中国空间站 On currently on 24th to 26th December 2021 Christmas eve, CNSA –China National Space Administrationin collaboration with CCTV9 China Central Radio and Television will telecast “Our Journey” is the first panoramic documentary produced by China National Space Administration and China Central Radio and Television in 4 years to show the complete course of China’s lunar exploration project in 17 years . It is a documentary . Documentary works with international vision, international expression, and international standards are excellent works that tell Chinese stories, spread space culture, and popularize space knowledge
The documentary consists of three episodes, each of 50 minutes, which truly presents the development of China’s lunar exploration project over the past 17 years, which has been through ups and downs, and left a tortuous but full history. This imprint records not only a huge and complicated super project, but also a testimony to the rapid growth of China’s aerospace industry and the common progress of the Chinese nation. The film fully and vividly interprets the spirit of lunar exploration of “chasing dreams, exploring courageously, coordinating fortifications, and win-win cooperation” , promotes the spiritual pedigree of the Chinese Communists , and conveys the spiritual power that China’s scientific and technological development and progress rely on.
Through character interviews, important development scenarios, and the combined application of various methods such as related materials, the film outlines the continuous and staggered cooperation and support between the various development units of the major systems, and demonstrates the Chinese people’s fearlessness in scientific exploration. Pursuit, as well as the admirable courage and wisdom devoted to this journey full of risks and challenges.
“Our journey” documentary will be held December 24 – the 26th in the Central Radio and Television CCTV-9 record channel 20:00 prime time heavy launch a new media center video, CCTV and other platforms will also be broadcast simultaneously.
Review of the first anniversary of the Chang’e 5 mission-returning home safely
One year ago today 24th November 2020 Now it’s the 24th November 2021 , the Chang Zheng – Long March Five Carrier Rocket Launched away in CNSA – China National Space Administration China Wenchang spaceport launch, Change Five Lunar probe into orbit, opened up towards China – People’s Republic of China’s first celestial bodies sample return trip from Mons Rumker on the Lunar Surface.……
At 23:10 on December 3, 2020, the Chang’e-5 ascender carried a lunar sample to take off from the lunar surface. About 6 minutes later, it entered an elliptical orbit around the moon. At 2:13 on December 6, the ascender accurately reached the scheduled “handover” position 50 kilometers in front of the orbit-return assembly and about 10 kilometers above it. At 5:42, the ascender and the orbit-returning assembly completed the rendezvous and docking. At 6 o’clock, the sample packaging container was transferred from the ascender to the returner. This process of autonomous rendezvous and docking and sample transfer is like the handover process in a 100-meter relay race. It is brilliant and highly technical. Using a lunar orbital rendezvous and docking after take-off from the lunar surface, rather than a direct lunar-to-ground transfer after taking off from the lunar surface, this design is conducive to collecting and carrying more samples back to the earth, and for technical accumulation and verification for subsequent missions.
After the Chang’e-5 probe undergoes a lunar-to-earth transfer, the returner and the orbiter are separated and transferred to the return re-entry section, using a semi-ballistic jump type, that is, a “drifting” return method. After two re-entry into the atmosphere, it decelerates in Beijing. At 1:59 on December 17, 2020, the returner successfully landed in the planned area of Siziwang Banner, Inner Mongolia, marking the successful completion of my country’s first extraterrestrial celestial body sampling and return mission.
At about 1 am on the 17th, the Beijing Aerospace Flight Control Center injected high-precision navigation parameters into the Chang’e-5 orbiter and returner combination through the ground measurement and control station. After that, the orbiter and the returner were normally unlocked and separated at a height of about 5,000 kilometers above the sea level of the South Atlantic Ocean, and the orbiter completed the evasive maneuver as planned. At 1:33 in the morning, the Chang’e-5 returner entered the earth’s atmosphere at a high speed close to the second cosmic speed (about 11.2 kilometers per second) at a height of about 120 kilometers above the ground, and performed the first aerodynamic deceleration. After descending to a predetermined altitude, the retractor jumps up out of the atmosphere and begins to slide down after reaching the highest point. After that, the returner enters the atmosphere again and performs a second aerodynamic deceleration. When descending to a height of about 10 kilometers above the ground, the retractor opened the parachute to complete the final deceleration and maintain a stable attitude, and then landed smoothly in the predetermined area.
During the 30-second parachute opening process, a total of 3 work phases were completed. A series of actions were completed to open the parachute with the flip cover, decelerate the deceleration parachute, pull out the main parachute by the deceleration parachute separation, open the parachute like a closed main parachute, and fully open the main parachute and descend steadily. The work of the recovery system is interlocked. Any mistake will cause the catastrophic consequences of the hard landing of the returner. All the work links cannot be controlled and adjusted from the ground. The recovery system needs to complete these accurately and reliably in such a short time. The action ensures that the returner can safely land at the predetermined location.
