Sled Return
The westbound segment of the launch loop closes the loop at altitude to provide extra lift for the stations, and close the loop without interfering with shipping channels in the ocean below.
The westbound segment can be used for a third purpose; returning launch sleds from the east station at the end of the launch run, back to west station for reeuse. If the unloaded sleds accelerate westward at full thrust, they can reach orbital velocity (and zero vertical track loading) much faster than an eastbound sled loaded with a vehicle. On the other hand, there will be less rotor velocity change and less power dissipated if acceleration is limited to three gees, like launch. The next two sections consider these two possibilities; a production launch loop designed by a clever engineering team will probably be better than either of these alternatives.
Two alternatives considered (and now superseded) are:
(1) lowering the sled from east station to the eastern surface platform, then flying it back to the western surface platform,
and
(2) releasing the sled just above orbital velocity at east station into a fractional orbit, then reentering it (with a heavy heatshield), deploying a parachute, and snagging it "Corona Spysat Film Cannister Style" with an aircraft near west station. This is a flyback sled return. It is risky, expensive and wastes energy, but should be mentioned and discarded before someone else stumbles across the same silly idea and pesters busy engineers with it.
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