"Article Highlights"
1. Why is this return praised by many experts as the "most accurate" return operation?
2. How long will it take for astronauts who have become accustomed to the space environment to adapt to The Earth again? What are the challenges?
3. The successful return of Shenzhou 13 marks the successful conclusion of the key technical verification stage of the space station. So what key technologies were validated during this mission?
4. For the Chinese space station, what can we continue to expect next?
Source: Xinhua News Agency
"Beijing, I have landed safely and the return capsule is smooth."
At 9:56 Beijing time on April 16, 2022, the shenzhou 13 manned spacecraft return capsule successfully landed in the predetermined area of the Dongfeng landing field, landing in a rare upright state - in the opinion of experts, this is the most ideal landing state, astronauts suffer the least impact.
The attempt to return to the capsule in such a landing posture depends on whether the astronaut "cuts" the rope of the parachute at the correct time, and if there is a slight deviation, the return module will tilt or be dragged down by the parachute. Among the 13 flights of China's manned spaceflight, in addition to the Shenzhou 13, only the Shenzhou 6 has achieved an upright landing.
Getting the return capsule to land upright is just one of the many challenges to achieve a successful return.
It's harder to get back to Earth than it is to go to space
Successfully returning to Earth from space may be, in a sense, more difficult than going to space.
The spacecraft in space along the circular orbit began to circle, when the Shenzhou spacecraft returned, the earth under the feet continued to rotate like an automatic slide, the spacecraft needed to wait for the right time in the orbit to lower the orbit and jump down.
Before returning to the ship, the astronauts should change into the cabin pressure suit worn when they went out; after the return module enters the atmosphere, the bottom temperature will be as high as thousands of degrees Celsius, and the vibration noise overload phenomenon in the cabin will also experience 4-6 minutes of "black barrier area", temporarily losing contact with the ground.
Broken down, God XIII's return to Earth is roughly divided into 5 steps:
Separation and evacuation: people on the "Shenzhou" spacecraft, separated from the space station assembly;
Brake de-orbit: the spacecraft enters the return orbit from the original flight orbit by adjusting the attitude, braking and decelerating;
Inertial gliding: waiting for the re-entry opportunity, the spacecraft propulsion module and the return module separate;
Re-entry into the atmosphere: the return capsule passes through the black barrier and undergoes the test;
Landing: open the umbrella, push back, land.
As the longest manned spacecraft on the mainland, Shenzhou XIII's return route also accounts for the "most" word - the fastest. At 0:44 on April 16, 2022, the Shenzhou XIII manned spacecraft was successfully separated from the space station Tianhe core module. Before the separation, the astronaut crew, with the cooperation of ground scientific and technological personnel, completed the pre-evacuation work such as the status setting of the space station assembly, the collation and transmission of experimental data, and the cleaning and transfer of materials left in orbit. More than 9 hours later, Shenzhou 13 had reached the landing site. Compared with the return trip of the previous spacecraft of more than twenty hours, it is really more than a little faster.
This speed originated from the rapid return scheme first adopted by the continental manned spacecraft. Yang Yanbo, deputy commander of the manned spacecraft mission of the Beijing Aerospace Flight Control Center, said that compared with the space station, the space of the spacecraft is relatively small, and the rapid return plan is to reduce the astronauts' residence time in the spacecraft.
In order to achieve a rapid return plan, they set up a design procedure for evacuation and return integration, and fully considered the meteorological conditions of the landing site to ensure the smooth and safe return. In order to ensure safety, two relay satellites were also called for monitoring and control. Therefore, it was originally necessary to circumvent the earth for more than a dozen laps to determine the return orbit, and Shenzhou 13 only took 5 laps to complete the accurate forecasting and return control of the orbit.
During this period, the Beidou satellite navigation system played an important role. The computer on the spacecraft formulates the most appropriate acceleration and orbit change plan according to the data provided by the Beidou satellite navigation system, which greatly reduces the workload of the ground staff and ensures the accuracy of the entire return process.
Re-adapt to the planet
After the return hatch was opened, the medical supervision and medical insurance personnel confirmed that Zhai Zhigang, Wang Yaping, and Ye Guangfu were in good health. But that doesn't mean they can immediately integrate into the normal life of the planet.
In an orbit nearly 400 kilometers above the ground, the Chinese space station can circle the ground every 90 minutes, bringing astronauts 16 sunrises and sunsets a day.
The Shen Thirteenth Team lived in outer space for 183 days, on the one hand, it refreshed the record of the space stay time of Chinese astronauts on a single mission; on the other hand, the long-term presence in space with strong radiation and microgravity also brought a certain burden to their bodies, including radiation-induced diseases and central nervous system changes.
Before them, the God Twelve Multipliers "traveled" in space for three months, and after returning to Earth, they recovered about half a year to devote themselves to normal work and life, and for the God Thirteen Multipliers who broke the record for time stationed in space, the recovery period would only be longer.
However, space, which is difficult for the human body to consume, provides convenient conditions for human beings to carry out life science research. Relying on the Chinese space station and Shenzhou 13, the mainland has established a long-term culture system and cell model of cells under space conditions for the first time. Using such systems and training models, researchers have completed several internationally leading life science experiments.
For example, the world's first experiment in extracting renal epithelial cells from human urine, converting them into stem cells through genetic reprogramming, and then differentiating cardiomyocytes. Scientists used gene editing technology to edit a fluorescent protein, and through the fluorescence of the fluorescent protein, the "calcium signal flicker" process of cardiomyocytes under weightless conditions was observed for the first time in human history.
