Question: What happens to satellites at the end of their working life?

Silvia Pardo answered on 8 Nov 2016:

A good question, and one of the big challenges of space technology! Satellites usually include enough fuel for operations, like orbit correction. When it’s time to end the mission, the mission engineers send instructions to the satellite and use the fuel to slow it down (if the satellite is close) or to push it outside of its orbit and further into space. In the first case the satellite will fall to Earth, burning when it comes in contact with the atmosphere. Mission engineers organize everything so whatever is left falls into the sea without harming anyone. In the second case… well, the satellite will become space junk. We will need to clean space up at some point when spaceships come to be as ordinary as cars!