Ultrasonic/sonic gopher for subsurface ice and brine sampling: analysis and fabrication challenges and testing results

Rock, soil, and ice penetration by coring, drilling or abrading is of great importance to a large number of space and earth applications. Proven techniques to sample Mars subsurface will be critical for future NASA astrobiology missions that will search for records of past and present life on the planet. An Ultrasonic/Sonic Drill/Corer (USDC) has been developed as an adaptable tool for many of these applications [Bar-Cohen et al., 2001]. The USDC uses a novel drive mechanism to transform the ultrasonic or sonic vibrations of the tip of a horn into a sonic hammering of a drill bit through an intermediate free-flying mass. The USDC design was modified to fabricate an Ultrasonic/Sonic Ice Gopher that is designed to core down to meters depth for in situ analysis and sample collection. This technology was demonstrated at Lake Vida in the Dry Valleys, Antarctica. Coring ice at -20°C as in Lake Vida has been a challenge and efforts were made to develop the required ice core cutting, ice chip handling and potential ice melting (and refreezing) during drilling. The analysis and fabrication challenges and testing results are presented in this paper.