After 6 months of business travel and 9 hours of home, where is God XIII?

At 9:56 on April 16, as the return module of the Shenzhou 13 manned spacecraft slowly landed at the Dongfeng landing field, the Shenzhou 13 manned mission was successful, which also marked the successful conclusion of the key technology verification phase of the Chinese space station.

Shenzhou 13, which broke many records and achieved many "firsts", refreshed a new height in China's spaceflight. What is the difference between the "space business trip" of the mainland astronauts and the previous missions?

Why is "space travel" 6 months

From October 16, 2021 to the safe landing on April 16, 2022, the "Space Travel" trio spent 6 months on the China Space Station, which doubled the three months of the Shenzhou XII crew and created a new space stay time record in China's space history. After the continental space station is fully completed, the 6-month duration will also become the regular rotation cycle of the continental space station.

But why 6 months? Can't astronauts stay on the space station for a longer period of time? Yang Yuguang, vice chairman of the Space Transport Committee of the International Astronautical Federation and researcher of the Second Academy of China Aerospace Science and Industry Group, explained to the Science and Technology Daily reporter that the 6-month rotation cycle is actually the result of comprehensive consideration of all aspects.

First of all, it is a consideration of the physical condition of the astronaut. Yang Yuguang pointed out that the impact of the weightless environment on human health will gradually increase with the increase of weightlessness time. The space treadmills, space bikes and other fitness equipment on the space station are set up to help astronauts overcome the negative effects of muscle atrophy and bone loss caused by the weightless environment. Huang Weifen, chief designer of the astronaut system of China's manned spaceflight project, also said: "The impact of long-term weightless environment on the human body's cardiovascular system, muscular and skeletal systems is more prominent, and the probability of emergency medical problems will increase." ”

Yang Yuguang said that at present, the mainland has relatively little experience in the long-term residence of astronauts on the space station, and the relevant health problems caused by long-term stay are still in the stage of continuous exploration and research. Therefore, a stay of 6 months is a more secure choice.

In addition, in addition to the need for astronauts to change shifts, manned spacecraft also need to rotate. Due to long-term exposure to space radiation, the radiation dose of some electronic components of the manned spacecraft accumulates over time, and there is an upper limit to the time in orbit. The 6-month mission duration can ensure that all indicators of the spacecraft are in a relatively stable state, and once the spacecraft is exposed in space for too long, it may produce unpredictable risks. Yang Yuguang said that the shift cycle of about 6 months is also an international practice.

Of course, this international practice is not without exception, and astronauts also have "overtime" situations - American astronaut Mark Van der Hay, who just returned from the International Space Station half a month ago, stayed on the space station for 355 days. However, according to Yang Yuguang, the situation of astronauts staying in orbit for up to one year is relatively rare and not normal. Even if there is a situation where individual astronauts stay for a long time, the manned spacecraft will also change shifts, "when the new crew visits the shift, the old crew will drive the old spacecraft back, leaving the new visiting spacecraft." Yang Yuguang said. Therefore, even if the astronaut can stay for nearly a year continuously, the spacecraft will have to "clock in and leave work at the point".

How could God XIII return so quickly

From 0:44 Beijing time on April 16, the Shenzhou 13 manned spacecraft was successfully separated from the Tianhe core module of the Chinese space station, and to the successful landing of the return module at 9:56 on the same day, the entire return process took only about 9 hours, roughly equivalent to the time from Beijing to Guangzhou by high-speed rail.

Shao Limin, deputy technical manager of the manned spacecraft system project of the Fifth Academy of China Aerospace Science and Technology Corporation, mentioned when introducing the Shenzhou 13 mission that Shenzhou 13 will implement rapid return for the first time to further improve the comfort of astronauts and the efficiency of mission implementation. It should be known that when Shenzhou XII returned, it took about 28.5 hours from the separation of the spacecraft from the Tianhe core module of the Chinese space station to its safe landing at the Dongfeng landing site. This, of course, included the 4.5 hours it took for the Shenzhou XII spacecraft to verify radial rendezvous and docking technology upon its return. If this part of the time is removed, the whole return process is exactly about 24 hours. The space inside the return module is small, and the 3 astronauts have to "squeeze" inside for 24 hours without moving, which is undoubtedly a double test of the astronauts' physical and psychological bodies.

From 28.5 hours to 9 hours, what is the faster way to return quickly?

Let's first review the return process of Shenzhou XII. The Shenzhou XII spacecraft is disengaged from the Chinese space station

After leaving, there is no rush to start the return program. Instead, it first went around to the bottom of the space station sky and core module, moved closer to the radial pair interface, and verified the various technologies of radial rendezvous and docking. It is also with the "paving" of Shenzhou XII that Shenzhou 13 successfully adopted radial rendezvous and docking technology for the first time during rendezvous and docking, laying the foundation for the full completion and operation of the subsequent space station.

