According to my
source (my
boss, during a
motivational speech on making decisions logically), the SV
booster rocket that takes the
space shuttle into
orbit, was originally conceived to be broader than its current 12-foot
diameter. Originally designed for use with the
Saturn V rocket for extra
thrust, the booster could be more effective if it were only a few feet wider.
But the manufacturer had to ship the thing by rail to the launch site. The diameter was limited by the width of tunnels along the railroad. The tunnels' widths were determined by the gauge of the railroad tracks.
The gauge of American railroad tracks was determined by the gauge of European railroad tracks.
The gauge of European tracks was determined by the ruts in the roads common in Europe before widespread road pavement and rail travel.
The ruts had been formed by horse-drawn wagons, the gauge of which was based on the ancient Roman chariot.
The gauge of the Roman chariot was such because the wheels needed to be that far apart to accommodate the breadth of two horses.
My boss' conclusion: the SV booster, the most advanced form of propulsion known to man, is the way it is because of a horse's ass in Rome.
Not sure how much of this actually makes sense, but it's good thought-food when pondering how to do a new thing if you wish to avoid automatically basing your idea on how things where done in the past.