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All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Carbon-Based Compounds and Exobiology

The Committee for Planetary and Lunar Explorations (COMPLEX) posed questions related to exobiological exploration of Mars and the possibility of a population of carbonaceous materials in cometary nuclei to be addressed by future space missions. The scientific objectives for such missions are translated into a series of measurements and/or observations to be performed by Martian landers. These are: (1) A detailed mineralogical, chemical, and textural assessment of rock diversity at a landing site; (2) Chemical characterization of the materials at a local site; (3) Abundance of Hydrogen at any accessible sites; (4) Identification of specific minerals that would be diagnostic of aqueous processes; (5) Textual examination of lithologies thought to be formed by aqueous activity; (6) Search for minerals that might have been produced as a result of biological processes; (7) Mapping the distribution, in three dimensions, of the oxidant(s) identified on the Martian surface by the Viking mission; (8) Definition of the local chemical environment; (9) Determination of stable-isotopic ratios for the biogenic elements in surface mineral deposits; (10) Quantitative analysis of organic (non-carbonate) carbon; (11) Elemental and isotopic composition of bulk organic material; (12) Search for specific organic compounds that would yield information about synthetic mechanisms, in the case of prebiotic evolution, and about possible bio-markers, in the case of extinct or extant life; (13) and Coring, sampling, and detection of entrained gases and cosmic-ray induced reaction products at the polar ice cap. A discussion of measurements and/or observations required for cometary landers is included as well.

Kerridge, John↗
NASA NTRS1997

Interface Shape and Growth Rate Analysis of Se/GaAs Bulk Crystals Grown in the NASA Crystal Growth Furnace (CGF)

Selenium-doped gallium arsenide, Se/GaAs, bulk crystals have been grown on earth using NASA's crystal growth furnace (CGF) in preparation for microgravity experimentation on the USML-2 spacelab mission. Peltier cooling pulses of 50 ms duration, 2040 A magnitude, and 0.0033 Hz frequency were used to successfully demark the melt-solid interface at known times during the crystal growth process. Post-growth characterization included interface shape measurement, growth rate calculation, and growth rate transient determinations. It was found that the interface shapes were always slightly concave into the solid. The curvature of the seeding interfaces was typically 1.5 mm for the 15 mm diameter samples. This was in agreement with the predicted interface shapes and positions relative to the furnace determined using a numerical model of the sample/ampoule/cartridge assembly (SACA).

Bly, J. M.↗
NASA NTRS2003

Effect of Molding and Machining on Neoflon CTFE M400H Polychlorotrifluoroethylene Rod Stock and Valve Seat Properties

Since 1997 numerous fires have been reported to the Food and Drug Administration involving cylinder valves installed on medical use oxygen cylinders sold and operated within the United States. All of the cylinder valves in question had polychlorotrifluoroethylene (PCTFE) valve seats. Subsequent failure analysis showed that the main seat was the primary source of ignition. A review of the incidents involving cylinder valve fires indicated three possible ignition mechanisms: contaminant promotion, flow friction, and resonance. However, gas purity analysis showed that uncombusted, residual oxygen was within specification. Infrared and energy dispersive spectroscopy further showed that no contaminants or organic compounds were present in the remaining, uncombusted valve seat material or on seat plug surfaces. Therefore, contaminant-promoted ignition did not appear to be responsible for the failures. Observations of extruded material along the outer edge of the coined or loaded seat area produced by cylinder overuse or poppet overload led to concerns that accelerated gas flow across a deformed seat surface could generate enough localized heating to ignite the polymeric seat. Low molecular weight or highly amorphous quick-quenched PCTFE grades might be expected to be especially prone to this type of deformation. Such a failure mechanism has been described as flow friction; however, the corresponding mechanistic parameters are poorly understood. Subsequent revelation of low-temperature dimensional instability by thermomechanical analysis (TMA) in a variety of PCTFE sheet and rod stock samples led to new concerns that PCTFE valve seats could undergo excessive expansion or contraction during service. During expansion, additional extrusion and accompanying flow friction could occur. During contraction, a gap between the seal and adjacent metal surfaces could form. Gas flowing past the gap could, in turn, lead to resonance heating and subsequent ignition as described in ASTM Guide for Evaluation Nonmetallic Materials for Oxygen Service (G 63). Attempts to uncover the origins of the observed dimensional instability were hindered by uncertainties about resin grade, process history, and post-process heat history introduced by machining, annealing, and sample preparation. An approach was therefore taken to monitor property changes before and after processing and machining using a single, well-characterized lot of Neoflon CTFE.1 M400H resin. A task group consisting of the current PCTFE resin supplier, two molders, and four valve seat manufacturers was formed, and phased testing on raw resin, intermediate rod stock, and finished valve seats initiated. The effect of processing and machining on the properties of PCTFE rod stock and oxygen gas cylinder valve seats was then determined. Testing focused on two types of extruded rod stock and one type of compression-molded rod stock. To accommodate valve seat manufacturer preferences for certain rod stock diameters, two representative diameters were used (4.8 mm (0.1875 in.) and 19.1 mm (0.75 in.)). To encompass a variety of possible sealing configurations, seven different valve seat types with unique geometries or machining histories were tested. The properties investigated were dimensional stability as determined by TMA, specific gravity, differential scanning calorimetry (DSC), compressive strength, zero strength time, and intrinsic viscosity. Findings are discussed in the context of polymer structure-process-property relationships whenever possible.

