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At least 127 records · Page 7
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NASA NTRS2015

Water Distribution in the Continental and Oceanic Upper Mantle

Nominally anhydrous minerals such as olivine, pyroxene and garnet can accommodate tens to hundreds of ppm H2O in the form of hydrogen bonded to structural oxygen in lattice defects. Although in seemingly small amounts, this water can significantly alter chemical and physical properties of the minerals and rocks. Water in particular can modify their rheological properties and its distribution in the mantle derives from melting and metasomatic processes and lithology repartition (pyroxenite vs peridotite). These effects will be examined here using Fourier transform infrared spectrometry (FTIR) water analyses on minerals from mantle xenoliths from cratons, plume-influenced cratons and oceanic settings. In particular, our results on xenoliths from three different cratons will be compared. Each craton has a different water distribution and only the mantle root of Kaapvaal has evidence for dry olivine at its base. This challenges the link between olivine water content and survival of Archean cratonic mantle, and questions whether xenoliths are representative of the whole cratonic mantle. We will also present our latest data on Hawaii and Tanzanian craton xenoliths which both suggest the intriguing result that mantle lithosphere is not enriched in water when it interacts with melts from deep mantle upwellings (plumes).

Peslier, Anne H.↗
NASA NTRS2015

The NASA MSFC Electrostatic Levitation (ESL) Laboratory: Summary of Capabilities, Recent Upgrades, and Future Work

The NASA Marshall Space Flight Center (MSFC) electrostatic levitation (ESL) laboratory has a long history of providing materials research and thermophysical property data. A summary of the labs capabilities, recent upgrades, and ongoing and future work will be provided. The laboratory has recently added two new capabilities to its main levitation chamber: a rapid quench system and an oxygen control system. The rapid quench system allows samples to be dropped into a quench vessel that can be filled with a low melting point material, such as a gallium or indium alloy. Thereby allowing rapid quenching of undercooled liquid metals. The oxygen control system consists of an oxygen sensor, oxygen pump, and a control unit. The sensor is a potentiometric device that determines the difference in oxygen activity between two gas compartments separated by an electrolyte, which is yttria-stabilized zirconia. The pump utilizes coulometric titration to either add or remove oxygen. The system is controlled by a desktop control unit, which can also be accessed via a computer. This system allows the oxygen partial pressure within the vacuum chamber to be measured and controlled, theoretically in the range from 10-36 to 100 bar. The ESL laboratory also has an emissometer, called the High-Temperature Emissivity Measurement System (HiTEMS). This system measures the spectral emissivity of materials from 600degC to 3,000degC. The system consists of a vacuum chamber, a black body source, and a Fourier Transform Infrared Spectrometer (FTIR). The system utilizes optics to swap the signal between the sample and the black body. The system was originally designed to measure the hemispherical spectral emissivity of levitated samples, which are typically 2.5mm spheres. Levitation allows emissivity measurements of molten samples, but more work is required to develop this capability. The system is currently setup measure the near-normal spectral emissivity of stationary samples, which has been used to take measurements of ablative materials, rocket nozzle coating materials, and materials for spacecraft instruments.

SanSoucie, Michael P.↗
NASA NTRS2016

Indigenous Carbonaceous Matter in the Nakhla Mars Meteorite

Detailed microanalysis of the Martian meteorite Nakhla has shown there are morphologically distinct carbonaceous features spatially associated with low-T aqueous alteration phases including salts and id-dingsite. A comprehensive suite of analytical instrumentation including optical microscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, focused ion beam (FIB) microscopy, transmission electron microscopy (TEM), two-step laser mass spectrometry (mu-L(sup 2)MS), laser mu-Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nanoscale secondary ion mass spectrometry (NanoSIMS) are being used to characterize the carbonaceous matter and host mineralogy. The search for carbonaceous matter on Mars has proved challenging. Viking Landers failed to unambiguously detect simple organics at either of the two landing sites although the Martian surface is estimated to have acquired at least 10(exp15) kg of C as a consequence of meteoritic accretion over the last several Ga. The dearth of organics at the Martian surface has been attributed to various oxidative processes including UV photolysis and peroxide activity. Consequently, investigations of Martian organics need to be focused on the sub-surface regolith where such surface processes are either severely attenuated or absent. Fortuitously since Martian meteorites are derived from buried regolith materials they provide a unique opportunity to study Martian organic geochemistry.

