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NASA NTRS2004

Analyses of IR-Stealthy and Coated Surface Materials: A Comparison of LIBS and Reflectance Spectra and Their Application to Mars Surface Exploration

Identification of non-silicate samples on Mars, such as carbonates, sulfates, nitrates, or evaporites in general, is important because of their association with aqueous processes and their potential as exobiology sites. Infrared (IR) and thermal emission (TE) spectroscopy have been considered the primary tools for remote identification of these minerals. This includes current and future orbital assets such as TES on MGS, THEMIS on Mars Odyssey, OMEGA on Mars Express, CRISM on MRO, and now the Mini-TES on the MER rovers. While reflectance and emission spectroscopy have clearly been the method of choice for these missions, the technique is not always successful in mineral identifications due to dust, surface weathering chemistry, coatings, or surface texture. Here we describe and show IR spectra of several such samples, and then report on the relative success of LIBS analyses in determining the rock type.

Wiens, R. C.↗

NASA NTRS1997

Structure of potato tubers formed during spaceflight

Potato (Solanum tuberosum L. cv. Norland) explants, consisting of a leaf, axillary bud, and small stem segment, were used as a model system to study the influence of spaceflight on the formation of sessile tubers from axillary buds. The explants were flown on the space shuttle Columbia (STS-73, 20 October to 5 November 1995) in the ASTROCULTURE (TM) flight package, which provided a controlled environment for plant growth. Light and scanning electron microscopy were used to compare the precisely ordered tissues of tubers formed on Earth with those formed during spaceflight. The structure of tubers produced during spaceflight was similar to that of tubers produced in a control experiment. The size and shape of tubers, the geometry of tuber tissues, and the distribution of starch grains and proteinaceous crystals were comparable in tubers formed in both environments. The shape, surface texture, and size range of starch grains from both environments were similar, but a greater percentage of smaller starch grains formed in spaceflight than on Earth. Since explant leaves must be of given developmental age before tubers form, instructions regarding the regular shape and ordered tissue geometry of tubers may have been provided in the presence of gravity. Regardless of when the signalling occurred, gravity was not required to produce a tuber of typical structure.

manned↗

NASA NTRS2001

Selective adsorption of L- and D-amino acids on calcite: Implications for biochemical homochirality

The emergence of biochemical homochirality was a key step in the origin of life, yet prebiotic mechanisms for chiral separation are not well constrained. Here we demonstrate a geochemically plausible scenario for chiral separation of amino acids by adsorption on mineral surfaces. Crystals of the common rock-forming mineral calcite (CaCO(3)), when immersed in a racemic aspartic acid solution, display significant adsorption and chiral selectivity of d- and l-enantiomers on pairs of mirror-related crystal-growth surfaces. This selective adsorption is greater on crystals with terraced surface textures, which indicates that d- and l-aspartic acid concentrate along step-like linear growth features. Thus, selective adsorption of linear arrays of d- and l-amino acids on calcite, with subsequent condensation polymerization, represents a plausible geochemical mechanism for the production of homochiral polypeptides on the prebiotic Earth.

Calcium Carbonate/metabolism↗

NASA NTRS1996

Search for past life on Mars: possible relic biogenic activity in martian meteorite ALH84001

Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest that the PAHs are indigenous to the meteorite. High-resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globules show that the globules contain fine-grained, secondary phases of single-domain magnetite and Fe-sulfides. The carbonate globules are similar in texture and size to some terrestrial bacterially induced carbonate precipitates. Although inorganic formation is possible, formation of the globules by biogenic processes could explain many of the observed features, including the PAHs. The PAHs, the carbonate globules, and their associated secondary mineral phases and textures could thus be fossil remains of a past martian biota.