Waller, Jess M.↗
NASA NTRS2017

Test and Analysis of Solid Rocket Motor Nozzle Ablative Materials

Asbestos free solid motor internal insulation samples were tested at the MSFC Hyperthermal Facility. Objectives of the test were to gather data for analog characterization of ablative and in-depth thermal performance of rubber materials subject to high enthalpy/pressure flow conditions. Tests were conducted over a range of convective heat fluxes for both inert and chemically reactive sub-sonic free stream gas flow. Instrumentation included use of total calorimeters, thermocouples, and a surface pyrometer for surface temperature measurement. Post-test sample forensics involved measurement of eroded depth, charred depth, total sample weight loss, and documentation of the general condition of the eroded profile. A complete Charring Material Ablator (CMA) style aero-thermal analysis was conducted for the test matrix and results compared to the measured data. In general, comparisons were possible for a number of the cases and the results show a limited predictive ability to model accurately both the ablative response and the in-depth temperature profiles. Lessons learned and modeling recommendations are made regarding future testing and modeling improvements that will increase understanding of the basic chemistry/physics associated with the complicated material ablation process of rubber materials.

Clayton, J. Louie↗
NASA NTRS2019

Noninvasive Breath Analysis Using NASA E-Nose Technology for Health Assessment

Clinical breath analysis is based on the fact that many important metabolites and biomarker molecules are present at detectable levels in exhaled breath, and many of these molecules correlate with human disease or correlate with physiological states that could lead to a decline in health. Presented is a technology that utilizes an array of chemical sensors combined with humidity, temperature and pressure for real time breath analysis to correlate the chemical information in the breath with the state and functioning of different human organs. For example, a marker for pulmonary inflammation processes of the lower respiratory tract, e.g. asthma, is the increase of the nitrogen oxide (NO) concentration in breath. Other volatile biomarkers may correlate with infectious process, metabolic conditions and inflammatory diseases, such as traumatic brain injury (TBI). This technology is also called "electronic nose" (E-Nose) in the sense that the device can mimic human nose to smell odors using a pattern recognition technique to analyze the sensor array data. Breath sampling is non-invasive and can be analyzed in real-time.

Li, Jing↗
NASA NTRSDate not supplied

Geometric Sensitivity of Residual Fields in Metal Additive Manufacturing

The sensitivity of geometrical parameters on the residual stress and distortion as computed by a metal additive manufacturing simulation is presented. A nozzle-like geometry was chosen with its length, wall thickness, and outer radius varied. A Latin hypercube sampling of 300 specimens produced the combinations of the geometrical parameters. Full thermomechanical simulations predicted the residual fields. Statistical analysis including regression curves shows that there is a strong correlation between these residual fields and the geometry, hinting that it may be possible to predictably influence the residual displacements and residual stresses by varying the overall geometry.

