|MadSci Network: Engineering|
A rocket must accelerate to a velocity of about 5 miles per second to reach and stay in Earth orbit. While we consider ourselves to be standing still, the Earth is in fact rotating about its axis and taking us and any rocket with it. If you were at the North or South Pole, the speed that you rotate around the Earth's axis would be close to zero. As you get closer to the equator, your speed increases. At the equator, you are travelling about 0.288 miles per second (1,038 mph).
Since a rocket must accelerate from its initial speed to orbital speed, the closer the rocket launch site is to the equator, the less it has to accelerate and the less fuel it will need. That is one of the reasons the Eurpoean Space Agency built the Ariane launch site in Kourou, French Guiana rather than in Europe. It is also why Boein g's Sea Launch system will steam from Long Beach, CA to a spot on the equator in the Pacific Ocean.
The site of the control of the flight is not critical because the shuttle and other rockets in low Earth orbit travel around the Earth about every 90 minutes. By having the launch site in Florida, the shuttle can start with a velocity of about 0.15 miles per second sitting still on the launch pad. Hawaii would be even better, but the logistics and cost of building a space port there were too much even during the Space Race.
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