Clemett, S. J.↗
NASA NTRS2016

Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

The Deep Impact Spacecraft mission was the first to boldly face the challenge of impacting the surface of a comet, 9P/Tempel 1, to investigate surface and subsurface 'pristine' materials. The Stardust mission to Comet 81P/Wild 2 brought back an exciting surprise: shocked minerals which were likely altered during the comet's lifetime. Signatures of shock in meteorites also suggest that the violent past of the solar system has left our small bodies with signatures of impacts and collisions. These results have led to the question: How have impacts affected the evolutionary path taken by comets and asteroids, and what signatures can be observed? A future planetary mission to a near-Earth asteroid is proposing to take the next steps toward understanding small bodies through impacts. The mission would combine an ESA led AIM (Asteroid Impact Mission) with a JHU/APL led DART (Double Asteroid Redirect Mission) spacecraft to rendezvous with binary near-Earth asteroid 65803 Didymus (1996 G2). DART would impact the smaller asteroid, 'Didymoon' while AIM would characterize the impact and the larger Didymus asteroid. With these missions in mind, a suite of experiments have been conducted at the Experimental Impact Laboratory (EIL) at NASA Johnson Space Center to investigate the effects that collisions may have on comets and asteroids. With the new capability of the vertical gun to cool targets in the chamber through the use of a cold jacket fed by liquid nitrogen, the effects of target temperature have been the focus of recent studies. Mg-rich forsterite and enstatite (orthopyroxene), diopside (monoclinic pyroxene) and magnesite (Mg-rich carbonate) were impacted. Target temperatures ranged from 25 deg to -100 deg, monitored by connecting thermocouples to the target container. Impacted targets were analyzed with a Fourier Transform Infrared Spectrometer (FTIR) and Transmission Electron Microscope (TEM). Here we present the evidence for impact-induced shock in the minerals through both spectra and TEM imaging and compare with unshocked samples.

Lederer, Susan M.↗
NASA NTRS2017

Heterogeneity of Water Concentrations in the Mantle Lithosphere Beneath Hawaii

The amount and distribution of water in the oceanic mantle lithosphere has implications on its strength and of the role of volatiles during plume/lithosphere interaction. The latter plays a role in the Earth's deep water cycle as water-rich plume lavas could re-enrich an oceanic lithosphere depleted in water at the ridge, and when this heterogeneous lithosphere gets recycled back into the deep mantle. The main host of water in mantle lithologies are nominally anhydrous minerals like olivine, pyroxene and garnet, where hydrogen (H) is incorporated in mineral defects by bonding to structural oxygen. Here, we report water concentrations by Fourier transform infrared spectrometry (FTIR) on olivine, clino- and orthopyroxenes (Cpx & Opx) from spinel peridotites from the Pali vent and garnet pyroxenite xenoliths from Aliamanu vent, both part of the rejuvenated volcanism at Oahu (Hawaii). Pyroxenes from the Aliamanu pyroxenites have high water concentrations, similar to the adjacent Salt Lake Crater (SLC) pyroxenites (Cpx ~400-500 ppm H2O, Opx ~200 ppm H2O). This confirms that pyroxenite cumulates form water-rich lithologies within the oceanic lithosphere. In contrast, the Pali peridotites have much lower water concentrations than the SLC ones (<25 ppm vs. 50-96 ppm H2O respectively) despite being relatively fertile with >10% modal Cpx and low spinel Cr# (0.09-0.10). The contrast between the two peridotite suites is also evident in their trace elements and radiogenic isotopes. The Pali Cpx are depleted in light REE, consistent with minimal metasomatism. Those of SLC have enriched light REE patterns and Nd and Hf isotopes consistent with metasomatism by alkaline melts. These observations are consistent with heterogeneous water distribution in the oceanic lithosphere that may be related to metasomatism, as well as relatively dry peridotites cross-cut by narrow (?) water-rich melt reaction zones.

