KISMET Lore dump: Most large terrestrial spaceports utilize a type of mana-assisted space elevator called a "Gateway" to speed up the process of planetary re-entry.  There is no physical tether between the space-side Gateway and the planet-side Gateway; instead, the two are connected through one or more man-made ley lines.  Landing planet-side is certainly possible without a Gateway's assistance,  but the physical heat damage caused to spacecraft by standard atmospheric re-entry makes the Gateways a more commercially viable operation.