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NASA NTRS2011

Toward Realistic Dynamics of Rotating Orbital Debris, and Implications for Lightcurve Interpretation

Optical observations of rotating space debris near GEO contain important information on size, shape, composition, and rotational states, but these aspects are difficult to extract due to data limitations and the high number of degrees of freedom in the modeling process. For tri-axial rigid debris objects created by satellite fragmentations, the most likely initial rotation state has a large component of initial angular velocity directed along the intermediate axis of inertia, leading to large angular reorientations of the body on the timescale of the rotation period. This lends some support to the simplest possible interpretation of light curves -- that they represent sets of random orientations of the objects of study. However, effects of internal friction and solar radiation are likely to cause significant modification of rotation states within a time as short as a few orbital periods. In order to examine the rotational dynamics of debris objects under the influences of these effects, a set of seven first-order coupled equations of motion were assembled in state form: three are Euler equations describing the rates of change of the components of angular velocity in the body frame, and four describe the rates of change of the components of the unit quaternion. Quaternions are a four-dimensional extension of complex numbers that form a seamless, singularity-free representation of body orientation on S3. The Euler equations contain explicit terms describing torque from solar radiation in terms of spherical harmonics, and terms representing effects of a prescribed rate of internal friction. Numerical integrations of these equations of motion are being performed, and results will be presented. Initial tests show that internal friction without solar radiation torque leads to rotation about the maximum principal axis of inertia, as required, and solar radiation torque is expected to lead to spin-up of objects. Because the axis of maximum rotational inertia tends to be roughly coincident with the normal to the largest projected cross-sectional area, internal friction is expected to lead to reduced variation of light curve amplitudes at a given phase angle, but a large dependence of the same on phase angle. At a given phase angle, databases are generated which contain reflected intensities for comprehensive sets of equally-likely orientations, represented as unit quaternions. When projected onto three dimensions (S2) and color-coded by intensity, the set is depicted as points within a solid, semi-transparent unit sphere, within which all possible reflected intensities for an object at a given phase angle may be inspected simultaneously. Rotational sequences are represented by trajectories through the sphere. Databases are generated for each of a set of phase angles separately, forming a comprehensive dataset of reflected intensities spanning all object orientations and solar phase angles. Symmetries in the problem suggest that preferred rotation states are likely, defined relative to the object-sun direction in inertial space and relative to the maximum principal axis of inertia in the body coordinate system. Such rotation states may greatly simplify the problem of light curve interpretation by reducing the number of degrees of freedom in the problem.

Ojakangas, Gregory W.↗

NASA NTRS1990

Reusable Reentry Satellite (RRS): Propulsion system trade study

The purpose of the Reusable Reentry Satellite (RRS) Propulsion System Trade Study described in this summary report was to investigate various propulsion options available for incorporation on the RRS and to select the option best suited for RRS application. The design requirements for the RRS propulsion system were driven by the total impulse requirements necessary to operate within the performance envelope specified in the RRS System Requirements Documents. These requirements were incorporated within the Design Reference Missions (DRM's) identified for use in this and other subsystem trade studies. This study investigated the following propulsion systems: solid rocket, monopropellant, bipropellant (monomethyl hydrazine and nitrogen tetroxide or MMH/NTO), dual-mode bipropellant (hydrazine and nitrogen tetroxide or N2H4/NTO), liquid oxygen and liquid hydrogen (LO2/LH2), and an advanced design propulsion system using SDI-developed components. A liquid monopropellant blowdown propulsion system was found to be best suited for meeting the RRS requirements and is recommended as the baseline system. This system was chosen because it is the simplest of all investigated, has the fewest components, and is the most cost effective. The monopropellant system meets all RRS performance requirements and has the capability to provide a very accurate deorbit burn which minimizes reentry dispersions. In addition, no new hardware qualification is required for a monopropellant system. Although the bipropellant systems offered some weight savings capability for missions requiring large deorbit velocities, the advantage of a lower mass system only applies if the total vehicle design can be reduced to allow a cheaper launch vehicle to be used. At the time of this trade study, the overall RRS weight budget and launch vehicle selection were not being driven by the propulsion system selection. Thus, the added cost and complexity of more advanced systems did not warrant application.

