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At least 253 records · Page 14

Large-scale atomistic model construction of subbituminous and bituminous coals for solvent extraction simulations with reactive molecular dynamics

Large-scale atomistic models for complex polycyclic aromatic hydrocarbon systems help understand the chemical properties and behaviors of complex feedstocks such as coal or petroleum. However, the development and utilization of large-scale models remain limited due to the difficulty in achieving the varied structural characteristics necessary to capture stochastic nature of these feedstocks. Here we demonstrate a systematic workflow to construct stochastic molecular systems from a broad analytical suite: high-resolution transmission electron microscopy (HRTEM), carbon-13 nuclear magnetic resonance spectroscopy ( 13 C NMR), laser desorption ionization mass spectroscopy (LDI-MS), and elemental analysis. We present a model construction and analysis utility of a new Python-based module. We selected one subbituminous and three high-volatile bituminous coals to construct large-scale models (~40,000 atoms). The constructed models were utilized to examine the affinity for solvent extraction (naphthalene or tetralin) and the effect of structural properties (e.g., aromatic cluster size, functional groups, and cross-linking) in reactive molecular dynamics simulations. Complex chemical reactions were monitored with bond order transitions, intermediates formation, and mass distributions. Reactive molecular dynamics simulations suggest a plausible chemical extraction process and products for the complex fossil feedstocks. The results indicated that radical formations with bond breaking of bridging oxygens and carbons were required at high temperatures to facilitate hydrogeneration and extraction of gas molecules from radical-free molecules. We observed that aliphatic chains of tetralin were easily decomposed and combined with radicals to form small size of molecules with aryl bonding, mainly increasing molecules in the 500–1000 Da, while naphthalene had little impact on chemical extraction process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Electron and proton conductivity of Fe-N-C cathodes for PEM fuel cells: A model-based electrochemical impedance spectroscopy measurement

Impedance spectra of a PEM fuel cell with three Fe-N-C cathodes have been measured under the H 2 /N 2 testing regime. The spectra have been fitted using a recently developed physics-based impedance model, which takes into account finite proton ($σ_p$) and electron ($σ_e$) conductivity of the oxygen-free cathode catalyst layer. Fitting allowed to extract numerical data for $σ_p$, $σ_e$, the double layer capacitance, and the inductance of cables used for measuring impedance spectra. The values of σp and σe are close to what previously found for standard Pt/C electrodes, which is found for the first time using PGM-free catalysts. The method enables simultaneous measurement of reference proton and electron conductivity of PEMFC cathode.

25 ENERGY STORAGE↗

Data Report: Pore Water Geochemistry at Green Canyon 955, deepwater Gulf of Mexico

Two holes were drilled in Green Canyon Block 955 (GC 955) in the deepwater Gulf of Mexico: Hole GC 955 H002 (H002) and Hole GC 955 H005 (H005). Here we present the solute concentrations and oxygen and hydrogen isotope ratios of pore water extracted from sediment whole-round samples collected from these holes. The analytical methods, degree of sample contamination, and the method for contamination correction are discussed as are the general trends in the geochemical data.

03 NATURAL GAS↗

Insights into the physiological and genomic characterization of three bacterial isolates from a highly alkaline, terrestrial serpentinizing system

The terrestrial serpentinite-hosted ecosystem known as “The Cedars” is home to a diverse microbial community persisting under highly alkaline (pH ~ 12) and reducing (Eh < -550 mV) conditions. This extreme environment presents particular difficulties for microbial life, and efforts to isolate microorganisms from The Cedars over the past decade have remained challenging. Herein, we report the initial physiological assessment and/or full genomic characterization of three isolates: Paenibacillus sp. Cedars (‘Paeni-Cedars’), Alishewanella sp. BS5-314 (‘Ali-BS5-314’), and Anaerobacillus sp. CMMVII (‘Anaero-CMMVII’). Paeni-Cedars is a Gram-positive, rod-shaped, mesophilic facultative anaerobe that grows between pH 7–10 (minimum pH tested was 7), temperatures 20–40°C, and 0–3% NaCl concentration. The addition of 10–20 mM CaCl 2 enhanced growth, and iron reduction was observed in the following order, 2-line ferrihydrite > magnetite > serpentinite ~ chromite ~ hematite. Genome analysis identified genes for flavin-mediated iron reduction and synthesis of a bacillibactin-like, catechol-type siderophore. Ali-BS5-314 is a Gram-negative, rod-shaped, mesophilic, facultative anaerobic alkaliphile that grows between pH 10–12 and temperatures 10–40°C, with limited growth observed 1–5% NaCl. Nitrate is used as a terminal electron acceptor under anaerobic conditions, which was corroborated by genome analysis. The Ali-BS5-314 genome also includes genes for benzoate-like compound metabolism. Anaero-CMMVII remained difficult to cultivate for physiological studies; however, growth was observed between pH 9–12, with the addition of 0.01–1% yeast extract. Anaero-CMMVII is a probable oxygen-tolerant anaerobic alkaliphile with hydrogenotrophic respiration coupled with nitrate reduction, as determined by genome analysis. Based on single-copy genes, ANI, AAI and dDDH analyses, Paeni-Cedars and Ali-BS5-314 are related to other species (P. glucanolyticus and A. aestuarii, respectively), and Anaero-CMMVII represents a new species. The characterization of these three isolates demonstrate the range of ecophysiological adaptations and metabolisms present in serpentinite-hosted ecosystems, including mineral reduction, alkaliphily, and siderophore production.

