Ordnance Safe and Arm Device

Ordnance Interrupter

Product Description

The Ordnance Safe and Arm Device (OSA) or Interrupter Device is an electro-mechanical safe & arm device used to initiate an explosive train once it is in the ARM state. The interrupter device also provides intrinsic safety against inadvertent initiation of the explosive train when it is in the SAFE state. The Interrupter utilizes a booster to provide the necessary output to initiate various ordnance devices in a continuing explosive train, such as an Flexible Confined Detonating Cord (FCDC).

Ordnance Safe and Arm Device
Key Features Applications Specifications Interface

Key Features

How An Ordnance Safe and Arm Device Works

When the Ordnance Safe and Arm Device is in the SAFE position, the booster is mechanically isolated from the explosive train outputs providing a barrier to prevent accidental explosive train initiation. When the interrupter is in the ARM position, the booster is moved in-line with the explosive train input and output ports, providing the correct state to facilitate explosive train initiation. The interrupter booster is initiated by an energetic input stimulus at the interrupter input port from FCDC, DBA, or other types of Initiator, than an electrical input. An electrical stimulus is used to place the interrupter in the ARM or SAFE position. The Interrupter contains both local visual (window) and remote electrical redundant SAFE and ARM position monitor circuits. In addition the Interrupter includes a safing mechanism for manual safing.


Our Ordnance Safe & Arm Device is qualified and extensively used on solid rocket motor missile and rocket systems, including Atlas and Delta rockets.


The OSA is used to initiate explosive trains where intrinsic safety against inadvertent initiation of the explosive train is demanded. Applications include rocket or missile assembly and deployment, especially where solid rocket motors are involved.


  • All-Fire Angle
    All-Fire angle for .999 reliability and 95% confidence = 81.2° from full safe
  • No-Fire Angle
    No-Fire angle for .999 reliability and 95% confidence = 43.9° from full arm
  • Input Stimulus
    FCDC, DBA or similar
  • Operating Temperature
    -54°C to +74°C
  • Arming/Safing Voltage
    22 to 35 VDC
  • Output
    Qualified to MIL-DTL-2365
  • Insulation Resistance
    22 to 35 VDC
  • Electrostatic Discharge Immunity
    Booster is immune to ESD pulses applied to the interrupter
  • Pre-function Leak Specification
    5 x 10-5 standard cc/second of Helium
  • Applicable Specifications
    Meets requirements of MIL-STD-1576 and MIL-STD-454
    Meets requirements of MIL-STD-464 (EMI)


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