Source record↗

NASA NTRS2004

Vibration Characteristics Determined for Stainless Steel Sandwich Panels With a Metal Foam Core for Lightweight Fan Blade Design

The goal of this project at the NASA Glenn Research Center is to provide fan materials that are safer, weigh less, and cost less than the currently used titanium alloy or polymer matrix composite fans. The proposed material system is a sandwich fan construction made up of thin solid face sheets and a lightweight metal foam core. The stiffness of the sandwich structure is increased by separating the two face sheets by the foam layer. The resulting structure has a high stiffness and lighter weight in comparison to the solid facesheet material alone. The face sheets carry the applied in-plane and bending loads (ref. 1). The metal foam core must resist the transverse shear and transverse normal loads, as well as keep the facings supported and working as a single unit. Metal foams have ranges of mechanical properties, such as light weight, impact resistance, and vibration suppression (ref. 2), which makes them more suitable for use in lightweight fan structures. Metal foams have been available for decades (refs. 3 and 4), but the difficulties in the original processes and high costs have prevented their widespread use. However, advances in production techniques and cost reduction have created a new interest in this class of materials (ref. 5). The material chosen for the face sheet and the metal foam for this study was the aerospace-grade stainless steel 17-4PH. This steel was chosen because of its attractive mechanical properties and the ease with which it can be made through the powder metallurgy process (ref. 6). The advantages of a metal foam core, in comparison to a typical honeycomb core, are material isotropy and the ease of forming complex geometries, such as fan blades. A section of a 17-4PH sandwich structure is shown in the following photograph. Part of process of designing any blade is to determine the natural frequencies of the particular blade shape. A designer needs to predict the resonance frequencies of a new blade design to properly identify a useful operating range. Operating a blade at or near the resonance frequencies leads to high-cycle fatigue, which ultimately limits the blade's durability and life. So the aim of this study is to determine the variation of the resonance frequencies for an idealized sandwich blade as a function of its face-sheet thickness, core thickness, and foam density. The finite element method is used to determine the natural frequencies for an idealized rectangular sandwich blade. The proven Lanczos method (ref. 7) is used in the study to extract the natural frequency.

Ghosn, Louis J.↗

NASA NTRS2001

Reverse Micelle Based Synthesis of Microporous Materials in Microgravity

Microporous materials include a large group of solids of varying chemical composition as well as porosity. These materials are characterized by channels and cavities of molecular dimensions. The framework structure is made up of interconnecting T-O-T' bonds, where T and T' can be Si, Al, P, Ga, Fe, Co, Zn, B and a host of other elements. Materials with Si-O-Al bonding in the framework are called zeolites and are extensively used in many applications. Ion-exchange properties of these materials are exploited in the consumer and environmental industries. Chemical and petroleum industries use zeolites as catalysts in hydrocarbon transform ations. Synthesis of new microporous frameworks has led to the development of new technologies, and thus considerable effort worldwide is expended in their discovery. Microporous materials are typically made under hydrothermal conditions. Influence of nature of starting reactants, structure directing agents, pH, temperature, and aging all have profound influence on the synthesis process. This is primarily because the most interesting open frameworks are not necessarily the stable structures in the reaction medium. Thus, the discovery of new frameworks is often tied to finding the right composition and synthesis conditions that allow for kinetic stabilization of the structure. This complexity of the synthesis process and limited understanding of it has made it difficult to develop directed is of microporous materials and most advances in this field have been made by trial and error. The basic issues in crystal growth of these materials include: (1) Nature of the nucleation process; (2) Molecular structure and assembly of nuclei; (3) Growth of nuclei into crystals; (4) Morphology control; and (5) Transformation of frameworks into other structures. The NASA-funded research described in this paper focuses on all the above issues and has been described in several publications. We present the highlights of our program, especially with the focus on possible experiments in microgravity.

