China is launching a probe to encounter a lunar fragment and an unusual comet. What is the mission all about?

According to a statement from the China National Space Administration, on February 20, the spacecraft "Tianwen-2" arrived at the Sichuan launch site and is preparing for its launch into space. It is known that the launch is expected to occur in the first half of the year, although earlier reports indicated that the flight was scheduled for May. The goal of the Chinese probe is to study a near-Earth asteroid that is a quasi-satellite of Earth, collect samples of its rock, and explore a main belt comet. These comets are quite unusual, as noted by SpaceNews.

"Tianwen-2": Journey to the Kamoaleva Asteroid

The "Tianwen-2" spacecraft is set to study the Kamoaleva asteroid, which measures between 40 and 100 meters in width, and collect samples of its rock. Afterward, these samples are expected to be returned to Earth around 2027. Scientists believe that Kamoaleva may be a fragment of the Moon that was ejected into space due to an impact on the surface of Earth's satellite by another asteroid. Researchers aim to obtain up to 1 kg of rock samples to determine the origin of the asteroid and to understand how its composition differs from that of other asteroids.

"Tianwen-2": Journey to a Main Belt Comet

Once "Tianwen-2" drops the capsule containing the asteroid samples on Earth, it will head towards a main belt comet named 311P/PANSTARRS, which it is expected to reach in 2034. Such comets are located in the main asteroid belt between Jupiter and Mars. They have orbital characteristics similar to asteroids but exhibit cometary activity. Scientists want to explore the nature of objects that are intermediate between asteroids and comets.

The "Tianwen-2" spacecraft will conduct remote sensing of the comet to characterize its orbit, shape, and rotation, study the composition of its surface, and investigate dust ejections and activity mechanisms to understand the behavior of main belt comets.

The two phases of the "Tianwen-2" mission aim to provide information about the composition and evolution of near-Earth objects and to understand the distribution of water and organic molecules, as well as the history of the early Solar System.

China's Plans for Mars and Jupiter

It is also known that China plans to send the "Tianwen-3" lander to Mars in 2028 or 2030 to collect Martian rock samples and return them to Earth. So far, no rock samples collected on Mars have ever been brought back to our planet. Additionally, the "Tianwen-4" mission is set to launch into space in 2030 to study Jupiter and its moons. One of the mission's objectives is for the spacecraft to enter orbit around Jupiter's moon Callisto. No probe has yet orbited a moon of another planet.