Microwave emission experiment with hypervelocity impacts and applications of its results

The experiments to detect microwave emission due to hypervelocity impacts have been carried out with significant improvements of time resolution. We can investigate waveforms up to 1 n sec so that the energy of the emitted microwave can be estimated. The emission is a random sequence of pulses which lasts more than 10 mu sec depending on the target destruction. The projectile is a nylon sphere of 0.21 gram, and is accelerated by a light-gas gun up to the velocity of 4 km/sec. The timing and duration of the emission are strongly dependent on the material and thickness of a target. Especially, large delay of the emission was observed in the cases a projectile penetrates a target. Therefore, those informations seem to include key suggestions to destruction process as well as the emission amplitude. This phenomena can be applied to the impact detection on a large space structure like a space station. The generated microwave propagate in vacuum and may be diffracted so that impacts can be detected more easily and at more flexible locations than by a vibration sensor or an accelerometer.