Dutta, Prabir K.↗

NASA NTRS1993

Near-ambient solid polymer fuel cell

Fuel cells are extremely attractive for extraterrestrial and terrestrial applications because of their high energy conversion efficiency without noise or environmental pollution. Among the various fuel cell systems the advanced polymer electrolyte membrane fuel cells based on sulfonated fluoropolymers (e.g., Nafion) are particularly attractive because they are fairly rugged, solid state, quite conductive, of good chemical and thermal stability and show good oxygen reduction kinetics due to the low specific adsorption of the electrolyte on the platinum catalyst. The objective of this program is to develop a solid polymer fuel cell which can efficiently operate at near ambient temperatures without ancillary components for humidification and/or pressurization of the fuel or oxidant gases. During the Phase 1 effort we fabricated novel integral electrode-membrane structures where the dispersed platinum catalyst is precipitated within the Nafion ionomer. This resulted in electrode-membrane units without interfacial barriers permitting unhindered water diffusion from cathode to anode. The integral electrode-membrane structures were tested as fuel cells operating on H2 and O2 or air at 1 to 2 atm and 10 to 50 C without gas humidification. We demonstrated that cells with completely dry membranes could be self started at room temperature and subsequently operated on dry gas for extended time. Typical room temperature low pressure operation with unoptimized electrodes yielded 100 mA/cm(exp 2) at 0.5V and maximum currents over 300 mA/cm(exp 2) with low platinum loadings. Our results clearly demonstrate that operation of proton exchange membrane fuel cells at ambient conditions is feasible. Optimization of the electrode-membrane structure is necessary to assess the full performance potential but we expect significant gains in weight and volume power density for the system. The reduced complexity will make fuel cells also attractive for smaller and portable power supplies and as replacement for batteries.

Holleck, G. L.↗

NASA NTRSDate not supplied

A Transmission Electron Microscopy Study of a Refractory Metal Grain from a Calcium-Aluminum-Rich Inclusion in the Leoville CV3 Chondrite

