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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Pulmonary toxicity of simulated lunar and Martian dusts in mice: I. Histopathology 7 and 90 days after intratracheal instillation

NASA is contemplating sending humans to Mars and to the moon for further exploration. Volcanic ashes from Arizona and Hawaii with mineral properties similar to those of lunar and Martian soils, respectively, are used to simulate lunar and Martian environments for instrument testing. Martian soil is highly oxidative; this property is not found in Earth's volcanic ashes. NASA is concerned about the health risk from potential exposure of workers in the test facilities. Fine lunar soil simulant (LSS), Martian soil simulant (MSS), titanium dioxide, or quartz in saline was intratracheally instilled into groups of 4 mice (C57BL/6J) at 0.1 mg/mouse (low dose, LD) or 1 mg/mouse (high dose, HD). Separate groups of mice were exposed to ozone (0.5 ppm for 3 h) prior to MSS instillation. Lungs were harvested for histopathological examination 7 or 90 days after the single dust treatment. The lungs of the LSS-LD groups showed no evidence of inflammation, edema, or fibrosis; clumps of particles and an increased number of macrophages were visible after 7 days but not 90 days. In the LSS-HD-7d group, the lungs showed mild to moderate alveolitis, and perivascular and peribronchiolar inflammation. The LSS-HD-90d group showed signs of mild chronic pulmonary inflammation, septal thickening, and some fibrosis. Foci of particle-laden macrophages (PLMs) were still visible. Lung lesions in the MSS-LD-7d group were similar to those observed in the LSS-HD-7d group. The MSS-LD-90d group had PLMs and scattered foci of mild fibrosis in the lungs. The MSS-HD-7d group showed large foci of PLMs, intra-alveolar debris, mild-to-moderate focal alveolitis, and perivascular and peribronchiolar inflammation. The MSS-HD-90d group showed focal chronic mild-to-moderate alveolitis and fibrosis. The findings in the O(3)-MSS-HD-90d group included widespread intra-alveolar debris, focal moderate alveolitis, and fibrosis. Lung lesions in the MSS groups were more severe with the ozone pretreatment. The effects of O(3) and MSS coexposure appeared to be more than additive. Results for the TiO(2) and quartz controls were consistent with the known pulmonary toxicity of these compounds. The overall severity of lung injury was TiO(2) < LSS < MSS < O(3) + MSS < quartz. Except for TiO(2), the increased duration of dust presence in the lung from 7 to 90 days transformed the acute inflammatory response to a chronic inflammatory lesion. This study showed that LSS and MSS are more hazardous in the lungs than nuisance dusts.

Non-programmatic↗
NASA NTRS2009

Particle Removal by Electrostatic and Dielectrophoretic Forces for Dust Control During Lunar Exploration Missions

Particle removal during lunar exploration activities is of prime importance for the success of robotic and human exploration of the moon. We report on our efforts to use electrostatic and dielectrophoretic forces to develop a dust removal technology that prevents the accumulation of dust on solar panels and removes dust adhering to those surfaces. Testing of several prototypes showed solar shield output above 90% of the initial potentials after dust clearing.

