Why does Astronauts Floats inside ISS, especially when its located very close to earth and within the earth Gravitational filed ?

When you throw a ball up, it will cover some distance and then due to Earth’s gravity, it will fall back, with a curved path. If you increase the speed of the ball, the ball will cover more distance and the curvature of the ball’s path will increase. Now, imagine you are standing on the top of a very high location in the world. When you keep throwing the ball with higher and higher speed, a time will come when the curve of the ball’s path will match Earth’s curvature. At this point, the ball won’t fall back to Earth. It will start orbiting around it. This is called Free-fall. The same happens with ISS. Its path’s curvature matches Earth’s curvature and it keeps orbiting the planet instead of falling. As the ISS is moving very close to Earth, it sometimes moves towards the Earth and can enter into Earth’s atmosphere.To prevent this, thrusters are used to move the ISS upward. But in the whole journey around the Earth, astronauts feel completely weightless.