Introduction: Calcium-aluminum-rich inclusions (CAIs) are an important component of chondritic meteorites. They can contain materials that are thermodynamically predicted and isotopically age dated to be among the first-formed solids in our solar system [1-5]. Observed in some CAIs are micron to sub-micron sized inclusions rich in Fe, Ni, and high-Z elements such as Pt, Os, Ir and W, in the form of refractory metal nuggets (RMNs), fremdlinges, and ‘nugget like objects’ (NLOs) [1,6]. Refractory siderophile elements such as Os, Ir and Ru are thermodynamically predicted to condense at temperatures well in excess of the major CAI phases such as melilite, perovskite, spinel and hibonite [2,7-9]. These refractory metal inclusions in CAIs can therefore serve as probes into the thermodynamic landscape of the early solar protoplanetary disk. Here we report on a refractory grain identified in a CAI of the Leoville CV3 chondrite. This work is part of an ongoing effort to gain insight into the thermochemistry of the early solar system through systematic analyses of the structure and chemistry of various components in CAIs [10-13]. Sample and Analytical Techniques: A fluffy type A CAI (Fig. 1A) was identified in a section of the Leoville, CV3 chondrite (Center for Meteorite Studies, Arizona State University collection, #821_C_3) using a JOEL-JXA 8530F electron microprobe at Arizona State University. Backscattered electron (BSE) imaging and energy-dispersive X-ray spectroscopy (EDS) were used to identify refractory metal grains in the CAI using a Thermo Fisher (formerly FEI) Helios NanoLab 660 G3 focused-ion-beam scanning-electron microscope (FIBSEM) located at the Kuiper Materials Imaging and Characterization Facility (KMICF) at the Lunar and Planetary Laboratory, University of Arizona. The FIB is equipped with an EDAX EDS system. We selected one of the larger (micron-sized) refractory metal grains, designated as ‘Spud’ (Fig. 1B) for further analysis. ‘Spud’ was extracted and thinned to electron transparency (<100 nm) using the FIB-SEM located in KMICF, following methods described by [14- 15]. The FIB section was analyzed using a 200 keV Hitachi HF5000 scanning transmission electron microscope (S/TEM) located at KMICF. The HF5000 is equipped with cold-field emission gun, 3rd-order spherical aberration corrector for STEM imaging, and an Oxford Instruments X-Max N 100 TLE energydispersive spectroscopy (EDS) system with dual 100 mm2 windowless silicon-drift detectors (Ω = 2.0 sr). Selected-area electron-diffraction (SAED) patterns were acquired to aid in determination of crystallinity and phase. Results: The mineralogy, texture, and morphology of the CAI are consistent with that of a fluffy type A (FTA) CAI [16]. BSE imaging at high magnifications revealed grains with high contrast, indicative of compositions rich in elements of higher atomic number relative to surrounding material. These high-Z grains have sizes that range from ∼250 nm to 4 µm. EDS analyses confirm that the bright grains are metal-rich inclusions. A minor fraction of the grains are composed of only Fe and Ni, but the majority (∼60%) of the identified inclusions also contained various refractory siderophiles including Os, Ru, Zr, Ir and Mo. EDS analysis on the FIB-SEM of Spud shows that it contains Fe, Ni, Mo and Ru. High-angle annular dark-field (HAAFD) imaging and EDS mapping in the TEM (Fig. 2) show that Spud occurs in melilite (Ca1.9Al1.99Si1.06O7). Spud contains a subhedral to anhedral morphology and is compositionally heterogenous (polyphasic, Fig. 2). Local spatial correlation occurs among Fe, Ni, and Pt, and also among Os, Ru, and Mo. SAED patterns show that the Fe-Ni-Pt, Fe-Os-Mo-Ru and Fe-Pt regions are crystalline. Discussion: CAIs can contain various types of inclusions rich in Fe, Ni and refractory siderophiles such as Os, Ru, W and Pt [1]. RMNs are micron-sized, single phase alloy grains and can contain Os, Ir, Ru and Rh [1,7,17]. NLOs are also micron-sized inclusions, but contain two phases, a refractory metal, and an oxide [6]. Fremdlinge are the largest of such inclusions (tens of microns in size) and are complex aggregates of Fe-Ni alloy, silicates, oxides, and sulfides [1,17]. While the size of Spud matches previous descriptions of RMNs and NLOs, Spud is neither a single-phase alloy like RMNs, nor does it contain one metal phase and one oxide like NLOs. Spud does not match the above described categories of refractory metal inclusions. The presence of refractory siderophiles such as Mo, Os, Ru, and Pt suggests a high-temperature origin. Thermodynamic modelling by [7] indicates condensation temperatures of 1917 K, 1693 K, 1613 K and 1415 K for Os, Mo, Ru and Pt respectively. These models also show that following the initial condensation of a refractory metal, alloying of solutes such as Fe, Ni and W, occurs in levels proportional to their partial pressures in the surrounding gas. Such alloying occurs at temperatures above the condensation temperatures of common CAI phases such as melilite (1529 K), perovskite (1441 K), spinel (197 K) and forsterite (1354 K) [2]. The polyphasic nature of Spud could be the result of such high-temperature alloying, possibly shortly after the condensation of Mo and Ru at 1693 K and 1613 K respectively. That Spud occurs as an inclusion is consistent with it having formed prior to and at temperature above that of its host melilite in this FTA CAI, which is qualitatively consistent with such prior thermodynamic modeling. Further, the polyphasic nature of Spud is similar to refractory grains from a FTA CAI in the Northwest Africa (NWA) 8323, CV3 chondrite [11-13]. These data suggest that such refractory metal grains could have been widespread in the inner and early solar protoplanetary disk and represent some of the earliest formed solids to have condensed. Acknowledgments: Research and instrumentation supported by NASA grants #NNX12AL47G, #NNX15AJ22G and #80NSSC19K0509, and NSF grants #1531243 and #0619599. Fig 2. STEM data on ‘Spud’. HAADF Image (Top) False-color EDS Maps (Bottom) References: [1] MacPherson G. J. (2014) T. of Geochem. Vol I: Met. And Cosmochem. Processes, 139-179. [2] Lodders K. (2003) ApJ, 591, 1220-1247. [3] Ebel D. S. (2006) Met. & the Early S. Sys. II., 253- 277. [4] Amelin Y. (2002) Science, 297, 1678-1683. [5] Connelly J.N. et.al. (2012) Science, 338, 651-655. [6] Schwander D. et al. (2015) GCA, 18, 70-87. [7] Palme H. and Wlotzka F. (1976) EPSL, 33, 45-60. [8] Berg T. et al. (2009) ApJ, 702, 172-176. [9] Liffman K. et al. (2021) Icarus, 221, 89-105. [10] Zega T.J. et al. (2021) PSJ, 2, 115. [11] Ramprasad T. et al. (2020) LPSC LI, Abstract #2472. [12] Ramprasad T. et al. (2021) Microscopy & Microanalysis, S1, 2792-2794. [13] Ramprasad T. et al. (2021) 84th MetSoc, Abstract #6123. [14] Zega T.J. et al. (2007) MAPS, 42, 1373-1386. [15] Ramprasad T. et al. (2022) MAPS, in revision. [16] Grossman L. (1975), GCA, 39, 433-454. [17] El Goresy A. et al. (1978) LPSC IX, Abstract#1100

T. Ramprasad↗

NASA NTRS2013

Organic Nano-Grains in Comet 103P/Hartley 2: The Organic Glue of Porous Aggregate Grains?

