No doubt this idea has been either attempted or demonstrated to be
impossible/impractical... but I'll ask anyway. Unlike CO2, which
extinguishes flame primarily by smothering (physical), substances such
as Halon work by disrupting one or more elementary steps of the chemical
mechanism for flame propagation. That is why it takes relatively little
Halon to put out a fire. Has work been done on such an extinguishing
medium for interrupting combustion in a solid-propellant motor?
The interrupting agent would be introduced into the head end when the
motor was to be stopped. Residual heat from the propellant surface
might be sufficient to restart combustion if the "off" time was short.
Or secondary ignition might be needed for a restart.
Lithium fluoride is an additive used to reduce combustion rates of solid
propellants. If it's the fluoride ions that do the job, perhaps a
fluorinated organic such as trifluoromethane or tetrafluoromethane could
be a candidate for such an approach.
Best -- Terry
--
Dr. Terry McCreary
Professor Emeritus
Murray State University
Murray KY 42071