NASA Discipline Number 52-10↗

NASA NTRS2004

Low Earth Orbital Atomic Oxygen Interactions With Spacecraft Materials

Atomic oxygen, formed in Earth s thermosphere, interacts readily with many materials on spacecraft flying in low Earth orbit (LEO). All hydrocarbon based polymers and graphite are easily oxidized upon the impact of approx.4.5 eV atomic oxygen as the spacecraft ram into the residual atmosphere. The resulting interactions can change the morphology and reduce the thickness of these materials. Directed atomic oxygen erosion will result in the development of textured surfaces on all materials with volatile oxidation products. Examples from space flight samples are provided. As a result of the erosive properties of atomic oxygen on polymers and composites, protective coatings have been developed and are used to increase the functional life of polymer films and composites that are exposed to the LEO environment. The atomic oxygen erosion yields for actual and predicted LEO exposure of numerous materials are presented. Results of in-space exposure of vacuum deposited aluminum protective coatings on polyimide Kapton indicate high rates of degradation are associated with aluminum coatings on both surfaces of the Kapton. Computational modeling predictions indicate that less trapping of the atomic oxygen occurs, with less resulting damage, if only the space-exposed surface is coated with vapor deposited aluminum rather than having both surfaces coated.

Banks, Bruce A.↗

NASA NTRS2007

Mafic Materials in Scott Crater? A Test for Lunar Reconnaissance Orbiter

Clementine 750 nm and multispectral ratio data, along with Lunar Orbiter and radar data, were used to study the crater Scott in the lunar south polar region. The multispectral data provide evidence for mafic materials, impact melts, anorthositic materials, and a small pyroclastic deposit. High-resolution radar data and Lunar Orbiter photography for this area show differences in color and surface texture that correspond with the locations of the hypothesized mafic and anorthositic areas on the crater floor. This region provides a test case for the upcoming Lunar Reconnaissance Orbiter. Verification of the existence of a mafic deposit at this location is relevant to future lunar resource utilization planning.

Cooper, Bonnie L.↗

NASA NTRS1996

Micro heat pipe panels and method for producing same

Flat or curved micro heat pipe panels are fabricated by arranging essentially parallel filaments in the shape of the desired panel. The configuration of the filaments corresponds to the desired configuration of the tubes that will constitute the heat pipes. A thermally conductive material is then deposited on and around the filaments to fill in the desired shape of the panel. The filaments are then removed, leaving tubular passageways of the desired configuration and surface texture in the material. The tubes are then filled with a working fluid and sealed. Composite micro heat pipe laminates are formed by layering individual micro heat pipe panels and bonding them to each other to form a single structure. The layering sequence of the micro heat pipe panels can be tailored to transport heat preferentially in specific directions as desired for a particular application.

Camarda, Charles J.↗

NASA NTRS1997

Method for producing micro heat panels

Camarda, Charles J.↗

NASA NTRS2003

Algorithms for Haptic Rendering of 3D Objects

Algorithms have been developed to provide haptic rendering of three-dimensional (3D) objects in virtual (that is, computationally simulated) environments. The goal of haptic rendering is to generate tactual displays of the shapes, hardnesses, surface textures, and frictional properties of 3D objects in real time. Haptic rendering is a major element of the emerging field of computer haptics, which invites comparison with computer graphics. We have already seen various applications of computer haptics in the areas of medicine (surgical simulation, telemedicine, haptic user interfaces for blind people, and rehabilitation of patients with neurological disorders), entertainment (3D painting, character animation, morphing, and sculpting), mechanical design (path planning and assembly sequencing), and scientific visualization (geophysical data analysis and molecular manipulation).

Basdogan, Cagatay↗

NASA NTRS2014

Investigating the Present Day Cosmic Dust Flux at the Earth's Surface: Initial Results from the Kwajalein Micrometeorite Collection

