The mission
The Chang’e-6 spacecraft consists of four separate components: an orbiter, lander, ascender, and reentry module. After launch, Chang’e-6 will travel to the Moon and enter lunar orbit. The spacecraft’s lander and ascender will travel to the surface, while the orbiter and reentry module stay in orbit.
The lander and ascender will touch down in the southern part of Apollo crater, within the SPA basin. They will collect 2 kilograms (4.4 pounds) of lunar material using a drill and scoop. The ascender will then blast back into lunar orbit and transfer the samples to the reentry module. The orbiter will carry the service module back to Earth and release it into the atmosphere, where it will parachute to a soft landing.
The entire mission is expected to last 53 days, much longer than Chang’e-5’s 23-day nearside sample return mission. While it is on the Moon’s far side, Chang’e-6 will communicate with Earth through the Queqiao-2 relay satellite, which launched in March 2024. Queqiao-2 is equipped with one of the largest parabolic antennas ever sent beyond Earth, with a diameter of 4.2 meters (13.8 feet).
The science
The samples Chang’e-6 returns to Earth will provide new insights into a messy period of Solar System history.
Most of the Moon’s impact basins formed about 3.9 billion years ago when large objects smashed into the Moon during an event known as the Late Heavy Bombardment, or lunar cataclysm.
What caused such a large number of impacts to occur at roughly the same time? There are two main theories. The first is that the orbits of the giant planets shifted, flinging leftover planet-forming materials toward the inner planets, producing a spike in impacts.
The second theory is that the Late Heavy Bombardment was not a spike at all. Instead, it may represent the end of a longer period of gradually declining impacts.
We can test these theories with samples from the SPA basin, which dominates the far side of the Moon. The basin is about 4.26 billion years old, predating the near-side impact basins.
Was the SPA formed as part of the Late Heavy Bombardment? Or was it a separate event? By obtaining precise dates for the basin and the craters overlying it, we will be able to better understand the Moon’s history.
This also has implications for understanding the origins of life on Earth. It’s possible that asteroids carried water and organic materials to Earth during the Late Heavy Bombardment. Understanding the timing and circumstances of this event is critical for unpacking our origin story.