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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Hydromechanical Advanced Coal Excavator

Water-jet cutting reduces coal dust and its hazards. Advanced mining system utilizes full-face, hydromechanical, continuous miner. Coal excavator uses high-pressure water-jet lances, one in each of cutting heads and one in movable lance, to make cuts across top, bottom and middle height, respectively, of coal face. Wedge-shaped cutting heads advance into lower and upper cuts in turn, thereby breaking coal toward middle cut. Thrust cylinders and walking pads advance excavator toward coal face.

Estus, Jay M.↗
NASA NTRS2005

Particle Size Distributions Measured in B757 Engine Plume During EXCAVATE

A ground-based test, the Experiment to Characterize Aircraft Volatile Aerosols and Trace Species Emissions (EXCAVATE), was conducted at NASA Langley Research Center, January 26 - 27, 2002, with a Boeing 757 aircraft. The aircraft was anchored on a tarmac and two probes were positioned downstream of the right-side engine, a Rolls Royce RB211-585. One probe was designed and fabricated by Arnold Engineering Development Center (AEDC) and had a 45.6 mm (1.794 in.) ID. A second probe, constructed of 6.4 mm (0.25 in.) stainless-steel tubing at NASA Langley Research Center, had a 6 mm (0.22 in.) ID. The engine was run on JP-5 with three different sulfur concentrations, 810 ppm, 1050 ppm, 1820 ppm; and was operated over a range of power settings from idle to near-full power. Particulate size-distributions and concentrations were measured at four downstream axial locations: 1 m and 10 m with the AEDC particulate probe, and 25 m and 35 m with the Langley probe. Fuel with various sulfur contents was tested to address the long-standing question of the role of sulfur in the formation of volatile species. Several experimental and modeling studies have shown a correlation between fuel sulfur-content and particulate-emissions. The object of EXCAVATE was to further study the effect of sulfur content on particulate number concentration and size-distribution as a function of location in the engine plume and engine operating conditions.

Sanders, Terry↗
NASA NTRS2007

Calculation of Excavation Force for ISRU on Lunar Surface

Accurately predicting the excavation force that will be encountered by digging tools on the lunar surface is a crucial element of in-situ resource utilization (ISRU). Based on principles of soil mechanics, this paper develops an analytical model that is relatively simple to apply and uses soil parameters that can be determined by traditional soil strength tests. The influence of important parameters on the excavation force is investigated. The results are compared with that predicted by other available theories. Results of preliminary soil tests on lunar stimulant are also reported.

Zeng, Xiangwu (David)↗
NASA NTRS2008

Excavation on the Moon: Regolith Collection for Oxygen Production and Outpost Site Preparation

The development of a robust regolith moving system for lunar and planetary processing and construction is critical to the NASA mission to the Moon and Mars. Oxygen production may require up to 200 metric tons of regolith collection per year; outpost site development may require several times this amount. This paper describes progress in the small vehicle implement development and small excavation system development. Cratos was developed as a platform for the ISRU project to evaluate the performance characteristics of a low center of gravity, small (0.75m x 0.75m x 0.3m), low-power, tracked vehicle performing excavation, load, haul, and dump operations required for lunar ISRU. It was tested on loose sand in a facility capable of producing level and inclined surfaces, and demonstrated the capability to pick up, carry, and dump sand, allowing it to accomplish the delivery of material to a site. Cratos has demonstrated the capability to pick up and deliver simulant to a bury an inflatable habitat, to supply an oxygen production plant, and to build a ramp.

Caruso, John J.↗
NASA NTRS2010

Target and Projectile: Material Effects on Crater Excavation and Growth

Scaling relationships allow the initial conditions of an impact to be related to the excavation flow and final crater size and have proven useful in understanding the various processes that lead to the formation of a planetary-scale crater. In addition, they can be examined and tested through laboratory experiments in which the initial conditions of the impact are known and ejecta kinematics and final crater morphometry are measured directly. Current scaling relationships are based on a point-source assumption and treat the target material as a continuous medium; however, in planetary-scale impacts, this may not always be the case. Fragments buried in a megaregolith, for instance, could easily approach or exceed the dimensions of the impactor; rubble-pile asteroids could present similar, if not greater, structural complexity. Experiments allow exploration into the effects of target material properties and projectile deformation style on crater excavation and dimensions. This contribution examines two of these properties: (1) the deformation style of the projectile, ductile (aluminum) or brittle (soda-lime glass) and (2) the grain size of the target material, 0.5-1 mm vs. 1-3 mm sand.

Anderson, J. L. B.↗
NASA NTRS2008

Percussive Excavation of Lunar Soil

It has been suggested using a percussive motion could improve the efficiency of excavation by up to 90%. If this is proven to be true it would be very beneficial to excavation projects on the Moon and Mars. The purpose of this study is to design, build and test a percussive tool which could dig a trench and then compare this data against that of a non-percussive tool of the same shape and size. The results of this test thus far have been inconclusive due to malfunctions in the testbed and percussive bucket; however, experimental results from small scale experiments confirm this higher efficiency and support further testing.

