# Would a “pyrotechnics” tag be useful?

We currently have an tag. It has 13 questions, ranging in topic from explosive decompression, explosives as a propellant, the ALSEP grenades, and pyrotechnics.

I have some interest in separating out the pyrotechnics questions into its own tag. There are 7 such questions, only one of which is also tagged explosives.

Opinions?

Either way, there is probably some tag cleanup needed in many of these questions.

• Do you really envision it growing a lot? Seems like explosives doesn't have much on its own to merit splitting. – called2voyage Mar 19 at 2:04
• @called2voyage: I have one or two potential questions. I rather lukewarm on the idea, which is why I am asking here instead of just doing it. – DrSheldon Mar 19 at 2:14
• – uhoh Mar 21 at 2:16
• I've just asked Are rocket self-destruct systems ever tested/proven? and wondered why we don't have the tag yet! – uhoh Apr 1 at 1:31

I'm rapidly warming to the idea;

### Yes!

Pyrotechnics are sophisticated, refined engineering tools that make so many disparate parts of spaceflight possible.

For example NASA has quite a track record with successful pyrotechnics from early on. I think it's close to zero failures ever or something like that. I think there is a question about that.

"Explosive bolts" (generic lay term) are embedded everywhere in space missions, they are major unsung heroes of spaceflight!

They are not used to simply create explosions, they are electromechanical devices which receive electronic signals and perform a carefully controlled mechanical manipulation of a component. Yes when they blow up buildings there are wires that go to detonator cords, but the cable cutters that disconnect a rover from a sky crane or allow a spacecraft to separate from a kick stage are not the same thing as bringing a building now.

From Wikipedia's Frangible nut:

The frangible nut is a component used in many industries, but most commonly by NASA[citation needed], to sever mechanical connections. It is, by definition, an explosively-splittable nut. The bolt remains intact while the nut itself is split into two or more parts.[1]

Space Shuttle

Frangible nuts secured the solid rocket boosters (SRB) of the Space Shuttle, which were bolted to the mobile launcher platform (MLP) until liftoff. On the Shuttle, they were separated using a NASA standard detonator (NSD). The space shuttle used two NSDs for the frangible nut atop each of the four 28-inch-long (71 cm), 3.5-inch-diameter (8.9 cm) bolts holding each SRB to the MLP. Once detonation occurred, the shuttle lifted free of the MLP. The broken nut and any fragments from detonation was captured by energy absorption material, such as metal foam, to prevent damage to the shuttle. In case of NSD failure, or incomplete clearance of the nut from the bolt, the SRB had ample thrust to break the bolt itself and launch unhindered.

From Wikipedia's Pyrotechnic fastener:

Standard pyrotechnic mixtures used by NASA

• Manganese / barium chromate / lead chromate: Time-delay mix, used for sequencing. Gasless burning.
• RDX / nitrocellulose: Gas generator, unsuitable for deep space missions, burn rate dependent on pressure.
• Boron / potassium nitrate: Gas generator and rocket-motor igniter, thermally stable, stable in vacuum, burn rate independent of pressure.
• Zirconium / potassium perchlorate: NASA standard initiator (NSI). Rapid pressure rise, little gas but emits hot particles, thermally stable, vacuum stable, long shelf life. Sensitive to static electricity. Known to cause circuit damage during ground testing.
• Lead azide: Used in detonators. Sensitive to impact, friction, and static electricity. Thermally and vacuum stable, if dextrin is not used for desensitizing. Long shelf life.
• Hexanitrostilbene: Used in detonators, linear shaped charges, and bulk explosives. Insensitive to stimuli other than explosion. Thermally stable. Vacuum stable. Detonates at 22,000 feet per second (6,700 m/s).