Examination of impact craters on the Long Duration Exposure Facility satellite indicate a present day micrometeoroid flux of approx. 30,000 tonnes [1 after 2]. But what portion of this material arrives at the Earth's surface as micrometeorites? Studies of available micrometeorite collections from deep sea sediments [e.g. 3], Greenland blue ice [e.g. 4] and the South Pole water well [e.g. 1] may be complicated by terrestrial weathering and, in some cases, collection bias (magnetic separation for deep sea sediments) and poorly constrained ages. We have recently set up a micrometeorite collection station on Kwajalein Island in the Republic of the Marshall Islands in the Pacific Ocean, using high volume air samplers to collect particles directly from the atmosphere. By collecting in this way, the terrestrial age of the particles is known, the weathering they experience is minimal, and we are able to constrain particle arrival times. Collecting at this location also exploits the considerably reduced anthropogenic background [5]. Method: High volume air samplers were installed on top of the two-story airport building on Kwajalein. These were fitted with polycarbonate membrane filters with 5μm diameter perforations. The flow rates were set to 0.5m3/min, and filters were changed once a week. After collection, filters were washed to remove salt and concentrate particles [see 5] in preparation for analysis by SEM. Results and Discussion: A selection of filters have been prepared and surveyed. Due to their ease of identification our initial investigations have focused on particles resembling cosmic spherules. The spheres can be divided into three main groups: 1. Silicate spherules rich in Al, Ca, K and Na (to varying degrees), 2. Silicate spherules rich in Mg and Fe and 3. Fe-rich spherules. Group 1 spherules are often vesiculated and can occur as aggregates. They are similar in appearance and composition to volcanic microspheres [e.g. 6] and are thus likely terrestrial in origin (volcanic). Those of groups 2 and 3, however, typically exhibit quenched surface textures consistent with cosmic spherules. Initial results suggest there is significant variation in the abundance of these groups from filter to filter. Work is ongoing to fully characterize these spherules and to constrain their flux with time.

Wozniakiewicz, P. J.↗

NASA NTRS2014

Atomic Oxygen Energy in Low Frequency Hyperthermal Plasma Ashers

Experimental and analytical analysis of the atomic oxygen erosion of pyrolytic graphite as well as Monte Carlo computational modeling of the erosion of Kapton H (DuPont, Wilmington, DE) polyimide was performed to determine the hyperthermal energy of low frequency (30 to 35 kHz) plasma ashers operating on air. It was concluded that hyperthermal energies in the range of 0.3 to 0.9 eV are produced in the low frequency air plasmas which results in texturing similar to that in low Earth orbit (LEO). Monte Carlo computational modeling also indicated that such low energy directed ions are fully capable of producing the experimentally observed textured surfaces in low frequency plasmas.

Oxygen atoms↗

NASA NTRS2015

Examining Volcanic Terrains Using In Situ Geochemical Technologies; Implications for Planetary Field Geology

Regardless of the target destination for the next manned planetary mission, the crew will require technology with which to select samples for return to Earth. The six Apollo lunar surface missions crews had only the tools to enable them to physically pick samples up off the surface or from a boulder and store those samples for return to the Lunar Module and eventually to Earth. Sample characterization was dependent upon visual inspection and relied upon their extensive geology training. In the four decades since Apollo however, great advances have been made in traditionally laboratory-based instrument technologies that enable miniaturization to a field-portable configuration. The implications of these advancements extend past traditional terrestrial field geology and into planetary surface exploration. With tools that will allow for real-time geochemical analysis, an astronaut can better develop a series of working hypotheses that are testable during surface science operations. One such technology is x-ray fluorescence (XRF). Traditionally used in a laboratory configuration, these instruments have now been developed and marketed commercially in a field-portable mode. We examine this technology in the context of geologic sample analysis and discuss current and future plans for instrument deployment. We also discuss the development of the Chromatic Mineral Identification and Surface Texture (CMIST) instrument at the NASA Goddard Space Flight Center (GSFC). Testing is taking place in conjunction with the RIS4E (Remote, In Situ, and Synchrotron Studies for Science and Exploration) SSERVI (Solar System Exploration and Research Virtual Institute) team activities, including field testing at Kilauea Volcano, HI..

