Results for “Lunar Dust Mitigation” — Page 11

NASA NTRSDate not supplied

Abrasive Effects of Lunar Regolith on Material Wear for Long-Term Lunar Applications

Long-term operations on the Moon’s surface require materials that can withstand the harsh lunar environment. Lunar dust and regolith pose significant threats to the long-term durability of materials used in lunar applications. Lunar dust, easily perturbed and dispersed, adheres and abrades materials due to its rough and irregular grain morphology. More closely representing this abrasion action through experimental laboratory testing is critical in assessing the durability of potential lunar candidate materials used in mechanical, sensor, and human-based systems. In this study, the performance of materials using Taber abrasive wheels made from lunar regolith simulant was assessed and compared to results obtained using standard ceramic-based abrasion materials. The results highlight a difference in the abrasive wear rates between the lunar regolith simulant and the standard ceramic-based abrasive. Utilizing the mechanisms and testing capabilities of this two-body abrasive interaction leveraging regolith-based abrasives may more closely represent the interplay between materials and lunar dust, which is vital for assessing the long-term viability of materials for extended lunar missions. Improved lunar testing capabilities may also enhance evaluations of the long-term performance degradation of passive and active dust mitigation methods.

Zachary Stein↗

NASA NTRS2007

Plume Impingement to the Lunar Surface: A Challenging Problem for DSMC

The President's Vision for Space Exploration calls for the return of human exploration of the Moon. The plans are ambitious and call for the creation of a lunar outpost. Lunar Landers will therefore be required to land near predeployed hardware, and the dust storm created by the Lunar Lander's plume impingement to the lunar surface presents a hazard. Knowledge of the number density, size distribution, and velocity of the grains in the dust cloud entrained into the flow is needing to develop mitigation strategies. An initial step to acquire such knowledge is simulating the associated plume impingement flow field. The following paper presents results from a loosely coupled continuum flow solver/Direct Simulation Monte Carlo (DSMC) technique for simulating the plume impingement of the Apollo Lunar module on the lunar surface. These cases were chosen for initial study to allow for comparison with available Apollo video. The relatively high engine thrust and the desire to simulate interesting cases near touchdown result in flow that is nearly entirely continuum. The DSMC region of the flow field was simulated using NASA's DSMC Analysis Code (DAC) and must begin upstream of the impingement shock for the loosely coupled technique to succeed. It was therefore impossible to achieve mean free path resolution with a reasonable number of molecules (say 100 million) as is shown. In order to mitigate accuracy and performance issues when using such large cells, advanced techniques such as collision limiting and nearest neighbor collisions were employed. The final paper will assess the benefits and shortcomings of such techniques. In addition, the effects of plume orientation, plume altitude, and lunar topography, such as craters, on the flow field, the surface pressure distribution, and the surface shear stress distribution are presented.

Lumpkin, Forrest↗

NASA NTRSDate not supplied

Metallic Environmentally Resistant Coating Rapid Innovation Initiative (MERCRII)

Mission concepts such as JPL’s Endurance-A utilize rovers such as Astrolab’s FLEX concept to explore the lunar surface. For these types of systems, lightweight alloys such as aluminum (Al) and titanium (Ti) are often specified to minimize mass while maintaining structural integrity. Such alloys, however, exhibit poor tribological response in the form of high friction and wear, especially in extreme space environments and with the additional presence of lunar regolith. This shortens the lifetimes of these systems which have a requirement to traverse 1,00km/year. This project is addressing the technology need of this and future rover missions by developing advanced wear- and radiation-resistant coatings for lightweight parts to extend the lifetime and sustainability of both lunar and Martian assets.

MISSE↗

NASA NTRS2009

A Conceptual Study for the Autonomous Direct Forming of Lunar Regolith into Flexlock (Trademark) Geomats for Lunar Surface Operations

We describe the conceptual method of an autonomously operable Direct Forming machine that would consume regolith or regolith slag to mold intimately, interlinked elements in a continuous process. The resulting product, one to three meter wide geomats, would be deployed over commonly traversed areas to isolate the astronauts and equipment from underlying dust. The porous geotextile would provide areas for dust settling, thereby mitigating dust impingement on astronaut suits or surface structures. Because of their self-supporting yet flexible structure, these geomats could be assembled into shields and buttresses to protect lunar habitants from radiation, forming a "flexoskeleton" from in situ materials.

