LATCHUP SUPPRESSION TO FACILITATE FAULT-TOLERANCE IN TERMINAL GUIDANCE COMPUTERS

Missile Defense Kinetic Kill Vehicle (MD-KKV) systems are required to operate in a fault tolerant manner even though exposed to the highly-stressing effects of nuclear-weapon detonations and the natural space radiation environments (which can be very harsh at northern latitudes during intense solar storms). Additionally, MD-KKV systems often are designed using commercial-grade/commercial-off-the-shelf (COTS) parts in order to utilize the highest performance parts available. Satisfying all requirements simultaneously is a non-trivial challenge, since many COTS parts are susceptible to radiation-induced latchup. When a part suffers latchup, it may be permanently damaged, or it may be placed in a high dissipation, non-functional state from which it can only recover by by toggling power off, then on again. In either case, the system controller reacts to the radiation pulse by initiating the power-cycle routine. Since time is critical in terminal guidance, any such interruption could be mission-ending. Clearly, then, the use of latchup-susceptible parts types is high risk for a fault-tolerant system. Full Circle Research, Inc. and Raytheon Missile Systems are collaborating to develop the latchup-mitigation process proposed herein,which, once qualified, would potentially make a large number of otherwise unusable or high-risk latchup-susceptible COTS part types usable and low-risk in nuclear-hardened MDA assets, particularly missile-defense interceptors.