Potential Future Shuttle Improvements

NASA has just recently completed the 104th flight of the Space Shuttle. Each of the four Orbiters in the Shuttle fleet have a design life of 100 flights each. Thus the fleet is capable of almost 300 more flights, and at current flight rates could potentially operate well past 2020 if necessary. This paper addresses some of the potential Shuttle system improvements that could be considered if the decision is made to continue operations of this vehicle for such an extended period. The national space transportation policy envisions a decision around 2005-2006 concerning readiness to start development of a Shuttle replacement system. Leading up to that decision point NASA is investing in the Space Launch Initiative (SLI) to reduce the development risks associated with key technologies needed for the next generation reusable launch vehicle (RLV). The Shuttle replacement could be a new design RLV or could be based on a Shuttle derived design: i.e., a vehicle based on the current Shuttle but with major design changes. The technology investment strategy of SLI is supportive of either approach. However, if NASA and industry are not ready to develop a replacement vehicle in the 2006-2012 timeframe, then another option would be to continue to make important, but evolutionary changes, to the existing Shuttle fleet. The overall strategy for next generation RLV planning, including possible Shuttle evolution, is captured in Figure 1.