Where Do Satellites Get Their Power From?

Satellites need electrical energy to deliver important weather, climate and ocean data to Earth.

The Sun is the main energy source for satellites, which is why all satellites have solar panel arrays mounted on them. Each array contains thousands of small solar cells which are made of silicon – a material that allows sunlight to be turned into electrical current.

Solar arrays are quite large. They have to be big because only 20% of the light arriving from the Sun is actually converted into electricity. Each array generates 4kW of power, which is just about what it takes to power 2 kettles!

Even though solar arrays are rotating and always pointed towards the Sun, sometimes a satellite has to operate through eclipses, which means that there is no sunlight to provide energy.

To keep satellites running in times like these, they are equipped with batteries. Both geostationary Meteosat Second Generation and polar-orbiting Metop satellites each have five batteries on board.

What is more, to keep the satellite in its orbit, it has to be moved every now and then.A manoeuvre is carried out by firing small reaction motors called thrusters. Thrusters are burning hydrazine fuel – a very toxic and flammable substance

In short, our satellites function with a combination of fuel for important manoeuvres, solar energy for everyday activities and batteries that provide power whenever the sun’s rays are not available. 
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