The Back Of The Moon Digging Mystery, Chang'e 6 Have Used Which Laser Technology?

On May 3, Chang'e 6 was successfully launched, embarking on mankind's first back-of-the-moon sampling return trip.
It is about to land on the back of the moon in the South Pole - Aitken Basin "digging", collection of different geographic areas, the age of the moon samples, brought back to Earth for in-depth study.
At present, Chang'e 6 has successfully completed the key step of "near-moon braking" (i.e., "space braking") and successfully entered circumlunar orbit.
It is worth mentioning that laser technology played a crucial role in this mission.
What laser instruments and technologies were used?
In addition to the detector (containing several key laser optical instruments) itself, the Chang'e 6 mission also carried payloads andprograms from four countries, including France's Radon Gas Detector, ESA's Negative Ion Detector, Italy's Laser Angular Reflector, and Pakistan's Cube Star. Among them, MoonLIGHT, the laser corner reflector of Italy's INFN, is particularly eye-catching.
(1) Italy INFN's Laser Angle Reflector MoonLIGHT
The laser corner reflector that Chang'e 6 will place on the back of the Moon is used to provide precise navigation services for satellites orbiting the Moon. The reflector is "MoonLIGHT" from INFN - National Institute of Nuclear Physics, Italy, which can help satellites calculate precise distances and grasp orbits to improve the accuracy of landing.
Laser Ranging (LR) is a technique used for precise distance measurement between a laser ground station and an optical target (Cube Corner Retroreflector, CCR).
As early as 1969, the U.S. Apollo 11 placed the first laser reflector on the Moon to accurately determine the distance between the Earth and the Moon. As a result, the realization of Lunar Laser Ranging (LLR) measurement became possible. Only five countries in the world, including ours, have the technical capability to accurately measure the distance between the Earth and the Moon with a laser. According to statistics, mankind has placed a total of five laser reflectors on the Moon in the last century.
In recent years, laser ground stations have improved significantly, but there are still limitations imposed by lunar vibration and so on. In order to achieve more accurate LLR measurements, the MoonLIGHT project, a high-precision test laser instrument, has been developed. MoonLIGHT adopts a new generation of compact design, with a reflecting surface diameter of 100 mm, which improves the measurement accuracy to within millimeters. In the future, with the MoonLIGHT, there will be a single large CCR to minimize the effects of vibration.
In addition to this MoonLIGHT, in January this year, the United Launch Alliance (ULA) "Peregrine Falcon" lunar lander carrying the Laser-Reflector Array (Laser-Reflecting Array, referred to as LRA), and NASA Mars Exploration "The Laser-Reflecting Array (LRA) on board the lunar lander of Falcon, and the Laser-Reflecting Array (LaRA) of NASA's Mars Exploration Program (MEP) are also of great interest.
(2) Several Key Laser and Optical Instruments of Shanghai Institute of Technology and Physics (SITP)
It is reported that the Chang'e 6 lunar mineral spectrum analyzer, laser ranging and velocimetry sensitizer and laser three-dimensional imaging sensitizer developed by the Shanghai Institute of Technology and Physics of the Chinese Academy of Sciences also lifted off with the probe.
According to the official website of the Shanghai Institute of Technology and Physics of the Chinese Academy of Sciences:
- The Lunar Mineral Spectrum Analyzer is one of the detector's payloads, which will carry out spectral detection and analyze the distribution of the mineral composition of the landing sample area on the lunar surface;
- The Laser Ranging and Velocimetry Sensor, which will provide long-range distance and speed information when the probe lands on the lunar surface, is an important stand-alone machine in the Attitude Control (GNC) subsystem;
- The laser 3D imaging sensitizer uses laser fast scanning imaging means to detect the topography and geomorphology of the lunar surface, enabling the lander to realize real-time obstacle avoidance and provide accurate 3D images of the lunar landing area when the probe is hovering.
In the 21st century, when China launched the Chang'e lunar exploration project, the idea of using lasers to measure the topography of the lunar surface in three dimensions was put forward. Shanghai Institute of Technology specializes in infrared physics and optoelectronic technology research, the last century in the airborne platform to realize the laser as a means of three-dimensional measurements of the surface, from "Chang'e I" began, space active photoelectric load development team began to transfer to the space mission, when many members are made into a spectroscopic technology like origin.
In addition, the Shanghai Institute of Silicate Technology of the Chinese Academy of Sciences has developed a series of "magical skins" and key materials for the "six girls" that have also attracted attention, including tellurium dioxide crystals for the infrared imaging spectrometer of the Chang'e 6 lunar rover and thermal control coatings for the detector. In the infrared imaging spectrometer of Chang'e 6 lunar rover, large-size tellurium dioxide crystals are the key materials for realizing large field of view, high spatial and spectral resolution, and its large-size tellurium dioxide crystals with excellent acousto-optic characteristics have ensured the completion of this key material on schedule.
What wonders will Chang'e 6 create this time?
The successful launch of the Chang'e 6 probe marks another major breakthrough in China's space industry!
After launching into orbit, the "Six Girls" will carry out a flight of about 53 days as planned, during which it will go through the phases of earth-moon transfer, near-moon braking, circumnavigation, landing and descent, lunar surface work, lunar surface ascent, rendezvous and docking and sample transfer, circumnavigation and waiting, lunar-earth transfer, and re-entry and recovery.
Sampling the backside of the moon is a miracle in itself. The terrain on the back side of the Moon is more rugged than the front side, which makes landing on the back of the Moon difficult, and this difficulty is also magnified on the back of the Moon by the problem of Earth-Moon communication.
The biggest difficulty, perhaps, lies in realizing precise docking: the lander-ascender combination needs to be docked with the orbiter-returner combination, which has the opportunity to turn to the front of the Moon in a circumlunar orbit, allowing the ground station to measure the trajectory and communicate with it, but the former does not have the support of any ground station on the surface of the Moon, and can only communicate with Magpie Bridge 2.
The temperature difference of several hundred degrees between day and night on the Moon also brings great test for the normal operation of various instruments. For this reason, the Shanghai Institute of Silicate has developed more than 10 kinds of inorganic thermal control coatings, and these "temperature control coatings" are used for the panoramic camera mechanism, lander, engine protection cylinder, lander lunar night temperature collector, laser pointing device, docking mechanism and so on.
In addition, China will also be in the process of these tasks, to sample the return, but also to create a miracle in technology - Chang'e VI must be accurate to do a good job "to go, under, on, back, into" five actions, each action can not appear any error.
This year, China will push ahead with the fourth phase of the Moon Exploration Project, which is planned to include the Chang'e-6, Chang'e-7 (searching for evidence of the existence of water on the Moon) and Chang'e-8 (the basic type for establishing an international lunar research station) missions. There are still many technical difficulties to be overcome before the scientific research station is fully completed.