After a full half year and 183 days, on April 16, 2022, the space "business trip" trio successfully triumphed and landed safely at the Dongfeng landing field in Inner Mongolia.
On October 16 last year, astronauts Zhai Zhigang, Wang Yaping, and Ye Guangfu boarded the Shenzhou 13 manned spacecraft at the Jiuquan Satellite Launch Center to enter the Tianhe core module, becoming the second batch of astronauts to stay on the Chinese space station. At this point, the flight crew of the Shenzhou 13 manned spacecraft after returning to The Earth has also set a new record for the continuous flight time of Chinese astronauts in orbit.
During the orbit period, with the support of ground scientific and technological personnel, the three astronauts successfully completed 2 outgoing activities and 2 "Tiangong Classroom" space teaching activities, and carried out a number of scientific and technological experiments and application projects, laying a solid foundation for the subsequent construction of the space station. This time, the three people returned home smoothly, which also means that the mainland will enter the construction stage of the space station project.
What was done during the orbit?
According to the China Manned Space Engineering Office, the Shenzhou 13 astronaut crew completed more than 20 scientific experiments in orbit on the basis of the preliminary work of the Shenzhou 12 astronaut crew. These experiments focus on the new technology of astronaut health monitoring, new scientific knowledge and data accumulation, complete a series of innovative research, and for the first time establish a long-term culture system and cell model of cells under space conditions.
Using this system and training model, researchers have completed several internationally leading life science experiments. For example, the renal epithelial cells in the human urine are converted into stem cells with multiple functions by genetic reprogramming, and they are differentiated into cardiomyocytes and fluorescent proteins, which is the first time that the "calcium signal flicker" of cardiomyocytes under weightless conditions has been observed in humans. In addition, the astronauts have also completed the world's first skin stem cell weightless suspension culture experiment.
On December 26, 2021, astronauts Ye Guangfu and Zhai Zhigang, dressed in "Feitian" extravehicular spacesuits, successfully exited the capsule from the Tianhe core module node module and carried out extravehicular operations.
The construction of the continental space station is divided into two stages: the verification of key technologies of the space station and the construction of the space station. Jiao Weixin, a professor at the School of Earth and Space Sciences of Peking University, said in an interview with reporters that the on-orbit work of Shenzhou 13 and Shenzhou 12 manned spacecraft belongs to the first stage and is to prepare for the subsequent construction of the space station.
The continental space station is a three-cabin structure, in the shape of a "T", and after the core module goes up, the remaining two sides are two experimental modules, Qingtian and Mengtian. "Each experimental cabin has more than 20 tons, and two big guys have to dock with the middle core cabin, and if they don't master it well, there will be a collision, which poses a challenge to safe docking." Jiao Weixin said that on this key issue, the flight crew of the Shenzhou 13 manned spacecraft has made outstanding contributions.
One of the contributions was the successful transposition of the robotic arm-assisted module during the astronaut's orbit. Jiao Weixin believes that considering the weight of the two experimental chambers, if it is docked directly from the side with the core cabin, the risk is greater. Therefore, when the experimental cabin is close to the core cabin, it is necessary to carry out axial docking first, and then use the rotating mechanical arm on the core cabin after docking, so that the experimental cabin and the core cabin are separated, and after turning 90 degrees, then docking from the side. In order to ensure that the docking between the experimental module and the core module is foolproof, the flight crew of the Shenzhou 13 manned spacecraft once used the Tianzhou-2 cargo spacecraft as an experimental object, took it as an experimental module, and rehearsed it in advance.
On December 9, 2021, the first lesson of "Tiangong Classroom" was officially launched, which was the first space teaching activity of the Chinese space station.
At the same time, the three astronauts also installed a cascade device for large and small robotic arms on the space station, increasing the crawling distance of the robotic arm. "When the two experimental modules are docked in the future, the two ends of the space station shape will become longer." If there is only one robotic arm, it will be difficult to install or transfer the device, so it is necessary to connect the large and small robotic arms together through the cascading device to make the robotic arm longer. Jiao Weixin told reporters.