Bizimis, M.↗
NASA NTRS2018

Microgravity Experiments of Solid Waste Conversion into Useful Commodities

This Summer I participated in two projects at Kennedy Space Center in Cape Canaveral, Florida. The projects focus on the NASA's Deep Space Gateway applications for future Mars travel. All of these projects use recycling technology to use resources found on Earth and on other planets for fuel and other environmental applications. The first project I took the lead on is “Plasma Arc Gasification.” Plasma is a high temperature and very efficient way to process waste to create usable byproducts. The plasma chamber in temperature is comparable to that of the sun and this energy will help create an environment in which the waste can be recycled properly for not only plant support, but also for possible fuel application as well. I preformed the tests in a quartz tube, which is used to hold the waste (cotton, plastics, nylon, paper and a human waste simulant) and the waste is then combusted using O2 (present in air) into gases such as H2, H2O, CH4 and CO2. I determined which gases are present using a Fourier-transform infrared spectroscopy (FTIR) machine, which analyzes the peaks of the gases using liquid nitrogen. Problems arose in the beginning from the reactor emitting electromagnetic waves (EMI) that interfered with the technology of the experiment, specifically the thermocouples. This was solved through multiple tests with the positioning of the thermocouple power supply further away from the plasma reactor. I worked with another intern, Daniel Santander, who developed a space plant chamber which uses CO2 and H2O (harvested from the plasma reactor) to grow plants in space. The chamber possess a CO2 monitor, which controls the amount of gas that enters the chamber, along with a water integration system to supply the amount of water needed for proper plan growth. This technology will then be used for plant growth in space for the Astronauts on future space flights and possibly on the International Space Station (ISS). The second project I worked on is the “Orbital Syngas / Commodity Augmentation Reactor (OSCAR)” which focuses on the issues experienced in long-duration space flight regarding waste disposal. In previous space flight missions, waste was stored on board and returned to Earth for disposal. This technique is not applicable to long space flight missions to Mars due to the rocket being months away from Earth. OSCAR is using microgravity waste disposal techniques to produce fuels from the recycled waste. The waste is converted to syngas through a thermal degradation process. This process helps create an environmentally friendly way to dispose and reuse trash on board the space craft. Currently waste is being tested in the form of cotton and plastics. OSCAR is designed as a microgravity reactor that is currently being tested in a drop tower rig at Glenn Research Center. I helped design the 3D model for the insulation that will line the reactor. The first few trials, I dissolved the plastic of the mold in acetone. This method worked, but was very costly. I then received a silicone material to construct the mold from Swamp Works here at Kennedy. Through multiple trials with the silicone, this method worked best for developing the end pieces of the insulation for the chamber.

Plasma↗
NASA NTRS2018

Signatures of the Impact Histories of Comets and Asteroids within Shocked Phyllosilicates, Enstatite, and Forsterite Minerals

Throughout the lifetime of the solar system, collisions between small bodies and impacts on the surfaces of small bodies in the Kuiper Belt have occured at speeds of 1.5 - 3 km s-1 (Stern, Astron J 124, 2002), typically at 1-10 km s-1 between Trojan asteroids (Marzari et al. Icarus 119, 1996), and at ~4-8 km s-1 in the asteroid belt (Farinella and Davis, Icarus 97, 1992). Shock effects recorded by minerals composing these bodies are one observable legacy of this evolutionary process, whether they were generated through large collisions, micrometeoroid impacts, or processing during the formation of the solar system. Shock metamorphism has been observed in cometary samples such as those from Comet Wild 2 (Keller et al. Geochim. Cosmochim. Acta 72, 2008; Tomeoka et al. MAPS 43, 2008; Jacobs et al. MAPS 44, 2009) as well as in forsterites and enstatites found in meteorites (McCausland et al. AGU, 2010). To investigate the observable signatures of these processes, we have conducted a suite of impact experiments at NASA Johnson Space Center's Experimental Impact Laboratory (EIL). Target materials included Mg-rich forsterite (olivine), Mg-rich enstatite (orthopyroxene), and antigorite and lizardite (both in the serpentine group of phyllosilicates). Alumina-ceramic spheres were launched at speeds ranging from ~2.0 - 2.6 km s-1 into targets at temperatures from 25degC to -100degC. Recent advancements have been made in cooling targets in the EIL's vertical gun. Liquid nitrogen (LN2) is fed through a unique jacket surrounding the metallic sample container to chill the samples. Real-time values from temperature sensors attached to the sample holder are converted to target temperature through predetermined regression relationships, providing the target temperature at the time of impact with sub-degree accuracy. Fourier Transform Infrared Spectrometer (FTIR) data in the near to mid-IR will be presented, along with trends relating temperature and velocity with impact speeds, and thereby peak shock stresses experienced by the impacted minerals.