Robertson, Luke B.↗

NASA NTRS2008

Lunar Dust Simulant in Mechanical Component Testing - Paradigm and Practicality

Due to the uniquely harsh lunar surface environment, terrestrial test activities may not adequately represent abrasive wear by lunar dust likely to be experienced in mechanical systems used in lunar exploration. Testing to identify potential moving mechanism problems has recently begun within the NASA Engineering and Safety Center Mechanical Systems Lunar Dust Assessment activity in coordination with the Exploration Technology and Development Program Dust Management Project, and these complimentary efforts will be described. Specific concerns about differences between simulant and lunar dust, and procedures for mechanical component testing with lunar simulant will be considered. In preparing for long term operations within a dusty lunar environment, the three fundamental approaches to keeping mechanical equipment functioning are dust avoidance, dust removal, and dust tolerance, with some combination of the three likely to be found in most engineering designs. Methods to exclude dust from contact with mechanical components would constitute mitigation by dust avoidance, so testing seals for dust exclusion efficacy as a function of particle size provides useful information for mechanism design. Dust of particle size less than a micron is not well documented for impact on lunar mechanical components. Therefore, creating a standardized lunar dust simulant in the particulate size range of ca. 0.1 to 1.0 micrometer is useful for testing effects on mechanical components such as bearings, gears, seals, bushings, and other moving mechanical assemblies. Approaching actual wear testing of mechanical components, it is beneficial to first establish relative wear rates caused by dust on commonly used mechanical component materials. The wear mode due to dust within mechanical components, such as abrasion caused by dust in grease(s), needs to be considered, as well as the effects of vacuum, lunar thermal cycle, and electrostatics on wear rate.

Jett, T.↗

NASA NTRS2010

Examining the Uppermost Surface of the Moon

Understanding the properties of the uppermost lunar surface is critical as it is the optical surface that is probed by remote-sensing data, like that which is and will be generated by instruments on orbiting missions (e.g. M3, LRO). The uppermost material is also the surface with which future lunar astronauts and their equipment will be in direct contact, and thus understanding its properties will be important for dust mitigation and toxicology issues. Furthermore, exploring the properties of this uppermost surface may provide insight into conditions at this crucial interface, such as grain charging and levitation

Noble, Sarah K.↗

NASA NTRSDate not supplied

Metallic Environmentally Resistant Coating Rapid Innovation Initiative (MERCRII)

Lightweight alloys such as aluminum (Al) and titanium (Ti) are often specified for space systems to minimize mass while maintaining structural integrity. These alloys, however, exhibit poor tribological response (high friction and wear) in extreme space environments and are exacerbated by the presence of lunar regolith. This leads to a shortened service life that poses a challenge for long term operations on the lunar surface. This project seeks to address this technology gap by developing advanced wear- and radiation-resistant coatings for lightweight parts to extend the lifetime and sustainability of both lunar and Martian assets and the missions they support.

dust mitigation↗

NASA NTRS2023

Hybrid CFD Engineering Model of Plume Induced Erosion and Crater Formation During Descent of Lunar Landers

With rapidly increased worldwide interest in landing on the moon, the issue of Plume Surface Interactions (PSI) is gaining attention. Hazards posed by lander plume induced dust and debris, as well as landing site deformation can be mitigated when better understood through predictive simulations. As simulation enabling computational power continues to increase, hybrid Computational Fluid Dynamics (CFD)/Engineering models provide the immediate ability to conduct parametric/trade studies driving design decisions for landers. Reduced order erosion engineering models apply correlations of the surface erosion rate to the plume induced surface forces with the correlations anchored to flight observations from Apollo LM landings. The MSFC propulsion fluid dynamics branch has developed such a hybrid model for predicting the plume induced viscous erosive regression of the Lunar surface beneath a landing vehicle. The (Descent Interpolated Gas Granular Erosion Model) DIGGEM was originally implemented as a post processing tool to calculate induced erosion rates through vehicle descent using CFD solutions of the vehicle plume at several fixed altitudes. This capability has since been advanced in the Loci/Chem-DIGGEM model to allow transient, moving vehicle, fully coupled viscous erosion modeling of vehicle descent PSI. This model has recently been used to make preflight predictions of the erosive regression of the ground beneath a Commercial Lunar Payload Services (CLPS) vehicle in support of measurements to be made by the Stereo Cameras for Lunar Plume Surface Studies (SCALPSS) instrument.

