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→Trigger Mechanisms
== Trigger Mechanisms ==
=== Pyrotechnic Cables and Bolt Cutters ===
This mechanism employs a small controlled expansion to propel a bolt towards a cable placed on an anvil. The bolt strikes the cable and cuts it, thus releasing the deployable that the cable was securing. An animation for the same can be found [http://spot4.cnes.fr/spot4_gb/images/pyro/pan.gif here].
==== Advantages ====
They are quick, small and simple in use
====Disadvantages ====
The explosion may generate a lot of internal force and create hazards for the satellite <br \> <br \>
----A very good animation can be found [http://spot4.cnes.fr/spot4_gb/images/pyro/pan.gif here].----
=== Burn Wire Mechanism ===
The release mechanism utilizes a compressed spring system to ensure permanent contact with the cable that is securing a deployable. When heated the burn wire would cut through the cable due to pre-compressed spring. After a successful cut the spring extends to its natural length. Usually the burn wire is made of Nichrome, which is heated to high temperature and the cable is made of Vectran (A high strength, high thermal stability and low creep fiber)
====Disadvantages ====
May fail to cut through the wire in one shot i.e. unreliable (To tackle this, usually redundant setups are used to ensure that the mechanism works well)
----For more information and graphics on burn wire mechanism, click [[Filehttps:Burn1//www.techbriefs.jpg|frame|center]com/component/content/article/tb/techbriefs/mechanics-and-machinery/24810 here]. ----
=== Shape Memory Alloy (SMA) ===