Why are the shuttle missions of such a short duration?
Why not stay up for as long as the shuttle safely can? The length of shuttle missions depends upon many factors including consumables margin, mission objectives, and overall shuttle manifest. The amount of consumables loaded on a specific mission depend upon projected usage, mission objectives, ascent lift/performance capability, etc. In general many of the shuttle missions do stay on orbit as long as consumables allow, but we do protect for two contingency days for weather and orbiter systems failures. BACK

Why does the shuttle program use nautical miles as a standard measurement?
Sailors were the first world travellers. They used nautical miles because 1 degree of latitude is 60 nm. They drew the maps to match. Thus the first flyers used nm, and so we in the space business use nm also. To comply with world aviation standards, we use nautical miles. BACK

How long does it take for a space shuttle to be prepared between missions?
The minimum time to get the Shuttle ready between flights is about 55 days. There are a LOT of variables that can affect this (malfunctioning equipment to be repaired from the previous flight, availability of spare parts, periodic/preventative maintenance and inspections, etc.). The Orbiter Processing Facility (OPF) looks a LOT like the set from the hangar scenes in Star Wars and is a REALLY busy place!