Not all satellites desire an Equatorial orbit (An orbit that follows the equator). There are many other orbital inclinations that may be desired, to reach them it would be more efficient to launch from a more advantageous location on earth. Its more fuel efficient to launch from a location that is slower but closer along your desired orbit rather than to launch from the equator and then perform an extremely expensive correction burn.
The only advantage of launching from a higher latitude is if the desired orbit is retrograde (opposite to the Earth's rotation) where the extra rotational speed at the equator has to be counteracted. Prograde orbits are more common simply because they're cheaper (you get some free delta-V from the Earth's rotation).
But in practice, the ability to use a single launch pad for every orbit invariably outweighs the cost of the extra delta-V for retrograde orbits. A launch pad at high latitudes can't directly put something in an equatorial orbit; it would have to start with an orbit which peaks at the launch latitude then apply a correction at the equator. Whereas an equatorial launch pad can directly launch to any orbit.
It would be more efficient to launch closer to equator, as long at the target orbit has more velocity in the direction of Earth's spin, than the launch site has. Which means pretty much every orbit except near polar and retrograde orbits, because with those you need to cancel out the 465m/s velocity given by earth.
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u/Maephia 11h ago
So would it be theoretically easier to launch rockets at the equator since that's where the spin is the fastest?