Robotic probe launched to the far side of the moon

The robotic probe Chang’e 6, tasked with the world’s first attempt to collect samples from the far side of the moon, began its historic journey from China’s southernmost province of Hainan on Friday.

A Long March 5 heavy-lift launch vehicle — the largest and most powerful space vehicle in China, standing 20 stories high and weighing 870 tons — lifted off from its launch pad carrying the 8.35-ton Chang’e at 5:27 p.m. 6 spacecraft on board and flew aloft, leaving hundreds of thousands of spectators in awe at and around the Wenchang Space Launch Center on the coast.

The launch marked the start of the country’s second lunar sampling expedition, following the successful Chang’e 5 mission in winter 2020.

Still, the unfolding mission will be far more difficult, challenging and compelling than Chang’e 5, which landed on the near side of the moon, and will certainly be recorded – whether a great success or an unfortunate failure – as a symbol. of daring and groundbreaking work in the history of humanity’s lunar exploration.

Previously, ten lunar sample return missions were undertaken by the United States, the former Soviet Union and China, but all of these samples were collected on the near side of the moon.

As one of China’s and also the world’s most important space voyages this year, major steps in the Chang’e 6 mission have made headlines around the world and attracted much attention from the Chinese people.

The local tourism authority in Wenchang estimated that at least 200,000 travelers arrived in Longlou, a township where the launch complex is located, on Friday to witness the launch.

According to the China National Space Administration, after flying for about 37 minutes, the Long March 5 rocket successfully placed the robotic lunar probe into an Earth-moon transfer trajectory, the gateway to our celestial neighbor.

Complex operation

In a few days, the Chang’e 6 probe will retrace its trajectory toward the moon and make some corrections before performing an important braking maneuver to avoid accidentally flying past the moon. The spacecraft will then be captured by the moon’s gravity and enter lunar orbit.

Like its predecessor, the Chang’e 6 spacecraft was designed and built by the Beijing-based China Academy of Space Technology, a subsidiary of China Aerospace Science and Technology Corp, and also consists of four components: an orbiter, a lander and a riser. and a reentry capsule.

The operational process will basically mimic that of the Chang’e 5 spacecraft. After the probe reaches lunar orbit, the components will separate into two parts, with the orbiter and reentry capsule remaining in lunar orbit while the lander and ascender begin approaching the lunar surface.

Once complete, the lander and riser combination will make a soft landing in the South Pole-Aitken Basin – a gigantic crater on the far side of the moon and also the largest, oldest and deepest basin recognized on the moon. It will then start using a drill and a mechanical arm to collect surface and subsurface samples.

If everything goes smoothly, up to 2 kilograms of rocks and soil are collected and packed in a vacuum-tight metal container in the ascender.

After the collection operation is complete, the ascender’s engines will carry it to lunar orbit to dock with the return capsule. The vacuum-sealed container containing the samples is transferred to the module before the riser clamp is disconnected.

The orbiter and reentry capsule combination will then leave the Moon’s orbit and return to Earth’s orbit, where the pair will separate and the reentry capsule will perform a host of complicated maneuvers to return to the Siziwang Banner Landing Site in the Inner Mongolia Autonomous Region. region.

The main difference between the Chang’e 5 and Chang’e 6 probes lies in their landing destination on the moon and the associated technical problems, the most crucial of which are the communication problems between the far side of the moon and Earth.

To establish a data link for the Chang’e 6 probe, China deployed a new relay satellite into the moon’s orbit in March.

Wang Qiong, deputy chief designer of the Chang’e 6 mission, said there will be a large number of challenges and uncertainties during the 53-day expedition, adding that Chinese scientists and engineers have made efforts to develop the best available solutions to work.

“During the Chang’e 5 mission, the probe worked on the near side, so we could monitor its work processes and send control signals to it at any time. But in the case of Chang’e 6, we will have to rely solely on the Queqiao 2 relay satellite to transmit data and signals. The satellite has limited coverage over the landing site, which will consequently limit our communications with the Chang’e 6 probe,” he said.

Wang said engineers have applied a number of new advanced technologies in the mission, such as a rapid sampling system and a smart data analysis mechanism, to ensure that the sample collection tasks are completed effectively and efficiently on the lunar surface within a shorter operating time.

In the event of a communication failure, the Chang’e 6 probe can perform some important maneuvers in accordance with preset programs, he added.