What is an orbit?
An orbit is falling around something instead of into it. Go sideways fast enough and the ground curves away as quickly as you fall, so you never land.
Newton explained it with a cannon on an impossibly tall mountain. Fire the ball gently and it lands nearby; harder and it lands further away; hard enough and it goes all the way round.
Low Earth orbit needs about 7.7 km/s sideways — roughly 27,600 km/h. That speed, not the height, is what costs the fuel.
Higher orbits are slower. The space station laps the Earth every 92.9 minutes; a satellite parked over one spot takes a whole day.
See it happen
Space & OrbitsFalling foreverSource: International Space Station