Plume Surface Interaction↗

NASA NTRS2023

Hybrid CFD Engineering Model of Plume Induced Erosion and Crater Formation During Descent of Lunar Landers

With rapidly increased worldwide interest in landing on the moon, the issue of Plume Surface Interactions (PSI) is gaining attention. Hazards posed by lander plume induced dust and debris, as well as landing site deformation can be mitigated when better understood through predictive simulations. As simulation enabling computational power continues to increase, hybrid Computational Fluid Dynamics (CFD)/Engineering models provide the immediate ability to conduct parametric/trade studies driving design decisions for landers. Reduced order erosion engineering models apply correlations of the surface erosion rate to the plume induced surface forces with the correlations anchored to flight observations from Apollo LM landings. The MSFC propulsion fluid dynamics branch has developed such a hybrid model for predicting the plume induced viscous erosive regression of the Lunar surface beneath a landing vehicle. The (Descent Interpolated Gas Granular Erosion Model) DIGGEM was originally implemented as a post processing tool to calculate induced erosion rates through vehicle descent using CFD solutions of the vehicle plume at several fixed altitudes. This capability has since been advanced in the Loci/Chem-DIGGEM model to allow transient, moving vehicle, fully coupled viscous erosion modeling of vehicle descent PSI. This model has recently been used to make preflight predictions of the erosive regression of the ground beneath a Commercial Lunar Payload Services (CLPS) vehicle in support of measurements to be made by the Stereo Cameras for Lunar Plume Surface Studies (SCALPSS) instrument.

Plume Surface Interaction↗

NASA NTRS2016

International Space Exploration Coordination Group Assessment of Technology Gaps for Dust Mitigation for the Global Exploration Roadmap

The International Space Exploration Coordination Group (ISECG) formed two Gap Assessment teams to evaluate topic discipline areas that had not been worked at an international level to date. Accordingly, the ISECG Technology Working Group (TWG) recommended two discipline areas based on Global Exploration Roadmap (GER) Critical Technology Needs reflected within the GER Technology Development Map (GTDM): Dust Mitigation and LOX/Methane Propulsion, with this paper addressing the former. The ISECG approved the recommended Gap Assessment teams, and tasked the TWG to formulate the new teams with subject matter experts (SMEs) from the participating agencies. The participating agencies for the Dust Mitigation Gap Assessment Team were ASI, CSA, ESA, JAXA, and NASA. The team was asked to identify and make a presentation on technology gaps related to the GER2 mission scenario (including cislunar and lunar mission themes and long-lead items for human exploration of Mars) at the international level. In addition the team was tasked to produce a gap assessment in the form of a summary report and presentation identifying those GER Critical Technology Needs, including opportunities for international coordination and cooperation in closing the identified gaps. Dust is still a principal limiting factor in returning to the lunar surface for missions of any extended duration. However, viable technology solutions have been identified, but need maturation to be available to support both lunar and Mars missions.

dust↗

NASA NTRS2016

International Space Exploration Coordination Group Assessment of Technology Gaps for Dust Mitigation for the Global Exploration Roadmap

The International Space Exploration Coordination Group (ISECG) formed two Gap Assessment teams to evaluate topic discipline areas that had not been worked at an international level to date. Accordingly, the ISECG Technology Working Group (TWG) recommended two discipline areas based on Global Exploration Roadmap (GER) Critical Technology Needs reflected within the GER Technology Development Map (GTDM): Dust Mitigation and LOX/Methane Propulsion, with this paper addressing the former. The ISECG approved the recommended Gap Assessment teams, and tasked the TWG to formulate the new teams with subject matter experts (SMEs) from the participating agencies. The participating agencies for the Dust Mitigation Gap Assessment Team were ASI, CSA, ESA, JAXA, and NASA. The team was asked to identify and make a presentation on technology gaps related to the GER2 mission scenario (including cislunar and lunar mission themes and long-lead items for human exploration of Mars) at the international level. In addition the team was tasked to produce a gap assessment in the form of a summary report and presentation identifying those GER Critical Technology Needs, including opportunities for international coordination and cooperation in closing the identified gaps. Dust is still a principal limiting factor in returning to the lunar surface for missions of any extended duration. However, viable technology solutions have been identified, but need maturation to be available to support both lunar and Mars missions.