59 BASIC BIOLOGICAL SCIENCES↗

Partial analysis of experiment LDEF A-0114

Due to delays in manifesting the return of the Long Duration Exposure Facility from space, attention was concentrated on extracting the maximum information from the EIOM-2 (oxygen interaction with materials experiment) flown on STS-8 in September 1983. An analysis was made of the optical surfaces exposed during that flight and an assessment made of the effect of the 5 eV atomic oxygen upon their physical and chemical properties. The surfaces studied were of two types: high-purity thin films sputtered or evaporated onto 2.54-cm diam lambda/20 fused silica optical flats, and highly polished bulk samples. Rapid etching of carbon and carbonaceous surfaces was observed with polycarbonate CR-39 showing the largest etch of any substrate flown and measured. Of the metals tested, only osmium and silver showed large effects, the former being heavily etched and the later forming a very thick layer of oxide. The first measurable effects on iridium, aluminum, nickel, tungsten and niobium thin films are reported.

Gregory, J. C.↗

Combustion of Metals in Reduced-Gravity and Extraterrestrial Environment

As a result of the ongoing exploration of Mars and the several unmanned and manned missions planned for the future, increased attention has been given to the use of the natural resources of the planet for rocket propellant production and energy generation. Since the atmosphere of Mars consists of approximately 95% carbon dioxide (CO2), this gas is the resource of choice to be employed for these purposes. Unfortunately, CO2 is also a final product in most combustion reactions, requiring further processing to extract useful reactants such as carbon monoxide (CO), oxygen (O2), and hydrocarbons. An exception is the use Of CO2 as an oxidizer reacting directly with metal fuel. Since many metals burn vigorously with CO2, these may be used as an energy source and as propellants for an ascent/descent vehicle in sample-collection missions on Mars. In response to NASA's Human Exploration and Development of Space (HEDS) Enterprise to search for appropriate in-situ resource utilization techniques, this investigation will study the burning characteristics of promising metal/CO2 combinations. The use of reduced gravity is essential to eliminate the intrusive buoyant flows that plague the high-temperature metal reactions, to remove the destructive effect of gravity on the shape of molten metal samples, and to study the influence of radiative heat transfer from solid oxides undisturbed by natural convection. In studies with large metal specimens, the burning process is invariably influenced by strong convective currents that accelerate the reaction and shorten the burning times. Although these currents are nearly absent from small burning particles, the high emissivity of the flames, rapid reaction, small length scales, and intermittent explosions make the gathering of any useful information on burning rates and flame structure very difficult. This investigation has the ultimate goal of providing a careful probing of flame structure and dynamics by taking advantage of large, free-floating spherical metal samples and their corresponding long burning times available in reduced gravity. The first set of experiments has been conducted with magnesium (Mg) samples burning in the low-gravity environment generated by an aircraft flying parabolic trajectories. Owing to its high adiabatic flame temperature, oxidizer/fuel ratio, and heat per unit mass of fuel, as well as its low toxicity and low ignition temperature, Mg has been identified as a promising metal fuel with CO2 as oxidizer. The experimental effort is complemented by the development of a numerical model combining gas-phase chemical kinetics and transport mechanisms.

Abbud-Madrid, A.↗

JSC Mars-1 Martian Soil Simulant: Melting Experiments and Electron Microprobe Studies

JSC Mars-1 has been developed as a Martian regolith simulant, and is the <1 mm size fraction of a palagonitic tephra (a glassy volcanic ash altered at low temperatures) from Pu'u Nene cinder cone on the Island of Hawaii. The Mars-1 simulant forms the basis for numerous terrestrial studies which aim to evaluate the suitability of Martian soil for materials processing. Martian soil may be sintered to form building materials for construction, and also melted or reacted to extract metals for various uses, as well as oxygen for life support.

