An Ultrasonic Drill for Lunar Lava Tube Drilling

In this paper, a helical groove conical composite horn structure with multi-point drive rotation was proposed. A high-performance ultrasonic driller suitable for drilling in the inner wall of lava tubes was developed. An equivalent impedance network model was used to model and analyze the ultrasonic driller to predict the response characteristics of ultrasonic driller. The possibility of this drilling probe in applying complex ground conditions of lava tubes was verified through low gravity multi-angle simulated drilling tests and data analysis. The results show that the drilling rate increases with the increase of the hole’s opening angle for a drill rod diameter of 3 mm and a drilling pressure of 10 N. The maximum unloaded rotary speed of the driller is 506 rad/min, the drilling rate is 6.4 mm/min for vertical drilling, and the rotary speed while drilling is 259 rad/min.