Midcourse Discrimination for the Phase One Strategic Defense System

Executive Summary The ability to differentiate adequately between true targets and false ones (discrimination) in the midcourse phase of attacking missiles 1 flight is a key requirement for a successful ballistic missile defense. This ability is of particular importance for the proposed initial configuration of the Strategic Defense System (SDS phase 1) because (1) the preponderance of the reentry vehicle (RV) negations are to occur in the midcourse and (2) the effectiveness of the system is leveraged through selective (adaptive) defense that depends on reliable attack assessment in midcourse. Discrimination in SDS phase 1 is to be performed remotely by a combination of radar and passive optical sensors, and will be based on hoped-for detectable differences in the emissions, shapes, and motions of the objects in a threat presumed to contain a variety of penetration aids accompanying the RVs. The BMD Panel of the Army Science Board has reviewed discrimination concepts, the current knowledge of threat characteristics and potential discriminants, the supporting experiments that have been conducted and are being planned, and the major uncertainties and open questions. Below are some of our observations and suggested actions. The full list of our conclusions and recommendations are too detailed to repeat in this summary, but can be found in the last pages of the report. o At the current stage, as a result of an inadequate information base, it is not possible to state with confidence whether we can or cannot achieve adequate midcourse discrimination against a probable reactive Soviet threat. Information is inadequate in the following areas: a) Soviet Penetration Aids The Soviets have not tested within our view a pen-aids suite that would be effective against SDS phase 1. This means that SDS developers must invent and build presumed Soviet pen-aids and test against them. Our current intelligence systems do not provide information on Soviet i bus deployment characteristics and minimal information on the missile tests on their inland range. This is a major inhibition to our learning about current or future Soviet pen-aids. b) U.S. Penetration Aids In trying to estimate the practicality of Soviet pen-aids, we have only very limited experience relative to our own strategic missiles from which to predict the difficulty and the cost in weight and time required to develop penetration devices to the state of operational utility. c) Optical Characteristics Good discrimination-related measurements and data are our critical shortfall. Radar information is adequate …