> The reason the shuttle carries a lower payload is because it must *change* it's orbital inclination to reach the 56 degree ISS orbit.
ERRR. WRONG. The Shuttle does not "change" it's orbital inclination to reach ISS; it launches straight to 56 degrees right from the pad. The Shuttle has nowhere near the delta-V capability to do an orbital inclination change of that magnitude while on orbit.
If the Earth did not rotate, then the Shuttle would have exactly the same payload no matter what orbital inclination, or what the launch latitude. it simply would not matter.But the rotation of the Earth provides a boost for low-latitude launch site flying low-inclination orbits. It provides no boost whatsoever to polar launch sites flying polar orbits. it provides a serious *hinderance* to low-latitude launch sites flying west. So far, only one nations - so far as I know - has ever launched satellites ina retrograde (west) orbit... israel. Cuz they don;t have the political option to fly east.
GourmetDan just got confused because this is a topic he knows nothing about.
When I said 'change' I was speaking of the need for the shuttle to change from it's natural low-inclination orbit to the ISS high-inclination orbit. Not that it needs to change once it gets into orbit.
"For a spacecraft to achieve Earth orbit, it must be launched to an elevation above the Earth's atmosphere and accelerated to orbital velocity. The most energy efficient orbit, that is one that requires the least amount of propellant, is a direct low inclination orbit. To achieve such an orbit, a spacecraft is launched in an eastward direction from a site near the Earth's equator. "
"Launching a spacecraft in a direction other than east, or from a site far from the equator, results in an orbit of higher inclination. High inclination orbits are less able to take advantage of the initial speed provided by the Earth's rotation, thus the launch vehicle must provide a greater part, or all, of the energy required to attain orbital velocity."
This is what the shuttle must do, launch in a direction other than due east, *changing* it's natural orbital inclination. Were the shuttle to launch into its natural low-inclination orbit, it would 'gain more' from the relative rotation than a craft launched from Baikonur, which is further north. It is the need to launch in a direction other than due east to reach the 56 deg inclination that is the key, as Cape Canaveral is further south than Baikonur and therefore gains more from relative rotation, not less. http://www.braeunig.us/space/orbmech.htm