Main information source: Xinhua News Agency - Shenzhou-17 manned spacecraft return capsule successfully landed The Shenzhou-17 manned mission was a complete success
Preface
In the past few days, the mainland has been full of happy events, and two major events have occurred one after another that make the mainlanders proud.
One is that the mainland's Shenzhou 18 has left the earth with armor and entered space for operations.
The second is that the mainland's Shenzhou 17 finally returned to Earth after five months.
Today, the mainland's aviation industry is undoubtedly a source of pride for the Chinese people.
We have achieved manned spaceflight, we have our own space station, and last year we got soil on the moon for experiments.
However, there is a phenomenon that makes many netizens puzzled by the return of Shenzhou 17 this time.
In today's advanced science and technology, why did Shenzhou 17 not use a satellite navigation system when it landed, but manually searched?
The mainland's satellite navigation system does not work?
On April 26, under the expectation of the people of the whole country, Shenzhou-18 officially entered space, stepped into the established orbit, and successfully handed over to Shenzhou-17.
On April 30, the completed Shenzhou-17 mission returned to the ground smoothly, and several highly respected astronauts were carried off the capsule unharmed, announcing the complete success of the Shenzhou-17 mission.
Before the three astronauts on the mainland landed, the mainland's Dongfeng landing site was already fully prepared, waiting for the triumphant return of the Shenzhou spacecraft.
In order to ensure a foolproof landing, the staff developed an emergency plan to ensure a safe landing.
According to live webcast data, after a period of flight, the re-entry capsule opened its parachute and completed the final stage of landing at an altitude of 10 km.
Eventually, the re-entry capsule landed on the ground at a speed of 2 meters per second.
Subsequently, the staff on the ground quickly came to pick up the astronaut as he walked out of the return capsule, and the astronaut did not stand and walk directly but sat on a chair.
Through the fast return technology, the entire return time is only about 9 hours, which is 19.5 hours shorter than that of Shenzhou 12.
Undoubtedly, the success of these technologies has directly proved the mainland's strong strength and is worthy of the pride of the mainland's 1.4 billion people.
But in this process, there is a program that makes many netizens puzzled, that is, why did Shenzhou 17 conduct a manual search when it landed? Could it be that the strength of the mainland is not enough?
You must know that the development of the mainland in recent years can be described as advancing by leaps and bounds, and the construction in space is also beyond the reach of the dust.
In 2020, the mainland's self-established space station officially entered the use stage, becoming one of the only two space stations in the world, the other being the International Space Station jointly established by the United States, Russia and other countries.
Projects that were once excluded from the mainland have now caught up with the world with their own efforts, and even done better.
It is reported that the robotic arm of the International Space Station has long been crumbling because of the serious damage of space debris, tinkering, and the age is too long.
In contrast, the continent's space station was built not long ago, and although the solar wing was damaged due to space debris before, it was repaired long before Shenzhou 17 returned to Earth.
Shenzhou 18 went into space with armor, and it brought a layer of armor to the space station, and the mainland's aerospace industry will only be smoother in the future, and landing on the moon is just around the corner.
To sum up, there is no doubt about the mainland's space technology, so is it not a technical problem that the reason for the need to manually search for the cause, but the reason for the satellite navigation system?
When it comes to satellite navigation systems, we can learn from the past.
At the beginning of the founding of the People's Republic of China, science and technology were backward, and only Russia and the United States had satellite navigation systems in the world.
Among them, Russia's satellite navigation system is inherited from the former Soviet Union, and the American satellite navigation system is the GPS that we often use.
The GPS in the United States was originally free to use and did not need to be paid, so the mainland did not have any burden when using it, but I did not expect that because of the satellite navigation system, the mainland would suffer from the hegemonic behavior of the United States
In 1993, the mainland merchant ship Galaxy departed from the mainland port, passed through Singapore and other places, and transported the merchant ship loaded with hardware to the Saudi ports of Dammam and Kuwait in the Middle East.
But as soon as the Galaxy entered the open sea near the Persian Gulf, it was intercepted by US helicopters and ships, claiming that the Galaxy contained chemicals destined for Iran.
At that time, relations between the United States and Iran were tense, and the mainland told them that there were no chemicals and that the mainland's Galaxy would not dock in Iran, but the United States insisted on its own view and asked for a search for ships.
