Developing Evaluation Measures for the Second Stage Next Generation Engine on Evolved Expendable Launch Vehicles

Abstract

The United States has been the leading nation in space technology, as space is a vital asset in military dominance. But to sustain its position in the area of space lift, the current U.S. second stage liquid propulsion engine, the RL10 (developed in 1958) needs to be replaced. This replacement requires systems engineering methods and new technological advances to adhere to mission requirements and constraints of current platforms. This thesis provides a history of the Evolved Expendable Launch Vehicle (EELV), U.S. liquid propulsion, and the RL10 LH2/LOX engine to analyze tradeoffs between major requirements in new upper stage development and to provide a recommendation of evaluation measures. The results are a proactive case presenting the benefits of a new upper stage engine on EELV, a tradeoff comparison between rocket propulsion engine cycles, a waterfall model for engine qualification and testing of liquid propulsion rocket engines, and testing recommendations for NGE qualification. Additionally, the thesis recommends specific impulse, thrust, and thrust-to-weight values that should be used as a design baseline for the next generation upper stage engine on EELV. These recommendations should be of value to engineers or program managers who are or will be responsible for acquiring replacement propulsion systems.