An unsteady burning of rocket fuel that can cause structural damage to the thrust chamber. Combustion instability was a problem experienced by many of the first launch vehicles, and also with the prototype ascent engine of the Apollo lunar module. These were usually caused by poor fuel injection and corrected by redesigns. To test for combustion instability, NASA engineers developed tiny ‘bombs’ to interupt the fuel flow and see if the engine could recover.
Subjects: Astronomy and Astrophysics.