Satellites are machines made from super light materials. They power themselves using rectangular wings with solar cells that use sunlight as energy. They'll normally carry objects on board that can do certain jobs like:
Satellites are launched on rockets into space. Examples of satellites include the International Space Station, which is the largest man-made satellite orbiting Earth - and where Tim Peake, ESA astronaut, worked!
- A way to power it - this could be solar power (using sunlight to produce energy) or nuclear power.
- An antenna that sends and receives information.
- A payload. This is made up of science instruments and experiments - e.g. a camera, telescope or gas sensor.
- A navigation system, usually called 'Attitude and Orbit Control', that makes sure the satellite stays in its position or moves where it needs to be.
Although some satellites can be as big as a minibus and heavier than an elephant, some satellites are only 10 cm cubes (most phones are about 13 cm tall) and weigh as much as a pineapple!
Where would you build a satellite?
Satellites need to be made in pristinely clean conditions - this means no dirt at all. They're assembled in something called a 'clean room'. In here, no bacteria, viruses or micro-organisms can enter the satellite. Satellites need to be protected against contamination as this can affect it from functioning properly. A clean room can look like this:
After the satellite is made, it's tested in a 'vacuum chamber'. Vacuum chambers are the closest thing to testing the satellite in outer space. They're big cylinder chambers which are sealed and have all the air pumped out to make a vacuum, like it is in space. Here, satellites also need to be able to show they can withstand the extreme temperatures of space. Vacuum chambers look like this:
The National Satellite Test Facility will be a whole new building dedicated to testing space craft and satellites to make sure they're ready to be launched into space. It will have several vacuum chambers that look like the ones above, but even bigger! This is how big the new vacuum chambers will look in comparison to the size of humans:
Once we've proven that the satellite will work at the temperatures and environment of space, there is still lots of testing to do. For instance, we need to be sure that the satellite and all of the scientific instruments on it won't become damaged during launch.
To do this, we will use a large shaker table that will shake the satellite in the same way that it will be shaken when it's attached to a rocket! All of this happens indoors and without the satellite 'lifting off' from the Harwell Campus.
Who builds a satellite?
The people who build satellites are called 'engineers'. They could be trained as electrical, mechanical or aerospace engineers. Engineers are people who make things. This includes designing, testing and building the things they make. Engineers also figure out how stuff works and how they can improve what already exists in a design. Anyone can be an engineer - it could be you, your teacher, your grandma, your best friend .... just maybe not your dog!
One thing that really matters when you're building a satellite is to make sure you wear the correct clothes for it. Satellites need to be kept super clean to make sure no dust or dirt gets on it - in zero gravity, the smallest speck of dust could ruin a piece of technology onboard.
When engineers build or test a satellite, the uniform they wear is called a 'full body smock'. You'll need to wear a head cover, face mask, body cover, gloves and special clean room boots. Perfume, cologne, hair spray, nail polish and make-up aren't allowed in clean rooms. You are also not allowed to bring paper into clean rooms and ESPECIALLY not selfie sticks! Once you're dressed in all this gear though, you're good to go.
Here's when we got some people your age to dress up as the engineers that build satellites:
