[ad_1]
Xiao Ming asks Chang’e 丨 Semi-ballistic jump back into the atmosphere to “float”
CCTV News Client 2020-12-13
Currently, Chang’e-5 is awaiting the second transfer from the Moon to Earth, after which it will return to Earth from the Moon.
Currently, Chang’e-5 is awaiting the second transfer from the Moon to Earth, after which it will return to Earth from above the Moon. When the Chang’e-5 orbital return assembly enters a position about 5,000 kilometers from the Earth’s surface, the orbiter responsible for the round-trip transportation task between Earth and the Moon will finish its mission and separate from the returning one. Finally the one who returns
Komei
Sister “Changwu”, where are the moon samples returned?
Chang’e 5
It is in the “belly” of the return device, which is a key protection object. When I started flying to the moon, the four machines were combined, namely the orbiter, the returner, the lander, and the ascendant. They all fulfilled their duties. After finishing the job, they finally returned to earth. , Only the return device that contains the moon rock.
Komei
How does this returnee return? Is it equivalent to being thrown from a great height?
Chang’e 5
Haha, it’s almost the same, but you have to throw it accurately and you can throw it with a special angle and line.
Komei
Special route? What is the route?
Chang’e 5
If it is a parabola thrown straight down, let it land completely according to inertia, that is called “ballistic return”. However, because the returner is returning at a speed of about 11 kilometers per second, it is already close to the speed of the second universe.At such a fast speed, the force and heat generated will make the returner be unbearable. After all, they are the key objects of protection and contain treasures from the moon. If they are pierced like this, they will not burn, but they will break. It is definitely not safe.
Komei
How can it be safe?
Chang’e 5
Then you have to control your return path, we call it a “semi-ballistic jump return”, which is equivalent to a “water drift” in the atmosphere.
Komei
What? Can the atmosphere be “diverted”? How to combat this “water drift”?
Chang’e 5
It consists of controlling the attitude of the one who returns to the atmosphere and letting him enter the atmosphere twice. You see, this is the first time it entered the atmosphere. When it first decelerated and descended about 60 kilometers above the ground, the arc shock wave that formed at the forward end of the returner’s outsole was used to cause it to jump again and expel the atmosphere. Then enter the atmosphere again and implement a second deceleration, which is safer. You see, does this process look like a “struggle”?
Komei
Well, “Dai Shui Diao” is really vivid. How much can this speed go down?
Chang’e 5
After “drifting,” the returner slowed from about 11 kilometers per second when it first entered the atmosphere to about 7.6 kilometers per second when it entered the atmosphere for the second time. However, if the returner enters the atmosphere twice, they will enter the black barrier twice.
Komei
What is the area of the black barrier?
Chang’e 5
The area of the black barrier is when the aircraft returns to the atmosphere at high speed, the friction with the atmosphere generates a high temperature of about 2000 ° C, which causes plasma to form around the returner, protects the electromagnetic waves and interrupts temporarily communicating with the ground. The atmospheric space is called the black barrier area, which generally appears between 35 and 80 kilometers above the earth. The process of the return device “floating” in the area of the black barrier can be said to be a leap of life and death!
Komei
My heart is pounding and I feel very nervous.
Chang’e 5
In fact, you don’t need to be overly nervous. We have already verified this type of high-speed reentry and return flight method in the 2014 Chang’e 5Q1 test. When the returnee enters the atmosphere for the second time and descends to a height of about 10 kilometers above the ground, the The parachute you are carrying will open, thus continuing to decelerate, and you can safely land in the predetermined zone.
Komei
Where is the scheduled landing area?
Chang’e 5
The landing area is Siziwang Banner, Inner Mongolia. The previous flight test landed in Siziwang Banner, Inner Mongolia. After landing, the search team responsible for search and recovery tasks will find the target in time and then arrive at the landing site to retrieve the returning one.
Komei
Oh I hope the water flows beautifully and falls steadily …
Publisher: Bao She