The GNIRS instrument on the Gemini 8-‐m telescope observed comet 103P/Hartley on 2010-‐ Dec-‐04UT, a month after the EPOXI Mission encounter, and detected the 3.3 and 3.4 um bands in emission. The 3.3/3.4 ratio and the broad band widths are consistent with experiments of heated (approximately 600 K) aliphatic carbon (-CH3, -CH2) thin films. For the 3.4 micron band to be in emission, the aliphatic bonds must be attached to a carrier possessing the strongly UV-‐absorbing C=C aromatic rings, and these rings have to be less than 50-‐100 carbon atoms (4-6 Angstrom) for attached -CH bonds to also generate a 3.3 micron-band in emission. Slightly larger (≥10Å) Very Small Grains (VSGs) can absorb single UV photons comparable to or exceeding their heat capacity, thermally fluctuate and release IR photon(s). The 3.3 micron and 3.4 micron bands observed by GNIRS suggest that organic macromolecules/ nano-‐grains with both aliphatic and aromatic bonds are fluorescing/thermally fluctuating in the coma. Aliphatic and aromatic materials have been seen in Stardust samples and the primitive carbonaceous chondrite 'Tagish Lake'. The larger the ratio of the -CH2/-CH3 components of the aliphatic 3.4 micron band, the more 'primitive' the organic material. In a Stardust organic globule, some aliphatic bonds were transformed into aromatic bonds during the low dosage of Transmission Electron Microscope imaging. Conversely, lab experiments show irradiation of ices containing small PAHs generates aliphatic organics. Photo-‐processing of ices also likely forms the ubiquitous aliphatic coatings that appear on the surfaces of all silicate subgrains constituting nine cometary interplanetary dust particles. The aliphatic coatings, dominated by -CH2, likely were important in sticking the aggregates together, and existed prior to incorporation of dust aggregates into comet nuclei. These comet aliphatics may be some of the sought-‐after precursors to the more robust and complex organics studied as Insoluble Organic Matter in carbonaceous chondrites. Aliphatic coatings on submicron grains, however, will not be observable in absorption because they are fairly transparent, nor do the aliphatic carbonaceous coatings produce the 3.4 micron emission band because the particles they are attached to are too large (too many vibration modes). We must probe the nano-‐sized organic carriers that undergo substantive thermal fluctuations in cometary comae and emit at 3.3 3.4 micron. Observations of the 3.3 and 3.4 micron emission features contribute to characterizing the evolution of organics prior to their incorporation into cometary nuclei as well as their rapid evolution in cometary comae, which in turn contributes to deepening our understanding of the evolution of organics on the surfaces of asteroids and outer icy bodies in our solar system. Studying organics in comets contributes to understanding the formation and evolution pathways of ISM organics through to the formation of the robust insoluble organic matter in meteorites. A'Hearn, M.F., et al. 2011, Science, 332, 1396; Bockelee-‐Morvan, D. et al. 1995, Icarus, 116, 18; De Gregorio, B.T., et al. 2010, GCA, 74, 4454; Dello Russo, N., et al. 2011, ApJ, 734, L8; Dischler et al. 1983, Solid State Communications, 48, 105; Flynn, G., et al. 2010a, LPSC, 41, #1079; Flynn, G., et al. 2010b, COSPAR, 38, F31-‐0012-‐10; Flynn, G., Wirick, S. 2011, LPSC, 42, #1856; Fomenkova, et al. 1994, GCA 58, 4503; Matrajt, G., et al. 2013, ApJ, 765, 145; Schutte, et al. 1993, ApJ, 415, 397; Wooden, D.H. et al. 2011, EPSC-‐DPS, 1557; Wooden, D.H. et al. 2013, submitted.

