Kiel Davis

Drilling Systems for Extraterrestrial Subsurface Exploration

Drilling consists of 2 processes: breaking the formation with a bit and removing the drilled cuttings. In rotary drilling, rotational speed and weight on bit are used to control drilling, and the optimization of these parameters can markedly improve drilling performance. Although fluids are used for cuttings removal in terrestrial drilling, most planetary drilling systems conduct dry drilling with an auger. Chip removal via water-ice sublimation (when excavating water-ice-bound formations at pressure below the triple point of water) and pneumatic systems are also possible. Pneumatic systems use the gas or vaporization products of a high-density liquid brought from Earth, gas provided by an in situ compressor, or combustion products of a monopropellant. Drill bits can be divided into coring bits, which excavate an annular shaped hole, and full-faced bits. While cylindrical cores are generally superior as scientific samples, and coring drills have better performance characteristics, full-faced bits are simpler systems because the handling of a core requires a very complex robotic mechanism. The greatest constraints to extraterrestrial drilling are (1) the extreme environmental conditions, such as temperature, dust, and pressure; (2) the light-time communications delay, which necessitates highly autonomous systems; and (3) the mission and science constraints, such as mass and power budgets and the types of drilled samples needed for scientific analysis. A classification scheme based on drilling depth is proposed. Each of the 4 depth categories (surface drills, 1-meter class drills, 10-meter class drills, and deep drills) has distinct technological profiles and scientific ramifications.

The 2005 MARTE Robotic Drilling Experiment in Río Tinto, Spain: Objectives, Approach, and Results of a Simulated Mission to Search for Life in the Martian Subsurface

The Mars Astrobiology Research and Technology Experiment (MARTE) simulated a robotic drilling mission to search for subsurface life on Mars. The drill site was on Peña de Hierro near the headwaters of the Río Tinto river (southwest Spain), on a deposit that includes massive sulfides and their gossanized remains that resemble some iron and sulfur minerals found on Mars. The mission used a fluidless, 10-axis, autonomous coring drill mounted on a simulated lander. Cores were faced; then instruments collected color wide-angle context images, color microscopic images, visible-near infrared point spectra, and (lower resolution) visible-near infrared hyperspectral images. Cores were then stored for further processing or ejected. A borehole inspection system collected panoramic imaging and Raman spectra of borehole walls. Life detection was performed on full cores with an adenosine triphosphate luciferin-luciferase bioluminescence assay and on crushed core sections with SOLID2, an antibody array-based instrument. Two remotely located science teams analyzed the remote sensing data and chose subsample locations. In 30 days of operation, the drill penetrated to 6 m and collected 21 cores. Biosignatures were detected in 12 of 15 samples analyzed by SOLID2. Science teams correctly interpreted the nature of the deposits drilled as compared to the ground truth. This experiment shows that drilling to search for subsurface life on Mars is technically feasible and scientifically rewarding.

Robotic Drill Systems for Planetary Exploration

The objective of the systems described in this report was to demonstrate that lowpowered drill systems could be fully autonomous in capturing subsurface samples, handing off samples to science instruments, and drilling. Two drills were designed with a logically selected suite of sensors and hardware which allowed for data to be collected both above and below the surface. Information received from these sensors was fed back to an intelligent drill control system to enable autonomy. Testing of these two drills at Mars analog sites demonstrated that fully autonomous drilling is possible with low-powered drill systems.

MARTE: Technology development and lessons learned from a Mars drilling mission simulation

29 pages, 21 figures, 2 tables.-- ISI Article Identifier: 000250768000006.-- Special issue: Mining Robotics.

Percussive digging systems for robotic exploration and excavation of planetary and lunar regolith

A percussive digging system has been demonstrated to decrease the amount of downforce needed to penetrate a given soil, thus reducing the required reaction loads and robot mass. Preliminary testing of a percussive digging system in compacted lunar regolith simulant, JSC-1A, has demonstrated a 15x (fifteen times) reduction in the downforce necessary to penetrate the regolith. Downforce reductions of this magnitude are sufficient to enable robotic exploration system architectures that would not otherwise be feasible.

Design and practices for use of automated drilling and sample handling in MARTE while minimizing terrestrial and cross contamination.

Mars Astrobiology Research and Technology Experiment (MARTE) investigators used an automated drill and sample processing hardware to detect and categorize life-forms found in subsurface rock at Río Tinto, Spain. For the science to be successful, it was necessary for the biomass from other sources--whether from previously processed samples (cross contamination) or the terrestrial environment (forward contamination)-to be insignificant. The hardware and practices used in MARTE were designed around this problem. Here, we describe some of the design issues that were faced and classify them into problems that are unique to terrestrial tests versus problems that would also exist for a system that was flown to Mars. Assessment of the biomass at various stages in the sample handling process revealed mixed results; the instrument design seemed to minimize cross contamination, but contamination from the surrounding environment sometimes made its way onto the surface of samples. Techniques used during the MARTE Río Tinto project, such as facing the sample, appear to remove this environmental contamination without introducing significant cross contamination from previous samples.

