Optical Investigation on the Hypergolic MMH/NTO Combustion in Spacecraft Propulsion

The hypergolic MMH/NTO combustion was optically investigated regarding the flame behaviour inside a glass combustion chamber as well as the exhausting gas characteristics of real thruster engines in development. Both plume and chamber measurements were conducted using absorption and emission spectroscopy. Strong signals of OH* and Na appeared during all test runs. High speed movie recording of crucial spectral features visualised the flame and monitored the injector performance. Moreover, FFT analysis of the emitted light clearly revealed a 35 Hz flickering consistent with the time resolved chamber pressure signal. Furthermore, a laser scattering experiment on a pulsed plume proved reliability of a LIDAR system