Multiscale Modeling↗
NASA NTRSDate not supplied

Metallic Environmentally Resistant Coating Rapid Innovation Initiative

Lightweight alloys such as aluminum (Al) and titanium (Ti) are often specified for space systems to minimize mass while maintaining structural integrity [1,2]. Such alloys however, have poor tribological response (high friction and wear), especially in extreme space environments, which becomes worse with the additional presence of lunar regolith. This leads to short lifetimes and premature failures that will ultimately limit long term operations on the lunar surface [2]. This project is addressing this technology gap by developing advanced wear- and radiation-resistant coatings for lightweight parts to extend the life-time and sustainability of both lunar and Martian assets. Ceramics were considered for their high wear resistance, but were rejected because of their low fracture toughness, which would be especially problematic for structural components. The novel and existing coating technologies and deposition methods are being tested in this project. The coating materials are Boron Nitride-Aluminum (BN-Al), Nickle Titanium (NiTi), Aluminum Oxide (AlO3), Ti64 with hBN at 2 and 10 vol percent (Ti-2vol%hBN and Ti-10vol%hBN), and the deposition techniques are high pressure cold-spray (CS) and ambient and vacuum plasma-spray (APS and VPS) [3,4,5]. BN-Al, NiTi, Ti-2vol%hBN, and Ti-10vol%hBN were applied with all three deposition techniques, and AlO3 was applied only using the APS deposition technique. A tungstenite (WS2) film was applied to the NiTi VPS coating. The coating and deposition technique configurations are being tested against several key end-use performance parameters. The parameters include the capabilities of the coatings under wear environments such as regolith simulant, thermal cycling from high (120°C) to cryogenic (-173°C), high vacuum (~10-7 torr), and pre- and post-exposure to ionizing particle radiation. Wear tests include pin on disk, three-body abrasion, and surface erosion by high velocity regolith impacts. The initial down selection is being performed using on virgin and environmental exposure samples using pin on disk and three body abrasion wear tests. From preliminary assessment of this testing, a few configurations were eliminated. Ti-10vol%hBN could not be applied using CS application and NiTi could not be applied using APS or CS application so these configurations did not get tested. Early pin on disk wear tests showed poor wear performance of BN-Al so this coating was eliminated early in the testing process. AlO3 on Al substrate did not survive thermal cycling, but wear testing is continuing for AlO3 on Ti substrate. A more detailed analysis is being con-ducted to further reduce the number of configuration for phase II and III. Phase II testing will include conventionally and additively manufactured substrates with surface erosion testing. In phase III, the coatings will be applied to three mechanism types: channel and slot, ball and socket, and a hinge joint. Each will demonstrate a different type of wear incidence. The mechanisms and their base materials are of direct interest to the end users and infusion points: the Human Landing System (HLS) and the Lunar Surface Innovation Initiative (sustained lunar surface operations). The technology development project is based out of Marshall Space Flight Center, has partnered with Florida International University (Miami, FL) and Plasma Processes (Huntsville, Al), and is supported by a group of NASA mentors from different centers.

dust mitigation↗
NASA NTRS1988

Characterization of a semicrystalline polyimidesulfone powder

A semicrystalline polyimidesulfone (PISO2) material has been synthesized and characterized. Characterization methods include thermal analysis by DSC and measurements of inherent viscosities, wide-angle X-ray diffraction, and viscoelasticity. The melt flow properties of both amorphous and semicrystalline samples were also investigated by means of a parallel plate plastometer. This material was found to be not readily recrystallizable at temperatures above its initial peak melting point of 225 C, when compared to other crystalline thermoplastics. This semicrystalline PISO2 demonstrated a flow about 5 times greater than the amorphous one as characterized by the plastometer. Such enhanced melt flow properties could be of great benefit in the adhesive and composite lamination processes.

