Originally Answered: Why do satellites not fall back on earth?

Man-made satellites don't fall out of space for the same reason that the moon (a big satellite) doesn't crash into the earth, or that the Earth doesn't crash into the Sun. The reason is ACTUALLY described through Newton's laws of motion.

A moving object will continue to move in a straight line at the same speed unless a force acts on it. For an object to move in a circle, a force has to act on it all the time.This force is called the centripetal force. It acts towards the centre of the circle. Gravity is the centripetal force that KEEPS planets moving around the Sun, and satellites moving around planets.

Gravity is the universal force of attraction between masses. It provides the centripetal force needed to KEEP a satellite in orbitaround a planet, or a planet in orbit around a star such as the Sun.

Even though gravity pulls on the satellites, they are moving. Satellites don't ever SLOW down in their orbits since there's almost no friction in space. The result is that they just spin around the sun, never actually falling in.If nothing pulled on them they would just keep GOING and end up going farther away from the earth. However, the earth's gravity pulls back down. The end result is that they move in a circle around the earth - in an orbit.