TITLE:
Visualization of High-Speed Impact of Penetrator into Icy Target
AUTHORS:
Kojiro Suzuki, Kazuya Namba, Yasumasa Watanabe
KEYWORDS:
Penetrator, Ice, Impact, Crater Forming, Ballistic Range, High-Speed Camera
JOURNAL NAME:
Journal of Flow Control, Measurement & Visualization,
Vol.4 No.2,
April
29,
2016
ABSTRACT: For application to exploration under the surface of icy objects in the solar system, the penetration
of an impact probe into an icy target was experimentally simulated by using the ballistic range.
Slender projectiles with a cylindrical body and various nose shapes were tested at the impact velocity
130 - 420 m/s. The motion of the penetrator, fragmentation of ice and crater forming were
observed by the high-speed camera. It revealed that the crown-shaped ejection was made for a
short time after the impact and then the outward normal jet-like stream of ice pieces continued
for much longer time. The concave shape of the crater was successfully visualized by pouring the
plaster into it. The two-stage structure, the pit and the spall, was clearly confirmed. The rim was
not formed around the crater. Observation of the crater surface and the ice around the trace of the
penetrator shows that both crushing into smaller ice pieces and recompression into ice blocks are
caused by the forward motion of the penetrator. In case of a body with a flow-through duct, ice
pieces entering the inlet at the nose tip were ejected from the tail, resulting in relaxation of the
impact force. The correlation of the penetration distance and the crater diameter with the impact
velocity was investigated.