cheeseywotsits to Ant, Dan, Matt, Mike, Steph on 15 Mar 2012. This question was also asked by connormacmillan.
Mike Salter answered on 15 Mar 2012:
Satellites are all really different, so its hard to generalise how they work. But I’ll give you an idea…
A satellite needs electrical power to operate and they use too much to run off just a battery. So most satellites use large solar panels to collect their power from the sunlight. The satellite will probably have a small battery on board, this is used to supply power when the satellite is in darkness and it’s recharged when it’s in sunlight.
Each satellite will also have an onboard computer, they look a bit different to the normal computers you and I use all the time but they work in the same way. The computer is used to control the satellite and make sure any scientific instruments are doing what they’re meant to.
A satellite will also have a radio transmitter, receiver and antenna. This allows it to communicate with earth. Scientists and engineers will decide what they want the satellite to do and will send instructions up to the radio receiver, this is known as “telecommand”. The satellite will use its transmitter to send any data it collects back to the scientists and engineers on earth, this is known as “telemetry”. We have a big satellite dish here at work which can be used to communicate with satellites.
Let me know if there’s anything more specific I can answer!
Anthony Hollingsworth answered on 17 Mar 2012:
they all stay in the air using the same principle though. gravity pulls them down towards us but they all spin around the earth at the right speed to cancel that out. if youve ever been on a roundabout then you will have felt the same force you get from spinning round trying to throw you off! satellites are put in a position where they feel the same amount of pull as push so they can stay up in space for as long as we need
Matt Maddock answered on 19 Mar 2012:
I don’t think I can answer any better than Mike and Ant!
Dan Veal answered on 19 Mar 2012:
See Mike and Ant for great descriptions. The cool things about satellites, the thing that makes them harder and unlike anything else, are…. among other things:
1. you only get one shot. Once it’s launched into space, everything better work because it’s not like your car, whcih you can send to the mechanic if it breaks, if it breaks it means hundreds of millions of pounds wasted and lots of time wasted.
2. it’s a vaccum, which means there’s no air up there, which makes things quite hard. On earth, if you want to cool something often you just run cold air over it (like the radiator on yoru car, that cools your engine as you drive by sucking in the nice cool air from outside), that’s called convection. In space, there’s no air, so you can’t cool anythign that way. So when things get hot, all you can do is radiate heat (like heat from a fire) or conduct it to a different part of a spacecraft (conduction is like a pot handle getting hot when it’s on the stove, head moving through the metal). All those things make it hard to design things!
3. There is radiation in space, which means unless you’re very close to the earth, basically all electronics will get fried in space unless they’re specailly radiation hardened (radhard is the term, i like that one). So often computers in satellite are equivalent to the power of computer about 15 or 20 years ago, because it takes a lot longer to get new technology space qualified, so it’s safe to use in space.
These are some reason satellites are awesome!