Height and period of orbit, do they make a difference?
Satellites stay in orbit because of gravity. They are continually falling towards the Earth’s surface BUT the Earth’s surface curves away beneath them and they are going so fast that they never hit it. One way to imagine how this works is to think about a bullet fired from a gun. The bullet is fired straight ahead but will fall towards the ground as it travels (as long as it doesn’t hit anything!) The faster the bullet it travelling, the further it will go before it hits the ground. Imagine it’s now travelling so fast it can get all the way round the Earth before it hits the ground. This is how a satellite works. So long as it is fast enough it will go round the Earth and won’t come down. The opposite is also true. If the bullet it travelling too fast it will go straight on instead of following the curvature of the Earth. A satellite travelling too fast will zoom off into space. Geostationary satellites, at a height of 36,000 km, travel relatively slowly and take 24 hours to orbit once
