The trajectory of Shenzhou VII after launch

1. Before flying out of the earth, the spacecraft moves in the direction of the earth's rotation, so it can rely on the speed of the earth's rotation. In this process, the power and resistance of the spacecraft are changing, not accelerating at a uniform speed;

2. What motion do you mean by parabola? Projectile motion? I don't quite understand;

3. After the spacecraft flies out of the earth, it first runs along an elliptical orbit. At this time, no extra power is needed, and the speed is the highest at perigee and the lowest at apogee. Usually, the spacecraft ignites at apogee and accelerates to the predetermined orbit (orbit higher from the ground or circular orbit). Apogee ignition is based on the inertia of the spacecraft, which can save fuel.

4. Each track corresponds to a speed. The higher the orbit, the greater the speed. Therefore, after the spacecraft is launched, it will generally accelerate to the predetermined orbit. If you reach a very high orbit at the beginning, you must slow down and waste fuel if you want to return to the scheduled orbit;

When the spacecraft returns to the earth, it only needs to slow down, because the lower the speed, the smaller the corresponding orbital height. When the centrifugal force is less than the gravity of the earth, it will be "sucked" back by the earth.

6. The process of the spacecraft's return is that the gravitational potential energy is converted into kinetic energy during landing, and the speed of the spacecraft is increased. At this time, it is necessary to open several parachutes in turn to slow down until the spacecraft is a few meters from the ground, start the thrust reverser, and finally slow down the spacecraft to make it land smoothly.

7. If you can't answer well or have any questions, just ask me and I will try my best to answer you.