The so-called "unstable system" refers to the natural expansion of small disturbances during rocket flight. For example, when a rocket is flying, if it is tilted by 1 degree, the angle will naturally expand due to the combined effects of inertial force (the rocket's self-reference system) and air resistance. The rocket was unstable at this time. A stable system is like a swing, push it and it tends to rearrange. Models fall over easily, but actual people react to the outside world, so not so easily. Other things, such as missiles and rockets, can also see tail fins. Proper tail fins keep missiles and rockets stable as they fly.
This is a very simple question. It is not as complicated and mysterious as some netizens said. We did encounter this problem when we first developed the rocket. In addition to the gravity factor of the rocket itself, the impact of other external factors (such as air resistance) after takeoff can also cause the rocket to roll vertically. However, scientists quickly found a way to completely solve the problem of rocket flight attitude control. Scientists used gyros to play To the limit, a gyroscope-based schedule was developed. The speedometer uses sensing or coupling to transmit the rocket's timely flight data to the computer. The computer calculates through the flight software and transmits the calculation results to the ground flight control center. Based on these results, the ground flight control center decides whether to issue various control instructions to the rocket. Despite the rapid development of modern rocket technology, flight control is still the weakest part. In order to ensure launch safety, China's Shenzhou series rockets have added a flight control system backup. If one system fails, the other system will start working immediately!
The seemingly simple vertical launch problem is an important part of current aerospace engineering. If the rocket's engine only provides power energy, the rocket will 100% overturn. Because the rocket will encounter horizontal airflow. As long as there is a little wind, the rocket will tilt in the vertical direction, the thrust of the engine will produce a component in the horizontal direction, and the rocket will explode immediately. This has also happened to airlines.
There are two main reasons why rockets can be launched vertically. The first one is the top. The self-symmetrical spin stability of the gyro when rotating at high speed is used to adjust the attitude problem at the top of the rocket during the launch phase. Generally speaking, the gyroscope connected to the sensor is placed in the posture control warehouse. The bottom of the gyroscope has a horizontal base. After the rocket is lifted off, an inclination angle will be generated between the base and the gyroscope. The sensor converts different tilt angles into potential differences of different phases, and then the computer pushes the rocket in different directions to achieve vertical launch. A gyroscope is like a tool that detects whether a rocket is vertical. In fact, the device that can be tuned is the vector engine.