Question: How do satellites work?

Lisa Baddeley answered on 6 Mar 2018:

Hi, Good question. Man-made satellites are just electrical items which orbit around our planet (although we do have a few in orbit around other planets also). They can do a lot of different things so some are communications satellites, others can have cameras onboard and so on. They can also be lots of different shapes and sizes – some can be as big as a double decker bus, whilst others can be small as a loaf of bread (called cubesats). They, generally, all have some form of transmitter and receiver on them so they can send and received radio signals. This means they can send information back down to receiving stations on the ground (this could be your tv antenna or you sat nav system in a car) and also receive signals giving them instructions. When they are launched they have small computers on them which tell them what to do and when to do it. This could be lots of things such as to take pictures of the Earth every 10 seconds or to transmit and receive different radio signals from different points on the Earth. Some satellites remain in a fixed position above one point on the Earth whilst others orbit around the Earth. They stay in orbit by moving at a speed fast enough to overcome the force of gravity (they are actually in continuous freefall and every now and again need a little speeding up as they slow down with time). The higher the orbit, the slower the satellite moves. Hope this answers your question.