Before welcoming the return of Chang’e 5 at the Siziwangqi landing site, a snowfall also arrived as expected, putting a layer of “dress” on the landing site and also brought great difficulty to the search and recovery of the mission. In order to ensure this mission, the search and recovery brigade of a certain base that performed the search and recovery mission organized several rounds of search and recovery exercises under extreme weather conditions such as “extreme cold, dark night, and freezing”. In the end, the search team arrived at the landing site about half an hour after landing and successfully completed the mission. Chang’e 5 obtained a total of 1,731 grams of lunar samples, which is also in line with the characteristics of China’s lunar exploration project. It took 17 years and went through three steps of “circumnavigating, descending, and returning” to draw a blueprint for China’s lunar exploration.
Reaching the moon in nine days, sailing shining galaxy;
Dream set sail, we walk along the way!
Looking forward to the next highlight of China’s lunar exploration project!
One year ago today 24th November 2020 Now it’s the 24th November 2021 , the Chang Zheng – Long March Five Carrier Rocket Launched away in CNSA – China National Space Administration China Wenchang spaceport launch, Change Five Lunar probe into orbit, opened up towards China – People’s Republic of China’s first celestial bodies sample return trip from Mons Rumker on the Lunar Surface.……
At 23:10 on December 3, 2020, the Chang’e-5 ascender carried a lunar sample to take off from the lunar surface. About 6 minutes later, it entered an elliptical orbit around the moon. At 2:13 on December 6, the ascender accurately reached the scheduled “handover” position 50 kilometers in front of the orbit-return assembly and about 10 kilometers above it. At 5:42, the ascender and the orbit-returning assembly completed the rendezvous and docking. At 6 o’clock, the sample packaging container was transferred from the ascender to the returner. This process of autonomous rendezvous and docking and sample transfer is like the handover process in a 100-meter relay race. It is brilliant and highly technical. Using a lunar orbital rendezvous and docking after take-off from the lunar surface, rather than a direct lunar-to-ground transfer after taking off from the lunar surface, this design is conducive to collecting and carrying more samples back to the earth, and for technical accumulation and verification for subsequent missions.
Aspect 1-chase in space
Both the ascender and the orbit-back assembly fly around the moon, but the orbital heights are different. The ascender runs on the outer track at a height of 210 kilometers, and the orbit-back assembly runs on the inner track at a height of 200 kilometers. The distance on the inner track is short, the track-back assembly runs slightly faster, and the ascender on the outer track runs slower. In order to realize the “transfer bar”, the rail-back assembly needs to raise the rail in the height direction and gradually approach the ascender in the front and rear direction. When approaching a certain distance, the orbit-back assembly will autonomously control the engine to change the direction of travel and take a shortcut to catch up with the ascender. During the entire chase process, multiple anchor points are set up, and the orbit-return assembly stops to keep the relative position unchanged, conducts a state inspection, and ensures that the measurement and control conditions meet the requirements during docking.
Picture: Lunar orbital rendezvous and docking flight phase division. (Source: Xu Yang, Ma Lin, Liu Tao, etc. Chang’e 5 Lunar Orbital Rendezvous and Docking Guidance, Navigation and Control System. Science in China: Technological Sciences, 2021, 51: 788–798)
Aspect 2-“High-precision measurement” + “Know yourself and the enemy”
During the rendezvous and docking process, it is necessary to make the orbit-return assembly and the ascender know the relative position, speed and attitude of each other. For this reason, a variety of sensors for relative measurement are configured to realize relative navigation. When the distance is 100 kilometers, the microwave radar starts to work. It not only provides the relative motion parameters of the two devices according to the traditional radar “call and answer” mode, but also upgrades to the “dialogue exchange” mode, between the orbital assembly and the ascender. Two-way transmission of remote control commands and telemetry parameters. At a distance of 20 kilometers, lidar “comes on the scene” to provide higher-precision measurement information. At about 100 meters, the optical sensor began to show its talents to achieve close distance and attitude measurement. These sensors are relayed to each other over the working distance and covered and connected, so as to ensure that there are at least two different systems of sensors available at any distance, so that the orbit-back assembly can be seen more accurately, the measurement is more precise, and the system is more reliable.
