26 degrees below zero! The search and rescue mission of the Shenzhou 14 return capsule may be the most difficult in history.

Since successfully entering the space station on June 5th, the three astronauts of Shenzhou XIV, Liu Yang and Cai, have been working and living in space for half a year. In order to welcome them to "go home" safely, the landing site system of Jiuquan Satellite Launch Center recently conducted the last full-process and all-factor search and rescue training.

Chen Shi, commander of the search and rescue air detachment of the Shenzhou 14 return capsule, said: "It has been more than a dozen times since 1999 started the search and rescue mission of the shenzhou spaceship return capsule. This time I summed it up as the most difficult in history. Because the extreme temperature can reach MINUS 26 degrees Celsius, the low temperature will cause some difficulties for our equipment and our personnel. "

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Dongfeng landing site is ready for communication, so prepare more.

According to the China Manned Space Engineering Office, China astronauts completed the first on-orbit handover by crew, and Shenzhou 14 astronauts will return to the Dongfeng landing site on February 4, 65438.

The low-temperature night search and rescue communication link is connected with the life channel.

The Dongfeng landing site returned by the Shenzhou 14 astronaut is a no-man's land of about 13000 square kilometers, where there is no network signal coverage. Satellite communication is the only means of communication at the landing site. There is such a search and rescue force at the scene. Their task is to establish a communication system accurately and quickly at the first time to ensure the smooth decision-making and command of astronauts' search and rescue work. Let's follow the reporter to get to know this search and rescue team.

Drilling screen

This is the third comprehensive system-wide drill for Shenzhou 14 to return to the Dongfeng landing site, and the search and rescue team members are building the first communication link of the Dongfeng landing site. Shenzhou 14 recycling mission is in winter. The continuous drop in temperature in these two days has brought great challenges to the search and rescue team.

The search and rescue team is building the first communication link at the Dongfeng landing site.

Headquarters reporter Liu _ Li: At present, the temperature is around MINUS 20 degrees Celsius, and team members are not allowed to operate with gloves in the process of setting up satellite communication. Now my hands are almost frozen. This portable station weighs about 50 kilograms, and two people have to approach 200 meters. It takes 10 minutes from the landing of the spacecraft to the successful establishment of satellite communication.

Li Tao, the head of the communication team of the Shenzhou 14 search and rescue mission, practiced again and again, and within the specified time, he was able to send images and sounds to Beijing for the first time, so that the people of the whole country could see the health status of the astronauts.

The natural conditions in the cold and dark night will bring a series of problems, such as difficult direction identification, hard and easy damage of communication cables, shortened battery life and so on.

Video screenshot

He Kaimian, the communication operator of the Shenzhou 14 search and rescue mission: The portable station is covered with a layer of felt to care for it like a baby, and some reflective signs are wrapped around the cable, causing artificial damage.

Dongfeng Landing Site started at 202 1 and became the main landing site for manned space flight. With the normal implementation of the space station mission by Chinese astronauts, the Dongfeng landing site is also being planned and constructed according to the requirements of digitalization and intelligence. At present, the Dongfeng landing site has completed the laying of optical fiber network, and will adopt wireless broadband and field access technology to realize high-speed and high-quality communication guarantee.

Bian Hancheng, deputy chief designer of the landing site system of manned spaceflight project: Next, we will rely on the optical fiber network. In any place of Dongfeng landing site, communication is accessible and the transmission quality is good. We can send high-definition images back to the command center anytime and anywhere. This is the direction of our next effort.

Visit the measurement and control points in the big tree of the landing site system.

The Dashuli TT&C point in Jiuquan Satellite Launch Center is an important link in the TT&C chain of Shenzhou 14 spacecraft. Whether the return capsule can be accurately captured and located in the first time plays an important role in predicting the landing position of the return capsule. Let's walk into the radar station of the landing site system-the measurement and control point in Dashuli, and see what preparations they have made for the return of the Shenzhou 14 team.

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Shen Ling, a reporter at the front desk: This is the measurement and control point in Dashuli of Jiuquan Satellite Launch Center. The scientific and technical personnel behind me are nervously carrying out the last comprehensive system-wide exercise of the Shenzhou 14 spacecraft returning to the Dongfeng landing site. If the measurement and control of spacecraft return is compared to relay running, then they are the crucial last stick for the landing site system to welcome astronauts home.

Yin, senior engineer in TT&C area of Dashuli, Jiuquan Satellite Launch Center: The radar at Dashuli point is mainly responsible for the exterior ballistic measurement of the return capsule from reentry to parachute opening. The high-precision measurement data obtained by TT&C is used as a guiding source to accurately guide other equipment in TT&C field to capture the target in time, which is also an important information source that affects the prediction and provides better TT&C support for search and recovery tasks.

The continuous tracking and accurate positioning of the return capsule is the premise to realize accurate search and rescue. When the return capsule enters the atmosphere and has fierce friction with the surrounding air, it will form an ionized gas layer with high temperature and high pressure, which will isolate the communication between the return capsule and the ground monitoring station and form a black barrier. This poses a challenge to the tracking ability of each measurement and control equipment.

Yin, senior engineer of Dashuli District of Jiuquan Satellite Launch Center: The target characteristics of the return capsule in the "black barrier section" will change dramatically, which will adversely affect our radar tracking. Faced with this arduous challenge, we carefully analyzed the data of previous missions, summed up the experience and lessons, improved the scheme, and carried out targeted training drills to ensure the continuous and stable tracking of the return capsule and improve the data quality.

