A new compact, self-compressing, vertical one and two-stage gas gun at the University of Kent

Abstract

A new gas gun configuration has been developed at the Centre for Astrophysics and Planetary Science, University of Kent, to produce vertical impacts at up to 2 km s−1. The vertical arrangement allows impact into non-cohesive target materials such as sand (representing loose regolith on the surface of solar system bodies) and water. Three key constraints had to be met: (1) the vertical gun had to fit in a laboratory with a ceiling of 3.5 m height, (2) the gun had to operate without a chemical propellant (i.e. gunpowder) and (3) it had to fire into the same target chamber as the existing horizontal Kent gun. In addition, the use of standard pipeline elements was adopted. The result was a self-compressing right angle shaped gun design, with single and two-stage variants for low and high speeds respectively. The gun assembly and its operation are described, together with ancillary components. The self-compressing first stage of the gun (using pressure generated by boiling liquid nitrogen) is horizontal leading into a vertical second stage. The gun has performed as expected, with shots in the speed range 0.3 to 2 km s−1. Results from the first study using the gun are presented for impacts of 1 mm diameter stainless steel spheres into sand over the full speed range, and are found to be compatible with previous work at low and high speed.