On the explosive formation of macroscopic hypervelocity projectiles for use in the study of planetary cratering

In this paper we show that by modifying a conventional lined hollow charge, such that the explosive is asymmetrically distributed, it is possible to form projectiles of controllable mass (up to ～1 g) moving in the forward direction with speeds of the order of 10 km s^?1. Measurements of the projectile speed and estimates of its mass are found to agree well with the predictions of the one dimensional theory of Carleone and Chou (1974). A comparison is made of the crater formation obtained by firing both modified and unmodified lined hollow charges at basalt. We indicate how it should be possible to increase the velocity of the projectile up to ～14 km s^?1 and the application that such a technique would have to problems in both cratering physics and planetary studies.