Young, K. E.↗

NASA NTRS2013

Spectrally Consistent Scattering, Absorption, and Polarization Properties of Atmospheric Ice Crystals at Wavelengths from 0.2 to 100 um

A data library is developed containing the scattering, absorption, and polarization properties of ice particles in the spectral range from 0.2 to 100 microns. The properties are computed based on a combination of the Amsterdam discrete dipole approximation (ADDA), the T-matrix method, and the improved geometric optics method (IGOM). The electromagnetic edge effect is incorporated into the extinction and absorption efficiencies computed from the IGOM. A full set of single-scattering properties is provided by considering three-dimensional random orientations for 11 ice crystal habits: droxtals, prolate spheroids, oblate spheroids, solid and hollow columns, compact aggregates composed of eight solid columns, hexagonal plates, small spatial aggregates composed of 5 plates, large spatial aggregates composed of 10 plates, and solid and hollow bullet rosettes. The maximum dimension of each habit ranges from 2 to 10,000 microns in 189 discrete sizes. For each ice crystal habit, three surface roughness conditions (i.e., smooth, moderately roughened, and severely roughened) are considered to account for the surface texture of large particles in the IGOM applicable domain. The data library contains the extinction efficiency, single-scattering albedo, asymmetry parameter, six independent nonzero elements of the phase matrix (P11, P12, P22, P33, P43, and P44), particle projected area, and particle volume to provide the basic single-scattering properties for remote sensing applications and radiative transfer simulations involving ice clouds. Furthermore, a comparison of satellite observations and theoretical simulations for the polarization characteristics of ice clouds demonstrates that ice cloud optical models assuming severely roughened ice crystals significantly outperform their counterparts assuming smooth ice crystals.

Optical properties↗

NASA NTRS2018

Probing Supraglacial Debris on Mars 2: Crater Morphology

Lobate debris aprons (LDA), lineated valley fill (LVF), and concentric crater fill (CCF) on Mars, interpreted to bedebris-covered glaciers, possess craters with a suite of distinct interior landforms (called "ring-mold craters")that have been attributed to the presence of glacial ice at depth or surface modification processes. We testedcurrent hypotheses for the formation of ring-mold craters by conducting a comprehensive analysis of the size andmorphology of 16,457 impact craters 125m in diameter formed within glacial deposits in DeuteronilusMensae. Two major groups, bowl-shaped craters and ring-mold craters, are found, with at least nine distinctcrater types. While there is statistical difference in median diameters between these crater types, this differenceis relatively small and is within the estimated uncertainty in diameter measurements and may be related to moreenhanced erosion of the rims of ring-mold craters. Clear degradation sequences are observed, supporting a rolefor post-impact modification in producing at least some of the diversity in crater landforms. The spatial densityof ring-mold craters is also directly correlated with the development of LDA, LVF, and CCF surface textures. Flowlineations cross-cut two ring-mold crater types but they maintain their circular planforms in some cases, suggestingthat the craters initially formed completely within mantling layers deposited after glacial flow hadceased. We also find analogous craters in non-glacial units; glacial ice is therefore not required to form theobserved morphologic diversity. Our observations are most consistent with formation of crater landforms byemplacement and modification of at least two depositional episodes of icy dust (i.e., "mantle"). This mantle wasinitially tens of meters in thickness to support crater formation, and has experienced much downwasting anderosion since emplacement. Derived crater retention ages of 460 Ma for LDA, LVF, and CCF features in the regiontherefore reflect deposition of mantle units and only give a very minimum age for the formation of LDA, LVF, andCCF

Geological↗

NASA NTRS2019

Applications of Atomic Layer Deposition in the Modification of Carbon Nanotubes

Atomic Layer Deposition (ALD) is a cost-effective nanoadditive-manufacturing technique that allows for conformal coating of substrates with atomic control in a benign temperature and pressure environment. Using paired precursor gases, thin films can be deposited on flat or textured surfaces ranging from glass, polymers, aerogels, and metals. Through atomic layer control, where single layers of atoms are deposited, fabrication of metal transparent films, nano-laminates, and coatings of nano-channels and pores is achievable. Reaction mechanisms in ALD are normally self-limiting, allowing for atomically accurate control of nanometer (nm) thicknesses. Therefore, high uniformity and precise thickness control make ALD an attractive process for the creation of novel nano-scale devices. Decreases in resistivity and density of electrical wire are needed to improve the function of electronics, electric motors and cables. Such improvements may be accomplished by adding ballistically conducting, metallic carbon nanotubes (CNT) to Cu. ALD was used to coat multiple substrates including CNT with Cu in an effort to make CNT-Cu composites which is more conductive and less dense than Cu. In addition, ALD can be used to as a method to deposit the catalyst layer seed layer for CNT growth using Ni. The ALD of copper metallic films can follow multiple reaction pathways depending on the ALD precursors used. For this work the reaction pathway was deposition of copper oxide and then post process annealing in a hydrogen environment. Copper(II) diacetylacetonate (Cu(acac)2) and ozone are used as precursors for copper oxide. As-deposited copper oxide films prepared at 180°C resulted in a growth per cycle of 1.0 A/cycle with low film resistivity.