Calle, C. I.↗
NASA NTRS2007

The Lunar Environment: Determining the Health Effects of Exposure to Moon Dusts

The Earth s moon presents a hostile environment in which to live and work. There is no atmosphere to protect its surface from the ravages of solar wind and micrometeorite impacts. As a result, the moon s surface is covered with a thin layer of fine, charged, reactive dust capable of entering habitats and vehicle compartments, where it can result in crewmember health problems. During the Apollo missions, lunar dusts were introduced into the crew vehicle, resulting in direct exposure and occasional reports of respiratory, dermal and ocular irritation. In order to study the toxicological effects of lunar dust, NASA formed the Lunar Airborne Dust Toxicity Advisory Group (LADTAG). This interdisciplinary group is comprised of leading experts in space toxicology, lunar geology, space medicine and biomedical research. LADTAG has demonstrated that lunar soil contains several types of reactive dusts, including an extremely fine respirable component. These dusts have highly reactive surfaces in the lunar environment; the grains contain surface coatings which are generated by vapor phases formed by hypervelocity impact of micrometeorites. This unique class of dusts has surface properties that are unlike any Earth based analog. These distinctive properties are why lunar dusts are of great toxicological interest. Understanding how these reactive components behave "biochemically" in a moisture-rich pulmonary environment will aid in determining how toxic these particles are to humans. The data obtained from toxicological examination of lunar dusts will determine the human risk criteria for lunar dust exposure and produce a lunar health standard. LADTAG s analysis of lunar dusts and lunar dust simulants will include detailed lunar particle characterizations, determining the properties of particle activation, reactivation of lunar dust, the process of dust passivation and discerning the pathology of lunar dust exposure via inhalation, intratracheal instillation, cell culture exposure, dermal exposure and ocular exposure. The resulting health standard will be time-based and will vary by the duration and type of exposure. It may also be necessary to set multiple standards for different types of lunar dust, as well as for dust in its activated form vs. aged & passivated dust. This standard, set to protect the health of our robust astronaut crews, will not only impact NASA medical operations, but engineering designs as well. The data from our multidisciplinary research are vital in developing remediation devices and environmental monitors. Ultimately, the engineering and safety groups will design and develop countermeasures for space vehicles, suits, rovers and habitats that will be sustained within the limits of the health standard.

Khan-Mayberry, Noreen↗
NASA NTRS2017

Rust Contamination from Water Leaks in the Cosmic Dust Lab and Lunar and Meteorite Thin Sections Labs at Johnson Space Center

On the early morning of September 15th, 2016, on the first floor of Building 31 at NASA-Johnson Space Center, the hose from a water chiller ruptured and began spraying water onto the floor. The water had been circulating though old metal pipes, and the leaked water contained rust-colored particulates. The water flooded much of the western wing of the building's ground floor before the leak was stopped, and it left behind a residue of rust across the floor, most notably in the Apollo and Meteorite Thin Section Labs and Sample Preparation Lab. No samples were damaged in the event, and the affected facilities are in the process of remediation. At the beginning of 2016, a separate leak occurred in the Cosmic Dust Lab, located in the same building. In that lab, a water leak occurred at the bottom of the sink used to clean the lab's tools and containers with ultra-pure water. Over years of use, the ultra-pure water eroded the metal sink piping and leaked water onto the inside of the lab's flow bench. This water also left behind a film of rusty material. The material was cleaned up and the metal piping was replaced with PVC pipe and sealed with Teflon plumber's tape. Samples of the rust detritus were collected from both incidents. These samples were imaged and analyzed to determine their chemical and mineralogical compositions. The purpose of these analyses is to document the nature of the detritus for future reference in the unlikely event that these materials occur as contaminants in the Cosmic Dust samples or Apollo or Meteorite thin sections.

Kent, J. J.↗
NASA NTRS2010

Active Dust Control and Mitigation Technology for Lunar and Martian Exploration

Mars is covered with a layer of dust that has been homogenized by global dust storms. Dust, levitated by these storms as well as by the frequent dust devils, is the dominant weather phenomenon on Mars. NASA's Mars exploration rovers have shown that atmospheric dust falling on solar panels can decrease their efficiency to the point of rendering the rover unusable. Dust covering the surface of the moon is expected to be electrostatically charged due to the solar wind, cosmic rays, and the solar radiation itself through the photoelectric effect. Electrostatically charged dust has a large tendency to adhere to surfaces. The Apollo missions to the moon showed that lunar dust adhesion can hinder manned and unmanned exploration activities. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The technology uses electrostatic and dielectrophoretic forces to carry dust particles off surfaces and to generate an electrodynamic shield that prevents further accumulation of dust. The concept of the electrodynamic dust shield was introduced by NASA in the late 1960s and later reduced to practice during the 1970s for terrestrial applications. In 2003, our laboratory, in collaboration with several universities, applied this technology to space applications, specifically to remove dust from solar panels on Mars. We show how, with an appropriate design, we can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. We have also been able to develop a version of the electrodynamic dust shield working under hard vacuum conditions that simulate the lunar environment. We have implemented the electrodynamic dust shield on solar arrays, optical systems, spectrometers, viewports, thermal radiators, batteries, and power systems, as well as on fabrics for spacesuits. We present data on the design and optimization of the electrodynamic dust shields and provide data on the performance of the different implementations of the technology for lunar and Martian exploration activities.

