How Satellites Work – Satellite Technology
A satellite is nothing more then a mirror, reflecting signals sent from Earth by a dish, and bouncing them back down to another dish at another location. You can see how this works for an example by getting a hand-held mirror and shining a flashlight into it, if you angle it right, the light will be shining onto the wall. This is the same way a satellite bounces signal.
Some satellites are equipped with positioning rockets and fuel to keep it in orbit. The most common method is by gravity; due to the elliptical orbit, it will stay on a path and never fall to the Earth.
What happens to the satellite when it reaches the end of its life?
The useful life of a satellite lasts as long as the satellite has fuel to be able to move within its orbital position. The effects caused by the gravitational field of the Earth, attraction forces from the sun and the moon cause the satellite to move slightly within its theoretical orbital position. The fuel on board the satellite since its launch is used in order to keep the satellite within the reduced space known as the orbit window. It is this fuel which determines the useful life of the satellite. Although the solar panels and the batteries powering the satellite also undergo a certain amount of wear over the satellite’s life, they do not limit the satellites operating life to the standard 10 to 15 years.
When the satellite ends its nominal useful life it goes through a transition phase, known as “inclined orbit”, in which the satellite is allowed to move a little more freely within its orbital window in a North-South direction. This way it can continue to function under certain conditions allowing for easy and calm transfer of its services to another new substitute satellite.
After this phase, the satellite is injected into an orbit which is further away from the Earth and in which a merger of forces and Earths gravity will pull the satellite further and further away from the position it had while in service.
Can a damaged satellite be repaired in space?
At present it is not possible to physically repair a satellite located in a geo stationary orbit, given that it is approximately 36,000 Km from the Earth. Communication satellites or other applications located in lower orbits can be recovered by space shuttles and repaired by astronauts or returned to the Earth to be repaired.
Geo stationary satellites are equipped with electronic and aeronautic systems, which are designed with extraordinary precision and proven reliability to be able to operate in the extreme temperature conditions of the geo stationary orbit and to be able to withstand the tremendous violence experienced during the launch into space. Furthermore, satellites are manufactured with many redundancies, that is to say with reserve or substitute circuits and components, in the event that any of the elements did not function within expected margins.