On June 2 China's Chang'e-6 lander touched down on the far side of the moon in the northeastern part of the South Pole-Aitken basin and will soon start collecting rock samples from the oldest lunar basin to bring back to earth. Payloads on board the Chang’e-6 include the “Negative Ions at the Lunar Surface” developed by the European Space Agency (ESA), the “Detection of Outgassing RadoN” from France, and the Italian passive laser retro-reflector. Around two kilograms of lunar rocks and soil are expected to be scooped up and brought back to earth, the first samples ever to be retrieved from the moon’s far side, which always faces away from the earth. “My colleagues and I are very excited. I hope the mission will be a complete success and make history,” Yang Wei, Geochemist from the Institute of Geology and Geophysics in Beijing, who has studied the Chang’e-5 moon samples, told the South China Morning Post. “When we finally get to analyze those samples in the lab, they will greatly advance our understanding of the moon’s history.”
Chang’e-6, which is named after the Chinese moon goddess, blasted off from the Wenchang spaceport in Hainan on May 3. Despite the rain, more than a hundred thousand people gathered on nearby beaches to watch the launch, according to CCTV. Entering lunar orbit four days later, the 8.35-ton spacecraft – which consists of a lander, ascender, orbiter, and return capsule – had been circling the moon, looking for the best spot and time to land. On May 30, the lander and ascender separated from the orbiter and return capsule. On June 2, the lander fired its 7,500-newton-thrust engine to slow down and began to descend from about 15 km above the lunar surface. In this process, the cameras on the lander snapped pictures of the landing area and transmitted them to computers on the lander to identify possible hazards on the surface, such as large rocks, so that the craft could maneuver to avoid them. At about 100 meters above the lunar surface, the craft suspended its descent and hovered for a moment to conduct accurate detection of smaller obstacles and determine the final landing spot before continuing to descend at a slower, steady speed. It was the second time a Chinese spacecraft landed on the far side of the moon.
The landing process was supported by Queqiao-2, a communications satellite orbiting the moon that relays signals between the spacecraft and mission control. Once the lander completes its two-day surface operations, the relay station will play a critical role in helping the ascender to blast off from the top of the lander, dock with the orbiter and transfer its cargo to the return capsule. With samples from the far side of the moon, scientists will be able to compare the chemical composition of rocks and find clues to why the moon’s two sides are so different, according to Quentin Parker, Astrophysicist from the University of Hong Kong, the South China Morning Post reports.
