One option available: add momentum very efficiently on the tether.
Rockets have to balance their specific impulse (efficiency) against their need for massive amounts of thrust immediately. You can't take off from the ground using an ion thruster, despite what Kerbal Space Program tells us.
But a tether system in orbit could be using a very efficient engine to gain momentum over a very long period of time (months, years, etc). Give it large solar arrays or a small nuclear plant on-board. It's getting a much better exchange rate on that delta-V than the rocket, which needs to fight earth's gravity and air resistance.
Rockets have to balance their specific impulse (efficiency) against their need for massive amounts of thrust immediately. You can't take off from the ground using an ion thruster, despite what Kerbal Space Program tells us.
But a tether system in orbit could be using a very efficient engine to gain momentum over a very long period of time (months, years, etc). Give it large solar arrays or a small nuclear plant on-board. It's getting a much better exchange rate on that delta-V than the rocket, which needs to fight earth's gravity and air resistance.