Orbit

The harder you throw a ball, the farther it goes before it lands. Throw it sideways at close to 8 km per second, and the Earth curves away below it as fast as the ball falls, so it never touches the ground and keeps going around. A path that is always falling but never reaching the ground is an orbit.

Orbits have different names depending on height. Below 2,000 km is low orbit, about 36,000 km is geostationary orbit, and in between is medium orbit. The lower you are, the better you can see the Earth and the faster signals travel, but you have to move faster. The higher you are, the more ground you can see at once. So a satellite is placed in the orbit that fits its job.

Think of a swing ride at a fair. If it spins fast enough, the chains pull tight and the seats do not fall. For a satellite, the pull of the Earth plays the part of the chain.

You hear that something was put into orbit, or failed to reach orbit, in almost every launch story. Once you know that getting up to the speed needed to stay in orbit is harder than just going high, launch news looks different.