Whittaker, Matthew P.↗
NASA NTRS2012

The Montana ALE (Autonomous Lunar Excavator) Systems Engineering Report

On May 2 1-26, 20 12, the third annual NASA Lunabotics Mining Competition will be held at the Kennedy Space Center in Florida. This event brings together student teams from universities around the world to compete in an engineering challenge. Each team must design, build and operate a robotic excavator that can collect artificial lunar soil and deposit it at a target location. Montana State University, Bozeman, is one of the institutions selected to field a team this year. This paper will summarize the goals of MSU's lunar excavator project, known as the Autonomous Lunar Explorer (ALE), along with the engineering process that the MSU team is using to fulfill these goals, according to NASA's systems engineering guidelines.

Lars Osborne↗
NASA NTRS2013

Regolith Advanced Surface Systems Operations Robot Excavator

The Regolith Advanced Surface Systems Operations Robot (RASSOR) excavator robot is a teleoperated mobility platform with a space regolith excavation capability. This more compact, lightweight design (<50 kg) has counterrotating bucket drums, which results in a net-zero reaction horizontal force due to the self-cancellation of the symmetrical, equal but opposing, digging forces.

Mueller, Robert P.↗
NASA NTRS2015

Regolith Advanced Surface Systems Operations Robot (RASSOR) Phase 2 and Smart Autonomous Sand-Swimming Excavator

The Regolith Advanced Surface Systems Operations Robot (RASSOR) Phase 2 is an excavation robot for mining regolith on a planet like Mars. The robot is programmed using the Robotic Operating System (ROS) and it also uses a physical simulation program called Gazebo. This internship focused on various functions of the program in order to make it a more professional and efficient robot. During the internship another project called the Smart Autonomous Sand-Swimming Excavator was worked on. This is a robot that is designed to dig through sand and extract sample material. The intern worked on programming the Sand-Swimming robot, and designing the electrical system to power and control the robot.

Regolith↗
NASA NTRS2015

Asteroid Icy Regolith Excavation and Volatile Capture Project

Icy regolith simulants will be produced in a relevant vacuum environment using various minerals, including hydrated minerals, that are found in C-type meteorites and in other types of planetary regolith. This will allow us to characterize the mechanical strength of the icy regolith as a function of ice content using penetration, excavation, and sample capture devices. The results of this study will benefit engineers in designing efficient regolith excavators and ISRU processing systems for future exploration missions to asteroids and other planetary bodies.

Technology Portfolio System↗
NASA NTRS2023

CESO 22-3: Simulated Excavation Environment for Lunar Operations Follow-on

As more lunar In-Situ Resource Utilization (ISRU) missions are planned and developed, a need was identified for a simulation environment with accurate regolith interaction mechanics that is less computationally expensive than commercially available multiphysics tools. The purpose of the Simulated Excavation Environment for Lunar Operations (SEELO) project was to develop an interactive simulation environment that efficiently models lunar ISRU excavation operations, including soil deformation, while running in faster-than-real-time.

Michael DuPuis↗
DOE OSTI2024

Modeling nuclear waste disposal in crystalline rocks at the Forsmark and Olkiluoto repository sites – Evaluation of potential thermal–mechanical damage to repository excavations

We conduct coupled thermo-hydro-mechanical modeling of a KBS-3V repository design in crystalline rocks, using data and conditions from the Forsmark in Olkiluoto repository sites in Sweden and Finland. The study focuses on repository performance related to the impact of thermal and hydraulic evolution on the potential for thermal–mechanical damage to underground repository excavations. For the designs and conditions considered at the Forsmark and Olkiluoto repository sites, the simulations show a peak temperature well under the adopted performance target of a 100°C maximum temperature, whereas there is still a high potential for thermal–mechanical damage to the KBS-3V waste deposition holes. The thermal–mechanical damage is much more likely if rock permeability is so low that it delays saturation and swelling of bentonite-clay-based backfill beyond the time for the thermal–mechanical peak, which occurs 50 to 100 years after nuclear waste deposition. We also found that sidewalls of the KBS-3V emplacement tunnels are vulnerable to tensile fracturing due to the combined effect of thermal stressing and backfill swelling. The study highlights a strong interaction between bentonite-based backfill and host rock through capillary suction along with induced rock desaturation. A careful design and selection of the bentonite-clay-based backfill materials for KBS-3V tunnels and deposition holes can facilitate a timely saturation and backfill swelling that in turn can minimize thermal–mechanical damage.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1974

The initiatives of the Los Alamos Scientific Laboratory in the transfer of a new excavation technology

A system for making vertical or horizontal holes in rock or soil by progressive local melting is described. In one operation the three major tasks of excavation are performed with the Subterrene concept: (1) rock fracturing; (2) debris removal; and (3) wall stabilization. Potential applications of the Subterrene system are indicated, with emphasis on extraction of geothermal energy and development of superconduction transmission lines for electrical power. A program in technology dissemination implemented by the staff members is described. It is indicated that a large scale commercial utilization of the technology is required to complete the transfer of technology.

