Initially, most satellites were launched into geostationary orbit, which stays at a fixed point above the Earth. To achieve that efficiently, it is best to launch eastwards, close to the Equator, to obtain the highest possible spin rate. "[The Earth at the Equator rotates at] about 1,400ft-per-second and in Scotland it's about 800ft-per-second,” says Scott Hammond, operations director at Shetland Space Centre. If you're at the Equator, and you want to go to geostationary, that's all free energy that throws you out."
