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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS2018

Preparing for Planetary Surface Exploration by Measuring Habitat Dust Intrusion with Filter Tests During an Analogue Mars Mission

As humans venture deeper into space more issues related to operations will become apparent. While the perils ofdust particles may not be widely recognized, it is one of the major issues astronauts will face on the surface of theMoon and Mars. Dust particles present a problem for both astronaut health and equipment as revealed during theApollo era lunar surface missions. Dust particles cling to spacesuits and field gear, which upon ingress would begincirculating throughout the spacecraft or habitat. An astronaut's health is compromised by the dust particle's potentialto embed in the lungs and cause respiratory illnesses. The extreme abrasiveness and granularity of the particles makeit near impossible to completely shield a spacecraft or habitat from dust related damage. NASA's Glenn ResearchCenter collaborated with Crew 188 at the Mars Desert Research Station (MDRS) in Utah to measure how much dustentered the habitat during a series of extravehicular activities (EVAs), or surface excursions. A NASA GRCdeveloped multistage filter system, coined the Scroll Filter System, was tested, for its effectiveness in removing dustthat entered the airlock and habitat after the EVAs. An optical particle counter measured the ambient airlockparticulates five times including: before the start of operations; after the crew left for EVA; in the middle of the EVAwith the settled air; before the crew entered the airlock after EVA; and finally, after the crew simulated repressurizationand suit brushing off in the airlock. Data was also collected in several of the working environmentlocations around MDRS and outside the habitat in the wind. Data collected from this research will help establishfilter equipment for life support systems and prescribed operations for astronaut transition from a planetary surfaceinto a desired clean habitat. Measurements may aid in updating a baseline expected dust load for a surface habitatand further facilitate the mitigation of astronaut's exposure to dust particles on the surface of celestial bodies.

Kobrick, Ryan L.↗
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 NTRS2012

Will Organic Synthesis Within Icy Grains or on Dust Surfaces in the Primitive Solar Nebula Completely Erase the Effects of Photochemical Self Shielding?

There are at least 3 separate photochemical self-shielding models with different degrees of commonality. All of these models rely on the selective absorption of (12))C(16)O dissociative photons as the radiation source penetrates through the gas allowing the production of reactive O-17 and O-18 atoms within a specific volume. Each model also assumes that the undissociated C(16)O is stable and does not participate in the chemistry of nebular dust grains. In what follows we will argue that this last, very important assumption is simply not true despite the very high energy of the CO molecular bond.

Nuth, Joseph A., III↗
NASA NTRS1991

The composition and plasma signature of a large dust impact on the Giotto spacecraft

At about 14,800 km from the Comet Halley nucleus, on the inbound leg, at least six of the sensors onboard the Giotto spacecraft observed an unusual, brief (about 30 to 500 ms) event: the ion-mass spectrometer data show a brief flow of energetic (up to several hundred electron volts) plasma consisting of protons, water group, and heavier ions. The Johnstone plasma analyzer data show a short burst of plasma, while the dust impact detector system data show an impact event in four of its detectors. The magnetometer signature of the event shows two brief dips in the field. The sudden change in the spacecraft attitude and spin rate observed by the camera at that same time has been interpreted as the result of a large (5 mg or more) dust-particle impact on the front bumper shield of the spacecraft. In addition, at about the same time the spacecraft star-tracker suffered damage. The report combines direct measurements of the composition and dynamics of a dust-impact plasma cloud, the dust particle mass, and the location of the impact on the spacecraft. Analysis of the data indicate that the impacting particle was water or ice-bearing, possibly loosely compared, and was composed of one or more of: carbon, nitrogen, and silicon.

Goldstein, R.↗
NASA NTRS1979

Atomic to molecular hydrogen transition in interstellar clouds

The photodestruction of molecular hydrogen is reexamined in the context of recent observational data. Improvements in the theory of radiation transfer are made by using a more accurate self-shielding integral, treating anisotropic scattering by dust grains, and including photodissociation from excited rotational states. The total column density of hydrogen required to obtain 10% conversion decreases with a parameter, epsilon, the ratio of the formation rate to the destruction rate, as epsilon to the -m power, with m in the range 1.4-1.6. Satisfactory agreement with the data for thicker diffuse clouds is obtained for epsilon of about 0.00006.

