NASA Standard Initiator

The NASA Standard Initiator (NSI) is a pyrotechnic device used to set off other pyrotechnic devices. It is the central multi-purpose component of a modular system of detonating cords, pyrotechnics and various other explosive charges with many different uses.[1]

The ignition charge of the device is a blend of zirconium, potassium perchlorate, Viton B and graphite, often abbreviated as ZPP.[2]

Uses of the device include:

* Setting off pressure cartridges, pocket sized gas generators which in turn pneumatically activate other systems.
* Setting off the NASA standard detonator, which itself activates other systems explosively.
* Triggering Pyrotechnic Circuit Interrupters, severing bundles of electrical cables.
* Triggering explosive valves to open/close pressurization lines or fuel lines.
* Triggering a pyrotechnic pin puller which opens a Marman clamp, separating two spacecraft.
* Acting as an igniter.

## Development

[edit]

The NASA Standard Initiator (NSI) was developed from the Single-Bridgewire Apollo Standard Initiator (SBASI) which was itself based on the Apollo Standard Initiator (ASI).[3]

To provide additional redundancy and thus make the spacecraft more reliable, a double-bridgewire design was utilized, but during development of the Apollo Standard Initiator it was found that the original design responded unfavorably to RF frequencies. This resulted in a redesign with a single bridgewire which was approved in 1966. This new design introduced several other changes to improve resistance and give the device a longer shelf life, such as switching the material of the body from 17-4 PH steel to Inconel 718.[4]
After the Apollo program ended, the Initiator was renamed and re-used on other spacecraft, such as the Space Shuttle.[3]

## References

[edit]

1. ^ Proceedings of Electric Initiator Symposium - 1963 (PDF). Franklin Institute, Philadelphia, Pennsylvania: U.S. Army Materiel Command. 1 October 1963. pp. 3-1 – 3-22. Archived from the original on 22 August 2022. Retrieved 24 August 2022.`{{cite book}}`: CS1 maint: bot: original URL status unknown (link)
2. ^ Seeholzer, Thomas L.; Smith, Floyd Z.; Eastwood, Charles W.; Steffes, Paul R. (1 January 1995). Applications catalog of pyrotechnically actuated devices/systems (PDF). Cleveland, OH: NASA Lewis Research Center. pp. 66–67\. Archived from the original (PDF) on 22 August 2022.
3. ^ a b Apollo Spacecraft and Saturn V Launch Vehicle Pyrotechnics/Explosive Devices (PDF). Houston, TX: NASA, Johnson Space Center. 1 January 2009. Archived from the original (PDF) on 6 January 2022.
4. ^ Apollo Experience Report - Spacecraft Pyrotechnic Systems (PDF). Houston, TX: NASA, Lyndon B. Johnson Space Center. 1 March 1973. Archived from the original (PDF) on 12 December 2020.

## See also

[edit]

* NASA standard detonator

This article related to the National Aeronautics and Space Administration is a stub. You can help Wikipedia by expanding it.

|

* v
* t
* e

This pyrotechnics-related article is a stub. You can help Wikipedia by expanding it.

|

* v
* t
* e

*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template