Hou, T. H.↗
NASA NTRS1994

Comet coma sample return instrument

The sample collection technology and instrument concept for the Sample of Comet Coma Earth Return Mission (SOCCER) are described. The scientific goals of this Flyby Sample Return are to return to coma dust and volatile samples from a known comet source, which will permit accurate elemental and isotopic measurements for thousands of individual solid particles and volatiles, detailed analysis of the dust structure, morphology, and mineralogy of the intact samples, and identification of the biogenic elements or compounds in the solid and volatile samples. Having these intact samples, morphologic, petrographic, and phase structural features can be determined. Information on dust particle size, shape, and density can be ascertained by analyzing penetration holes and tracks in the capture medium. Time and spatial data of dust capture will provide understanding of the flux dynamics of the coma and the jets. Additional information will include the identification of cosmic ray tracks in the cometary grains, which can provide a particle's process history and perhaps even the age of the comet. The measurements will be made with the same equipment used for studying micrometeorites for decades past; hence, the results can be directly compared without extrapolation or modification. The data will provide a powerful and direct technique for comparing the cometary samples with all known types of meteorites and interplanetary dust. This sample collection system will provide the first sample return from a specifically identified primitive body and will allow, for the first time, a direct method of matching meteoritic materials captured on Earth with known parent bodies.

Albee, A. L.↗
NASA NTRS2010

Optical Imaging and Radiometric Modeling and Simulation

OPTOOL software is a general-purpose optical systems analysis tool that was developed to offer a solution to problems associated with computational programs written for the James Webb Space Telescope optical system. It integrates existing routines into coherent processes, and provides a structure with reusable capabilities that allow additional processes to be quickly developed and integrated. It has an extensive graphical user interface, which makes the tool more intuitive and friendly. OPTOOL is implemented using MATLAB with a Fourier optics-based approach for point spread function (PSF) calculations. It features parametric and Monte Carlo simulation capabilities, and uses a direct integration calculation to permit high spatial sampling of the PSF. Exit pupil optical path difference (OPD) maps can be generated using combinations of Zernike polynomials or shaped power spectral densities. The graphical user interface allows rapid creation of arbitrary pupil geometries, and entry of all other modeling parameters to support basic imaging and radiometric analyses. OPTOOL provides the capability to generate wavefront-error (WFE) maps for arbitrary grid sizes. These maps are 2D arrays containing digital sampled versions of functions ranging from Zernike polynomials to combination of sinusoidal wave functions in 2D, to functions generated from a spatial frequency power spectral distribution (PSD). It also can generate optical transfer functions (OTFs), which are incorporated into the PSF calculation. The user can specify radiometrics for the target and sky background, and key performance parameters for the instrument s focal plane array (FPA). This radiometric and detector model setup is fairly extensive, and includes parameters such as zodiacal background, thermal emission noise, read noise, and dark current. The setup also includes target spectral energy distribution as a function of wavelength for polychromatic sources, detector pixel size, and the FPA s charge diffusion modulation transfer function (MTF).

Ha, Kong Q.↗
NASA NTRS2019

Characterizing Lunar Polar Volatiles at the Working Scale: Going from Exploration Goals to Mission Requirements

The economic evaluation of natural resources depends on the accuracy of resource distribution estimates. On Earth such estimates are necessary in making decisions about opening new mines or in planning future investment for operating mines or industrial deposits. A frequently discussed lunar resource is water ice, however, we are only at the first stages of understanding its potential as a resource. In particular, we currently do not have a sufficient understanding of the distribution of water or its form at the scales it would be extracted and processed, that is, the “working scale”. Here the “working scale” is defined to be the scales at which sufficient material can be processed to meet some basic demand (for example, 100s of square meters), and the anticipated heterogeneity in the water distribution across those scales (scales <5 - 10s of meters). Several mission concepts have been developed to better understand lunar water, motivated by both scientific and exploration goals. This paper provides an analysis of the number and distribution of observations needed to provide the necessary next steps in lunar water ISRU. We use a combination of Monte Carlo studies and classic geostatistical approaches to go from the exploration goal of “understand the distribution of water” to quantification of specific mission sampling requirements.

