CONFLIDENTTAT Effect of Passive Measures on Active Defenses If the bombcarrieris killed but not the weaponitself, there is a strong likelihood that intolerable levels of fallout might result (App H). One solution to killing the bombis the use of nuclear warheads in the defending missiles. Figure 41 indicates that there is a safe corridor of altitudes for attacking aircraft. At these altitudes or below, the use of highyield warheadsis denied the ground commanderbecause of the danger of inflicting death or injury to personnel in best shelter available on the ground. This corridor is based on the assumption that 1-psi overpressure on the ground would constitute a “‘safe” limit, and that 2 psi would be the absolute maximum peak overpressure that could be sustained by the population. For personnelin shelter capable of withstanding 30 and 100 psi the size of this corridor is reduced to academic proportions (Fig. 41); 10-kt warheads could be used at practically any altitude feasible for the attacking aircraft. The corridor for any likely yield in the defending missile is less than 1000 ft. Thus a program of shelter construction could be utilized to deny the attacking aircraft a corridor in which he could have assumed that nuclear warheads could not be used against him. ORO-R-17 (App B) 57 CONFIDENTIAL