On this basis, using the gravity-sensitive characteristics of cardiomyocytes, according to the experimental observations of astronauts in orbit, the impact of weightlessness on humans is better studied than the contraction process and contraction characteristics of cardiomyocytes under gravity conditions and weightless conditions. This can help people understand the characteristics of cardiovascular changes under weightless conditions, and provide a very good experimental model for the occurrence of heart disease and even the regeneration and aging of the human body.
The space station's key technology verification phase ends
The Shenzhou 13 manned spacecraft has created many firsts in the history of manned spaceflight on the mainland, such as staying for six months for the first time, having the first space rescue capability, and the first Chinese female astronaut Wang Yaping to carry out the space rescue activities... As the second manned mission of the Chinese space station, this mission is also the closing stage of the key technology verification phase of the space station.
The successful return of Shenzhou XIII marks the end of the space station's key technology verification phase.
On April 29, 2021, the First Vehicle of the Chinese Space Station Mission, the Tianhe Core Module, was successfully launched, embarking on a journey to explore the universe. The Tianhe Core Capsule, the largest and most complex spacecraft developed by the mainland so far, not only carries astronauts for a long time, but also carries out a large number of scientific experiments and technical verification in orbit, and all of this requires sufficient power as a support. To this end, scientific and technological personnel have tailored a new space "wing" for it - flexible solar array.
Compared with the traditional solar array, the thickness of the flexible solar wing single plate is less than 1mm, and the unit area weight is only half of the traditional solar array, which can not only repeat the collection, but also increase the power generation capacity by 1 times, and greatly extend the life of the spacecraft.
In addition to sufficient energy supply, in terms of manned environmental control, the core module is equipped with a regenerative life support system, which realizes the regeneration of oxygen in the cabin, the treatment of human metabolites such as carbon dioxide and the removal of harmful gases, and realizes the recycling of water resources, ensuring the long-term residence of astronauts in orbit, and greatly reducing the upward carrying capacity of consumables such as oxygen and water. It is equipped with an active temperature control fluid circuit, that is, an air conditioning system, to ensure that the air temperature, humidity and the operating temperature of the instrument and equipment are within the appropriate range, ensuring the safety and comfort of the residence.
Berlin Hou, deputy chief designer of the space station system of the Fifth Academy of China Aerospace Science and Technology Corporation, said in an interview: "We use regenerative life protection technology, which can recycle the condensate collected in the cabin or the urine of astronauts and treat it into drinking water." At the same time, we will electrolyze it into oxygen that astronauts can use. This is also the first time we have used it. The whole system has been working very well, and during the 3-month residency period of the Shenzhou 12 multiplier and the 6-month residency period of the Shenzhou 13 multiplier, we use renewable resources. ”
During the Shenzhou 13 mission, the feasibility and effectiveness of the assisted module of the robot arm were tested through the tests of robotic arm auxiliary module translocation and hand-controlled remote operation, and the space station's module transposition technology and robotic arm large-load control technology were verified.
In addition, There are 3 commonly used pair interfaces for China's space station, because the forward port of the previous space station Tian and the core module has been docked by the Tianzhou-2 cargo spacecraft, and the rear port is connected to Tianzhou-3, and the Shenzhou-13 mission can only be docked from radial direction. Axial docking only requires the spacecraft to remain at the same orbital altitude as the space station, and the radial docking taken by Shenzhou XIII is much more complicated. After the successful docking, the docking flight time of Shenzhou 13 was increased to 6 months.
In the one year on orbit, the manned space project completed a total of 5 launch missions, and verified 7 key technologies in orbit, including: space station propellant replenishment, regenerative bio-protection, flexible solar cell wings and drive mechanisms, large flexible combination control, assembly and construction, extravehicular operation, and on-orbit maintenance. Taking advantage of the mission gap, the astronauts also conducted two "Tiangong Classroom" space lectures, as well as a series of unique activities, such as opening a painting exhibition in tiangong and playing a guzheng at the Lantern Festival.
The Chinese space station will enter the construction phase
Source: Air China
With the safe return of the Shenzhou 13th group, the Chinese space station will usher in a major makeover.
Researchers will conduct a comprehensive assessment of the space station's key technology verification, and after the results meet the requirements, the space station will move to the construction stage. This stage will launch the Tianzhou-4 cargo spacecraft, the Shenzhou 14 manned spacecraft, the experimental module I and the experimental module II., as well as the Tianzhou-5 cargo spacecraft and the Shenzhou 15 manned spacecraft, a total of six spacecraft, and finally complete the construction of the T-shaped space station assembly, and the entire assembly and construction process will take about seven months.
After the completion of the construction of the Chinese space station, it will continue to carry out astronaut residency and multi-field space science and technology tests, and the active space in the cabin will exceed 110 cubic meters, providing 6 sleeping areas and 2 health areas, which can achieve long-term 3-person and short-term 6-person residency.
It is understood that this year will launch 2 space station experimental modules, 2 manned spacecraft, 2 cargo spacecraft, and send 6 astronauts to the Chinese space station. Crews of astronauts to carry out two manned missions during the construction phase of the space station have been selected and mission training has begun.
Resources
Science and Technology Daily, China Net, China Aerospace Science and Technology Group, Our Aerospace, CCTV News, China Science Expo, etc.