At present, the search for existing or past life in the universe is one of the most important objectives of international society. For this purpose, effective instruments USDC that are driven by an ultrasonic/sonic actuator are being developed to probe and sample rocks, ice and soil, and conduct in-situ astrobiology analysis. At the ultrasonic or sonic frequency, free mass driven by ultrasonic piezoelectric driver impacts to the bit to samples. The principle of ultrasonic actuator is analyzed in this paper, including the interactions of free mass and actuator, the solid horn tip and free mass, free mass and drill stem.