(noun) An
explosive bolt is a term used for a
self-destructing fastener which contains and utilizes
pyrotechnics to cause itself to fail. They are used in the
aerospace industry for connections which require great strength but must be
severed instantly either at a
predetermined time (once) or in case of failure. Two
high-profile examples include the bolts attaching the
Solid Rocket Boosters to the
External Tank of the
Space Shuttle, as well as those connecting the
External Tank to the
Orbiter; also,
jet aircraft with
canopies and
ejection seats tend to have explosive bolts designed to quickly
jettison the
canopy so that the seat and pilot can get clear, and/or sever the seat from the airframe.
Explosive bolts typically utilize an electrical charge for ignition (see electronic fuse) although some may be percussion sensitive.