CCTV News: Chang'e-6 is a "key link" in the fourth phase of the mainland's lunar exploration project, and will complete important tasks such as sampling and returning from the back of the moon. On May 8, under the precise control of the Beijing Aerospace Flight Control Center, the Chang'e-6 probe successfully implemented near-moon braking and successfully entered the orbit around the moon. Near-moon braking is a key orbital control of the Chang'e-6 probe during flight. When the Chang'e-6 probe flies near the moon, it implements "braking" braking to make its relative speed lower than the moon's escape velocity, so that it is captured by the moon's gravity and flies around the moon.
Breakthrough retrograde orbit technology will apply intelligent sampling on the back of the moon
With the implementation of near-moon braking, Chang'e-6 entered the orbit around the moon. Unlike the previous Chang'e-5 lunar exploration mission, Chang'e-6 uses a retrograde orbit. What is a retrograde track? In our solar system, all the great planets revolve around the Sun in the direction of the Sun's rotation, and such orbits are called anterograde orbits.
Retrograde orbit means a spacecraft orbiting the planet that is flying in the opposite direction to the planet's rotation. According to experts, the retrograde orbit will increase the relative velocity between the probe and the moon, which can allow the orbiter to better stabilize in the orbit around the moon.
Subsequently, with the support of the Queqiao-2 relay satellite, the Chang'e-6 probe will adjust the altitude and inclination of the circumlunar orbit, and choose the opportunity to separate the orbiter returner assembly from the lander ascender assembly. After that, the lander ascent assembly landed on the far side of the moon, sampled the far side of the moon as planned, and returned to the mission.
How to choose the landing site of Chang'e to collect samples on the back of the moon?
Chang'e-6's main mission this time is to sample and return, and the most critical step before collecting samples from the back of the moon is to land on the moon. Researchers should not only choose a scientifically valuable landing area for Chang'e-6, but also facilitate follow-up work.
Chang'e-6 is planned to land on the northeastern side of the South Pole-Aitken Basin on the far side of the Moon, the oldest known impact basin in the solar system. The far side of the Moon is the side of the Moon facing away from the Earth, and because the rotation and rotation of the Moon are synchronized, one side of the Moon can never face the Earth.
The location of the moon must not only have scientific value, but also the difficulty of the implementation of the project should be fully considered. Spacecraft work in space are powered by their own solar wings, and Chang'e-6 is no exception. The location of landing on the back of the moon should fully consider all aspects such as lighting to ensure the feasibility of the mission. 53 days of space "business trip" What did Chang'e-6 do?
From the launch of the rocket to the return of samples from the back of the moon to the return to the ground by Chang'e-6, the whole process takes 53 days. What are you going to do in these 53 days? What does the whole process look like?
Hu Zhenyu, head of the overall launch site engineering technical group of the Chang'e-6 mission project, introduced that the Chang'e-6 mission mainly goes through 11 flight stages, namely the launch into orbit section, the Earth-Moon transfer section, the near-moon braking stage, the circumlunar flight section, the landing descent stage, the lunar surface working section, the lunar surface ascent section, the rendezvous and docking and sample transfer section, the circumlunar waiting section, the moon-to-ground transfer section and the re-entry recovery section. During this period, the four components of the probe, namely the ascender, lander, returner and orbiter, were also involved in multiple separations and transfers. Chang'e-6 can be said to be interlocking and the key step by step.
After Chang'e-6 stepped on the "brakes" on May 8, it will take about 20 days to adjust its position in the circumlunar phase to prepare for the moon landing. When everything is ready, Chang'e-6 will begin to land on the moon, work on the lunar surface for 48 hours to complete the sampling of samples on the back of the moon, and after the sampling is completed, it will carry out the lunar ascent and the rendezvous and docking of the lunar orbit. During this period, Chang'e-6 also carried four international "packages", and they also had to carry out a number of scientific explorations at the same time.
Hu Zhenyu introduced that Chang'e-6 carried four international payloads, and the French radon detector carried out in-situ detection of radon isotopes on the surface of the moon; ESA's Lunar Surface Negative Ion Analyzer detects negative ions on the lunar surface and studies the interaction mechanism between plasma and the lunar surface. Pakistan's CubeSat carries out in-orbit imaging missions; The Italian laser corner reflector, as an absolute control point for positioning on the far side of the moon, can carry out joint ranging and positioning research with other lunar exploration missions.
After completing all the tasks, Chang'e-6 will start its way home. After about 5 days of flight re-entry into the atmosphere and return to the landing site of Siziwangqi, the entire "business trip" on the back of the moon will take 53 days.
Source: CCTV
Editor: Xiong Gongjie
Editor-in-charge: Gao Yang Review: Du Hongli Final review: Zou Yan