Aspect 3-precise “handover baton” from 380,000 kilometers away
The weight of the orbit-return assembly is more than 2 tons, but the mass of the ascender is only one-sixth of its mass. If the traditional collision docking is used, it is very easy to cause the ascender to be knocked into flight. For this reason, a claw-type catching and docking mechanism is specially designed. Each pair of claws is like two arms, which are quickly closed within 1 second to form a closed space, and the passive lock handle of the ascender is firmly restrained inside. Can’t escape. It has to be accurate, and the accuracy requirement after docking is better than 0.5 mm, which is like “threading a needle” in space. The use of 3 sets of claw mechanism star-shaped circumferential layout and self-centering design realizes the automatic centering of the two aircraft after docking, and realizes the lightweight design while ensuring high-precision docking.
The design of the transfer mechanism is also very clever. In order to realize the transfer of long-stroke sample containers of more than six hundred millimeters, the designers found inspiration from the inchworm. Based on the principle of movement stroke amplification + relay transfer, they proposed a relay mechanism for imitating the inchworm. The simple circular expansion and contraction movement of the parallel link can realize the continuous movement of the object. The entire transfer process is like the movement of a caterpillar, stretching and shrinking, continuously advancing.
One year ago today 24th November 2020 Now it’s the 24th November 2021 , the Chang Zheng – Long March Five Carrier Rocket Launched away in CNSA – China National Space Administration China Wenchang spaceport launch, Change Five Lunar probe into orbit, opened up towards China – People’s Republic of China’s first celestial bodies sample return trip from Mons Rumker on the Lunar Surface.……
Highlight 1: Narrow window launch The launch window is the ignition time period for the launch vehicle to meet the needs of the transfer to the moon. Due to the typhoon and strong tropical cyclone in Wenchang area, high-altitude wind, heavy rainfall, thunderstorms and other meteorological conditions are very complicated, it can be imagined. The narrower the window, the greater the risk of launching large cryogenic launch vehicles. There are many factors that determine the launch window, such as the relative position of the launch site and the target point, the safe landing zone of the rocket wreckage, the time of sunlight after the launch probe (satellite) enters orbit, the measurement and control arc, the lunar landing zone, and the lunar take-off time , Re-entry return time, etc. The more the launch constraint conditions, the narrower the launch window. In order to ensure the reliable implementation of the Chang’e-5 mission, it is necessary to solve the design difficulties of the multi-orbit moon launch scheme under the constraints of the range of launch, the safety of the landing zone, the measurement and control of the ascent section, and the rocket taxi time.
Aspect 2: During the two-stage taxiing process of the accurate low-temperature launch vehicle in the landing zone of the rocket, the quality of the propellant will decline with the passage of time, so the longer the taxiing time, the more unfavourable the startup of the low-temperature power system. For this reason, the rocket system has carried out a large number of ground tests, and the three flights of the Long March 5 have fully evaluated and verified the long sliding ability of the model. The rocket area of the Chang’e-5 mission must fly over the Philippine Islands. The booster landing area is located west of the Philippines, the fairing landing area is located east of the Philippines, and the core landing area is located in the Pacific Ocean. Multi-ballistic launching has caused significant horizontal and vertical dispersion in the sub-level wreckage landing area. Therefore, if the mission permits, the range of the shooting direction and dispersion must be minimized to optimize the safety of the landing area. The scientific research team carried out multiple rounds of optimization design for the horizontal and vertical dispersion of the multi-ballistic trajectory to the moon with variable firing direction and variable glide time. In the end, the rocket wreckage landed exactly in the intended sea area. Aspect 3: Multi-trajectory, “moving target shooting”
A key technology in the launch phase of the Chang’e-5 mission is multi-ballistic launch, that is, within 3 consecutive days, there are 5 nominal trajectories with 10 minute intervals between take-offs every day, evenly covering the 50-minute launch window. The purpose of multiple ballistics is to achieve “mobile shooting” with different take-off points and the same destination during the relative movement of the earth and the moon. As long as the launch vehicle ignites within the launch window and sends the probe into a predetermined Earth-Moon transfer orbit, the probe can fly to the near-moon point at exactly the same time, altitude, incident angle, illumination, and measurement and control conditions. Through the detailed orbit design, the outstanding performance of the launch vehicle systems, and the concerted cooperation of various departments, the Chang’e-5 probe was sent into the scheduled orbit with very high accuracy, laying a solid foundation for the subsequent flight missions.
Aspect 3: Multi-trajectory, “moving target shooting” A key technology in the launch phase of the Chang’e-5 mission is multi-ballistic launch, that is, within 3 consecutive days, there are 5 nominal trajectories with 10 minute intervals between take-offs every day, evenly covering the 50-minute launch window. The purpose of multiple ballistics is to achieve “mobile shooting” with different take-off points and the same destination during the relative movement of the earth and the moon. As long as the launch vehicle ignites within the launch window and sends the probe into a predetermined Earth-Moon transfer orbit, the probe can fly to the near-moon point at exactly the same time, altitude, incident angle, illumination, and measurement and control conditions. Through the detailed orbit design, the outstanding performance of the launch vehicle systems, and the concerted cooperation of various departments, the Chang’e-5 probe was sent into the scheduled orbit with very high accuracy, laying a solid foundation for the subsequent flight missions.
