Space Harpoon Projectile Analysis for Space Debris Capture

Abstract

Space debris will become a more prevalent issue in this decade as technological advancements and greater dependencies on communications require more satellites in orbit, with some companies already hosting mega-constellations. Mitigating the debris using a space-tether is the most viable method to construct a space debris capture regime with current technology levels. Harpoon heads for the tethers are key design interests as these will penetrate through the satellites and/or debris. The focus of this paper is the analysis of an aluminium 6082, flat and conical head design, used to perforate aluminium 1050A plates using a gas gun laboratory. The aim is to conduct experiments to achieve a low Minimum Ballistic Velocity (MBV) where this velocity is the minimum velocity needed to perforate a material. Maximum perforation intertwined with minimal fragmentation is the desired balance sought from the designs. A high-speed camera records times taken for the events before and after perforation which deduces the MBV. 10 bar, 12.5 bar, and 15 bar of pressure were used, as well as 3mm, 1.5mm and 1mm Aluminium plate thickness, to provide diverse results for analysis. The MBV was calculated at 49.54m/s for 3mm thickness, with the conical head. The plates were cooled using dry ice to mimic space-like environments where tensile and yield strength increased with the cooler climates, resulting in higher MBVs. After impact, perforation profiles are analysed using a DSLR camera, resulting in ‘punches’ of material with the flat head and ‘petaling’ for the conical head. Conical perforation allows for material to be retained within the plate whilst flat head designs possess the potential for further space debris creation. The results retain reliability through validation checks with an oscilloscope and taking tolerances throughout the experiment. The results feed as a foundation to venture into future work with further ergonomic and bespoke designs.