New Space Mission Promises to Reveal Secrets of the Far Side of the Moon

On May 3, China launched one of the most complicated space missions yet endeavored, which aims to retrieve samples from the far side of the Moon, for the first time ever. The Chang’e-6 mission involves four separate vehicles—an orbiter, a lander, an ascender and a re-entry module.

Unlike most other missions, there will be no “direct” contact with the vehicles, as much of the action will be occurring on the side of the Moon which never faces the Earth, making it extremely complicated. Indirect contact will be maintained through the Queqiao-2 relay satellite. The satellite is already in place in an elliptical “frozen orbit”, a Lagrange point, around the Moon, and will transmit signals back to Earth. There are similarities to the Chang’e-4 mission, in which China became the first country to land a rover on the far side of the Moon in January 2019, and used the Queqiao-1 relay satellite for transmission. With this mission, however, a technically more advanced relay was needed since, in addition to the Chang’e-4 lander and a rover, Yutu, they also have the new mission vehicles to deal with on the far side. With Chang’e-5, the Chinese gained experience by returning a sample from the near side of the Moon. But this a bit more complicated.

The Chang’e-6 is also a collaborative effort with international partners, with a cubesat satellite being deployed for the first time by Pakistan in lunar orbit, a Detection of Outgassing Radon (DORN) experiment from France, a Negative Ions at the Lunar Surface (NILS) experiment from Sweden, supported by the European Space Agency, and a laser retroflector from Italy. It is scheduled to be a 53-day round trip, and will collect 2 kilograms of soil and rocks from the lunar landing site.

Chang’e-6 will have profound significance for our knowledge of the universe. It will tell us much about the origin of the Moon, as the far side has been continually exposed to the surrounding cosmic bombardment. It could also give us a better understanding of the origin of our own Earth, since the primary hypothesis about the Moon is that it separated from the Earth as the result of cosmic bombardments on the Earth. In all likelihood, there may be new and hitherto unknown minerals coming from the far side.