Salt grains in hypervelocity impacts in the laboratory: Methods to sample plumes from the ice worlds Enceladus and Europa

The plumes naturally erupting from the icy satellite Enceladus were sampled by Cassini spacecraft in high-speed fly-bys, which gave evidence of salt. This raises question how salt behaves under impact, and it can best be future missions to such plumes. We present results 35 impacts onto aluminum targets a variety salts (NaCl, NaHCO3, MgSO4, MgSO4·7H2O) at speeds 0.26 7.3 km s?1. Using SEM-EDX, identifiable projectile residue was found craters all speeds. It possible distinguish NaCl NaHCO3 each other, magnesium sulfates, but not separate hydrous anhydrous sulfates. Raman spectroscopy on sulfates residues failed find signal low impact (<0.5 s?1) where there insufficient material deposited sites. At intermediate (0.5 2–3 s?1), spectra craters, higher speeds, indicating loss structure during high speed impacts. Thus, intact capture solid metal surfaces requires between 0.75 2