Images and visuals are from Weibo and their respectives…. Of CNSA China National Space Administration …
On October 19th Thursday 2021, theChinese Academy of Sciences released the latest research results of the Chang’e-5 lunar scientific research samples. A number of breakthroughs have given a new understanding of the evolution of the moon. The research results of the lunar samples of Chang’e 5 show that magma activity still existed on the moon until 2 billion years ago. The lunar mantle source area of late magma activity is not rich in radioactive heat-generating elements and is very “dry”. This series of research is led by the Institute of Geology and Geophysics of the Chinese Academy of Sciences and the National Astronomical Observatory, and jointly carried out by a number of research institutions. The related results have formed 4 papers, one published in the “National Science Review”, and published in the international academic journal “Nature” 3 articles.
The duration and geochemical characteristics of the lunar basalt magma are the “keys” for understanding the thermal-chemical evolution of the moon. Previous studies have confirmed that magma activity on the moon lasted at least approximately 2.8 to 3 billion years ago. However, there has been controversy in the scientific community about the exact time when the lunar magma activity ceased. The study found that the lunar sample of Chang’e 5 is a new type of lunar basalt, which is different from the lunar samples collected and returned by the United States and the Soviet Union. Researchers analyzed more than 50 uranium-rich minerals in the basalt cuttings of the Chang’e 5 lunar sample and determined that the basalt formation age was 20.30±0.04 billion years, indicating that there was still magma activity on the moon until 2 billion years ago, which is more than the limit of previous lunar samples. Magma activity has been extended for about 800 million years.
The cause of the most recent magmatic activity on the Moon has always been an unsolved mystery. At present, there are two possible explanations in the scientific community: the lunar mantle source is rich in radioactive elements to provide a heat source, or the lunar mantle is rich in water to lower its melting point. The latest study found that the lunar mantle source area of the basalt from the lunar sample of Chang’e 5 is not enriched in “Krip material.” Since the “Krip material” is rich in radioactive heat-generating elements, this result proves that the radioactive heat-generating elements of the lunar mantle are not the main reason for the formation of the basalt of the Chang’e-5 lunar sample. Regarding whether the magma source area is rich in water, the research team measured the water content and hydrogen isotopic composition in the basalt of the Chang’e 5 lunar sample, and found that the water content in the lunar mantle source area was only 1 to 5 micrograms/g, which means that the lunar mantle Very “dry”. This discovery also excludes the hypothesis that the lunar mantle is rich in water and has a low melting point, resulting in an abnormally prolonged duration of magma activity in this area.
Water content and hydrogen isotopic composition of apatite and melt inclusions in the Chang’e-5 basalt sample
Backscattered scanning electron microscope image of apatite and magma inclusions in the Chang’e-5 basalt (a) A complete picture of the basalt cuttings (406-010,023) in the alloy target. The cuttings are mainly composed of olivine (Ol), It is composed of pyroxene (Px), feldspar (Pl) and ilmenite (Ilm), and a small amount of iron olivine (Fa), meteorite (Tro), spinel (Sp), apatite (Apa) and Quartz (Q). (B), (c) and (d) are the partial images of the cuttings respectively. (B) The figure shows the melt inclusion (MI) surrounded by ilmenite. (C) and (d) show that apatite is mainly produced in the intergranular area and is euhedral or semi-automorphic
According to the hypothesis of the origin of the big impact, the original Earth collided with a planetary planet the size of Mars, forming a “disk” composed of high-temperature magma and gas around the earth. When the temperature begins to cool, materials such as silicate first gather to form the moon (Figure 1), and water is a highly volatile material that escapes into space in a gaseous form and is lost. Therefore, the moon born in this way contains almost no water and is a nearly dry planet. The research results of the lunar samples of Chang’e 5 further provided supporting evidence for the origin and evolution of the moon, raised new scientific questions for the study of the lunar thermal evolution history, and proposed new directions for future lunar exploration and research.
We welcome domestic and foreign scientists to join the ranks of the research on these data and samples. At present, research on lunar samples is mainly carried out by domestic scientific research institutions, and foreign scientists have joined the Chinese team to carry out joint research. In the follow-up, we will issue relevant policies, uphold the principles of “equality and mutual benefit, peaceful use, and inclusive development”, expand international exchanges and cooperation, and provide more Chinese wisdom, Chinese solutions, and Chinese power for the peaceful use of space and the promotion of a community with a shared future for mankind.