Hanold, R. J.↗
NASA NTRS1979

Excavation costs for lunar materials

A lunar strip mining system is presented which is capable of excavating and transporting 3 million metric tons of ore per year to a central processing plant on the moon's surface. The mining system would grow from a single front-end loader in the first year, to a fleet of ten haulers in the 30th year. Lunar personnel requirements would consist of a single individual, whose primary function would be to perform maintenance. All of the mining equipment would either operate automatically or by remote control from earth. The projected cost for the lunar mining system is approximately $12 to $37 per ton of ore over the life of the mine, an important part of the overall economics of exploiting lunar resources.

Carrier, W. D., III↗
NASA NTRS1985

Compact Hydraulic Excavator and Support Unit

Continuous-coal-mining machine maneuverable. Hydraulic coal excavator combined with chock, or roof-support structure, in self-contained unit that moves itself forward as it removes coal from seam. Unlike previous such units, new machine compact enough to be easily maneuverable; even makes small-radius right-angle turns.

Lewis, E. V.↗
NASA NTRS1993

Petrologic constraints on the surface processes on asteroid 4 Vesta and on excavation depths of diogenite fragments

The eucrite-howardite-diogenite meteorite groups are though to be related by magmatic processes. Asteroid 4 Vesta has been proposed as the parent body for these basaltic achondrite meteorites. The similarity of the planetesimal's surface composition to eucrite and diogenite meteorites and the large size of the asteroid (r = 250 km) make it an attractive source, but its position in the asteroid belt far from the known resonances from which meteorites originate make a relation between Vesta and eucrite-howardite-giogenite group problematic. It has been proposed that diogenites are low-Ca pyroxene-rich cumulates that crystallized from a magnesian parent (identified in howardite breccias), and this crystallization process led to evolved eucrite derivative magmas. This eucrite-diogenite genetic relationship places constraints on the physical conditions under which crystallization occurred. Elevated pressure melting experiments on magnesian eucrite parent compositions show that the minimum pressure at which pyroxene crystallization could lead to the observed compositions of main series eucrites is 500 bars, equivalent to a depth of 135 km in a 4 Vesta-sized eucrite parent body. Therefore, the observation of diogenite on the surface of 4 Vesta requires a post-crystallization process that excavates diogenite cumulate from depth. The discovery of diogenite asteroidal fragments is consistent with an impact event on 4 Vesta that penetrated the deep interior of this planetesimal.

Grove, T. L.↗
NASA NTRS1994

Distribution of materials excavated by the lunar crater Bullialdus and implications for the geologic history of the Nubium region

Previous spectroscopic studies of the lunar crater Bullialdus, located in the Nubium Basin, indicated an unusual stratigraphy of two gabbroic layers overlying a noritic unit. The possible existence of a layered mafic pluton at Bullialdus was suggested. To investigate the geologic context with more detailed spatial information, charge-coupled device (CCD) images of Bullialdus were obtained using eight filters. A linear mixing model was used to investigate the fractional abundances of spectral end-members chosen from within the multispectral image. Since the reflectance properties of lunar materials over this wavelength range are sensitive to variations in composition and soil maturity, fractional abundance images were used to create a new geologic map of the crater. The spatial relationships of the surface materials confirm the previously inferred stratigraphy, and further reveal the central peaks to exhibit two distinct compositional units: noritic anorthosite and anorthositic norite. Three models for the origin of the observed stratigraphy are considered: Bullialdus has excavated stratigraphic units containing (1) early mare basalt overlying anorthositic-noritic crustal material, (2) part of a layered mafic pluton, and/or (3) part of an impact melt sheet formed by the Nubium Basin impact event.

Tompkins, Stefanie↗
NASA NTRS2003

Initial Assessment of the Excavation and Deposition of Impact Lithologies Exposed by the Chicxulub Scientific Drilling Project, Yaxcopoil, Mexico

The Chicxulub Scientific Drilling Project (www.icdp-online.de) recovered a continuous core from a depth of 404 m (in Tertiary cover) to 1511 m (in a megablock of Cretaceous target sediments), penetrating approx. 100 m of melt-bearing impactites between 794 and 895 m. The Yaxcopoil-1 (YAX-1) borehole is approx. 60-65 km from the center of the Chicxulub structure, which is approx. 15 km beyond the limit of the estimated approx. 50 km radius transient crater (excavation cavity), but within the rim of the estimated approx. 90 km radius final crater. In general, the impactite sequence is incredibly rich in impact melts of unusual textural variety and complexity, quite unlike melt-bearing impact formations from other terrestrial craters.

Kring, David A.↗