Rockets will burn at high temperature when they cross the atmosphere and return to earth. Why don't they take off?

Mainly the influence of speed. The faster the speed, the greater the friction of the atmosphere and the heat generated.

In fact, you can imagine that rocket launching satellite and satellite returning are two completely opposite processes. After the rocket is launched, the higher it is, the slower it will be, because the gravity of the rocket will compete with the gravity of the earth at this time, and the higher it is, the slower it will be, because the fuel power is weakened. In the end, it will only have the same speed as an ordinary fighter. The rocket will return at a speed of more than 7 kilometers per second. With such a big speed difference, the friction will of course be completely different.

Of course, if the friction between the rocket and the atmosphere is not intense, there will be no high-temperature combustion. Although the rocket is very fast and has no atmospheric resistance, it will not burn naturally. Rockets don't burn at high temperature when they are launched. Once a fire breaks out, scientists also have policies to deal with it. They will coat the rocket shell with a layer of high-temperature resistant material "titanium" to avoid damaging the rocket at high temperature.

Satellite return

Apollo spacecraft in the United States are all loaded with lift when they return, including Shenzhou 5 (also a clock) in China, but its return process is controlled by GNC subsystem, so it is ballistic-lift reentry.

Lift reentry can achieve a more accurate landing point than ballistic reentry, and the lift reentry phase will be corrected by the intervention of the control system, so the width of its reentry corridor will be greatly increased to cope with various return situations, such as returning to the moon orbit at the second cosmic speed. If you return by trajectory, it will probably become a meteor, so even the parachute can't be opened at high speed (China Small Flight 20 13 (Chang 'e V? T 1 flight tester, nickname? Wu Di) uses Shui Piao ballistic lift to re-enter).