Dwivedi, Vivek H.↗

NASA NTRSDate not supplied

Additive Manufacturing for Rocket Propulsion Applications

Metal Additive manufacturing (AM) is changing how components are being fabricated for current and next generation spaceflights. AM provides many advantages including cost and schedule reduction, enhanced complexity for light-weighting, consolidation of parts, and improved performance using novel alloys and improved designs. This presentation will highlight some of the use cases of AM in rocket propulsion applications, the various processes and attributes for proper selection, and the integrated lifecycle for proper AM use. As AM evolves, there is a need to better understand these lifecycle design constraints such as geometry, microstructure and resulting properties, and surface texture for proper implementation. Ongoing research is being conducted on integral channel heat exchangers, such as combustion chambers and nozzles, using some of the AM processes. The presentation will conclude with a focus on this AM heat exchanger research and how it may be applied for future spaceflight.

Additive Manufacturing↗

NASA NTRSDate not supplied

Making & Breaking the Rules for DED Design

Design for Additive Manufacturing (DfAM) is widely used to describe design activities and guidelines employed in the creation of Additively Manufactured (AM) parts. Basic design rules for widely adopted processes like Powder Bed Fusion (PBF) are relatively understood including material performance, part size constraints, self-supporting angles, overhangs, wall thicknesses, and feature resolution. Complexity is often inherent with PBF using organically inspired solutions through generative design and topology optimization software to create designs that often cannot be realized via traditional manufacturing processes. The design rules for Directed Energy Deposition (DED) are less well known, and, in some cases, the lack of understanding is likely inhibiting broader application of the various DED processes. This presentation covers key design rules for DED fusion processes and elucidates opportunities like multi-material deposition and build approaches ranging from basic features to complex large-scale parts. Complementary to the opportunistic characteristics of DfAM for DED, Manufacture for AM (MfAM) encompasses the restrictive aspects of the manufacturing lifecycle with limitations due to bead width and wall thickness, self-supporting angles, surface texture, microstructural evolution, and residual stresses. AM enabled part design must always consider the entire value chain starting with incoming feedstock (e.g. plate, wire, or powder) and progressing through the printing process, post-processing (e.g. machining, inspection), and final system assembly. Key considerations, like the tradeoffs between feature resolution and build rate, for process and part selection and economic assessments will be discussed as DED is often traded against other AM processes. After highlighting typical DED design rules, we will also show how some of those rules can be broken via use cases and part designs that span the full spectrum of DED processes with examples of various DED part designs.

Additive Manufacturing↗

NASA NTRS2026

Artemis Suit Material Effects of Calendaring Woven Fabrics on Dust Resistance

This paper presents one element of an ongoing NASA technology-infusion effort to design, fabricate, and test a new outer shell fabric for a lunar Extravehicular Activity (EVA) space suit, a critical component of sustained lunar exploration. A primary challenge for suit textiles is preventing lunar dust, which is highly abrasive, electrostatically charged, and capable of infiltrating even tightly woven fabrics from penetrating the Environment Protection Garment (EPG) and compromising suit durability and astronaut safety. To enhance dust-blocking performance, the Artemis Suit Materials Team investigated calendaring, a continuous roll to roll mechanical finishing process in which fabric passes through heated rollers under high pressure to compress and flatten the weave, thereby reducing pore size and modifying surface texture without significantly affecting other properties. Targeted testing of calendared Teflon™ T-162 and Ortho Fabric samples provides new insight into how calendaring influences dust resistance, informing future material development and advancing EVA suit technology for long-duration lunar missions.

Dust↗