Skyhook

A long cable extending from low orbit to high orbit. Ships can dock at the low orbit end and be lifted to the high orbit end along the cable. Less fuel is needed by the ship to get to the lower end. The ship can stop anywhere along the cable, and habitats can be placed anywhere along its length. Ships can reach the lower orbit end with less fuel than it takes to get to orbit. The ship then rides along the cable to reach orbit. The long cable is alomost always stellar powered (solar powered) and uses a magnetic field pushing against the planet's magnetic field to maintain orbit.