ay The T-l97 dewices allowed arsing and firing signals to pass the warhead only if the trajectory was correct; the timing dewice generated araing and firing signals in proper sequence for warhead operation. Toe firing signal was delivered by the missile progracmer in series with contacts clased by the fuze timing device. wore accurate control of the burst point. for additizaal reliabilicy. This was done in order to provide A backup firing signal was provided Ome of the warhead arning signals was required to be contimoms; if detonation did not occur om either firing signal, this signal would hswe been interrupted by the fuze tizers, causing the X-unit to discharge, and thus to "dud" the warhead. 10.1.5 Safery A study was made of safety considerations involved in the Teak and Orange tests.279 The conclusion reachec Sy this study was that probability of a muc- lear detonatica at an altitude of less than about 90,000 feet was less than 1077, Safecy against a ouclear detonation was dependent primarily upon the T-107 safing and arming devices and upon a missile-generated signal indicating that the missile trajectory is normal before warhead arming is allowed. The T-107 devices sense missile accelergtions and require that a predetermined sequence of aissile accelerations be experienced at proper times, and that certain signals be received from the missile guidance and control system. These signals include the guidance~check signal, which indicates that the trajectory is such that the missile vill be at a safe altitude at burst time. The warhead electrical system was slightly modified to allow direct control of arming by the Task Force arming coordinator prior to missile launch. The circuit between the high-voltage battery and the X-unit was interrupted and connected to two receptacles mounted on the external skin of the warhead. A tuclear 2etouation could mot cceur under any circumstances unless the circuit between these receptacles had been completed. This was accomplished at approx- imately H - 55 mimites by means of a jumper cable installed by the arming party. The warheads were monitored as necessary for personnel protection against exposure to tritium gas in the event of a leak. A 1-269/336 installation was used in the assembly buildings and was operated contimuously wherever a unit was in che bay. At other times during warhead handling operations, T-290 portable air samplers were used.