Stardust samples↗

NASA NTRS2012

Burning Questions in Gravity-Dependent Combustion Science

Building upon a long history of spaceflight and ground based research, NASA's Combustion Science program has accumulated a significant body of accomplishments on the ISS. Historically, NASAs low-gravity combustion research program has sought: to provide a more complete understanding of the fundamental controlling processes in combustion by identifying simpler one-dimensional systems to eliminate the complex interactions between the buoyant flow and the energy feedback to the reaction zone to provide realistic simulation of the fire risk in manned spacecraft and to enable practical simulation of the gravitational environment experienced by reacting systems in future spacecraft. Over the past two decades, low-gravity combustion research has focused primarily on increasing our understanding of fundamental combustion processes (e.g. droplet combustion, soot, flame spread, smoldering, and gas-jet flames). This research program was highly successful and was aided by synergistic programs in Europe and in Japan. Overall improvements were made in our ability to model droplet combustion in spray combustors (e.g. jet engines), predict flame spread, predict soot production, and detect and prevent spacecraft fires. These results provided a unique dataset that supports both an active research discipline and also spacecraft fire safety for current and future spacecraft. These experiments have been conducted using the Combustion Integrated Rack (CIR), the Microgravity Science Glovebox and the Express Rack. In this paper, we provide an overview of the earlier space shuttle experiments, the recent ISS combustion experiments in addition to the studies planned for the future. Experiments in combustion include topics such as droplet combustion, gaseous diffusion flames, solid fuels, premixed flame studies, fire safety, and super critical oxidation processes.

Urban, David↗

NASA NTRS2024

MSFC-TVC | TB-03: Derivation of Thrust Vector Control (TVC) Actuator-Force / Gimbal-Torque Transformation Matrix

Thrust vector control (TVC) systems for rocket engine propulsion traditionally use a simple linear relationship to convert between actuator forces and torques about the engine gimbal’s center-of-rotation (COR). As shown in Equation (1), the torque about the gimbal COR is proportional to the applied actuator force and the TVC moment arm (MA)—the perpendicular distance between the TVC actuator’s line-of-action (LOA) and the engine gimbal’s COR. While this fundamental relationship remains valid and accurate in a two-dimensional (2D), one-degree-of-freedom (1-DOF) context—particularly in its non-linear formulation as described in the ER63 Technical Bulletin TB-02 (Derivation of Thrust Vector Control (TVC) Engine-Gimbal / Actuator Moment-Arm Geometry)—it becomes limited when extended to three-dimensional (3D), two-degree-of-freedom (2-DOF) analyses. In 3D, out-of-plane angular displacements can arise, causing the gimbaled engine plane-of-motion to become non-coplanar with the respective actuator plane-of-motion. Such misalignments occur due to the rod-end (RE) and/or tail-stock (TE) mounting geometry of individual TVC actuators. These geometric complexities lead to inaccuracies in calculating engine torques and corresponding actuator forces if only the traditional TVC MA relationship is employed. For higher gimbal angular displacements (e.g., greater than 5 degrees), these inaccuracies become more pronounced, necessitating a more robust mathematical framework. This document presents a comprehensive 3D (2-DOF) derivation of a transformation matrix that accurately converts between gimbaled engine torques and TVC actuator forces. By incorporating the necessary geometric and rotational considerations, this new approach corrects the limitations of the traditional TVC MA method. Subsequent sections compare the newly formulated approach to the traditional method, demonstrating its enhanced accuracy and reliability for a broad range of gimbaled engine conditions.

Thrust Vector Control↗

NASA NTRS1994

Petrologic evolution of CM chondrites: The difficulty of discriminating between nebular and parent-body effects

We wish to draw attention to a major controversy that has arisen in the area of CM-chondrite petrology. The problem is important because its resolution will have profound implications for ideas concerning nebular dynamics, gas-solid interactions in the nebula, and accretionary processes in the nebula, among other issues. On the one hand, cogent arguments have been presented that 'accretionary dust mantles,' were formed in the solar nebula prior to accretion of the CM parent asteroid(s). On the other hand, no-less-powerful arguments have been advanced that a significant fraction of the CM lithology is secondary, produced by aqueous alteration in the near-surface regions of an asteroid-sized object. Because most, if not all, CM chondrites are breccias, these two views could coexist harmoniously, were it not for the fact that some of the coarse-grained lithologies surrounded by 'accretion dust mantles' are themselves of apparently secondary origin. Such an observation must clearly force a reassessment of one or both of the present schools of thought. Our objective here is to stimulate such a reassessment. Four possible resolutions of this conflict may be postulated. First, perhaps nature found a way of permitting such secondary alteration to take place in the nebula. Second, maybe dust mantles could form in a regolith, rather than a nebular, environment. Third, it is possible that dust mantles around secondary lithologies are different from those around primary lithologies. Finally, perhaps formation of CM chondrites involved a more complex sequence of events than visualized so far, so that some apparently 'primary' processes postdated certain 'secondary' processes.

