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 systemofdetonating 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:
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 relieable, 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 re-design 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 steeltoInconel 718.[4]
After the Apollo program ended, the Initiator was renamed and re-used on other spacecraft, such as the Space Shuttle.[3]
 | This article related to the National Aeronautics and Space Administration is a stub. You can help Wikipedia by expanding it. |
 | This pyrotechnics-related article is a stub. You can help Wikipedia by expanding it. |
