Study of sample drilling techniques for Mars sample return missions

To demonstrate the feasibility of acquiring various surface samples for a Mars sample return mission the following tasks were performed: (1) design of a Mars rover-mounted drill system capable of acquiring crystalline rock cores; prediction of performance, mass, and power requirements for various size systems, and the generation of engineering drawings; (2) performance of simulated permafrost coring tests using a residual Apollo lunar surface drill, (3) design of a rock breaker system which can be used to produce small samples of rock chips from rocks which are too large to return to Earth, but too small to be cored with the Rover-mounted drill; (4)design of sample containers for the selected regolith cores, rock cores, and small particulate or rock samples; and (5) design of sample handling and transfer techniques which will be required through all phase of sample acquisition, processing, and stowage on-board the Earth return vehicle. A preliminary design of a light-weight Rover-mounted sampling scoop was also developed

Development of the RANCOR Rotary-Percussive Coring System for Mars Sample Return

A RANCOR drill was designed to fit a Mars Exploration Rover (MER) class vehicle. The low mass of 3 kg was achieved by using the same actuator for three functions: rotation, percussions, and core break-off. Initial testing of the drill exposed an unexpected behavior of an off-the-shelf sprag clutch used to couple and decouple rotary-percussive function from the core break off function. Failure of the sprag was due to the vibration induced during percussive drilling. The sprag clutch would back drive in conditions where it was expected to hold position. Although this did not affect the performance of the drill, it nevertheless reduced the quality of the cores produced. Ultimately, the sprag clutch was replaced with a custom ratchet system that allowed for some angular displacement without advancing in either direction. Replacing the sprag with the ratchet improved the collected core quality. Also, premature failure of a 300-series stainless steel percussion spring was observed. The 300-series percussion spring was ultimately replaced with a music wire spring based on performances of previously designed rotary-percussive drill systems

Experimental Study of Down-the-Hole Percussive Drilling

In the literature of percussive drilling, several laboratory and field experimental studies have reported the existence of optimum drilling states. The rate of penetration increases with axial thrust (weight-on-bit) up to an optimal value, beyond which it decreases with further increase of thrust. In this research project, novel laboratory and field experiments were carried out to investigate whether the occurrence of optimum drilling states stems from an intrinsic property of the bit-rock interface

Evaluation of drilling performance and penetration mechanisms using seismic while drilling and acoustic emission methods

In oil and gas industry, drilling provides the path to exploit underground resources. Increasing rate of penetration (ROP) is one of the goal of drilling engineers to build this path. This dissertation focuses on study of a novel drilling technique, i.e. passive Vibration Assisted Rotary Drilling (pVARD) technique, and characterization of drilling mechanisms in comparison to the other two widely used drilling techniques, i.e. rotary drilling and rotary-percussion drilling (RPD). In terms of the fundamental differences between drill bit vibrations from three drilling techniques, seismic while drilling (SWD) and acoustic emission (AE) technologies are used to study drill bit sources and corresponding drilling mechanisms. First, geomechanics response of synthetic rock is studied using AE technique based on standard confined compressive strength (CCS) tests. This research aims to compare synthetic to natural rock in terms of deformation properties and provides support for the following drill-off test (DOT). Second, pVARD tool drillings are conducted in comparison to rotary drilling both in laboratory and field tests using AE and SWD techniques, respectively. In laboratory, AE signal energy and cutting size distribution are correlated to polycrystalline diamond compact (PDC) bit drilling performance. Results show that micro crack is generated from drag bit shearing action and the higher AE energy, coarser cuttings and higher ROP are obtained. In field test, surface wave energy and frequency bandwidth are correlated to drill bit vibration and drilling performance. Third, laboratory active vibration DOTs are conducted to study the penetration mechanisms from a diamond coring bit using AE technique. Spectral and energy analysis of the AE signals indicate that the higher ROP and larger cutting size are correlated with a higher AE energy and a lower AE frequency, indicating larger fractures are being created to generate the larger size of cuttings. Fourth, rotary-percussion drilling sources are studied by two field experiments on weak shales and hard arkose using SWD technique. Characterization of these sources consist of spectral analysis and mean power study, along with field measurements of the source radiation patterns. In addition, polarization analysis is conducted on P-waves recorded at surface geophones for understanding the particle motions

Concept Development of a Water Hydraulic Actuation System

European Union’s need of mining inside its borders generates a demand for innovative mining machinery. The objective of the ROBOMINERS project’s mining robot is to meet that demand. This kind of innovative mining machinery require innovative systems and procedures to solve different environmental, legislative and engineering challenges. This thesis lays down the foundations of water hydraulic systems and water hydraulic actuators for the actuation system development of the mining robot prototype. Since mineral oil is more commonly used in hydraulics, the use of water as a hydraulic fluid is examined. After the examination of water hydraulic systems and its components, the aim was moved towards hydraulic artificial muscles (HAMs). The possibilities and challenges of this kind of actuators were studied, as they will be utilised in the mining robot. One type of commercial off-the-shelf (COTS) HAM was tested to ensure the findings of these studies and to start the development of the mining robot’s actuating mechanisms. The study indicates that water hydraulic systems are a viable drivetrain option for the mining robot. In addition, 3 European suppliers of water hydraulic components were found. COTS components from these suppliers will help in the building process of the actuation system. Furthermore, findings and testing of the HAMs gave some base information for the use of this kind of actuators. It was found, that the Festo’s Fluidic Muscles should be suitable for the mining robot prototype, as they reach over 14 kN maximum force and allow 14 bars of overpressure. This thesis can also be used as an introduction to water hydraulic systems and water hydraulic actuators for the ROBOMINERS project group