dust↗

NASA NTRS2007

Predicting the Blast of Lunar Soil Under a Rocket's Exhaust Jet

The blast of lunar soil represents a problem for the future missions planned for the moon. When the lander approached the ground during the Apollo missions, huge showers of dust particles were sent in all directions at extremely high velocities - including upwards towards the landing spacecraft. This represents a clear danger to the lander because the loss of visibility and the damage that can be produced to the vehicle itself. If there had been equipment on the ground, these showers of particles would have created a sand blasting effect over the equipment, possibly damaging optics and contaminating the equipment and depending on the size and velocity of the particles maybe even more extensive damage as the particles penetrated the outer surface of the equipment. Since the there is no air on the moon to slow down the particles, they can travel large distances at high speeds, in fact in some instances they can reach near escape velocity and go into an orbit around the moon and come all the way back to almost the same point where they were at the beginning; meaning that some of the lunar dust that came up during landing will shower back over the site. Once on the surface, the extremely fine dust had a habit of getting itself everywhere. During the Apollo missions it not only covered the astronauts' suits, but managed to work its way inside, damaging airtight joints and scratching up glass visors. The dust found its way inside the spacecraft, contaminating the floor and electronic systems inside, clogging air filters in the process. This is due to the fact that the lunar soil is extremely cohesive. The Lunar soil causes all of the same problems as sand does on Earth but unlike sand particles on Earth, which have smooth spherical shapes, the dust on the Moon is more like small particles of glass with sharper edges since there is no erosion on the lunar surface. During the Apollo missions the dust problem did not cause a big problem due to the fact of the length of duration of the missions. But as NASA plans to have long term missions to the moon the dust problem becomes an issue, due to multiple landings and the equipment that will be accumulated on the site. In order to mitigate these problems it is needed first to understand the physics of the problem in order to find the most suitable solution to protect equipment and vehicles during the next lunar missions..

Diaz, Carlos J. Sanchez↗

NASA NTRS2012

Decision Gate Process for Assessment of a Technology Development Portfolio

The NASA Dust Management Project (DMP) was established to provide technologies (to TRL 6 development level) required to address adverse effects of lunar dust to humans and to exploration systems and equipment, which will reduce life cycle cost and risk, and will increase the probability of sustainable and successful lunar missions. The technology portfolio of DMP consisted of different categories of technologies whose final product is either a technology solution in itself, or one that contributes toward a dust mitigation strategy for a particular application. A Decision Gate Process (DGP) was developed to assess and validate the achievement and priority of the dust mitigation technologies as the technologies progress through the development cycle. The DGP was part of continuous technology assessment and was a critical element of DMP risk management. At the core of the process were technology-specific criteria developed to measure the success of each DMP technology in attaining the technology readiness levels assigned to each decision gate. The DGP accounts for both categories of technologies and qualifies the technology progression from technology development tasks to application areas. The process provided opportunities to validate performance, as well as to identify non-performance in time to adjust resources and direction. This paper describes the overall philosophy of the DGP and the methodology for implementation for DMP, and describes the method for defining the technology evaluation criteria. The process is illustrated by example of an application to a specific DMP technology.

Kohli, Rajiv↗

NASA NTRS2012

Decision Gate Process for Assessment of a NASA Technology Development Portfolio

The NASA Dust Management Project (DMP) was established to provide technologies (to Technology Readiness Level (TRL) 6) required to address adverse effects of lunar dust to humans and to exploration systems and equipment, to reduce life cycle cost and risk, and to increase the probability of sustainable and successful lunar missions. The technology portfolio of DMP consisted of different categories of technologies whose final product was either a technology solution in itself, or one that contributes toward a dust mitigation strategy for a particular application. A Decision Gate Process (DGP) was developed to assess and validate the achievement and priority of the dust mitigation technologies as the technologies progress through the development cycle. The DGP was part of continuous technology assessment and was a critical element of DMP risk management. At the core of the process were technology-specific criteria developed to measure the success of each DMP technology in attaining the technology readiness levels assigned to each decision gate. The DGP accounts for both categories of technologies and qualifies the technology progression from technology development tasks to application areas. The process provided opportunities to validate performance, as well as to identify non-performance in time to adjust resources and direction. This paper describes the overall philosophy of the DGP and the methodology for implementation for DMP, and describes the method for defining the technology evaluation criteria. The process is illustrated by example of an application to a specific DMP technology.