Lederer, Susan M.↗
NASA NTRS2018

Robust Bonding Through Process Control

Process control has been proven to be the most reliable means of safeguarding the quality of adhesive bonds according to Federal Aviation Administration (FAA). A method for implementing process control for reduction in risk in a bonded joint fabrication process is demonstrated in this study using a selected bonding system. The stepwise method included risk analysis to identify defects with the highest impact and likelihood to occur, evaluation of various pre-bond surface analysis tools to monitor for the selected defects, and demonstration of the benefits of in-process monitoring utilizing threshold limits determined from bond performance tests. The bonded system selected for investigation was an aerospace carbon fiber epoxy composite substrate surface prepared with random orbital sanding using 180 grit aluminum oxide sand paper. A series of portable, pre-bond surface analysis tools were investigated for their ability to be used for in-line bond process control. Results and threshold limits are presented from roughness, ballistic water contact angle (WCA), color, gloss, and Fourier transform infrared spectroscopy (FTIR) surface analysis tools. Results demonstrated how in-process inspection methods can be used to ensure quality of a surface preparation for a selected bonding system. A framework is provided for implementation of bond process control for robust bonding.

Kutscha, Eileen O.↗
NASA NTRS2019

Characterization of Thermal Protection Systems: An Analysis of Optical & Thermal Properties

Thermal Protection System Materials & thermal control coatings were characterized by a variety of methodologies including heat flow meter method (HFM), dynamic scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), and Ultra-Violet & Visible light spectroscopy (UV-VIS). Physical properties were measured to aid in the construction of thermal response models for a number a projects including MEDLI and MEDLI2. Comparing pre-flight predictions with actual flight data can allow for a reduction of margins and improve designs. The models enable design of TPS for flight missions and analysis of flight data to understand aerothermal environments experienced on the mission. This presentation reveals critical information: heat capacity (cp vs T), thermal conductivity ( vs T), and emissivity (E vs T) for Super Lightweight Ablative (SLA), Phenolic Impregnated Carbon Ablative (PICA-D), & Heatshield for Extreme Entry Environment Technology (HEEET). These properties were also measured for various thermal control coatings manufactured by AZ Technology. A portion of this work is incomplete and highlights questions to investigate in the future.

Cole, Brian↗
NASA NTRS2017

Fourier Transform Infrared Spectroscopy

KSC's Analytical Laboratories branch provides Center-wide chemical analysis support for the identification of contaminants found in payloads, flight hardware, clean rooms, and processing facilities for programs such as Orion, and almost every payload launched from KSC including commercial operations. This is a common but very serious issue and there are stringent health and safety restrictions pertaining to foreign object debris and contamination in aerospace systems due to their extremely sensitive nature and potential to interface with the astronauts aboard the ISS. When contamination is discovered, such as fibers, particles, residues, etc., it is sampled and then analyzed to determine its identity. Fourier Transform Infrared spectroscopy (FTIR) is a critical component of this analysis.