Carpenter, P.↗

Materials Design Directions for Solar Thermochemical Water Splitting

The sustainable, economical production of molecular hydrogen is a crucial component of a net zero-greenhouse-gas-emissions future. Solar thermochemical water splitting (STWS) offers a renewable route to hydrogen with the potential to help decarbonize several industries, including transportation, manufacturing, mining, metals processing, and electricity generation, as well as provide sustainable hydrogen as a chemical feedstock. STWS uses high temperatures generated from concentrated sunlight or other sustainable means for high-temperature heat to produce hydrogen and oxygen from steam. For example, in its simplest form of a two-step thermochemical cycle, a redox-active metal oxide is heated to ≈1700-2000 K, driving off molecular oxygen while producing oxygen vacancies in the material. The reduced metal oxide then cools (ideally with the extracted heat recuperated for re-use) and, in a separate step, comes into contact with steam, which reacts with oxygen vacancies to produce molecular hydrogen while recovering the original state of the metal oxide. Despite its promising use of the entire solar spectrum to split water thermochemically, the current estimated cost of hydrogen produced via STWS is ≈4-6× the U.S. Department of Energy (DOE) Hydrogen Shot target value of $1/kg. One contributing approach to bridging this cost gap is the design of new materials with improved thermodynamic properties to enable higher efficiencies. The state-of-the-art (SOA) redox-active metal oxide for STWS is ceria (CeO 2 ), due to its close to optimal, although too high, oxygen vacancy formation enthalpy and large configurational and electronic entropy of reduction. However, ceria requires high operating temperatures and its efficiency is insufficient. Therefore, efforts to increase the efficiency of STWS cycles have focused on further optimizing oxygen vacancy formation enthalpies and augmenting the reduction entropy via substitution or doping and materials discovery schemes. Examples of the latter include the perovskites BaCe 0.25 Mn 0.75 O 3 and (Ca,Ce)(Ti,Mn)O 3 . These efforts and others have revealed intuitive chemical principles for the efficient and systematic design of more effective materials, such as the strong correlation between the enthalpies of crystal bond dissociation and solid-state cation reduction with the enthalpy of oxygen vacancy formation, as well as configurational entropy augmentation via the coexistence of two or more redox-active cation sublattices. The purpose of this chapter is to prepare the reader with an up-to-date account of STWS redox-active materials, both the SOA and promising newcomers, as well as to provide chemically intuitive strategies for improving their cycle efficiencies through materials design – in conjunction with ongoing efforts in reactor engineering and gas separations – to reach the cost points for commercial viability. First, we will introduce the thermodynamics of STWS using a two-step, metal-oxide, thermochemical cycle with economics in mind. We also will compare the pros and cons of processes that do or do not involve phase changes. Second, we will describe the qualities that make ceria the SOA STWS redox-active material, as well as its limitations. Third, we will survey some of the most promising candidates to date in the search for materials to supplant ceria, emphasizing the post-ternary, metal-oxide-perovskite alloys. Lastly, we will enumerate and discuss the following materials design directions for STWS redox-active materials: crystal reduction potentials as a proxy for oxygen vacancy formation enthalpies, engineering the electronic and configurational entropy of reduction via f-shells and simultaneous redox, and vetting materials stability via temperature-dependent phase diagrams and melting-point prediction.

08 HYDROGEN↗

Irradiation Impact on Uranium Recovery Under Direct Extraction Conditions

Reducing the quantity of high-level radioactive waste is essential for minimizing environmental impact and improving efficiency of using natural resources for nuclear power. The current standard, Plutonium Uranium Solvent EXtraction (PUREX), uses tributyl phosphate (TBP) ligands to extract complexes of uranium and plutonium from a nitric acid (HNO3) phase. Although this method is effective, large volumes of HNO3 and the non-incinerable phosphate ligands increase the amount of hazardous waste produced. Alternative extractants and flowsheets have been proposed that allow for more selective extraction of radioactive metals, reduced nitric acid use, and easier incineration by only containing carbon, hydrogen, oxygen, and nitrogen (CHON). One candidate, N,N-di(2-ethylhexyl)-isobutyramide (DEHiBA) exhibits promising properties for direct extraction. A HNO3 pre-equilibrated DEHiBA phase selectively extracts U(VI), leaving plutonium, transuranics, and fission products behind as precipitate and reducing the volume of radioactive HNO3 produced.

