In‐situ mass spectrometric observation of impact vaporization of water‐ice at low temperatures

Abstract

Abstract.Impact experiments on water ice targets were carried out to investigate the partitioning of energy and the mass of water vaporized. A copper projectile accelerated by an electromagnetic gun impacted a low-temperature ice target under a high vacuum condition. The mass of vaporized water gas was measured as a function of impact velocity (54-329 m/s) and ice temperature (130-185 K). Some 0.01-0.03 % of the impact energy is partitioned into ice vaporization at velocities _< 100 m/s. For impacts in the 100-180 m/s range, the energy partitioned into water vaporization drastically increases to 18-26 % of the impact energy. The estimated shock pressure is 277 MPa for a copper-ice impact at 100 m/s. This is close to the pressure at the Hugoniot elastic limit for ice. It is considered that the drastic change in energy partition at 100 m/s is due to the large increases in surface area and localized heating via shear banding occurring at the Hugoniot elastic limit.

Direct measurements of impact devolatilization of calcite using a laser gun

“…Here we report a new experimental method to observe impact‐induced devolatilization of rock directly by gas analysis using a laser gun and a quadrupole mass spectrometer (QMS). Observation using a QMS is suitable for impact‐induced devolatilization experiments, similar to the study by Sugi et al [1998] of impact‐vaporization of ice. We used a laser gun for this study to avoid contamination by soot and gun debris.…”

Measurement of Impact Ejecta from Regolith Targets in Oblique Impacts

“…Figure 1 shows the experimental configuration. Staple-shaped projectiles of 0.24 g mass were accelerated by using the electromagnetic gun (see Sugi et al 1998). The projectile was made of copper wire, with a diameter of 1.2 mm because of its high electrical conductivity and high shock impedance.…”

Study on Dynamics of Penetrator into Ice

“…For design and development of the flight model, experiments in the lowtemperature vacuum chamber 11) are necessary to simulate the actual environment of an icy object for exploration, because the strength of ice depends on the temperature. 12) Figure 2 shows the shape of the experimental model.…”