Federman, S. R.↗
NASA NTRS1993

Radio observations of D I and fractionation

We report observations to detect the 327 MHz line of atomic deuterium in the primarily molecular clouds towards Cas A and Sgr A, making appropriate choices of spectral and spatial resolution. Our best results for Cas A, based on 1253 hr of observing with the 85 foot (26 m) Hat Creek telescope and 45 hr with the very large array (VLA), yield an upper limit for the fraction of deuterium in atomic form, D I, of 0.14. We present an approximate analytical analysis of deuterium fractionation in translucent clouds, which shows that gas-phase ion-molecule reactions, assisted by dust and HD line self-shielding, are efficient in converting deuterium to HD. We conclude that little atomic deuterium is present in the molecular clumps in the Cas A clouds and that much higher sensitivity observations would be required to detect 327 MHz line in molecular clouds. We have also attempted to detect the 72 GHz line of DCO(+) toward Cas A. The observed upper limit to the DCO(+)/HCO(+) ratio of approximately 0.03 is not much larger than our theoretical estimate, and the DCO(+) line should be detectable with existing instrumentation, unless the temperature of these clouds is much larger than usually assumed.

Heiles, Carl↗
NASA NTRS2024

Wear and Neutron Shielding Resilience of Titanium-Hexagonal Boron Nitride Coatings Against Extreme Lunar Radiation and Thermal Cycles

Ti6Al4V and Al6061 are aerospace alloys used in lunar structural components and rovers owing to their high specific strength. However, they deteriorate rapidly when subjected to demanding conditions of the lunar environment, such as extreme thermal cycles, solar particle radiation, and abrasive regolith. Cryo-milled powders were employed to deposit hBN-reinforced protective titanium coatings through plasma spray (atmospheric APS and vacuum-VPS) with 2 and 10 vol% of hBN on Ti6Al4V and Al6061 substrates. These coatings were evaluated for durability under extreme lunar-like conditions, including thermal cycling, electron radiation, and synergistic (electron radiation-thermal cycle) exposure. The coatings exhibited radiation-induced hardening, resulting in a substantial increase in their microhardness ~20–40% compared to virgin condition. Bright-field transmission electron microscopy (TEM) analysis reveals the presence of high dislocation densities, black dot defects, and dislocation clusters, providing evidence of the severe impact of synergistic environmental stresses. Ball-on-disk tribological tests were conducted in the presence of JSC-1 A lunar regolith simulant to evaluate the wear performance of coatings. Compared to conventional Ti6Al4V substrate, 50%, 90%, and 70% reductions in wear volume were observed in the Ti/2 vol% hBN coatings in thermal-only, radiation-only, and synergistic environments. Neutron shielding tests indicate that the synergistic coatings offer higher neutron shielding performance by up to 28% compared to virgin coatings, attributed to improved neutron capture by 10B isotopes. Upon a comprehensive assessment and ranking of multiple coatings under varying conditions, the VPS Ti/2 vol% hBN coating emerges as the top choice for protection against extreme radiation and thermal cycles for future lunar explorations.

Boron nitride↗
NASA NTRS1991

Sand and dust issues for the MESUR mission

The presence of particles in the Martian atmosphere increases the rate of erosion of the heat shield during the entry phase of the MESUR mission. Preliminary analysis has shown that under certain conditions particles will penetrate the bow shock of the entry vehicle, impact and erode the heat shield, above the anticipated rate from the ablation process. Knowledge of the distribution, sizes, and composition of particles suspended in the atmosphere will permit the estimation of the heat shield recession both for a nominal Mars atmosphere and in dust storm conditions. On the surface of Mars, sand and dust can effect the operations and design of the science instruments (i.e., imaging) and lander subsystems (i.e., solar arrays). Distribution and deposition of sand and dust on the planet's surface will dictate the feasibility of using solar arrays as a power source for the lander. Furthermore, the potential abrasive nature of blowing particles must be understood in order to properly select suitable materials for lander structure and any components exposed to the environment. The selection of lander material may also be dictated by corrosive and chemically active properties of particles at a potential landing site. Some key interests concerning sand and dust on the surface and in the atmosphere are summarized in a number of questions that are included.

