JSC USPE Molniya projects to develop electric ignition systems for liquid-propellant rocket engines that use non-hypergolic propellant components

The paper describes the history and results of JSC USPE Molniya projects to develop electric ignition systems for oxygen-hydrogen and oxygen-kerosene engines, it describes the desirability of using electric ignition systems to enable multiple engine restart capability. It reviews ignition systems for engines RD0120 and RD0146 developed by JSC KBKhA, describes major challenges encountered in the process of designing, the solved problems, that enabled meeting the requirements for reliable ignition of propellant components in the engine under all of its operating conditions. It describes basic differences between various ignition systems, and provides a comparison of their mass-dimensional parameters. It discusses the ignition system KN-11B, which was used in engines 17D15, 17D16, gas generator units of the combined propulsion system for the space system Buran developed by RSC Energia. It describes the ignition system structural design features involving two separate housings, and the special aspects of the ignition system operation under flight conditions: operation in vacuum, requirements to support up to 40,000 restarts, reliable operation when products of incomplete propellant combustion are deposited on the duty face of the spark plug. It demonstrates feasibility of supporting at least 1,000,000 restarts of the engines. It describes the SZE-7 ignition system that is being developed for a low-thrust engine to be used in the system for restarting the engine 11D58MF, which represent further development of design solutions used in the ignition system KN-11B, and provides a comparison of their specifications.