38 - RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCL↗

The atmosphere of Mars - Resources for the exploration and settlement of Mars

This paper describes methods of processing the Mars atmosphere to supply water, oxygen and buffer gas for a Mars base. Existing life support system technology is combined with innovative methods of water extraction, and buffer gas processing. The design may also be extended to incorporate an integrated greenhouse to supply food, oxygen and water recycling. It is found that the work required to supply one kilogram of an argon/nitrogen buffer gas is 9.4 kW-hr. To extract water from the dry Martian atmosphere can require up to 102.8 kW-hr per kilogram of water depending on the relative humidity of the air.

Meyer, T. R.↗

Detection of Crystalline Hematite Mineralization on Mars by the Thermal Emission Spectrometer: Evidence for Near-surface Water

The Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor (MGS) mission has discovered a remarkable accumulation of crystalline hematite ((alpha-Fe2O3) that covers an area with very sharp boundaries approximately 350 by 350-750 km in size centered near 2 S latitude between 0 and 5 W longitude (Sinus Meridiani). Crystalline hematite is uniquely identified by the presence of fundamental vibrational absorption features centered near 300, 450, and >525/cm, and by the absence of silicate fundamentals in the 1000/cm region. Spectral features resulting from atmospheric CO2, dust, and water ice were removed using a radiative transfer model. The spectral properties unique to Sinus Meridiani were emphasized by removing the average spectrum of the surrounding region. The depth and shape of the hematite fundamental bands show that the hematite is crystalline and relatively coarse grained (>5-10 micron). Diameters up to and greater than 100s of micrometers are permitted within the instrumental noise and natural variability of hematite spectra. Hematite particles <5-10 micron in diameter (either as an unpacked or hard-packed powders) fail to match the TES spectra. The spectrally-derived areal abundance of hematite varies with particle size from approximately 10% for particles >30 micron in diameter to 40-60% for unpacked 10 micron powders. The hematite in Sinus Meridiani is thus distinct from the fine-grained (diameter <5-10 micron), red, crystalline hematite considered, on the basis of visible, near-IR data, to be a minor spectral component in Martian bright regions like Olympus-Amazonis. Sinus Meridiani hematite is closely associated with a smooth, layered, friable surface that is interpreted to be sedimentary in origin. This material may be the uppermost surface in the region, indicating that it could be a late-stage sedimentary unit, or it could be a layered portion of the heavily cratered plains units. We consider five possible mechanisms for the formation of coarse-grained, crystalline hematite. These processes fall into two classes depending on whether they require a significant amount of near-surface water: (1) chemical precipitation that includes origin by (a) precipitation from oxygenated, Fe-rich water (iron formations), (b) hydrothermal extraction and crystal growth.

Christensen, P. R.↗

The Power Reclamation of Utilizing Micro-Hydro Turbines in the Aeration Basins of Wastewater Treatment Plants

Upgrading the aeration basin technology can improve the oxygen transfer efficiency (OTE), while keeping the energy consumption at its minimum level. Therefore, this paper introduces a new idea of installing micro-propeller turbines in the aeration basin of a wastewater treatment plant (WWTP) to extract power from the high-velocity location in the water column. This extracted power can be used to operate a mixer at the top of the membrane to induce the mixing in that region, which will drive the less oxygenated wastewater into the water column. The rest of the extracted power will rotate microturbine rotors for electric power generation. By applying the proposed microturbines to the 13 audited facilities, it was demonstrated to achieve a gross annual energy-savings of 3,836.9 MWh, a gross annual cost-saving of $260,497, and total CO 2 emissions that would be reduced by 2,714 metric tons/year. Generally, the addition of the proposed microturbines can save up to 15.7% of the annual plant electricity consumption (1.3–12.8% of the plant annual electricity bills).