The mainland crew refused the request of the United States, and the United States turned off the GPS system, so that the mainland could not find the direction to continue traveling, and drifted on the high seas for more than 30 days.
In the end, for the sake of the lives of the crew, we had to compromise and agree to let a third country intervene in the search, and in the end, of course, the United States found nothing.
Although the United States has done something wrong, it has not apologized to us for this, and this incident has made us feel very "nested" and have made up our minds to develop our own satellite navigation system.
With the passage of time, the Beidou satellite navigation system independently developed by the mainland has been successfully put into use in many countries around the world, and some navigation software on the mainland is also used in the navigation mode of combining GPS and Beidou satellite navigation system.
Therefore, if Shenzhou-17 needs a satellite navigation system, it can use the satellite positioning system independently developed by the mainland, which is safe and stable, and there is no need to worry about emergencies.
It can be seen that Shenzhou 17 needs to be manually searched for another hidden reason!
The truth of manual searching
The use of manual search is not because the mainland is not skilled, but for the safety of the mainland's astronauts.
The way to return from Shenzhou-17 is to adopt a "fast return" scheme, and the first step is to brake and deorbit.
This stage is the process of moving the spacecraft from its original flight trajectory to its return orbit by adjusting its posture, braking, and deceleration.
First, the spacecraft adjusts its attitude in such a way that the orbital module, the return module, and the propulsion module are arranged from the front to the back, and then the orbital module and the return module begin to separate after deceleration.
The orbital module will remain in orbit, and after the return module will enter the intended orbit, the propulsion module will push the orbital module into the atmosphere, and then the propulsion module will also return to the module for separation
This is the first and most important step.
The second step is to slow down, at which point only the return capsule is moving at high speed.
When passing through the atmosphere, the speed of movement is too fast, and the friction between the air and the re-entry capsule will ignite a flame, and the temperature of the re-entry capsule will reach about 1,000 degrees.
What the astronauts in the return capsule saw was a hot fireball surrounded by flames, as if they were in a sea of fire, which was very terrifying, and the astronauts needed to have a strong psychological quality at this time.
Of course, there is no need to worry about the safety of the astronauts, and the materials on the exterior of the re-entry capsule can withstand the flames.
The third step is to open the parachute of the return capsule, which is used to land a total of four parachutes, the first is two guide parachutes, and the guide parachute will guide out the deceleration parachute, which can reduce 200 meters per second to 90 meters per second.
When the ground reaches 80 km, the real parachute opens, and finally, at a distance of six km from the ground, a thrust reverser engine appears, giving the return capsule an upward force.
When the final return capsule lands, the speed is about one to two meters per second, which can greatly reduce the damage of the impact to the astronauts.
In this process, our Beidou satellite navigation system is tracked and accurately positioned throughout the process.
So why do you need a human search?
There are two reasons for this, one is that although there is accurate positioning, in the process of returning, in the second step, it will enter the black barrier area.
The black barrier area is an area that is completely shielded from the signal, and our satellite navigation system cannot accurately track it, and any dangerous situation may occur at this time.
Therefore, manual search is to explore the situation of astronauts more accurately, and once an unexpected dangerous situation occurs, we can find it as soon as possible and solve it quickly.
The second is to be able to quickly discover the landing site of astronauts.
Although we carefully calculate the position of the return capsule before the return trip, it is inevitable that there will be deviations.
We can generally be sure that it is within a certain range, but after all, there are some situations in the landing process that we cannot predict, so we need to search manually.
After making sure that the re-entry capsule had landed safely, the re-entry capsule was quickly located and our astronauts were lifted out of the capsule.
The mainland has always attached great importance to the safety of astronauts, which is why it has made double guarantees at all times.
For example, after each manned spacecraft takes off, there will be another manned spacecraft on the ground at any time, and there are corresponding astronauts ready at all times.
In the event of any danger to the astronauts in space, our manned spacecraft will immediately go into space to rescue our astronauts.
To sum up, manual search does not mean that the technology is backward, and the safety of astronauts is the top priority we care about.
I hope that the mainland's aerospace industry can get better and better, and I also hope that the astronauts who go into space every time can return safely!