Author(s)

Kojiro Suzuki¹, Kazuya Namba², Yasumasa Watanabe²

¹Department of Advanced Energy, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan.
²Department of Aeronautics and Astronautics, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.

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.

Penetrator, Ice, Impact, Crater Forming, Ballistic Range, High-Speed Camera

Suzuki, K. , Namba, K. and Watanabe, Y. (2016) Visualization of High-Speed Impact of Penetrator into Icy Target. Journal of Flow Control, Measurement & Visualization, 4, 56-69. doi: 10.4236/jfcmv.2016.42006.