Kohli, Rajiv↗

NASA NTRS2008

Desert Research and Technology Studies (RATS) 2007 Field Campaign Objectives and Results

Desert "RATS" (Research and Technology Studies) is a combined, multi-discipline group of inter-NASA center scientists and engineers, net-working and collaborating with representatives of industry and academia, for the purpose of conducting planetary surface exploration-focused remote field exercises. These integrated testing exercises conducted under representative analog Lunar and Mars surface terrain conditions, provide NASA the capability to validate experimental prototype hardware and software systems as well as to evaluate and develop mission operational techniques in order to identify and establish technical requirements and identify potential technology "gaps" applicable for future planetary human exploration. The 2007 D-RATS field campaign test activities were initiated based on the major themes and objectives of a notional 5-year plan developed for conducting relative analog test activities in support of the engineering evaluation and assessment of various system architectural requirements, conceptual prototype support equipment and selected technologies necessary for the establishment of a lunar outpost. Specifically, the major objectives included measuring task efficiency during robot, human, and human-robot interactive tasks associated with lunar outpost site surveying and reconnaissance activities and deployment of a representative solar panel power and distribution system. In addition, technology demonstrations were conducted with a new Lithium-ion battery and autonomous software to coordinate multiple robot activities. Secondary objectives were evaluating airlock concept mockups and prototype removable space suit over-garment elements for dust mitigation, and upgrades to the prototype extravehicular activities (EVA) communication and information system. Dry run test activities, prior to testing at a designated remote field site location, were initially conducted at the Johnson Space Center (JSC) Remote Field Demonstration Test Site. This is a multi-acre external test site located at JSC and has detailed representative terrain features simulating both Lunar and Mars surface characteristics. Both the local JSC and remote field test sites have terrain conditions that are representative and characteristic of both the Moon and Mars, such as strewn rock and volcanic ash fields, craters, rolling plains, hills, gullies, slopes, and outcrops. The D-RATS 2007 field campaign, representing the completion of its tenth year of analog testing, was conducted at the large Cinder Lake volcanic ash bed area adjacent to Flagstaff, Arizona.

Kosmo, Joseph↗

NASA NTRS2008

Risk-Assessment for Equipment Operating on the Lunar Surface

Particle-size distribution of lunar dust simulant is evaluated using scanning electron spectroscopy in order to consider approaches to evaluating risk to individual mechanical components operating on the lunar surface. Assessing component risk and risk-mitigation during actual operations will require noninvasive continuous data gathering on numerous parameters. Those data sets would best be evaluated using data-mining algorithms to assess risk, and recovery from risk, of individual mechanical components in real-time.

Richmond, R. C.↗

NASA NTRSDate not supplied

Cultivating Capabilities for Lunar Extreme Environments

Space Directive 1 establishes that NASA is to " return of humans to the Moon for long-term exploration and utilization". Inherent in this direction, there are environmental challenges including ionizing radiation, extreme thermal ranges, and lunar dust. NASA is making significant investments in technologies to address the array of destinations and mission applications inherent in that challenge. As part of commercial, industry, and academic engagement, NASA has established Lunar Surface Innovation Consortium (LSIC) as an open forum to engage a larger community through six focus groups: in-situ resource utilization (ISRU), excavation and construction, power, extreme access, dust mitigation, and extreme environments. A general overview of the investments – both technology and community development – is presented.

technology↗

NASA NTRS2024

Measurements of Silicosis Factors in Lunar and Martian Simulants

Simulants are geologically complex materials that are developed to represent the physical and/or compositional characteristics of a planetary surface (e.g., a naturally occurring soil or regolith). There are dozens of commercially available simulants that have been developed over the years; each simulant exhibits unique physical, chemical, and mineralogical characteristics. Simulants are derived from either natural or synthetic sources (i.e., “feedstocks”) of glass, minerals, and rocks. These feedstock components are processed by crushing, pulverizing, melting, etc., and then combined in the appropriate proportions to represent a particular site, surface, or region (e.g., Lunar Highlands Regolith). The process of creating simulants therefore requires the mechanical breakdown and reincorporation of feedstock components which may contain crystalline silica minerals such as quartz, cristobalite, and tridymite. Certain crystalline silica particles of the respirable fraction (<10 μm in diameter) are of great concern; chronic and acute exposure to these respirable crystalline silica (RCS) can lead to permanent damage and scarring of lung tissue, incurable lung diseases (i.e., silicosis), lung cancer, COPD (chronic obstructive pulmonary disease), and kidney disease. Planetary simulants are used extensively as test materials in the in scientific and engineering communities (e.g., testing of dust mitigation technologies, in-situ resource utilization, rover mobility, hardware, soft goods etc.). As such, this assessment was developed to serve as a guide for simulant users, local Safety and Occupational Health professionals, and Industrial Hygienists to evaluate the risk of silicosis across a wide variety of Lunar and Martian simulants. The goal of these works is to ensure that those working with simulant can do so safely and with an informed understanding of potential health risks.

Lunar↗