In addition, the on-orbit astronauts also completed the hand-controlled operation of the docking of the cargo spacecraft with the space station. Jiao Weixin handles the hand-controlled rendezvous docking and automatic rendezvous docking, which is likened to the left and right hands of the space rendezvous and docking, and they are backed up for each other, which is an important guarantee for the reliability of the system.
Previously, under the close coordination of ground scientific and technological personnel, after about 2 hours, the Shenzhou 13 astronaut crew adopted a hand-controlled remote operation method in the core module of the space station, and successfully completed the rendezvous and docking test of the Tianzhou-2 cargo spacecraft and the space station combination. This test also preliminarily verified the functions and performance of the manual remote operating system of the space station and the visiting aircraft, as well as the scientific rationality of the cooperative working procedure between heaven and earth.
What preparations did the astronauts make before they went home?
It is understood that before the 3 astronauts return to the earth, they also need to do a good job in material inventory and transfer, cleaning and maintenance of the cabin environment, packing downlink items, setting up unmanned flight mode, checking the working status of the spacecraft, and monitoring the body. "Shenzhou XIII returned, in addition to bringing 3 astronauts, we can also bring about 100 kilograms of stuff." Pang Zhihao, chief scientific communication expert of national space exploration technology, said.
"The things that should be returned should be returned to the position, and all kinds of items should also be sorted out in different categories to prevent floating around and damaging other equipment on the core cabin." Other items will remain on it to help the next crew work and live on track. Pang Zhihao said that some items need to be put into the orbital module and fall into the atmosphere with the orbit, and some items need to be brought back to earth by astronauts, including some experimental samples and related data.
On April 2, after bidding farewell to the Tianzhou-2 cargo spacecraft, the Crew of Shenzhou 13 astronauts flying in orbit was making intensive preparations for the spacecraft's return.
Pang Zhihao said that some garbage has been transported back to Earth through the Tianzhou-2 cargo spacecraft. Before returning home, astronauts may also sort out some residual food waste, sanitary product waste, waste generated by on-orbit experiments, etc., put them into the orbital module, and then fall into the atmosphere with the orbital module and burn up. After finishing the finishing, the astronauts also need to carry out comprehensive cleaning and maintenance of the cabin environment to control the growth of microorganisms in the space station complex.
It is worth noting that in order to ensure safe return, astronauts also need to strengthen physical monitoring and exercise. According to the China Manned Space Engineering Office, there are a large number of cargo bags used for the on-orbit medical monitoring of astronauts in the cabin, in order to ensure the safety of astronauts, ground personnel have adjusted the astronauts' physical exercises in orbit and other protective programs according to the astronauts' physical inspection in orbit and the data obtained.
"Mainly because astronauts work and live in a microgravity environment for a long time, the body will change a lot." For example, muscle atrophy, bone loss, decreased body fluids, and even immune system disorders. Therefore, before they go home, they also need to carry out intensive exercises to make adaptive adjustments in advance for returning to the ground. Pang Zhihao explained.
According to him, before the astronaut leaves the space station, it is necessary to do a good job of setting the temporary state, set up electricity, water, gas, communications and other aspects in place, and further familiarize themselves with the necessary operations and emergency plans in the process of return, so as to be foolproof.
What other procedures do I need to go home this time?
Previously, Shenzhou XII group returned to the earth in total, needed to leave the "station" on the "ship" and evacuate the space station assembly; perform the first "radial rendezvous" test after the roundabout; wait for the return voyage, synchronize with the earth; complete the separation of the "two cabins" before entering the atmosphere; enter the atmosphere, experience the test of high temperature vibration and harsh environment; open the parachute, and land steadily and other 6 major steps.
According to the China Manned Space Engineering Office, the return mission adopted the "rapid return plan" for the first time. This means that Shenzhou 13 is not only the spacecraft that has been in orbit on the mainland for the longest time, but also the fastest spacecraft to return. It is understood that the "rapid return scheme" adopted by Shenzhou 13 for the first time has reduced the number of flying circles, reduced the return process of astronauts from 11 to 5 circles, and controlled the return time within a few hours.
"This time the program was optimized, and some of the tandem work was changed to parallel work, which improved the comfort of the astronauts in the cabin and the efficiency of return." Pang Zhihao said.