At the same time, in order to ensure that the tracking accuracy and stability of radar equipment are not affected in cold weather, the measurement and control point in Dashuli has carried out in-depth physical examination of all participating equipment. At present, * * * has completed more than 30 task-specific trainings, 3 in-system joint debugging tests and 3 system-wide comprehensive performances in Dashu, which is ready for the task.

The panoramic view of the "smart brain" of the landing site presents the picture of the astronauts going home.

As one of the seven systems of manned space flight, TT&C communication system plays an extremely important role in manned space flight. It is the only information line to contact the ground after the launch of the spacecraft, and it is also the telephone line for the astronauts to return. There is an important computer room in the command and display hall of Jiuquan Satellite Launch Center, which provides decision-making basis for the headquarters by receiving continuous signals.

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Front desk reporter Wu: This is the command exhibition hall of Jiuquan Satellite Launch Center. What is going on now is the third and final comprehensive exercise of the Shenzhou 14 search and rescue mission. The mission headquarters in this hall can be said to be the existence of the super brain in the mission. How they master the whole task process without leaving home is the secret in the computer room behind me. Refers to the obvious operation room, in which participants should always stare.

As the "clairvoyance" and "clairvoyance" between heaven and earth, satellite communication equipment is the management and command center of voice and image between heaven and earth, and is responsible for sending key data such as voice, image, measurement and control of each measurement and control point to the center, providing basis for command and decision.

Headquarters reporter Wu: Take the screen in front of me as an example. This screen shows a real-time dynamic map of a landing site. How did this image get to Dongfeng Center without the network? Thanks to our super-high-tech satellite communication means.

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Staff Li Xiaofang: What we are seeing now is a real-time picture taken by the camera on the helicopter. After signal processing, this picture is sent directly to our communication satellite, and then sent back to our command center by the communication satellite. After decoding the display, we can see such a real-time picture.

If you want to see all kinds of images of astronauts in the space station on TV, you need to encode and compress the audio and video through the image codec terminal of the space station to meet the requirements of multi-cabin and multi-scene image transmission of manned space station, complete the transmission of low-speed images, high-definition images, panoramic images and other image information, and build a visualization platform for heaven and earth linkage. During the search and rescue mission of Shenzhou XIV, the members of this group have to complete the image visualization of about 50 signals in 3 seconds to ensure that every picture returned by astronauts is clear and smooth.

What challenges will be brought by two shenzhou spaceship * * orbital return missions?

Shenzhou 14 astronauts are about to return by group. Compared with the past, there is a big difference in this return mission, that is, two manned spacecraft, Shenzhou 14 and Shenzhou 15, docked at the space station. So, what challenges will this feature bring to the return task?

Wu, a reporter from CCTV headquarters: As can be seen from the sign of the manned mission of Shenzhou XV, both manned spacecraft are moored in the space station, which brings a problem that everyone may be very concerned about. Which ship will Shenzhou XIV take to return collectively?

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Ren Changwei, the overall chief designer of the manned spacecraft system of the Fifth Academy of Aerospace Science and Technology Group: The current arrangement is which spacecraft the astronauts take to launch, because he is most familiar with the state of this spacecraft. In addition, the spacecraft itself also has requirements for on-orbit life. At present, we are designed according to the on-orbit life of not less than 6 months, so the on-orbit spacecraft basically meets the normal life requirements, so he will also return on this spacecraft.

Data screen

This is the first time that two manned spacecraft are in orbit at the same time in China Space Station. In the return phase, every spacecraft should be prepared, and the two spacecraft should have independent control ability at the same time, and the information between them must be smooth and not interfere with each other. This puts higher demands on the flight control team.

Zhang Fusheng, chief designer of manned spacecraft system in the Fifth Academy of Aerospace Science and Technology Group: If the ground is monitored and controlled, it may be necessary to talk to two ships in the sky at the same time. For this reason, our manned spacecraft distinguishes our two ships by keys, pseudo codes and ship identifiers, and there are channels such as USB, which can ensure that our two ships communicate with the ground one by one and will not send the wrong object.

The Dongfeng landing site will usher in the first night low temperature return.

The crew of Shenzhou 14 astronauts will return to the Dongfeng landing site on February 4, 65438. This is the first time that the Dongfeng landing site has carried out a return mission on a winter night. In order to ensure the mission is infallible, a lot of preparations have been made from the aspects of spacecraft design, measurement and control means, ground search and rescue, etc.

The cold weather and the night with low visibility are not only a test for the search and rescue team, but also the corresponding design scheme needs to be made in advance for the first landing of Shenzhou 14 spacecraft at the Dongfeng landing site in such a harsh environment.

Zhang Fusheng, Chief Designer of Manned Spacecraft System of the Fifth Academy of Aerospace Science and Technology Group: Manned spaceships are designed to meet this low temperature, and some of them are designed such as returning to this measurement and control at night and ranging. However, for our Shenzhou XIV, returning to the Dongfeng landing site for the first time this winter is actually a new state for our entire Shenzhou XIV crew. Therefore, when they return at low temperature at night, we may also pay attention to some corresponding ground conditions during the search and rescue process.

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In order to ensure the "in-cabin arrival", the astronauts were welcomed home at the first time. Two weeks before the return of Shenzhou 14, the Dongfeng Search and Rescue Brigade began to inspect and modify the equipment for the first night low-temperature return mission and train the team members.

Li, a member of the space search and rescue team of Jiuquan Satellite Launch Center: Because the weather is too cold now, it is about MINUS 25 degrees, which also poses new challenges to our equipment. Our team has done some research on the modification of the battery box, which can make the battery automatically start to keep warm in the box. In winter, some people will be regularly organized to fly in the wild for training. By adapting to the cold, everyone's skill level can be improved.

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