Seeing the spacecraft falling from the sky, some netizens may be worried about whether the spacecraft will hit people, houses, and cars when it returns to the earth. After all, we have seen such news before, that is, the discarded battery from the International Space Station fell from space and smashed into a house of a resident in the United States, and the debris passed directly through the 2nd floor of the house.
The ISS battery fell and smashed through the house
In 2021, the International Space Station threw away 9 discarded batteries weighing 2.6 tons into space, and after these discarded batteries were thrown into space, they did not immediately return to the Earth's atmosphere, but continued to fly around the Earth. On March 7 this year, ESA had already issued an early warning, claiming that the discarded batteries would be returned to Earth on March 8.
On March 8, an unidentified object fell from the sky and smashed directly through the house of a resident in Naples, Florida, USA, directly through 2 floors. This also illustrates how fast the unidentified object descended. Although there was no evidence of where the unidentified object came from at first, the owner of the house believed that it was space junk from the International Space Station.
From the perspective of time, the time when the house was smashed through by an unknown object and the time predicted by astronomers to fall from the discarded battery of the International Space Station are basically mild, with a difference of only 5 minutes. Later, NASA also confirmed this situation, claiming that the unidentified object that smashed through the house was a battery from the International Space Station.
Seeing the 2.6-ton discarded battery of the International Space Station smashed down, some netizens may be scared, whether such a heavy waste space junk will cause serious damage to the ground, in fact, you don't need to worry. Although the discarded batteries were more than 2 tons, the metal alloy that smashed through the house was actually very small, only 0.7 kilograms, so it did not cause serious damage to the ground.
This is because this space junk burns violently during its return to Earth. They fly quite fast, and when they re-enter the Earth's atmosphere, the aerodynamic heating effect is very strong, and the temperature rises sharply, up to one or two thousand ° C. Under such high temperatures, most of the parts of space junk will be directly turned into ashes, burning to the ground, and generally only some high-temperature resistant materials can survive and fall, hit the ground or fall into the sea.
Why landed at the Dongfeng landing field
The mainland's manned spacecraft mainly landed at two landing sites, from the Shenzhou 1 spacecraft to the Shenzhou 11 spacecraft, all of which landed at the Siziwangqi landing site in Inner Mongolia, and after entering the space station era, the Dongfeng landing field was activated, and from the Shenzhou 12 spacecraft, they all landed at the Dongfeng landing site.
At the beginning of the manned spaceflight project, in fact, these two landing sites were prepared, but because in the early days of manned spaceflight, each manned mission was not long, and they landed at the Mongolian Siziwangqi landing site, and the Dongfeng landing site was used as a backup landing site.
After entering the space station era, the Shenzhou manned spacecraft has a flight time of several months, and most of the time is docked at the Chinese space station assembly, which means that the spacecraft will have more time options for returning. If, at the scheduled return time, the weather conditions at the landing site are not very good, then the spacecraft can return to Earth a little later. Since the time of return can be chosen, there is no longer a need to set up two landing fields, the main and the standby, and the Dongfeng landing field is used as the landing site for the manned spacecraft in the space station stage.
Located in the central and southern region of Ejina Banner of Alxa League, Inner Mongolia Dongfeng Landing Field covers an area of 20,000 square kilometers, although the environment here is not very livable, the winter is very dry and cold, the summer is very hot, less rain and more windy, but because the area is large enough, at the same time there are many opportunities to return, and the measurement and control equipment can be fully utilized and many other favorable conditions.
In addition, there is another very important reason, that is, in the era of the space station, our space station is expected to run for more than ten years, and the service life may be extended through equipment replacement, upgrades and other measures, so there needs to be a normalized emergency standby search and rescue force, and a search and rescue force needs to be deployed when the spacecraft is launched and returned.
Relying on the human resources of the Jiuquan Satellite Launch Center, the Dongfeng landing site only needs to set up a limited professional search and rescue force to form a powerful search and rescue force, which can not only meet the search and rescue needs of the spacecraft when it is launched, but also meet the search and rescue needs of the spacecraft when it is in orbit and returns home. In this way, the normalized search and rescue team of the Dongfeng landing field can actually meet all the requirements and greatly reduce the cost.
Will the return capsule of the spacecraft hit people?
The discarded batteries of the International Space Station fell and smashed through the house, so will the manned spacecraft hit people when it returns? This may be something that many netizens are worried about, but such things generally do not happen.
Because the process of returning to the manned spacecraft is controllable, before returning to Earth, the crew will calculate the operation of the spacecraft, including the flight trajectory, flight speed, and some conditions of the landing site. After combining many factors, determine the time for the spacecraft to return to Earth, let the spacecraft return to Earth at a suitable time, and then land at the landing site, and the pre-selected landing sites are generally selected in those deserted places.
Although the spacecraft needs to open its parachute to slow down during its return to Earth, which will be affected by the wind and cause the actual landing site to deviate from the pre-selected landing site, it will generally not deviate very far. So, under normal circumstances, when the ship lands on the ground, there are no people nearby, and there are no buildings.
Even if the spacecraft has a strong wind during the landing process and blows the return capsule farther away, it will generally not hit people. After all, during the landing of the spacecraft, the search and rescue teams in the air and on the ground were already tracking the flight of the spacecraft, so as to calculate the approximate landing location. If it is found that the spaceship may fall into a crowded place, it will definitely evacuate people in advance.
Moreover, during the landing of the spacecraft, a huge parachute will be dragged, and the area of the parachute will reach 1,200 square meters. Therefore, under normal circumstances, the spacecraft will not hit people when it returns. You don't need to worry.