Uniaxial compressive strengths of rocks drilled at Gale crater, Mars

Measuring the physical properties of geological materials is important for understanding geologic history. Yet there has never been an instrument with the purpose of measuring mechanical properties of rocks sent to another planet. The Mars Science Laboratory (MSL) rover employs the Powder Acquisition Drill System (PADS), which provides direct mechanical interaction with Martian outcrops. While the objective of the drill system is not to make scientific measurements, the drill's performance is directly influenced by the mechanical properties of the rocks it drills into. We have developed a methodology that uses the drill to indicate the uniaxial compressive strengths of rocks through comparison with performance of an identically assembled drill system in terrestrial samples of comparable sedimentary class. During this investigation, we utilize engineering data collected on Mars to calculate the percussive energy needed to maintain a prescribed rate of penetration and correlate that to rock strength

Impact of Drilling Operations on Lunar Volatiles Capture: Thermal Vacuum Tests

In Situ Resource Utilization (ISRU) enables future planetary exploration by using local resources to supply mission consumables. This idea of 'living off the land' has the potential to reduce mission cost and risk. On the moon, water has been identified as a potential resource (for life support or propellant) at the lunar poles, where it exists as ice in the subsurface. However, the depth and content of this resource has yet to be confirmed on the ground; only remote detection data exists. The upcoming Resource Prospector mission (RP) will 'ground-truth' the water using a rover, drill, and the RESOLVE science package. As the 2020 planned mission date nears, component level hardware is being tested in relevant lunar conditions (thermal vacuum). In August 2014 a series of drilling tests were performed using the Honeybee Robotics Lunar Prospecting Drill inside a 'dirty' thermal vacuum chamber at the NASA Glenn Research Center. The drill used a unique auger design to capture and retain the lunar regolith simulant. The goal of these tests was to investigate volatiles (water) loss during drilling and sample transfer to a sample crucible in order to validate this regolith sampling method. Twelve soil samples were captured over the course of two tests at pressures of 10(exp-5) Torr and ambient temperatures between -80C to -20C. Each sample was obtained from a depth of 40 cm to 50 cm within a cryogenically frozen bed of NU-LHT-3M lunar regolith simulant doped with 5 wt% water. Upon acquisition, each sample was transferred and hermetically sealed inside a crucible. The samples were later baked out to determine water wt% and in turn volatile loss by following ASTM standard practices. Of the twelve tests, four sealed properly and lost an average of 30% of their available water during drilling and transfer. The variability in the results correlated well with ambient temperature (lower the temperature lower volatiles loss) and the trend agreed with the sublimation rates for the same temperature. Moisture retention also correlated with quantity of sample: a larger amount of material resulted in less water loss. The drilling process took an average of 10 minutes to capture and transfer each sample. The drilling power was approximately 20 Watt with a Weight on Bit of approximately 30 N. The bit temperature indicated little heat input into formation during the drilling process

J Occup Environ Hyg

Rotary-type percussion dowel drilling machines, which drill horizontal holes in concrete pavement, have been documented to produce respirable crystalline silica concentrations above recommended exposure criteria. This places operators at potential risk for developing health effects from exposure. United States manufacturers of these machines offer optional dust control systems. The effectiveness of the dust control systems to reduce respirable dust concentrations on two types of drilling machines was evaluated under controlled conditions with the machines operating inside large tent structures in an effort to eliminate secondary exposure sources not related to the dowel-drilling operation. Area air samples were collected at breathing zone height at three locations around each machine. Through equal numbers of sampling rounds with the control systems randomly selected to be on or off, the control systems were found to significantly reduce respirable dust concentrations from a geometric mean of 54\uc2\ua0mg per cubic meter to 3.0\uc2\ua0mg per cubic meter on one machine and 57\uc2\ua0mg per cubic meter to 5.3\uc2\ua0mg per cubic meter on the other machine. This research shows that the dust control systems can dramatically reduce respirable dust concentrations by over 90% under controlled conditions. However, these systems need to be evaluated under actual work conditions to determine their effectiveness in reducing worker exposures to crystalline silica below hazardous levels.CC999999/Intramural CDC HHS/United States2017-09-01T00:00:00Z27074062PMC498239

INTEGRATED DRILLING SYSTEM USING MUD ACTUATED DOWN HOLE HAMMER AS PRIMARY ENGINE

A history and project summary of the development of an integrated drilling system using a mud-actuated down-hole hammer as its primary engine are given. The summary includes laboratory test results, including atmospheric tests of component parts and simulated borehole tests of the hammer system. Several remaining technical hurdles are enumerated. A brief explanation of commercialization potential is included. The primary conclusion for this work is that a mud actuated hammer can yield substantial improvements to drilling rate in overbalanced, hard rock formations. A secondary conclusion is that the down-hole mud actuated hammer can serve to provide other useful down-hole functions including generation of high pressure mud jets, generation of seismic and sonic signals, and generation of diagnostic information based on hammer velocity profiles