CCTV News reported that the Shenzhou 13 manned spacecraft was the first to separate from the space station Tianhe core module. Before separation, astronauts need to close the two-way pressure-bearing module door connecting the Tianhe core module with Shenzhou 13 and formally evacuate the space station. After entering the Shenzhou 13 spacecraft, the astronauts need to immediately change into the cabin pressure suit they wore when they went out on the expedition. After that, the astronauts must be on duty in the return module, waiting for the return flight.
Then, before entering the atmosphere, the separation of the "two chambers" is completed. Before the Shenzhou spacecraft is de-orbited, the orbital module and the return module will first be separated. The engine then starts, the spacecraft gradually descends its altitude, and completes the separation of the propulsion module before entering the atmosphere, and the return module enters the return orbit.
"This action is generally not risky when the orbital module and the return capsule are separated, but when the orbital module and the return capsule are separated, the sealing device in the middle is not sealed, resulting in the astronaut's acute lack of oxygen and boiling body fluids and death." Jiao Weixin told reporters that after the lesson learned in history, aerospace experts designed an on-orbit sealing leak detection device, and now there will be basically no such error.
Jiao Weixin said that the spacecraft's return capsule descended to about 100 kilometers above the ground and entered the atmosphere, which is also the most harsh stage of the return process, during which it will experience a "black barrier area" of 4 to 6 minutes. "The temperature is high and the surrounding gases are ionized, forming a plasma sheath. The dense ion sheath prevents electromagnetic waves from passing through, so the return capsule loses contact with the ground at this time, but the ground can also be tracked by means such as electrosponsive radar. ”
Finally, at an altitude of about 10 kilometers above the ground, the return capsule will open the guide parachute, the deceleration parachute and the main parachute in turn, and throw off the heat-proof outsole. At about 1 meter above the ground, the reverse thrust engine is started, and the descent speed is reduced to about 2 meters per second, and finally the return capsule is safely landed.
"In addition to the main umbrella, we also have a spare umbrella of more than 700 square meters, if the main umbrella cannot be opened, you can use the spare umbrella at this time." Pang Zhihao said.
Where do you land after coming back?
On May 8, 2020, the return module of the new generation of manned spacecraft test ship on the mainland successfully landed in the predetermined area of the Dongfeng landing field. Since then, the Dongfeng landing field has got rid of the "standby" identity, began to "turn positive", and opened the landing field system's normalized emergency standby search and rescue mode.
On September 17, 2021, the Shenzhou 12th return capsule landed safely at the Dongfeng landing site, and Three astronauts, Nie Haisheng, Liu Boming, and Tang Hongbo, returned to the ground safely. The Dongfeng landing field also successfully ushered in the Shenzhou 13 return capsule that fell from the sky.
Dongfeng landing field is located in the central and southern region of Ejina Banner of The Alxa League of Inner Mongolia, with a vast area, sparsely populated, dry and cold in winter, hot in summer, with little rain and wind. There are deserts, Gobi, mountains, and basically cover all kinds of landing terrain that need to be tested.
"It is also relatively close to the Jiuquan Satellite Launch Center, and the transfer of some equipment and personnel is relatively convenient." In addition, there are few areas where farmers and herders live and produce, which does not have a great impact on the population. Jiao Weixin said that as a result of the previous support experience, dongfeng landing field has a professional search and rescue team, but also has a professional search and rescue capability.
Bian Hancheng, deputy chief designer of the landing field system of China's manned space project, once said that relying on the Jiuquan Satellite Launch Center to build the Dongfeng landing field and deploy a search and rescue force, it can perform diversified search and rescue tasks in various mission sections of launch, operation, and return, not only can search and rescue the spacecraft return module, but also search for rocket debris and realize the normalization of astronauts' emergency search and rescue missions.
According to CCTV News, according to the characteristics of the Shenzhou 13 return mission, the search and rescue recovery detachment set up a total of 11 search and rescue detachments in the east and west areas of the Dongfeng landing field, invested nearly 100 vehicles, 5 helicopters, and 1 fixed-wing aircraft, and coordinated the corresponding civilian search and rescue forces around the landing site to jointly guard the safe return of astronauts.
Source: Xinhua News Agency WeChat public account, "All-China Women's Federation Women's Voice" WeChat public account, comprehensive "know NEWS"