13 HYDRO ENERGY↗

Surface oxygen exchange kinetics of mixed conducting oxides: Dilatometric vs electrical conductivity relaxation study

The surface oxygen exchange kinetics of mixed ionic-electronic conducting (MIEC) oxides play a crucial role in a variety of applications, including solid oxide fuel/electrolysis cells (SOFCs/SOECs), permeation membranes and sensors. To date, a variety of methods, including isotope exchange, electrical conductivity, optical absorptivity and thermogravimetry relaxation, and impedance spectroscopy have been used to measure the oxygen exchange coefficient of MIEC oxides. Each of these methods have their advantages and limitations, depending on the physical and chemical properties of the investigated materials and their sample dimensions and densities. Here, we demonstrate the ability to precisely measure the surface oxygen exchange coefficient (k chem ) of MIEC model material Pr 0.1 Ce 0.9 O 2-δ (PCO) by use of dilatometric relaxation measurements, particularly of interest for materials that exhibit larger chemical expansion coefficients. This is achieved by use of porous bulk specimens to ensure that the contribution of oxygen exchange to the overall kinetics is dominant. We demonstrate that k chem values extracted from chemical expansion relaxation measurements on PCO are nearly identical to those derived from electrical conductivity relaxation measurements. As a result, this provides the opportunity to precisely investigate the oxygen exchange and chemical expansion kinetics of a wide range of materials used in high-temperature applications, particularly where more conventional methods are difficult or inappropriate to apply.

(Pr,Ce)O2-x↗

Near-Critical CO 2 -Assisted Liquefaction-Extraction of Biomass and Wastes to Fuels and Value-Added Products

With the growing need for sustainable carbon-neutral liquid fuels, low-grade feedstocks, such as lignocellulosic biomass, and municipal solid wastes offer sufficient potential via thermochemical conversion. But the existing thermochemical means are limited in feed flexibility and scalability and require significant processing (energy and costs) of the intermediates. Bio-oil/biocrude intermediate from fast pyrolysis and hydrothermal techniques is impeded by issues of stability and oxygen content, along with hydrotreating viability. To address these issues, we investigated a novel pathway of near-critical CO 2 -assisted integrated liquefaction-extraction (NILE) technology in conceptual aspects for conversion of various biomass and municipal solid wastes into high-quality biocrude with high compatibility for co-hydrotreating with traditional fossil crude for liquid fuel needs in power and transportation sectors. Using supercritical CO 2 for dewatering wet feedstocks, for liquefaction, and extraction for lighter biocrude has produced biocrude with lower oxygen content by 50%, lowered metal content by 90%, stable viscosity, low acidity, and good aging stability compared to that produced from hydrothermal liquefaction along with higher hydrotreating and co-hydrotreating compatibility. Hydrotreating of the biocrude extract from supercritical CO 2 extraction also was feasible with no detected coke deposition, an oxygen content of 1%, and catalyst deactivation. Here, the validation and capabilities of the NILE concept urge for its further development to obtain sustainable liquid fuels with lower greenhouse gas emissions and costs.

09 BIOMASS FUELS↗

Series Bosch Carbon Formation Reactor Trade Study and Down-Select

Human exploration missions to Mars and other destinations beyond low Earth orbit require highly robust, reliable, and maintainable life support systems that maximize the recovery of oxygen (O2). One process in development and under consideration is the Series-Bosch System (S-Bosch). This system is a two stage reactor process that reduces carbon dioxide (CO2) with hydrogen (H2) to produce water and solid carbon. Theoretically, the Bosch process can recover 100% of the O2 from CO2 in the form of water, making it an attractive option for long duration missions. The Series Bosch system includes a reverse water gas shift (RWGS) reactor, a carbon formation reactor (CFR), a H2 extraction membrane, and a CO2extraction membrane. To further the development of oxygen recovery systems, NASA awarded Phase I contracts to several entities under the Game Changing Development Program addressing Spacecraft Oxygen Recovery (SCOR). Two of the hardware deliverables were integrated into the Carbon Dioxide Reduction Test Stand (CORTS) as carbon formation reactors and performance evaluations were executed at Marshall Space Flight Center. A trade study was performed between these two reactors along with one developed at MSFC. This paper provided the necessary information for the Advanced Exploration Systems/Life Support Systems Project (AES/LSS) managers to select a CFR for further development and discusses the process of selection.

Bosch↗

Conceptual design of a lunar oxygen pilot plant Lunar Base Systems Study (LBSS) task 4.2

The primary objective was to develop conceptual designs of two pilot plants to produce oxygen from lunar materials. A lunar pilot plant will be used to generate engineering data necessary to support an optimum design of a larger scale production plant. Lunar oxygen would be of primary value as spacecraft propellant oxidizer. In addition, lunar oxygen would be useful for servicing nonregenerative fuel cell power systems, providing requirements for life support, and to make up oxygen losses from leakage and airlock cycling. Thirteen different lunar oxygen production methods are described. Hydrogen reduction of ilmenite and extraction of solar-wind hydrogen from bulk lunar soil were selected for conceptual design studies. Trades and sensitivity analyses were performed with these models.

