Detection of the amino acid histidine and its breakup products in hypervelocity impact ice spectra

Velocity Dependence of Submicron Ice Grain Rebound, Sticking, Particle Fragmentation, and Impact Ionization up to 2.4 km/s

“…Namely, there is interest in measuring the survivability of entrained organic solutes as a function of impact speed. While modeling and other analogue experiments measuring entrained molecule bond fragmentation already supports a flythrough velocity of 4 km/s, − the AIS equipped with an impact ionization mass spectrometer would provide complimentary data with more comparable conditions to the space flight scenario. It would be very valuable to have a well-supported answer for the ideal flythrough velocity for a future mission to Enceladus.…”

“…However, there are a number of stipulations for how the measurement conditions still differ from the Enceladus flythrough sampling scenario. First, an upper impact velocity of 2400 m/s measured in this work still falls short of the expected minimum flythrough velocity of a future mission of 4 km/s , A velocity of 4 km/s is thought to provide a good balance between efficient impact ionization and minimal bond breakage of entrained molecules to be identified in the Enceladus plume grains. − Another stipulation is in the difference in target materials. The Cassini CDA and other dust analyzer instruments have used target materials, such as rhodium, gold, and iridium, for their resistance to oxidation.…”

“…Important parameters for normal impact dynamics studies include particle composition, particle size, incident velocity, and target material. , To mimic the Enceladus flythrough sampling scenario, these criteria are a particle composition of ice, a near-micron particle size, impact velocities greater than 4 km/s, − and a metallic target material. While there have been many studies of scattering dynamics for applications such as atmospheric aerosol measurement, aircraft in-flight icing, , meteoroid impacts, and astrogeology of icy surfaces, , there are only two studies that meet the current criteria of particle composition, size, and target material.…”

“…30 This principle has since been used in a variety of detectors including the HEOS-2 micrometeoroid detector, 32 the ULYSSES dust measurements, 33 the Galileo dust detector, 34 and the CDA of the Cassini mission. 6 While there have been studies of metallic dust impacting ice surfaces, 15,19,20,35 there have been no laboratory studies on impact ionization of icy particles impacting a metal surface until the work presented here. The present study provides the first reported experimental measurement of the velocity threshold at which impact ionization becomes an important impact behavior for ice grains.…”

Unraveling the Fate of Impacted Ice Particles and the Consequences for Plume Fly‐Through Missions

“…However, these methods are not easily transferred to water ice due to inherent experimental challenges (i.e., formation, handling, and acceleration of particles that are highly temperature sensitive). Some efforts have accelerated metal dust (Burchell et al., 1996; Nelson et al., 2016; Timmermann & Grün, 1991; Ulibarri et al., 2023) into ice. These experiments can provide valuable insights into the impact outcome as it relates to impact‐induced ionization mass spectrometry because shock waves propagate through both the target and the particle upon impact causing ionization of both the particle and the target (Drapatz & Michel, 1974), yielding detectable chemical signatures relevant to both.…”