In order to fully exploit the Shuttle orbiter's payload delivery and retrieval capabilities and to provide on-orbit servicing of other spacecraft systems, a remotely piloted free-flyer will be an essential element of the developing space transportation system. Not only will a free-flying system be able to deliver payloads to a significantly higher orbit than can the Shuttle, it will be able to retrieve satellites from their operational orbit and return them to the orbiter or the earth for servicing. Ultimately, the free-flyer can be used in the construction of large space systems that exceed a single Shuttle launch capability. Following completion of its mission, the free-flyer can return to the earth, or it can remain in orbit for storage between Shuttle missions to eliminate relaunch expenses. The free-flyer may be controlled from either the aft flight deck or a ground based station. Remote control from a ground based station has distinct advantages because it will eliminate all requirements imposed on the Shuttle for aft flight deck and cargo bay flight support equipment and interfaces.
Choice of mission trajectory plans and conceptual design of electrical propulsion module for launching payloads into circumterrestrial orbits
