Deep planetary drills offer a wealth of information to planetary geologists and astrobiologists. The Auto-Gopher drill is a wire-line rotary-hammer drill, whose depth of penetration is limited only by the length of the wire it is suspended from. 

Auto-Gopher Drill

The Auto-Gopher employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor to rotate the drill bit and capture powdered cuttings. It incorporates a wireline architecture; the drill is suspended at the end of a small diameter tether that provides power, communication, as well as structural support needed for lowering and lifting the drill out of the borehole.&nbsp;Thanks to this unique architecture, the maximum drilling depth is limited only by the length of the tether. The wireline operation used on the Auto-Gopher removes one of the major drawbacks of traditional continuous drill string systems—the need for multiple drill sections that can add significantly to the mass and the complexity of a deep drill. As such, the Auto-Gopher system mass and volume can be kept quite low for shallow or deep holes.&nbsp;While drilling, numerous sensors and embedded instruments can perform in situ analysis of the borehole wall. Upon reaching a preset depth, the drill is retracted from the borehole, the core and/or cuttings are removed for detailed analysis by onboard instruments, and the drill is lowered back into the hole to continue the penetration process. Auto-Gopher can be deployed from a variety of platforms, providing deep subsurface access with a small surface footprint. This technology also enables new in-situ analysis applications through integration of in-drill sensors — in essence, bringing the instruments to the deep subsurface sample

Describes the project, it's design, and fabrication & testing. 

Auto-Gopher - A wire-line rotary-hammer ultrasonic drill

Describes the ultrasonic/sonic driller/corer description and modeling, the gopher, tests & conclusions.

ASnic frequency	60 - 1000	Hz
Motor Power	~90	W
Rotation Speed	245-277	RPM
Motor Voltage	48	V
Motor Current	~1.9	A