REDUCTION OF PYRO SHOCK IN STAGE SEPARATION MECHANISM BY USE OF GAS GENERATOR SYSTEMS

Pyro actuated devices are widely used for carrying out separation of structural components, as well as to deploy or release appendages. These pyro cartridges, upon initiation of the explosive charge, generates high pressure gas which initiates the mechanism. Pyro cartridges are highly compact, lightweight, and highly reliable systems for attaining on-command separation. Pyro-initiated separation bolts (or pyro bolts) are used for stage separation of launch vehicle systems. These pyro cartridges generate high levels of shock waves, which leads to failure of many critical components like avionics and electronic packages in the vicinity of the pyro shock source. Anecdotal evidence suggests that the shock can only be reduced if the pyro initiation is replaced by non-pyro initiation methods such as electrical initiation of unlocking mechanism, pneumatic initiation, or initiation by gas generator. The electrical/electro-mechanical and pneumatic initiation comes with a penalty of bulky sub structures. Studies have been carried out for reduction of shock by implementing gas generator (GG)-based cartridge in place of pyro cartridges. The GG cartridge generates the required minimum pressure for initiating the release mechanism of the separation bolt. Separation bolt ejec-tion test has been carried out with pyro cartridge as well as with gas generator-based cartridge; the generated shock has been monitored. There is an order reduction of shock with the use of gas generator cartridge as compared to that of a pyro cartridge. We describe the development work carried out for design, realization, and testing of GG cartridge and its prospective application for a low shock stage separation mechanism.