Lethality

Lethality is a measure of the ability of the BMDS to prevent a threat ballistic missile from producing lethal effects. Preventing a threat missile from completing its mission could entail the use of kinetic energy (hit-to-kill and blast fragmenting weapons) or directed energy (laser) to intercept and neutralize the target. Adequate lethality of the interceptor missile ensures the destruction of incoming enemy warheads to minimize potential threats.

Lethality effects are described as either hard kills or soft kills. A hard kill occurs when damage done directly to the threat at the point of intercept results in the payload's immediate destruction. A soft kill occurs when damage done to the threat either causes the threat's destruction due to the effects of atmospheric drag/reentry on surviving payloads or prevents the payload from reaching its intended target. Lethality analyses begin at the moment of impact and continue through to interaction of the target pieces and any surviving payload contents with the Earth. The MDA is developing criteria to evaluate the lethality capability of BMDS technology against various threats. Potential enemy threats could include bulk High Explosive, High Explosive-laden submunitions, nuclear, biological, chemical, and bulk chemical payloads carried on tactical ballistic missiles.

Lethality studies include the monitoring and analysis of threat payload destruction and dispersion during intercepts of test threat targets. Although limited testing is done on actual lethal agents under controlled laboratory conditions, most of the testing relies on a number of payload simulants that, while chemically and biologically neutral, mimic the significant qualities, such as dispersion, weight, and viscosity of a toxic or hazardous substance for test purposes. Testing would require the use of existing simulants and may require the use of newly developed ones.

The MDA divides lethality into four areas of interest. The first is target response, which analyzes the actual ballistic missile intercept of a threat. The second is the formation of the debris cloud containing both pieces of the target and any payload surviving the intercept. The third looks at the atmospheric conditions for transport and dispersion of the debris cloud. Last, the lethality program examines where and how much of the debris, especially the payload, impacts the Earth.

Lethality tests include investigating the impact of the intercept of various threat payloads at various altitudes and speeds. This involves using a mix of laboratory experiments, field tests, flight tests of opportunity, models, and hydrocode simulations and computational analysis. One critical objective of lethality testing is to calculate weapons of mass destruction intercept effects and consequences. Intercepts would occur in the boost phase of target flight or in the endo- or exoatmosphere. Therefore, the altitude and speed of intercepts may affect the effectiveness of an intercept and fate and transport of threat payloads. Because the nature of an incoming threat payload is unknown, lethality testing would assist in establishing a methodology to allow warhead typing based on impact response.

Simulant payloads would be incorporated into targets already scheduled to participate in BMDS element and system flight tests. This "piggy-back" method of data collection allows for the observation of tests of opportunity and the gathering of post-engagement lethality information. Analysis would be done to determine the damage done to submunitions (for both high explosive and chemical payloads) from interceptor missile impact. Submunitions are individual containers in the target designed to distribute a threat payload to a wider area. Multi-wavelength sensors would be used to track and characterize the resulting intercept debris cloud and its eventual impact on the ground.

Testing would also include the study of lethality enhancers, which aim to increase the kill radius of an interceptor missile. Examples of lethality enhancers could include additional explosives or tungsten pellets that explode out of the interceptor upon impact. In some cases, the additional explosives are included in the interceptor missile's FTS. Data collected from these tests would be used to continue to refine existing core lethality models. These studies are currently being conducted at federally funded research development centers, academic institutions, and DoD facilities in the U.S. and abroad. Simulated bulk chemicals can be dispersed upon impact with the interceptor and/or by using an explosive device. Using an explosive charge in the payload can enhance the dispersion of the chemicals, and thereby reduce the concentration of the simulant before it reaches ground level. In the event of a missed intercept, a termination device may be used to disperse the chemicals.