and the history of debris in the solar system. The mission aims to return samples from Kamoʻoalewa to Earth by 2027, which may provide insights into the Moon's geological history and the processes that shaped it.

Following the sample collection, Tianwen-2 will continue its journey to 311P/Pan-STARRS, an intriguing celestial body that orbits like an asteroid but displays comet-like characteristics, including a dust tail. The probe is anticipated to reach this target in early 2035, where it will spend a year conducting observations.

Planetary scientist Teddy Kareta from Lowell Observatory remarked, "There’s a tremendous amount we don’t know about either object. I’m sure some of our current understanding for either object is completely wrong, and I’m excited to see how." The insights gained from this mission could potentially shed light on the origins of water and organic life in the solar system.

The Tianwen-2 mission represents a major milestone for China’s space exploration program, which has made significant strides in recent years. This mission builds upon the success of previous projects, including the Chang'e lunar missions and the Tianwen-1 Mars mission, which has established China as a formidable player in the global space race.

As Tianwen-2 embarks on its decade-long expedition, the scientific community and the public await the discoveries it will bring. The mission not only aims to enhance our knowledge of the solar system’s formation but also to showcase China’s growing capabilities in space exploration, with implications for international collaboration and competition in this vital field.