Replicating hypervelocity Solar System impacts in the laboratory

Hypervelocity impacts (>3 km s-1) deliver a substantial amount of energy and foreign material to the impacted body and involve several interacting processes (e.g. mixed phase flow, fragmentation, melting, ionisation and vaporisation). Many of these impact events are so energetic that the resulting self-luminous plume or ‘impact flash’ (e.g. on the Lunar surface) can be observed using modest facilities. Laboratory studies of impact flashes are increasingly being used to provide meaningful interpretation of data from these observed events via an improved understanding of the associated phenomena. Light-gas guns are typically used to replicate these hypervelocity impacts, utilising high speed photography, photometry, and spectroscopy to examine the inherent physical and chemical processes. These experiments also aim to interpret the relative importance of the many impact parameters, such as target and projectile material properties, impact speed, and impact angle, which play an important role in the spatial and temporal evolution of the impact flash. The capture and subsequent analyses of ejected material from these laboratory impacts by analytical chemistry techniques (e.g. GC-MS) also provide a better understanding of the dynamic chemistry and ‘shock synthesis’ caused by the extreme environmental conditions within the impact site and expanding plume. This presentation will describe how investigating these impact phenomena in the laboratory allow a better understanding of high speed collisions involving planetary bodies, asteroids, orbital debris and spacecraft, and showcase some recent developments in chemical analyses of impact ejecta.