FTIR↗
NASA NTRS2019

Optically Enhanced Bonding Workstation for Robust Bonding

Process control is one of the methods recommended by the FAA to reduce risk in fabrication of structurally bonded composite joints for aircraft structure based on guidance provided in circular AC-107B for certification of structurally bonded joints. An Optically Enhanced Bonding Workstation is presented here that reduces the risk in bonded joint fabrication. Results will be presented demonstrating the benefits of process monitoring and its ability to reduce risk in performing pre-bond composite surface preparation steps. This supports reduction in the timeline to certification of bonded composite structures through development of a robust bonding process upstream of any part certification steps. Sanding surface preparation has been identified as a high risk process step that is known to impact bond performance. Control of sanding during surface preparation can be performed using portable surface analysis tools previously identified including included gloss, color, Fourier Transform Infrared spectroscopy (FTIR) and optically stimulated electron emissions (OSEE). Threshold limits for the surface analysis tool measurements were determined based on an example objective bonding system utilizing a common EA9394 paste adhesive measured using standard double cantilever beam fracture toughness testing. The patented Optically Enhanced Bonding Workstation (OEBW), was tailored to monitor and control the epoxy composite surface preparation step. Surface analysis tool threshold limits were incorporated into the OEBW to demonstrate improved composite bond performance through process control. The surface analysis tools investigated here can easily be incorporated into an automated system due to their applicability to rapidly quantify the composite sanded surface treatment and their portability.

Kutscha, Eileen O.↗
NASA NTRSDate not supplied

TPSAS-NF1676L-34417-DND

A boron nitride nanotube (BNNT), an electrically-insulating counterpart of a carbon nanotube (CNT), is a great nanofiller candidate for ferroelectric polymeric nanocomposites due to BNNT?s exceptional properties in piezoelectricity, thermal stability, mechanical strength, and radiation shielding capability. Fast and high-yield polar crystallization of polyvinylidene fluoride (PVDF) was accomplished by incorporating BNNTs as a nucleating agent. As-fabricated BNNT-PVDF nanocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), and differential scanning calorimetry (DSC) to identify and quantify chain conformations. Besides, piezoelectric constants, d33 of BNNT-PVDF nanocomposites were measured and compared with that of a mechanically drawn beta phase polar PVDF. The polar transformation due to BNNT incorporation has a great advantage over conventional beta or gamma transformation methods that require (1) mechanical drawing often resulting in defects or (2) high-temperature annealing for an extended time. In addition to the fast polar crystallization, BNNTs had a role of reinforcement of the polymer matrix. The improved Young?s modulus and electromechanical coupling coefficient of BNNT-PVDF nanocomposites indicated potential applications in energy harvesting under harsh environments such as large deformation, wide temperature cycles, and high radiation.

Dongwon Lee↗
NASA NTRSDate not supplied

Increasing Flexibility of Polymers in the Application of Complex Space Craft Heat Shield Geometries

Highly crosslinked polymers, commonly utilized in spacecraft component fabrication, especially for heatshields, have historically encountered challenges due to their inherent brittleness. To overcome this issue, researchers have explored the incorporation of additives into the polymer backbone to enhance flexibility and durability. This study aims to improve the flexibility and durability of highly crosslinked polymers by introducing long-chain aliphatic silicon-based additives with varying molecular weights into the polymer backbone. By increasing the flexibility of these brittle polymers, they can be effectively employed in constructing intricate curvatures for heatshields, eliminating the need for gap fillers. In this study, we investigated six different additives, comparing them to a highly crosslinked high-temperature polymer used as a baseline. Various characterization techniques, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dilatometry, dynamic mechanical analysis (DMA), nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR), were employed to assess the properties of the materials. The FTIR and NMR results indicated the successful incorporation of the silicon-based additives into the polymer backbone. Furthermore, thermal characterization results demonstrated that certain additives exhibited superior flexibility and lower densities compared to the baseline polymer.

Tane Boghozian↗
NASA NTRSDate not supplied

Additive Manufacturing and Working Fluid Characterization of Ceramic Heat Pipes

In this work, additively manufactured (AM) aluminum nitride (AlN) ceramic heat pipes were developed to improve spacecraft heat rejection capabilities beyond the current state-of-the-art metal systems. A low sintering temperature aluminum nitride slurry is developed for digital light processing printing (DLP) and the optimal debinding curves are examined. Printed AlN parts are characterized via SEM and optical profilometry. AlN 3D-printed parts are also tested for compatibility with aluminum bromide, aluminum chloride, and iodine, among other proposed working fluids at 350-600 K in an inert atmosphere, with reactivity measured via SEM and Fourier transform infrared spectroscopy (FTIR).

