The term “rotary percussive autogopher” denotes a proposed addition to a family of apparatuses, based on ultrasonic/sonic drill corers (USDCs), that have been described in numerous previous NASA Tech Briefs articles. These apparatuses have been designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. In the case of the rotary percussive auto-gopher, the emphasis would be on developing an NTB 05Mech/Mach 0809:Layout 1 7/20/09 9:54 AM Page 38 apparatus capable of penetrating to, and acquiring samples at, depths that could otherwise be reached only by use of much longer, heavier, conventional drilling-and-sampling apparatuses.

Anchoring and Rotary Mechanisms and a fluted drill bit would be added to an ultrasonic/sonic gopher.
To recapitulate from the prior articles about USDCs: A USDC can be characterized as a lightweight, low-power jackhammer in which a piezoelectrically driven actuator generates ultrasonic vibrations and is coupled to a tool bit through a free mass. The bouncing of the free mass between the actuator horn and the drill bit converts the actuator ultrasonic vibrations into sonic hammering of the drill bit. The combination of ultrasonic and sonic vibrations gives rise to a hammering action (and a resulting chiseling action at the tip of the tool bit) that is more effective for drilling than is the microhammering action of ultrasonic vibrations alone. The hammering and chiseling actions are so effective that the size of the axial force needed to make the tool bit advance into soil, rock, or another material of interest is much smaller than in ordinary rotary drilling, ordinary hammering, or ordinary steady pushing.

The predecessor of the rotary percussive auto-gopher is an apparatus, now denoted an ultrasonic/sonic gopher and previously denoted an ultrasonic gopher, described in “Ultrasonic/Sonic Mechanism for Drilling and Coring” (NPO-30291), NASA Tech Briefs Vol. 27, No. 9 (September 2003), page 65. The ultrasonic/sonic gopher is intended for use mainly in acquiring cores. The name of the apparatus reflects the fact that, like a gopher, it periodically stops advancing at the end of the hole to bring excavated material (in this case, a core sample) to the surface, then re-enters the hole to resume the advance of the end of the hole. By use of a cable suspended from a reel on the surface, the gopher is lifted from the hole to remove a core sample, then lowered into the hole to resume the advance and acquire the next core sample.

The rotary percussive auto-gopher would include an ultrasonic/sonic gopher, to which would be added an anchoring and a rotary mechanism and a fluted drill bit (see figure). If, as intended, the ultrasonic/sonic gopher were rotated, then as in the case of an ordinary twist drill bit, the flutes would remove cuttings from the end of the hole, thereby making it possible to drill much faster than would be possible by ultrasonic/sonic hammering and chiseling action alone. The anchoring mechanism would brace itself against the wall of the drilled hole to enable the rotary mechanism to apply a small torque and a small axial preload to rotate the ultrasonic/ sonic gopher drill bit and push the drill bit against the end of the hole. The anchoring and rotary mechanisms would be parts of an assembly that would follow the ultrasonic/sonic gopher down the hole.

This work was done by Yoseph Bar-Cohen, Mircea Badescu, and Stewart Sherrit of Caltech for NASA’s Jet Propulsion Laboratory. NPO-45949

Topics:
Assembling Cables Cutting Drilling Machining processes Manufacturing processes Mechanical Components Mechanics Parts Sensors and actuators Soils Tools and equipment
This Brief includes a Technical Support Package (TSP).
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Rotary Percussive Auto-Gopher for Deep Drilling and Sampling

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NASA Tech Briefs Magazine

This article first appeared in the August, 2009 issue of NASA Tech Briefs Magazine (Vol. 33 No. 8).

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Overview

The document outlines the development of the Rotary Percussive Auto-Gopher, a novel deep drilling and sampling technology designed for NASA's exploration missions. This invention addresses critical challenges associated with subsurface sampling on planetary bodies, particularly in environments like Mars, Europa, and Titan. The Auto-Gopher is engineered to penetrate various planetary media, including rocks, ice, permafrost, and regolith, enabling the collection of volatiles, powdered cuttings, and cores from depths greater than 2 meters.

One of the primary problems the Auto-Gopher aims to solve is the need for a deep drill that can provide its own anchoring and preload without requiring additional mechanisms for cuttings removal. Traditional deep drills are often heavy and necessitate high axial preload, which complicates their operation. The Auto-Gopher overcomes these limitations by utilizing a cyclic operation mechanism that reels the drill down on an active tether, allowing it to create a borehole and retrieve samples efficiently.

The document details the technical features of the Auto-Gopher, including its active anchoring mechanism, which secures the drill in place while it operates. This mechanism enhances the drill's stability and allows it to follow its path down the borehole. Additionally, the design incorporates flutes on the cutting bit to facilitate faster drilling and effective removal of cuttings, significantly improving the drilling rate compared to previous models.

The Auto-Gopher's design is particularly relevant for future missions, such as the Mars Sample Return, where concerns about cosmic ray damage to molecular structures at greater depths necessitate advanced sampling techniques. The document emphasizes the potential applications of the Auto-Gopher beyond Mars, highlighting its versatility for use on other celestial bodies.

Overall, the Rotary Percussive Auto-Gopher represents a significant advancement in deep drilling technology, promising to enhance NASA's capabilities in planetary exploration and sample collection. The document serves as a technical support package, providing insights into the invention's purpose, solution, and operational mechanisms, while also inviting further collaboration and inquiries through NASA's Innovative Partnerships Program.