Imagine a drill that penetrates granite using only the power of a flashlight battery. Then imagine sending that energy-efficient drill to another planet to explore beneath the surface. Or, visualize putting the lightweight, sensitive instrument to work on Earth to improve medical care. Such a drill, recently developed at JPL and Cybersonics, Inc., has that power and potential.
The demonstration unit for the device, known as the Ultrasonic/sonic driller/corer, weighs roughly 700 grams (1.5 pounds) and is able to drill 12-millimeter (half-inch) holes into hard rocks. Attached to the robotic arm of a future lander or on board a small rover, the drill could extract samples from the surface of an asteroid or planet during space missions. On Earth, potential medical uses include extracting pacemaker leads, assisting surgeries or facilitating diagnostic procedures that involve drilling into bone.
The drill relies on a novel mechanism, pizeoelectric wafers, to produce high-frequency vibrations and convert them to a hammering action at low frequency. Pizeoelectric wafers are ceramic layers that change in thickness when electrically excited. They are powered by a battery. The drill consists of only three moving parts, and it does not require gears, motors or lubricants. The drill requires very little pressure. It operates efficiently, drilling both soft and very hard rock, and it does not need sharpening. It extracts the produced debris by transporting it up the drilling shaft. The instrument is ideal for the exploration of other planets since it can operate in a wide range of temperatures and in a vacuum.
A more advanced drill model, called the ultrasonic gopher, is currently being developed to reach depths of several meters, or yards. This deep drill will be equipped with sensors that will make it even more effective for detecting samples. These sensors will also analyze samples at the remote location. Such a device could also be used on Earth to detect buried objects and for geophysical studies.
Dr. Yoseph Bar-Cohen of JPL led the development team, which includes Drs. Xiaoqi Bao, Zensheu Chang, Benjamin Dolgin and Stewart Sherrit, also of JPL, and the staff of Cybersonics, Inc. in Erie, Penn. For more information, see http://ndeaa.jpl.nasa.gov/nasa-nde/usdc/usdc.htm.