Source record↗

NASA Lunabotics Robotic Mining Competition 10th Anniversary (2010-2019): Taxonomy and Technology Review

Space Mining for resources such as water ice, and regolith, which contain many elements in the form of metals, minerals, volatiles and other compounds, is a necessary step for In-Situ Space Resource Utilization (ISRU). One of the primary goals is to extract propellants from the regolith and water ice, such as oxygen and hydrogen which could then be used for in-space transportation. In addition, the space mining system can be used for various construction tasks that can benefit human and robotic exploration as well as scientific investigations based on excavated exposed topography, such as the side walls of trenches. The National Aeronautics & Space Administration (NASA) "Lunabotics" Robotic Mining Competition (RMC) is a university-level competition designed to engage and retain students in science, technology, engineering and mathematics (STEM). NASA has directly benefited from the competition by encouraging the development of innovative lunar excavation concepts from universities which has resulted in clever ideas and solutions which could be applied to an actual lunar excavation device or payload. The challenge is for students to design and build a remote controlled or autonomous excavator, called a "lunabot", which can collect and deposit a minimum of 10 kilograms of lunar simulant within 15 minutes. In recent years the goal has been changed to excavate a minimum of 1 kg of simulated icy regolith which is found under an overburden of regolith simulant. The complexities of the challenge include the abrasive characteristics of the lunar regolith simulant, the weight and size limitations of the lunabot, and the ability to control the lunabot from a remote-control center or operate it autonomously. This paper will present the results of the ten Lunabotics Robotic Mining Competitions held between May 2010 and May 2019. Each year over 50 university teams have attended, resulting in over 500 lunabot designs and subsequent prototypes. Over 6,000 university students have been part of the on-site competition at KSC. Even more students and the public were engaged via internet broadcasting and social networking media. The various designs have been cataloged and categorized here to provide information to future Lunabotics RMC mining robot designers and competitors. Categories will focus on both the mechanical design as well as the autonomy architecture/design. It is also expected to be of value for actual future space missions, as knowledge is gained from testing many innovative prototypes in simulated lunar regolith. A taxonomy of robotic excavator designs has been presented. In addition, the paper will discuss changes in learning paradigms occurring in the current generation of students, and how this competition leverages those changes to challenge students to develop skills in graduate level concepts and apply them. Examples of how this translates to hiring opportunities for commercial sponsors has also been discussed.

Robert P Mueller↗

NASA LUNABOTICS ROBOTIC MINING COMPETITION 10TH ANNIVERSARY (2010 – 2019): TAXONOMY AND TECHNOLOGY REVIEW

Space Mining for resources such as water ice, and regolith, which contain many elements in the form of metals, minerals, volatiles and other compounds, is a necessary step for In-Situ Space Resource Utilization (ISRU). One of the primary goals is to extract propellants from the regolith and water ice, such as oxygen and hydrogen which could then be used for in-space transportation. In addition, the space mining system can be used for various construction tasks that can benefit human and robotic exploration as well as scientific investigations based on excavated exposed topography, such as the side walls of trenches. The National Aeronautics & Space Ad-ministration (NASA) Lunabotics Robotic Mining Competition (RMC) is a university-level competition designed to engage and retain students in science, technology, engineering and mathematics (STEM). NASA has directly benefited from the competition by encouraging the development of innovative lunar excavation concepts from universities which has resulted in clever ideas and solutions which could be applied to an actual lunar excavation device or payload. The challenge is for students to design and build a remote controlled or autonomous excavator, called a lunabot, that can collect and deposit a minimum of 10 kilograms of lunar simulant within 15 minutes. In recent years the goal has been changed to excavate a minimum of 1 kg of simulated icy regolith which is found under an over-burden of regolith simulant. The complexities of the challenge include the abrasive characteristics of the lunar simulant, the weight and size limitations of the lunabot, and the ability to control the lunabot from a remote control center. This paper will present the results of the 10 Lunabotics Robotic Mining Competitions held between May 2010 and May 2019. Each year over 50 university teams have attended, resulting in over 500 lunabot designs and subsequent prototypes. Over 5,000 university students have been part of the competition on-site at KSC. More students and the public were en-gaged via internet broadcasting and social net-working media. The various designs will be cataloged and categorized to provide information to future Lunabotics mining robot designers and competitors. It is also expected to be of value for actual future space missions, as knowledge is gained from testing many innovative prototypes in simulated lunar regoith. A taxonomy of robotic excavator designs will be presented.

Competition↗