An Explosively Driven Launcher Capable of 10 km/s Projectile Velocities

TL;DR

This paper introduces an explosively driven light-gas gun capable of launching projectiles over 10 km/s, demonstrating a compact design and potential scalability for higher velocities in hypervelocity research.

Contribution

Development of a novel explosively driven launcher that achieves hypervelocity projectile speeds beyond current technology, with detailed design and scalability analysis.

Findings

Successfully launched 8 mm magnesium projectiles at 10.4 km/s

Demonstrated a compact launcher design under 1 meter in length

Explored scalability to larger projectile sizes and higher velocities

Abstract

Launching large (> 1 g) well-characterized projectiles to velocities beyond 10 km/s is of interest for a number of scientific fields but is beyond the reach of current hypervelocity launcher technology. This paper reports the development of an explosively driven light-gas gun that has demonstrated the ability to launch 8 mm diameter, 0.36 g magnesium projectiles to 10.4 km/s. The implosion-driven launcher (IDL) uses the linear implosion of a pressurized tube to shock-compress helium gas to a pressure of \SI{5}{\giga\pascal}, which then expands to propel a projectile to hypervelocity. The launch cycle of the IDL is explored with the use of down-bore velocimetry experiments and a quasi-one-dimensional internal ballistics solver. A detailed overview of the design of the 8 mm launcher is presented, with an emphasis on the unique considerations which arise from the explosively driven propellant compression and the resulting extreme pressures and temperatures. The high average driving pressure results in a launcher that is compact, with a total length typically less than a meter. The possibility to scale the design to larger projectile sizes (25 mm diameter) is demonstrated. Finally, concepts for a modified launch cycle which may allow the IDL to reach significantly greater projectile velocities are explored conceptually and with preliminary experiments.