Colaprete, A.↗
NASA NTRS2025

Components Refurbishment and Chemical Analysis Facility, SWMU #041 - Per- and Polyfluoroalkyl Substances Site Assessment Report Kennedy Space Center, Florida

This PFAS Site Assessment (SA) Report presents the activities and results associated with PFAS investigations at the Components Refurbishment and Chemical Analysis (CRCA) facility located at Kennedy Space Center (KSC), Florida. In 2022, CRCA was identified as an Area of Potential Concern because the facility stores several potential PFAS-containing chemicals. A groundwater sample collected from an onsite monitoring well detected PFOA and PFOS at concentrations greater than State of Florida provisional Groundwater Cleanup Target Levels (pGCTLs). PFAS SA activities were conducted between March 2022 and February 2024. During this timeframe, a total of 16 direct-push technology (DPT) locations and 82 discrete samples were collected from these locations, along with 90 monitoring well samples. The analytical data screening process focused on State of Florida pGCTLs and United States Environmental Protection Agency (USEPA) Regional Screening Level (RSLs) from November 2023 to evaluate the data. Analytical results identified PFOS, PFOA, and PFBA at concentrations exceeding their respective RSLs at each depth interval (shallow, intermediate, and deep). PFOS and PFOA had the largest footprint of RSL exceedances in each depth interval, but pGCTL exceedances were only observed at limited locations in the shallow and intermediate intervals. PFBA had the highest detections of any PFAS compound, with concentrations exceeding 180,000 nanograms per liter (ng/L), which is 100-times the RSL of 1,800 ng/L in the shallow and intermediate intervals and 10-times the RSL in the deep interval. The maximum PFBA detection was 841,000 ng/L at shallow monitoring well, MW0006. The PFAS SA also included samples collected from the onsite hydraulic containment system (HCS) which was installed to control and treat the onsite chlorinated volatile organic compound (CVOC) plume. Influent and effluent aqueous samples were collected monthly from the system. PFAS concentrations were relatively the same for both influent and effluent samples, indicating that while the HCS has been effective for CVOC treatment, it does not provide any additional treatment for PFAS compounds. Since the HCS has achieved its objectives, the system was shut down in December 2024. PFAS data gaps still exist, to include surface water and soil, which were not sampled during this SA. Soil sampling near the Chemical Process Area is recommended. Surface water and soil sampling at select stormwater outfalls is also recommended. Additionally, further groundwater sampling is recommended (DPT and monitoring well) in all depth intervals to delineate the extent of PFAS impacts at CRCA.

K Alex Murphy↗
NASA NTRS1988

Frequency-dependent dielectric analysis - Monitoring the chemistry and rheology of thermosets during cure

Frequency-dependent dielectric measurements in a curing resin sample were performed using an impedance analyzer and a permittivity sensor, to separate and measure the ionic (sigma) and dipolar (tau) mobilities, used as molecular probes of the cure reaction in the resin. The resin samples were tetraglycidyl 4,4-prime-diaminodiphenylmethane epoxy resins which included catalyzed (Hercules 3501-6) and uncatalyzed l3502 resin samples. The values of sigma and tau were used to quantitatively determine the viscosity, the degree of cure, and the T(g) of the resin. It is shown that the values of the Arrhenius and WLF constants during the cure process reflect the buildup of the crosslink network.

Kranbuehl, D.↗
NASA NTRS1993

Heterogeneity in small aliquots of Apolllo 15 olivine-normative basalt: Implications for breccia clast studies

Most of the recent advances in lunar petrology are the direct result of breccia pull-apart studies, which have identified a wide array of new highland and mare basalt rock types that occur only as clasts within the breccias. These rocks show that the lunar crust is far more complex than suspected previously, and that processes such as magma mixing and wall-rock assimilation were important in its petrogenesis. These studies are based on the implicit assumption that the breccia clasts, which range in size from a few mm to several cm across, are representative of the parent rock from which they were derived. In many cases, the aliquot allocated for analysis may be only a few grain diameters across. While this problem is most acute for coarse-grained highland rocks, it can also cause considerable uncertainty in the analysis of mare basalt clasts. Similar problems arise with small aliquots of individual hand samples. Our study of sample heterogeneity in 9 samples of Apollo 15 olivine normative basalt (ONB) which exhibit a range in average grain size from coarse to fine are reported. Seven of these samples have not been analyzed previously, one has been analyzed by INAA only, and one has been analyzed by XRF+INAA. Our goal is to assess the effects of small aliquot size on the bulk chemistry of large mare basalt samples, and to extend this assessment to analyses of small breccia clasts.

