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As of Dec. 29, 2004 there were 9,233 objects large enough to be tracked. Of this total there were 2,297 payloads, along with 6,306 objects classed as rocket bodies and debris. The cumulative mass of these objects is approximately 2,000,000 kg.
A target can be punctured by an object larger than about a third of the target thickness. Because of the high speed , the kinetic energy of HVI is very large. An impact of this type would be more like an explosion. As an example, a 1 cm sphere moving at 10 km/s has an impact energy corresponding to the explosive force of a hand grenade. The momentum transfer during impact can change spacecraft altitude and disrupt formation flying. Short circuits in solar panels can result in a loss of power and cripple a spacecraft. Every impact creates an “impact plasma” which can lead to electrical noise in circuits and interfere with experiments. The impact plasma can also trigger electrostatic discharge if the space environment had charged up the spacecraft before hand.
The mode of the frequencies and amplitudes was used to increase the accuracy of the maps. The amplitude maps will provide a standard of comparison with the maps of the LGG impacted plates when they are completed. Since the maps correspond with the bottom plate (where the PZTs are attached) a wave pattern can be seen coming from the rods. The areas of high amplitude represent constructive interference of waves, while the areas of lower amplitude represent destructive interference of waves. Higher amplitudes tend to occur in the region of PZTs.  As far as the frequency maps, it is more difficult to come to some logical conclusion as to what is going on there. There is not an observable pattern. One can, however, see how the frequency is distributed on the plate. Future work will complete the mapping of impacted plates and then a comparison can be made to the control plates to see if amplitudes and frequencies are shifted. In this way dangerous impacts with space debris can be monitored, hopefully predicting potential problems.