The increased incidence of improvised explosives in military conflicts has brought about an increase in the number of traumatic brain injuries (TBIs) observed. Although physical injuries are caused by shrapnel and the immediate blast, encountering the blast wave associated with improvised explosive devices (IEDs) may be the cause of traumatic brain injuries experienced by warfighters. Assessment of the effectiveness of personal protective equipment (PPE) to mitigate TBI requires understanding the interaction between blast waves and human bodies and the ability to replicate the pressure signatures caused by blast waves. Prior research has validated compression-driven shock tube designs as a laboratory method of generating representative pressure signatures, or Friedlander-shaped blast profiles; however, shock tubes can vary depending on their design parameters and not all shock tube designs generate acceptable pressure signatures. This paper presents a comprehensive numerical study of the effects of driver gas, driver (breech) length, and membrane burst pressure of a constant-area shock tube. Discrete locations in the shock tube were probed, and the blast wave evolution in time at these points was analyzed to determine the effect of location on the pressure signature. The results of these simulations are used as a basis for suggesting guidelines for obtaining desired blast profiles.

Many regions of Earth orbit are ideal for satellites that provide commonly used services, including communication, television, and navigation. However, defunct satellites, spent upper stages, and other space debris are crowding these vital regions of space, resulting in the need for methods for their removal. For remediation methods that depend on docking with the debris, eliminating the residual spin of the debris before docking is desirable, and perhaps necessary. The purpose of this work is to model the use of laser ablation to despin large space debris objects before surface contact. With a three-dimensional surface mesh of a known debris geometry, an assumed initial spin for the debris, and an offboard location for the laser, a targeting algorithm computes which faces are targetable at each instant based on geometric constraints. The location that generates the most desirable change in angular momentum is then targeted at each instant while integrating the equations of motion over time. The effects of nonoptimal targeting distance, incidence angle, surface ablation physics, and laser power are considered in the evaluation of total time to despin the debris object. It is shown that the time required to despin a representative object with a 250 W pulsed laser is on the order of days.

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