After the Long March No. 5 B-type Yao-2 rocket sent the core module of Tianhe into space, it did not land immediately. As of the time of publication of this article, it was still in circular motion around the earth at the outer edge of the earth's atmosphere, but it The time of landing is just these two days. Professionals speculate that it will land on May 8-10 through its operation.
The reason why the Long March 5 B-type Yao-2 rocket did not land immediately after the launch of the Tianhe core module was because it (the core-stage rocket) directly sent the Tianhe core module to the predetermined orbit of space, so that a Its speed has also reached , the first cosmic speed of , and it can basically run in common orbit with the core module of Tianhe. However, because it has a reverse thrust when it is separated from Tianhe, its speed will be compared. Tianhe will be slower, and the orbit will continue to decrease, and eventually it will still enter the Earth's atmosphere and fall to the Earth's surface, roughly within 10 days of launch.
But this incident has caused some people and media in the West to quarrel. They believe that the Long March 5 B-type Yao-2 rocket is an uncontrolled man-made object. After falling from space, it is likely to cause damage to the ground and land. The location of the rocket is unpredictable, and it may even land in a big city, raising a topic of "the threat of loss of control of Chinese rocket wreckage." Consider interception, which is pure fuss, or something out of nothing.
The Long March 5 core-stage rocket is very large, about 33 meters long and 5 meters in diameter. It can be said that its main body is larger than the core module of the Tianhe space station, and it was lowered from orbit by 80 in one week after launch. kilometers, but as of May 6, it is still more than 300 kilometers, but this orbit is already very low, because of its large size and low orbit, it is easy to see it on a clear night under its flight .
The weight of the wreckage of the Long March 5 core-stage rocket is not easy to determine, some say 18 tons, some say 22 tons, but personally feel that these two figures are too small, some experts say that the weight of the Long March 5 B-type rocket is about 837.5 tons (not counting the load), but about 90% of this weight is fuel , that is to say, the weight of the rocket fuel outer arrow body is only about 83.75 tons, in this weight, remove the fairing and 4 auxiliary The weight of the booster is the weight of the core-stage rocket. The weight of the fairing is lighter, and the weight of the 4 boosters or the core-stage rocket may be similar. Therefore, it is speculated that the weight of the core-stage rocket may be between 30 and 40 tons. time, and the possibility that there is a small amount of residual fuel in it, so the weight of the Long March 5 core-stage rocket is not low, so where will it hit when it lands? Will it be dangerous?
After the Long March-5 B-type rocket sends the core module of Tianhe into orbit, its engine will be shut down, and it is basically impossible to restart on-orbit, so the core stage of the Long March-5 B-type rocket belongs to the uncontrolled artificial celestial body , a few The spacecraft is ten meters long, 5 meters thick, and weighs dozens of tons. The potential energy of falling from space to the earth is quite large. If it hits the city, the possibility of causing a disaster exists. It seems normal for some people in the West and the media to worry, but in fact But that's not the case.
Although the wreckage of the Long March 5 is very large, due to the fast landing speed, when it re-enters the atmosphere, the speed will be near the first cosmic speed, or slightly less than 7.8 kilometers per second. At this speed, the spacecraft will The ablation phenomenon occurs due to severe friction with the air, so most of them will be burned in the atmosphere, and some small parts may fall to the earth, but since most of the earth's surface is not a human settlement, it is represented by a data It is the living area of human beings, which occupies far less than 1% of the surface of the earth. Therefore, when a spacecraft in space crashes on the surface of the earth, the probability of hitting human buildings or hurting people is too small.
Furthermore, in fact, for any launch of aerospace , the body of the rocket will fall, but the second-stage and third-stage rocket and other core first-stage rockets will not enter orbit, and their fall time is earlier. , but it will fall sooner or later, and it is also uncontrolled. The probability of hitting people or buildings is basically the same as the wreckage of the Long March 5, and most of the wreckage of the second- and third-stage rockets will return. The atmosphere falls to the earth's surface, and they are also uncontrolled, just in terms of size and weight.
The United States is the country with the largest number of rockets and spacecraft launches in the world. Except for some controlled landing rockets manufactured by Musk Space Exploration Technology Company in recent years, whether it is NASA or Boeing's aerospace company , the first-stage, second-stage, third-stage rockets they launched, and even the Saturn V rocket , etc., all these rocket wreckage eventually fell to the earth, who asked about their "uncontrolled landing event of rocket wreckage"? ? In fact, even Musk's Falcon 9 , the world's only reusable commercial rocket, the second stage of its rocket crashed to Earth as an uncontrollable wreckage.
Not only American rockets, but American spacecraft have also crashed more from space than other countries. The American Skylab is the largest single spacecraft in history, about 30 meters long and weighing more than 80 tons, more than the Long March 5. The wreckage is much heavier. When it fell in 1979, some of the wreckage hit the coastal town of Esperance in the south of Australia , possibly destroying some trees or buildings in the town. Compensation was filed, and the amount requested was only $400. However, the United States and NASA did not pay attention to them at all, and did not give a cent! The Australian town had to withdraw its compensation claim in dismay. Until more than 30 years later, a host named DJ Scott Barley on the California radio station heard about this and thought that the United States and NASA were doing something wrong, so he raised $400 from the American public in his own name and handed it over to the American public. To the Australian town of Esperance.
References:
"Beijing News Network" May 6 article "Chang 5B rocket wreckage returns to Earth, Chinese and foreign professionals agree..."