Wercinski, P. F.↗
NASA NTRS2010

Spectroscopic Observation of the Stardust Re-Entry in the Near UV with SLIT: Deduction of Surface Temperatures and Plasma Radiation

Thermal radiation of the heat-shield and the emission of the post-shock layer around the Stardust capsule, during its re-entry, were detected by a NASA-led observation campaign aboard NASA's DC-8 airborne observatory involving teams from several nations. The German SLIT experiment used a conventional spectrometer, in a Czerny-Turner configuration (300 mm focal length and a 600 lines/mm grating), fed by fiber optics, to cover a wavelength range from 324 nm to 456 nm with a pixel resolution of 0.08 nm. The reentering spacecraft was tracked m uansuinaglly a camera with a view angle of 20 degrees, and light from the capsule was collected using a small mirror telescope with a view angle of only 0.45 degrees. Data were gathered with a measurement frequency of 5 Hz in a 30-second time interval around the point of maximum heating until the capsule left the field of view. The emission of CN (as a major ablation product), N2(+) and different atoms were monitored successfully during that time. Due to the nature of the experimental set up, spatial resolution of the radiation field was not possible. Therefore, all measured values represent an integration of radiation from the visible part of the glowing heat shield, and from the plasma in the post-shock region. Further, due to challenges in tracking not every spectrum gathered contained data. The measured spectra can be split up into two parts: (i) continuum spectra which represent a superposition of the heat shield radiation and the continuum radiation of potential dust particles in the plasma, and (ii) line spectra from the plasma in the shock layer. Planck temperatures (interpreted as the surface temperatures of the Stardust heat shield) were determined assuming either a constant surface temperature, or a temperature distribution deduced from numerical simulation. The constant surface temperatures are in good agreement with numerical simulations, but the peak values at the stagnation point are significantly lower than those in the numerical simulation if a temperature distribution over the surface is assumed. Emission bands of CN and N2(+) were tracked along the visible trajectory and compared to a spectral simulation with satisfying agreement. Values for the integrated radiation of the transitions of interest for these species were extracted from this comparison.

Winter, Michael W.↗
NASA NTRS1990

Aerobraking in a dusty Martian atmosphere

The effects of dust particle impacts on the erosion of the heat shield were estimated for a 26 m diameter aerobraking vehicle entering the Mars atmosphere at 8.6 km/sec. An explicit Navier-Stokes code was used to compute the flow field about the vehicle for the actual Martian atmospheric composition at a speed of 7.5 km/sec. The deceleration and melting of the dust particles within the forebody shock-layer was computed for dust spherules having initial diameters from 3 to 10 microns. Two heat shield materials were considered: Shuttle tiles with glassy surfaces and a low-density ablator known as Avcoat.

Chang, I-Dee↗
NASA NTRS2003

Application of THEMIS Data to an Investigation of a Long Lava Flow in the Tharsis Montes Region of Mars

The Tharsis region of Mars has long been known for the numerous lava flows radiating from the Tharsis Montes shield volcanoes. A 480-km-long flow southwest of Ascraeus Mons has been the subject of previous investigations using Viking and MGS data. The new data currently being obtained with the Thermal Emission Imaging System (THEMIS) on the Mars Odyssey spacecraft can shed new light on the volcanology of Martian lava flows, illustrated in this paper by two THEMIS images of the previously studied flow near Ascraeus Mons. The lava flow examined is on the western flank of the topographic saddle between the Ascraeus Mons and Pavonis Mons shield volcanoes. Flow morphology in the dust-covered Tharsis region is revealed in exquisite detail in daytime IR and VIS images from THEMIS, which will aid in documentation and analysis of lava flow features on Mars and improve constraints for volcanic modeling.