Calle, C. I.↗
NASA NTRS1976

Lunar microcraters and interplanetary dust fluxes

Conflicting depth/diameter ratios reported for lunar microcrater pits, microcrater pit morphology and size distribution, the composition and structure of pit glasses, and various alternative 'clocks' for estimating exposure time of microcrater pits are examined. Surface exposure time 'clocks' discussed include: galactic cosmic ray tracks, cosmogenic nuclides (involving changes in host rock isotopic composition induced by nuclear reactions), tracks produced in lunar top surfaces by nuclei accelerated during solar flares, and solar wind sputtering. 'Calibration' of the disparate types of surface exposure time 'clocks' with one another is discussed. The sensitive relationship between determinations of meteoroid flux and surface exposure time is examined.

Hartung, J. B.↗
NASA NTRSDate not supplied

Electrostatic Charging of the Lunar Surface

Lunar regolith dust particles accumulate charge and interact electrostatically with rover wheels, astronaut boots, and equipment. We have developed instrumentation for in situ measurements of the electrostatic charge developed by the interactions of lunar regolith dust with the space-rated materials on these devices. This instrument is also capable of measuring the distribution of electric fields on or near the lunar surface and the ion currents present near the lunar surface. We also report on our efforts to characterize the charging behavior of lunar dust in low gravity environments. This behavior is nonintuitive due to complex interactions between individual dust grains. We are developing an experiment to study this interaction in a microgravity vacuum environment. Better understanding of this interaction will allow for improved dust mitigation on the lunar surface.

electrostatics↗
NASA NTRSDate not supplied

Electrostatic charging of the lunar regolith

Lunar regolith dust particles accumulate charge and interact electrostatically with rover wheels, astronaut boots, and equipment. We have developed instrumentation for in situ measurements of the electrostatic charge developed by the interactions of lunar regolith dust with the space-rated materials on these devices. This instrument is also capable of measuring the distribution of electric fields on or near the lunar surface and the ion currents present near the lunar surface. We also report on our efforts to characterize the charging behavior of lunar dust in low gravity environments. This behavior is nonintuitive due to complex interactions between individual dust grains. We are developing an experiment to study this interaction in a microgravity vacuum environment. Better understanding of this interaction will allow for improved dust mitigation on the lunar surface.

electrostatics↗
NASA NTRS2009

Decay of Reactivity Induced by Simulated Solar Wind Implantation of a Forsteritic Olivine

In returning humans to the Moon, the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) must address many problems faced by the original Apollo astronauts. Major among these is control of the fine dust (<20 microns) that makes up approx.20 wt% portion of the lunar surface. This ubiquitous, clinging, sharp, abrasive, glassy dust caused a plethora of problems with seals, abrasion, and coatings, in addition to possible health problems, including lunar dust hayfever. The lifetime of reactive sites on the surfaces of irradiated lunar dust grains is of interest to those studying human health because of the free radicals and toxic compounds that may be formed and may not passivate quickly when exposed to habitat/spacecraft air.