Drilling Results in Ice‐Bound Simulated Lunar Regolith

Reaching the cold traps at the lunar poles and directly sensing the subsurface regolith is a primary goal of lunar exploration, especially as a means of prospecting for future In Situ Resource Utilization (ISRU) efforts. The Construction and Resource Utilization Explorer project (CRUX) addressed technology development associated with a modular, drilling‐based payload to achieve this goal. As part of the development of a lunar drill capable of reaching a depth of two meters, a preliminary drilling study was performed using custom designed drill bits and augers in simulated ice‐bound lunar regolith. Lunar regolith is known to be very abrasive, but the mechanical properties and “drillability” of the purported ice‐bound material in the lunar cold traps is unknown. Preliminary drilling experiments were performed in the frozen samples, to determine the effectiveness of the drilling hardware and to point the way towards optimized drilling strategies. Additionally, a preliminary experiment was performed to demons...

Miniature Control Moment Gyroscope development

Honeybee Robotics Spacecraft Mechanisms Corporation has developed a Control Moment Gyroscope product suitable for small spacecraft. Each individual CMG exhibits a nominal angular momentum of 56 mNm-s with a peak of 86 mNm-s, and corresponding output torques of 112 mNm and 172 mNm respectively. Each unit measures 48 × 48 × 91 mm and weighs 600 grams. The control electronics are capable of driving 4 CMGs and executing a steering law to synthesize individual actuator commands from a torque triple or torque quaternion command. The industry will see an increasing role in the near future for small satellites in the 20-100 kg size range. We frame the CMG array capability by presenting a baseline application - using the Coral Reef Ecosystem Spectro-Photometric Observatory (CRESPO) mission concept (100 kg satellite) combined with requirements for the Hyperspectral Imager for the Coastal Ocean (HICO) on the International Space Station. We show how a small CMG array is capable of the representative slew maneuvers by exceeding the necessary slew rates of 0.75 deg/s for a “Soak and Shoot” flight plan, with maximum slew rates in excess of 1.5 deg/s. This paper will discuss the demonstrated performance of the system, including environmental test results, and the baseline application.

The Phoenix Mars Lander Robotic Arm

The Phoenix Mars Lander Robotic Arm (RA) has operated for 149 sols since the Lander touched down on the north polar region of Mars on May 25, 2008. During its mission it has dug numerous trenches in the Martian regolith, acquired samples of Martian dry and icy soil, and delivered them to the Thermal Evolved Gas Analyzer (TEGA) and the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA). The RA inserted the Thermal and Electrical Conductivity Probe (TECP) into the Martian regolith and positioned it at various heights above the surface for relative humidity measurements. The RA was used to point the Robotic Arm Camera to take images of the surface, trenches, samples within the scoop, and other objects of scientific interest within its workspace. Data from the RA sensors during trenching, scraping, and trench cave-in experiments have been used to infer mechanical properties of the Martian soil. This paper describes the design and operations of the RA as a critical component of the Phoenix Mars Lander necessary to achieve the scientific goals of the mission.

Mars2020 sample acquisition and caching technologies and architectures

The goal of the Mars2020 mission is to acquire up to 28 rock/regolith samples and 3 blanks (or 34 rock/regolith samples and 3 blanks), and cache these for the future sample return mission. Honeybee Robotics investigated three architectures; however only two showed promise. In the One Bit One Core (OBOC) architecture, individual drill bits with core samples are cached. This is the least complex architecture and results in the total mass (cache+bits+rocks) of less than 2 kg and Orbital Sample diameter of 19 cm for the 31 cores case and slightly more (<;2.4 kg cache and 20 cm OS) for the 37 cores. In the One Breakoff System One Core (OBSOC) architecture, the breakoff tube and the sleeve with cores are removed from the drill bit and cached. The architecture also uses one time use bit assemblies (plus spares). This architecture results in the lowest cache mass and OS diameter but the trade is complexity and sampling system mass. The OBSOC cache mass is ~1.5 kg and ~1.86 kg for the 31/37 cases respectively, while the OS diameter is 17 cm and 17.5 cm for the 31/37 cases respectively. All architectures use SLOT bit that allows inspection of rock samples along their lengths prior to caching. The paper also introduces several key technologies developed by Honeybee Robotics over the past 15 years, including the SLOT caching bit, the Powder and Regolith Acquisition Bit, Rock Abrasion and Brushing Bit (RABBit), PreView Bit, Percussive and Core Breakoff technologies.