Zimbelman, J. R.↗
NASA NTRS2015

Exploring Dust Impacts on Tropical Systems from the NASA HS-3 Field Campaign

One of the overall scientific goals of the NASA Hurricane and Severe Storm Sentinel (HS-3) field campaign is to better understand the role of the Saharan Air Layer (SAL) in tropical storm development. During the 2012 HS-3 deployment, the Cloud Physics Lidar (CPL) observed dust within SAL air in close proximity to a developing Nadine (September 11, 2012). Throughout the mission, the NASA GEOS-5 modeling system supported HS-3 by providing 0.25 degrees resolution 5-day global forecasts of aerosols, which were used to support mission planning. The aerosol module was radiatively interactive within the GEOS-5 model, but aerosols were not directly coupled to cloud and precipitation processes. In this study we revisit the aerosol forecasts with an updated version of the GEOS-5 model. For the duration of Hurricane Nadine, we run multiday climate simulations leading up to each respective Global Hawk flight with and without aerosol direct interaction. For each set of simulations, we compare simulated dust mass fluxes to identify differences in SAL entrainment related to the interaction between dust aerosols and the atmosphere. We find that the direct effects of dust induce a low level anticyclonic circulation that temporarily shields Nadine from the intrusion of dry air, leading to a more intense storm.

hurricanes↗
NASA NTRS1983

Atomic and molecular hydrogen in the circumstellar envelopes of late-type stars

The distribution of atomic and molecular hydrogen in the expanding circumstellar envelopes of cool evolved stars is discussed. The main concern is to evaluate the effects of photodestruction of H2 by galactic UV radiation, including shielding of the radiation by H2 itself and by dust in the envelope. One of the most important parameters is the H/H2 ratio which is frozen out in the upper atmosphere of the star. For stars with photospheric temperatures greater than about 2500 K, atmospheric models suggest that the outflowing hydrogen is mainly atomic, whereas cooler stars should be substantially molecular. In the latter case, photodissociation of H2 and heavy molecules contribute to the atomic hydrogen content of the outer envelope. The presented estimates indicate that atomic hydrogen is almost at the limit of detection in the C-rich star IRC + 10216, and may be detectable in warmer stars. Failure to detect it would have important implications for the general understanding of circumstellar envelopes.

Glassgold, A. E.↗
NASA NTRS1992

Mitigation of adverse environmental effects on lunar-based astronomical instruments

The galactic cosmic-ray flux incident on the moon was examined for its potential adverse impact on the performance of the large lunar telescope (LLT) proposed as a part of NASA's Space Exploration Initiative (SEI). Noise produced by the cosmic-ray flux in the charge coupled devices to be used as the primary photodetector in the telescope was estimated. It was calculated that approximately 2.5 m of regolith would provide the shielding necessary to reduce the noise to an acceptable level. Dust is an omnipresent environmental concern for any human-assisted or robotic scientific instruments deployed on the moon. The degree to which dust poses an operational risk to the telescope was examined. Three potential methods for reducing this risk were identified: locating scientific instruments at remote locations; utilizing a prepared, dust-free site for all rocket activities; and covering the optics during high-risk times.

Johnson, Charles L.↗
NASA NTRS1994

Mitigation of adverse environmental effects on lunar-based astronomical instruments

The galactic cosmic-ray flux incident on the Moon was examined for its potential adverse impact on the performance of the large lunar telescope (LLT) proposed as a part of NASA's Space Exploration Initiative (SEI). Noise produced by the cosmic-ray flux in the charge coupled devices (CCD's) to be used as the primary photodetector in the telescope was estimated. It was calculated that approximately 2.5 m of regolith would provide the shielding necessary to reduce the noise to an acceptable level. Dust is an omnipresent environmental concern for any human-assisted or robotic scientific instruments deployed on the Moon. The degree to which dust poses an operational risk to the telescope was examined. Three potential methods for reducing this risk were identified: locating scientific instruments at remote locations; utilizing a prepared, dust-free site for all rocket activities; and covering the optics during high-risk times.