Kuhlman, K.R.↗
NASA NTRS2008

Adsorption of Water on Simulated Moon Dust Samples

A lunar regolith simulant dust sample (JSC-1a) supported on a silica wafer (SiO2/Si(111)) has been characterized by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), and Auger electron spectroscopy (AES). The adsorption kinetics of water has been studied primarily by thermal desorption spectroscopy (TDS) and also by collecting isothermal adsorption transients. The support has been characterized by water TDS. JSC-1a consists mostly of aluminosilicate glass and other minerals containing Fe, Na, Ca, and Mg. The particle sizes span the range from a few microns up to 100 microns. At small exposures, H2O TDS is characterized by broad (100 to 450 K) structures; at large exposures distinct TDS peaks emerge that are assigned to amorphous solid water (145 K) and crystalline ice (165 K). Water dissociates on JSC-1a at small exposures but not on the bare silica support. It appears that rather porous condensed ice layers form at large exposures. At thermal impact energies, the initial adsorption probability amounts to 0.92+/-0.05.

Goering, John P.↗
NASA NTRS2021

MBSE Validation and Verification: Case Study for LADEE

The Lunar Atmosphere Dust Environment Explorer (LADEE) mission orbited the moon in order to measure the density, composition, and time variability of the lunar dust environment. The successful mission launched September 7, 2013 and was de-orbited and impacted the moon's surface on April 17, 2014. The ground-side and onboard flight software for the mission was developed using a “Model-Based Software Engineering” (MBSE) methodology combined with strong reuse of Government and Commercial Off-The Shelf (G/COTS) components. Models of the spacecraft and flight software were developed in a graphical dynamics modeling package. Flight Software requirements were prototyped and refined using the simulated models. After the model was shown to work as desired in the simulation framework, C-code software was automatically generated from the models. The auto-generated software was then tested in real-time Processor-in-the-Loop and Hardware-in-the-Loop test beds. “Traveling Road Show” test beds were used for early integration tests with payloads and other subsystems. Traditional techniques for verifying computational sciences models were used to characterize the spacecraft simulation. A lightweight set of formal methods analysis, static analysis, formal inspection, and code coverage analyses were utilized to further reduce defects in the onboard flight software artifacts. These techniques were applied early and often in the development process, iteratively increasing the capabilities of software and fidelity of vehicle models and test beds.

Model-Based Software Engineering, Validation and V↗
NASA NTRS2013

Validation and Verification of LADEE Models and Software

The Lunar Atmosphere Dust Environment Explorer (LADEE) mission will orbit the moon in order to measure the density, composition and time variability of the lunar dust environment. The ground-side and onboard flight software for the mission is being developed using a Model-Based Software methodology. In this technique, models of the spacecraft and flight software are developed in a graphical dynamics modeling package. Flight Software requirements are prototyped and refined using the simulated models. After the model is shown to work as desired in this simulation framework, C-code software is automatically generated from the models. The generated software is then tested in real time Processor-in-the-Loop and Hardware-in-the-Loop test beds. Travelling Road Show test beds were used for early integration tests with payloads and other subsystems. Traditional techniques for verifying computational sciences models are used to characterize the spacecraft simulation. A lightweight set of formal methods analysis, static analysis, formal inspection and code coverage analyses are utilized to further reduce defects in the onboard flight software artifacts. These techniques are applied early and often in the development process, iteratively increasing the capabilities of the software and the fidelity of the vehicle models and test beds.

Gundy-Burlet, Karen↗
NASA NTRS1972

Lunar microcraters and interplanetary dust.

The ratio of spall to pit diameter of lunar microcraters decreases with decreasing crater size. The trend from micron-sized to cm-sized craters involves a transition of crater types from pit-only to pit-plus-spall craters. Some spall-only craters may have possessed a pit originally. Most microcraters are formed by the impact of primary interplanetary dust particles because melting occurred during their formation. According to experimental and theoretical data such melting phenomena require impact velocities which are consistent only with the velocity distribution of extralunar particles.

Hartung, J. B.↗
NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗
NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗
NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