Electronic Control System for Cryogenic Space Power System

This paper discusses an electronic technique to control mixture ratio in a combustion process using cryogenic propellants. Propellant density variation from liquid to gaseous hydrogen dictated an elaborate pulse-width-amplitude-modulated control system. Requirements of millisecond total flow change, mixture ratio variation, and summed rate plus dual temperature sensing caused further sophistication. The resultant system provides positive control(3%) of critical temperature for catalytic H2 - O2 combustion even during an abrupt, non-predictable relocation of the reaction flame front within the catalyst bed.