JSSG Air Vehicle

Nuclear EMP hardening has been integrated into the electromagnetic interference/compatibility (EMI/C) electromagnetic environment design activities. For air vehicles, additional EMP design requirements are balanced based on cost-benefits and risks. Retrofitting EMP hardening as a modification is costly and will not likely achieve the benefits potentially available if designed into the air vehicle from the beginning. The need to provide additional EMP hardening characteristics, for air vehicles intended to remain in the inventory for decades, must be carefully considered and weighed against the consequences of not providing such characteristics.

Nuclear overpressure, gust, and thermal hardening have been required for high value air vehicles that had a base escape requirement. Nuclear hardening effectively decreases the needed escape distance and reaction time. For air vehicles, overpressure, gust, thermal design requirements are dependent on the threat postulated. Careful consideration, including costbenefit and risk analyses, are necessary since such characteristics can be design drivers in air vehicle development but are exceedingly more difficult and expensive to retrofit into an existing
air vehicle.

TREE hardening has been required for high value, high altitude air vehicles. TREE includes these weapon effects: neutron fluency, total dose, and gamma dose rate. At lower altitudes (less than ~30,000 ft), TREE damage occurs well inside the damage radius of other nuclear weapons effects (overpressure, gust, thermal). TREE hardening requires detail circuits analysis and piece-part data. Only a small fraction of available piece parts are designed as radiation hardened parts. If TREE hardening requirements are near the inherent hardness of the piece parts, then little additional military capability has been achieved – why spend the effort? If TREE hardening requirements are beyond the inherent hardness of the piece parts, significant piece-part control during assembly and throughout the life cycle is required. Piece parts that are inherently harder than the typical part is dependent upon the manufactures processing. Controlling the manufacturing process for each inherently harder piece part is counter to the way that DoD manages piece parts. For air
vehicles, TREE design requirements are not recommended unless the nuclear threat is significant.