A hypervelocity 38 mm bore two-stage light-gas gun impact facility and integrated diagnostic framework

• Commissioning of a 38 mm two-stage light-gas gun. • Achieves velocities beyond 6.5 km s-1 for up to 100 g projectiles. • Integrated diagnostics for hypervelocity impact and HED physics studies. • Techniques to quantify static and dynamic effects on projectile motion. This paper presents the design, commissioning, and operation of a 38 mm-bore, two-stage light-gas gun (2SLGG) facility at First Light Fusion Ltd (FLF), Oxford, UK. The system is capable of accelerating projectile packages up to 100 g to velocities exceeding 6.5 km s − 1 and was fully commissioned within ten months. Over 300 shots have been conducted to date, and the facility now serves as a flexible platform for interdisciplinary hypervelocity-impact research. A comprehensive suite of high-fidelity diagnostics including ultrafast optical imaging, photonic Doppler velocimetry (PDV), and both point and line VISAR systems enables precision velocimetry and detailed characterisation of projectile and impact dynamics; additional radiography and spectroscopy further extend the capability. Achieving minimal projectile tilt and high impact planarity is critical for experimental reproducibility in HED physics. The paper details methods used to characterise static and dynamic contributors to projectile motion, demonstrating repeatability of tilt below 1 ∘ at 6.5 k m s − 1 . The facility offers a versatile platform for high-precision impact experiments across aerospace, planetary science, materials and armour, and high-energy-density physics, supporting studies of equation of state, shock dynamics, ejecta formation, cratering, and structural response.