Nonlinear optimization techniques are used to quantify the impact of adding a space fueling station and reusable tug to the Space Transportation System (STS). The Shuttle deploys all space traffic to the station at which a tug is used to launch a representative satellite fleet across the entire gamut of inclinations and altitudes. Annual Shuttle launches are calculated by summing the total mass required to deploy and operate the system and dividing by the Shuttle cargo mass capacity. The station altitude and inclination are variables specified when Shuttle launches are minimized. Launch rates for onetwo-, and three-station scenarios are compared to the author's estimate of the corresponding rates for current STS operations. The use of both chemically and ionpropelled tugs are evaluated. Applying vector optimization to the latter minimizes both the average tug flight time and annual Shuttle launches. The resulting efficient operating frontier specifies a set of optimal inclinations, altitudes, and tug sizes. The Shuttle launch rates for the chemical and ion systems are potentially less than for current STS projections. Equally important for existing ion thruster technology, the round trip flight time of the tug to geosynchronous orbit can be less than 60 days.