Rocket-engine control-system reliability-enhancement analysis

This paper presents a case study analysis of the process used in identifying and quantifying redesign improvements to enhance the mission reliability of an existing rocket engine. As part of a reliability enhancement program, the historical drivers of unreliability within the system must first be understood. Based on this information, design improvements can then be identified which will provide the optimum benefit to the overall system. This approach was used in analyzing the RL10, an existing upper stage rocket engine designed by Pratt and Whitney in the late 1950s. This engine has been used for over 30 years to launch unmanned satellites, using a design that has been relatively unchanged. In today's environment, where a one-of-a-kind satellite cost can exceed a half billion dollars, and multi year schedule delays can result if satellites have to be replaced, ensuring maximum mission success of the launch vehicle is paramount to these programs. With the advent of reliable, light weight electronics, existing engine designs like the RL10, which utilize single string pneumatic and hydro-mechanical controls systems, can be enhanced with redundancy to improve mission reliability, performance, diagnostics, and reduce risk.