The ultrasonic/sonic driller/corer (USDC) as a subsurface drill, sampler, and lab-on-a-drill for planetary exploration applications

摘要

The search for existing or past life in the Universe is one of the most important objectives of NASA's mission. For this purpose, effective instruments that can sample and conduct in-situ astrobiology analysis are being sought. In support of this objective, a novel Ultrasonic/Sonic Driller/Corer (USDC) based mechanism has been developed to probe and sample rocks, ice and soil. The USDC consists of an ultrasonic actuator that impacts a coring or drilling bit at sonic frequencies through the use of an intermediate free-mass. The USDC can produce both a core and powdered cuttings as well as emit elastic waves into the penetrated medium. For planetary exploration, this mechanism has the important advantage of requiring low axial force, virtually no torque, and can be duty cycled to require low average power. This low axial load advantage overcomes a major limitation of planetary sampling in low gravity environments and when operating from lightweight robots and rovers. The low average power operation produces a minimum temperature rise which is important for the acquisition of biologically meaningful samples. The development of the USDC is being pursued on various fronts ranging from analytical modeling to improvements of the mechanism while seeking a wide range of applications. In this paper, the latest status of the USDC development and applications that are underway is reviewed and discussed.