Thermal Management↗
NASA NTRSDate not supplied

Homogenized Ground-Based and Profile Ozone Datasets From the TOAR-II/HEGIFTOM Project: Methods and Station Trends

Within the framework of the second phase of the Tropospheric Ozone Assessment Report (TOAR-II), it was recognized that an essential first step for deriving accurate trends from the ground-based networks that monitor ozone in the free troposphere is putting the measurements on the same basis with respect to absolute references and processing methods. The relevant procedures are referred to as “harmonization” or “homogenization”. The TOAR II working group, “HEGIFTOM” (Harmonization and Evaluation of Ground-based Instruments for Free-Tropospheric Ozone Measurements), has carried out harmonization for five types of network (Figure below) instruments (mid-1990s to 2020): ozonesondes, commercial aircraft IAGOS landing/takeoff profiles, Fourier-Transform Infrared spectrometer (FTIR), tropospheric Lidar, and Brewer/Dobson Umkehr. First, we summarize the homogenization effort for each network that provides new quality-assessed ozone profile or segment (partial column) data sets, including uncertainty estimates and quality flags. Second, with the HEGIFTOM datasets forming the basis for a global assessment of tropospheric ozone column trends, results derived with various trend detection algorithms will be presented. The ultimate goal is evaluation of the consistency of the calculated trends among different techniques at selected stations and/or regions.

ozone↗
NASA NTRSDate not supplied

Variable Emittance Coatings

Variable emittance coatings (VECs) can reduce thermal control system mass and power by passively changing radiator heat rejection according to spacecraft and environment heat loads. VECs make establishing a lunar presence easier since this technology helps overcome challenges with harsh thermal environments on the lunar surface and in transit. This CIF focuses on creating testing capabilities to assess VECs from collaborators in academia and industry. Two main testing capabilities were created. First, a set of temperature dependent Fourier Transform Infrared Spectroscopy (FTIR) measurement accessories were designed, fabricated, and used to measure samples received from collaborators. These accessories are capable of measuring the transmittance and reflectance of semi transparent and opaque samples. Second, a vacuum calorimetry experiment was designed and built to assess the variable heat rejection of larger coupons.

Sydney Taylor↗
NASA NTRS2008

Checking Contamination during Storage of Carbonaceous Chondrites for Micro FTIR Measurements

We examined organic contamination by Fourier transform infrared micro spectroscopic (micro FTIR) measurements of carbonaceous chondrite samples. Carbonaceous chondrites, Tagish Lake (C2), Murchison (CM2) and Moss (CO3), and some mineral powder samples pressed on aluminum plates were measured by micro FTIR before and after storage in several containers with silicone rubber mat. During storage, samples did not touch directly anything except the holding aluminum plates. The carbonaceous chondrites containing hydrous minerals (Tagish Lake and Murchison) pressed on aluminum plates and measured by transmission-reflection micro FTIR measurements were found to be contaminated during storage after only one day, as revealed by an increase of approximately 2965 /cm and approximately 1260 /cm peaks. The Moss meteorite which contains no hydrous minerals, did not show an increase of these peaks, indicating no organic contamination. This difference is probably related to the differing mineralogy and physical properties (including porosity and permeability) of these chondrites. Hydrous minerals such as antigorite, muscovite, montmorillonite and silica gel showed organic contamination by the same infrared measurements, while anhydrous materials such as SiO2 and KBr showed no contamination. These results indicate importance of surface OH groups for the organic contamination. Organic contamination was found on silica gel samples pressed on aluminum plates when they were stored within containers including silicone rubber, silicone grease or adhesive tape. Long path gas cell FTIR measurements for silicone rubber indicated methylsiloxane oligomers were released from the silicone rubber. In-situ heating infrared measurements on the contaminated antigorite and Tagish Lake showed decrease of the 1262 /cm (Si-CH3) and 2963 /cm (CH3) peaks from room temperature to 200-300 C indicating desorption of volatile contaminants. These results indicate that careful preparation and storage are essential for FTIR measurements on precious astromaterial samples such as meteorites, IDPs and samples returned from comets, asteroids and Mars. Every possible contamination source should be evaluated before anything is done to these samples.

Zolensky, Michael E.↗