Chang’e 5 has landed on the surface of the Moon. On December 1, the lander safely landed near the Mons Rümker formation. Chang’e 5, China’s most ambitious lunar mission to date, is expected to retrieve two kilograms of lunar samples. Previously such task was completed by the Soviet Luna 24 probe in 1976. You can read more about the developments of the mission here.

Chang'e 5 landing area / LRO/NASA Jaka Pelan/Arkeomapia/2020
Chang’e 5 landing area / LRO/NASA Jaka Pelan/Arkeomapia/2020

The Chang’e 5 landing site

Chang’e 5 landed east of the Mons Rümker formation. It is one of the younger regions on the lunar surface. You can see it on the left in the image above. This bulge consists of many volcanoes and is about 70 kilometers in diameter. The plateau of solidified lava is about 1.2 billion years old. Thus, the gathered samples will be the “youngest” rocks brought back from the Moon. By comparison, samples collected by the six crewed Apollo missions between 1969 and 1972 were much older, around 3 billion years old.

Chang'e 5 lander located by the Lunar Reconnaissance Orbiter / NASA
Chang’e 5 lander located by the Lunar Reconnaissance Orbiter / NASA

The Americans also confirmed the location of the Chinese lander using a satellite of their own – the Lunar Reconnaissance Orbiter. It has been in use around the Moon since 2009. The satellite’s LROC instrument resolution allows to distinguish details greater than 50 cm in diameter. Thus, the LRO mission is able to find hardware of several space missions on the lunar surface.

Taking lunar samples

Following the landing, Chang’e 5 quickly started to conduct its tasks. China was concerned about time spent on the surface, as the entire process of sampling, transferring and re-launching into lunar orbit had to be completed within a few days. The main concern in this case was the power supply to the lander, which was only equipped with solar panels. As a full day on the Moon lasts 28 Earth days, so the mission controllers had theoretically only two weeks of daylight to complete all objectives.

Chang'e 5 takes lunar soil samples / News.CN image crop
Chang’e 5 takes lunar soil samples / News.CN image crop

Chang’e 5 took the samples with a special drill capable of going two meters below the surface. In the recordings and images published by the Chinese media, you can see the places where soil samples were taken.

Following the sampling, the robotic arm with the attached drilling mechanism transferred the soil samples into the ascent section. This process can be seen in the recordings received from the lander. Notice that Chang’e 5 did not only sampled dusty regolith soil, but also small rock fragments. In total, the probe took as many as 12 samples.

Render of the Chang'e 5 sampling instrument / CNSA
Render of the Chang’e 5 sampling instrument / CNSA

Ascend to Moon orbit, and back to Earth

On December 3, the next stage of the mission began. The Chang’e 5 ascent section took off from the Moon’s surface. After six minutes of flight, it entered a temporary orbit at an altitude of 15 by 180 km. In the following two days, the ascent section made as many as four orbit adjustments. This allowed it to finetune its flight trajectory to the Chang’e 5 orbiter circling the Moon, and finally to dock to it.

Both spacecrafts docked on December 5 and again a sample transfer followed. This time they were placed into the return capsule, in which they are to survive the last stage of the mission. After completing the sample transfer, the ascent section was no longer needed. It undocked from the orbiter and made a controlled deorbit, that is a hard landing on the surface, on December 7th.

On December 12, the orbital section restarted its engines and carried out the first maneuver known as TEI-1. It placed the spacecraft into a highly elliptical orbit. From this trajectory, less fuel will be needed for the next maneuver, TEI-2, which will put Chang’e 5 on a path towards Earth. Currently, the return of the samples is scheduled for December 16.

New Chang'e 5 orbit / CNSA
New Chang’e 5 orbit / CNSA

Cooperation with the European Space Agency

It is worth mentioning that the European Space Agency (ESA) also contributed to the Chinese success. Shortly after the launch of the mission, ESA antennas in French Guiana tracked the signals from the probe. Especially inn the early stages of the mission, the exact location of the probe and the analysis of its signals were of key importance. The data received from Kourou was transferred directly to the Beijing flight control center.

Antennas located in the Canaries will be used when the Chang’e 5 return section will journey back to Earth. ESA will be listening for signals through the Spanish Maspalomas station. ESA has also collaborated with China on previous Chang’e missions.