Video imaging of debris clouds following penetration of lightweight spacecraft materials

The structure of debris clouds following hypervelocity penetration of thin materials is of special interest to spacecraft designers--it forms the basis for damage equations from meteoroids, orbital debris, and other kinetic energy threats. Today, video imaging offers the experimenter a new view into the structure and development of debris clouds following penetration of these thin materials. This technique is of special interest in its application to lightweight, thin, or other low density target materials whereflash x-ray experimental imaging has proven difficult to apply, including fibrous materials (such as Nextel and Kevlar), multi-layer insulation (MLI), aluminum foam, and so on. This paper has two purposes: (1) to describe new developments in video imaging of debris clouds using high-speed multi-frame cameras (with frame rates of up to one million frames per second) and still video cameras with extremely high shutter speeds (as short as 3 nanoseconds), and (2) to present video images of debris clouds from light gas gun testing of aluminum and nylon spheres penetrating at 5 to 7 km/sec through thin aluminum plates, aluminum foam, and multi-layer insulation materials. The paper then compares the video images results to previous flash x-ray images (Piekutowski, 1997) and comments on similarities and new features that may be observed using this improved experimental technique.