Lindstrom, Marilyn M.↗
NASA NTRS2012

The Sample Analysis at Mars Investigation and Instrument Suite

The Sample Analysis at Mars (SAM) investigation of the Mars Science Laboratory (MSL) addresses the chemical and isotopic composition of the atmosphere and volatiles extracted from solid samples. The SAM investigation is designed to contribute substantially to the mission goal of quantitatively assessing the habitability of Mars as an essential step in the search for past or present life on Mars. SAM is a 40 kg instrument suite located in the interior of MSL's Curiosity rover. The SAM instruments are a quadrupole mass spectrometer, a tunable laser spectrometer, and a 6-column gas chromatograph all coupled through solid and gas processing systems to provide complementary information on the same samples. The SAM suite is able to measure a suite of light isotopes and to analyze volatiles directly from the atmosphere or thermally released from solid samples. In addition to measurements of simple inorganic compounds and noble gases SAM will conduct a sensitive search for organic compounds with either thermal or chemical extraction from sieved samples delivered by the sample processing system on the Curiosity rover's robotic arm,

Mahaffy, Paul↗
NASA NTRSDate not supplied

Generating Global CH4 NASA GEOS Product by Assimilating TROPOMI

Radiative properties of methane (CH4) significantly contribute to climate change and the recent acceleration of global CH4 growth requires thorough investigation into its causes. Examination of temporal and spatial CH4 variability is crucial for better understanding the shifts that are currently taking place. Integrating different CH4 observations to create a reliable, easily to use global atmospheric CH4 product could contribute to assessment of emissions processes, but remains challenging due to the lack of long satellite data records. Here we present the NASA Goddard Earth Observing System (GEOS) based global CH4 product constrained by atmospheric transport from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) and assimilated CH4 from the TROPOspheric Monitoring Instrument (TROPOMI). This product uses the Constituent Data Assimilation System (CoDAS) component of the GEOS capability, which has been expanded and generalized to assimilate any satellite, ground-based, or in situ observation of atmospheric composition that can be expressed as a vertical sounding or point sample. The product is similar to the one generated by assimilating carbon dioxide (CO2) data into GEOS from Orbiting Carbon Observatory 2 (OCO-2): OCO-2 GEOS Level 3 daily and monthly, 0.5x0.625 assimilated CO2 V10r. The preliminary product is investigated using a variety of quality check approaches with the help of in situ observations to examine bias correction, error inflation, and performance of the assimilation system. Potential applications of this approach include support for interpretation of high-resolution point source detection approaches, climate and greenhouse gas reanalyses, and boundary conditions for regional modeling approaches.

Nikolay Balashov↗
NASA NTRS1989

Bivariate conditional sampling of buoyancy flux during an intense cold-air outbreak

The joint frequency distribution technique was used to analyze buoyancy fluxes in the marine atmospheric boundary layer (MABL) for the cloud street regime noted during the Genesis of Atlantic Lows Experiment. It is found that for the lower half of the MABL, the buoyancy flux is mainly generated by the rising thermals and the sinking compensating ambient air, and is mainly consumed by the entrainment and detrainment of thermals, penetrative convection, and the entrainment from the MABL top. If the buoyancy flux is primarily driven by the temperature flux, these buoyancy-flux generating processes should be the same for the lower boundary layers over land and ocean. The results of the scale analysis of the buoyancy flux agree well with those obtained for mesoscale cellular convection during the Air-Mass Transformation Experiment.

Chou, Shu-Hsien↗
NASA NTRS1981

AgRISTARS: Foreign commodity production forecasting. The 1980 US/Canada wheat and barley exploratory experiment

The crop identification procedures used performed were for spring small grains and are conducive to automation. The performance of the machine processing techniques shows a significant improvement over previously evaluated technology; however, the crop calendars require additional development and refinements prior to integration into automated area estimation technology. The integrated technology is capable of producing accurate and consistent spring small grains proportion estimates. Barley proportion estimation technology was not satisfactorily evaluated because LANDSAT sample segment data was not available for high density barley of primary importance in foreign regions and the low density segments examined were not judged to give indicative or unequvocal results. Generally, the spring small grains technology is ready for evaluation in a pilot experiment focusing on sensitivity analysis to a variety of agricultural and meteorological conditions representative of the global environment.

Payne, R. W.↗