Johnson, Les↗
NASA NTRS2017

Ion Microprobe Measurements of Comet Dust and Implications for Models of Oxygen Isotope Heterogeneity in the Solar System

The oxygen isotopic compositions of anhydrous minerals in carbonaceous chondrites reflect mixing between a O-16-rich and O-17, O18-rich reservoir. The UV photodissociation of CO (i.e. selfshielding) has been proposed as a mass-independent mechanism for producing these isotopically distinct reservoirs. Self-shielding models predict the composition for the CO gas reservoir to be O-16-rich, and that the accreting primordial dust was in isotopic equilibrium with the gaseous reservoir [1, 2]. Self-shielding also predicts that cometary water, presumed to represent the O-17, O-18-rich reservoir, should be enriched in O-17 and O-18, with compositions of 200 -1000per mille, and that the interaction with this O-17, O-18-rich H2O reservoir altered the compositions of the primordial dust toward planetary values. The bulk composition of the solar nebula, which may be an approximation to the 16O-rich gaseous reservoir, has been constrained by the Genesis results [3]. However, material representing the O-17, O-18-rich end-member is rare [4], and dust representing the original accreting primordial dust has been challenging to conclusively identify in current collections. Anhydrous dust from comets, which accreted in the distal cold regions of the nebula at temperatures below approximately 30K, may provide the best opportunity to measure the oxygen isotope composition of primordial dust. Chondritic porous interplanetary dust particles (CP-IDPs) have been suggested as having cometary origins [5]; however, until direct comparisons with dust from a known comet parent body were made, link between CP-IDPs and comets remained circumstantial. Oxygen isotope analyses of particles from comet 81P/Wild 2 collected by NASA's Stardust mission have revealed surprising similarities to minerals in carbonaceous chondrites which have been interpreted as evidence for large scale radial migration of dust components from the inner solar nebula to the accretion regions of Jupiter- family comets [6]. These studies have been largely focused on the coarse-grained terminal particles extracted from aerogel collectors; hypervelocity capture into aerogel resulted in fine-grained material that was melted and intimately mixed with the SiO2 capture medium. Hypervelocity impacts into Al foils surrounding the aerogel tiles produced impact craters that captured material from the impactor without significant oxygen contamination, allowing for analysis of both the coarse and fine-grained components of the Wild 2 dust. To date, no particles with definitive hydrated mineralogy have been observed in Stardust samples, though this may be a result of alteration due to hypervelocity capture. High-carbon hydrated CS-IDPs have been suggested as resulting from the aqueous alteration of CP-IDPs [7], and may retain evidence for interaction with O-17, O-18-enriched "cometary" water predicted by CO self-shielding. Here we present results of oxygen isotope measurements of twelve Stardust foil craters and four C-rich hydrated IDPs [8, 9], and discuss implications for models of oxygen isotope heterogeneity in the early solar system.

Snead, C. J.↗
NASA NTRS1981

Abundances of refractory elements in quasars

A comparison of previous and new observations of iron, silicon, aluminum, magnesium and carbon lines in quasars with theoretical models shows that the gas-phase abundances of these refractory elements cannot be much less than solar, and that they do not show the order-of-magnitude depletions that are found in planetary nebulae and the interstellar medium. In light of this lack of refractory element depletions, it is suggested that the broad emission-line clouds must be devoid of dust.

Gaskell, C. M.↗
NASA NTRS2009

KSC Tech Transfer News, Volume 2, No. 2

This issue contains articles about: (1) the Innovative Partnerships Program (IPP) and the manager of the program, Alexis Hongamen, (2) New Technology Report (NTR) on a Monte Carlo Simulation to Estimate the Likelihood of Direct Lightning Strikes, (3) Kennedy Space Center's Applied Physics Lab, (4) a virtual ruler that is used for many applications, (5) a portable device that finds low-level leaks, (6) a sun-shield, that supports in-space cryogenic propellant storage, (7) lunar dust modeling software, (8) space based monitoring of radiation damage to DNA, (9) the use of light-emitting diode (LED) arrays vegetable production system, (10) Dust Tolerant Intelligent Electrical Connection Systems, (11) Ice Detection Camera System Upgrade, (12) Repair Techniques for Composite Structures, (13) Cryogenic Orbital Testbed, and (14) copyright protection.

Makufka, David↗