A safe and arm (S&A) device is disclosed. The device utilizes a no-fire
separation distance and a mechanical configuration of primary
explosive/booster explosive and secondary explosive to establish a safe
mode. While in safe mode, the device would allow no more than 1 in 1
million detonation transfers to occur from primary to secondary. In armed
mode, the no-fire separation distance is taken away, allowing reliable
detonation transfer. Two arming environments, which occur after launch
and safe separation, are used to move the S&A device to armed mode. The
first environment is the release event of the projectiles from their
packed state in a dispenser. The second environment is a target sense
mechanism. If either arming environment returns to its original state,
the mechanism returns to safe mode. The S&A device will not allow
inadvertent packing into the dispenser of explosive devices in the armed
state.