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, perhaps, 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 Ultrasonic/sonic driller/corer demonstration unit weighs roughly .7 kilograms (1.5 pounds) and is able to drill 12-millimeter (half-inch) holes into hard rocks.