The Fluyt stage would broaden the mission range of the SKYLON spaceplane by transporting payloads from a 300km LEO to more elevated orbits including Geostationary Earth Orbit (GEO) and Lunar Transfer Orbit. Essentially, the Fluyt stage can perform a wide variety of space missions but ultimately it is the GEO transfer mission which drives the performance of an Orbit Transfer Vehicle.
The reason for this is that it is the most energy demanding and highly desirable orbit for commercially operated space transport systems, as many types of satellite such as those designed for earth observation, military and communications, are positioned in GEO. While the feasibility design for Fluyt exposed some new engineering challenges and ideas, it is also necessary to incorporate some level of proven technologies from existing and previous space engineering practice.
Fluyt is capable of carrying 15 tonnes of payload LEO to GEO and return back to its starting point in LEO at the end of its mission. It is also configured to compliment the operational characteristics of the D1 SKYLON launch vehicle and to incorporate many of the elements used throughout the SKYLON support infrastructure such as propellant and standardized payload interface systems. The Fluyt stage also makes use of the existing Vinci rocket engine being developed for the upper stage of the Ariane 5 Launcher and exploits the same Hydrogen/Oxygen fuel combination which is used by the SABRE engine in the SKYLON launcher.
For more on Fluyt, visit Reaction Engines SKYLON Pages.