After the completion of the verification mission, Shenzhou XII entered the orbiting stage. Simply put, it is a non-stop circle around the earth. Yang Yuguang explained that the circle is to find a suitable "window period". Due to the limited fuel carried by the manned spacecraft, it is impossible to actively adjust the orbital surface to align the landing site in the area when returning. Therefore, only the landing field can be allowed to "actively target" the spacecraft. Due to the limitations of the Earth's rotation and the spacecraft's orbit, such an opportunity is only once per circumference. The spacecraft continuously circled the earth in order to find a time, weather and other conditions are in the best return "window period". When Shenzhou XII returned, it took a lot of time at this stage, and it made about 11 turns around the earth, each of which took 1.5 hours. Therefore, reducing the number of "circles" as much as possible is the key to the rapid return of Shenzhou 13.

Yang Yuguang introduced that through the precise calculation of the optimal return "window period", Shenzhou 13 can arrange the timing of leaving the space station in advance, so as to ensure that the spacecraft leaves the space station and enters the orbit around the earth Soon after, the Dongfeng landing field can "aim" at the spacecraft, eliminating a lot of time around the ground. It is understood that the Shenzhou 13 only orbited the earth 5 times at this stage. "The whole process requires a series of complex operations, so it must be ensured that the technology is mature and stable before it can be carried out." Yang Yuguang believes that the application of rapid return technology is also a symbol of the mainland's aerospace industry constantly moving towards maturity and strength.

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What to prepare for a non-professional space station

During the recent Two Sessions of the National People's Congress, Yang Liwei, deputy chief designer of China's manned space project, was asked whether ordinary people have the opportunity to enter the Chinese their own space station in the future, and he confidently said: "As long as there is such a demand, our resources allow, technology is not a problem." ”

Just about 10 days ago, on April 9, Eastern Time, after nearly 21 hours of flight, the "Endeavour" Dragon spacecraft of the American Space Exploration Technology Company successfully arrived at the International Space Station and successfully completed docking. The Endeavour Dragon spacecraft carried the world's first "private space group" to visit the International Space Station. They will stay on the International Space Station for about 8 days.

Although there have been ordinary people visiting the International Space Station before, they usually only make short stops as a group of entourage. This is the first time that an all-private crew has driven a private spacecraft to the International Space Station, which can be said to be a real "self-funded business trip". Unlike previous purely private space tourism, the team has a clear scientific goal this time - they will conduct about 100 hours of multidisciplinary research on the International Space Station, including astrophysics, optics, communications, biology, health care, neurology and so on.

Of course, this is not the first time that ordinary people have gone to space, but compared to space travel just to "visit here", is it really feasible for a normalized private team to enter the space station to conduct research?

When a private team enters the space station to conduct research, the first threshold to cross is the expensive "travel expenses". Taking the Endeavour Dragon spacecraft as an example, in addition to the retired nasa astronaut who served as the commander and the vice president of the American Congregational Corporation, Alegria, the other three people each need to pay about 55 million US dollars (about 350 million yuan) of "ferry tickets". The American Congregational Space Company, which launched the mission, has to pay a huge transportation fee to the American Space Exploration Technology Company and the use of the International Space Station to NASA.

But even that doesn't mean everyone can access the space station. In fact, before entering the space station for a certain period of time, ordinary people must undergo rigorous physical training, such as altitude adaptation training, centrifuge training, microgravity and simulator training, emergency exercises, etc. In particular, the body should adapt to the powerful acceleration of gravity when the spacecraft takes off and lands, and the long-term weightlessness in the space station.

In addition to the physiological health problems that may be faced, the space station environment is relatively small and closed, and mixed with complex noise, vibration, etc., which often causes mental health problems for astronauts who live and work in it for a long time. And all of this needs to be overcome through pre-training.

In addition, if you want to engage in scientific research activities in the space station, you must also learn to master various related theoretical knowledge and operating procedures. However, compared with the astronauts who stay for half a year and have heavy tasks, the training time required for ordinary people to enter the space station will be reduced.

According to the "2021 China Aerospace" white paper, the mainland will cultivate and develop space tourism during the "14th Five-Year Plan" period. Yang Liwei also believes that commercial aerospace will be a major trend in the development of the aerospace industry in the future. From an engineering point of view, the participation of more enterprises of different natures will also help the development of the aerospace industry.

Source: Science and Technology Daily

Guangzhou Daily New Flower City Editor Lin Chuanling