Kerridge, J. F.↗

NASA NTRS2010

Single Spatial-Mode Room-Temperature-Operated 3.0 to 3.4 micrometer Diode Lasers

Compact, highly efficient, 3.0 to 3.4 m light emitters are in demand for spectroscopic analysis and identification of chemical substances (including methane and formaldehyde), infrared countermeasures technologies, and development of advanced infrared scene projectors. The need for these light emitters can be currently addressed either by bulky solid-state light emitters with limited power conversion efficiency, or cooled Interband Cascade (IC) semiconductor lasers. Researchers here have developed a breakthrough approach to fabrication of diode mid-IR lasers that have several advantages over IC lasers used for the Mars 2009 mission. This breakthrough is due to a novel design utilizing the strain-engineered quantum-well (QW) active region and quinternary barriers, and due to optimization of device material composition and growth conditions (growth temperatures and rates). However, in their present form, these GaSb-based laser diodes cannot be directly used as a part of sensor systems. The device spectrum is too broad to perform spectroscopic analysis of gas species, and operating currents and voltages are too high. In the current work, the emitters were fabricated as narrow-ridge waveguide index-guided lasers rather than broad stripe-gain guided multimode Fabry-Perot (FP) lasers as was done previously. These narrow-ridge waveguide mid-IR lasers exhibit much lower power consumptions, and can operate in a single spatial mode that is necessary for demonstration of single-mode distributed feedback (DBF) devices for spectroscopic applications. These lasers will enable a new generation of compact, tunable diode laser spectrometers with lower power consumption, reduced complexity, and significantly reduced development costs. These lasers can be used for the detection of HCN, C2H2, methane, and ethane.

Frez, Clifford F.↗

NASA NTRS2005

Galileo SSI Observations of Volcanic Activity at Tvashtar Catena, Io

Introduction: We report on the analysis of the Galileo SSI's observations of the volcanic activity at Tvashtar Catena, Io as discussed by Milazzo et al. Galileo's Solid State Imager (SSI) observed Tvashtar Catena (63 deg N, 120 deg W) four times between November 1999 and October 2001, providing a unique look at the distinctive high latitude volcanism on Io. The November 1999 observation spatially resolved, for the first time, an active extraterrestrial fissure eruption. The brightness temperature of the lavas at the November 1999 fissure eruption was 1300 K. The second observation (orbit I27, February 2000) showed a large (approx. 500 sq km) region with many, small spots of hot, active lava. The third observation was taken in conjunction with a Cassini observation in December 2000 and showed a Pele-like plume deposition ring, while the Cassini images revealed a 400 km high Pele-type plume above the Catena. The final Galileo SSI observation of Tvashtar was acquired in October 2001, and all obvious (to SSI) activity had ceased, although data from Galileo's Near Infrared Mapping Spectrometer (NIMS) indicated that there was still significant thermal emission from the Tvashtar region. We have concentrated on analyzing the style of eruption during orbit I27 (February 2000). Comparison with a lava flow cooling model indicates that the behavior of the Tvashtar eruption during I27 does not match that of "simple" advancing lava flows. Instead, it may be an active lava lake or a complex set of lava flows with episodic, overlapping (in time and space) eruptions.

Milazzo, M. P.↗

NASA NTRS2020

Disruptive Technologies and Their Putative Impacts Upon Society and Aerospace- Entering The Virtual Age

Developments in technology over the recent decades have been extraordinary. They include the IT, bio, nano, and now quantum and energetics technology arenas and their many combinatorial interactions and impacts. In the main, these are at the frontiers of the small and in a combinational, synergistic feeding frenzy with each other. They fall under the broad category of Disruptive Technologies and have greatly altered society. The outlook for the runout of these and other technology developments augers mid-term to later alterations in components of the human existence theorem, including the requirement to work for our living and our physiological makeup and longevity (Ref 1). The IT revolution began in the 1950s with the development of solid-state electronics. The biologics revolution began later in the 1960s and 1970s with DNA and genomics, and the nano revolution in the 1990s with self-forming nano systems and carbon nanotubes. Quantum technology is now developing rapidly, aided by enabling nano systems, and the energetics revolution is providing ever more efficient and less expensive renewable energy sources. The IT revolution has produced improvements of an astounding eleven orders of magnitude in computing speed since the late 1950s. As we shift from silicon to biological, optical, nano, molecular, and atomic computing, improvements of some 4 orders of magnitude are evidently possible from either optical or DNA computing [Refs 2and 3], then there are combinatorials. Then there is quantum computing, under development worldwide for an increasing number of applications and proffering phenomenal capabilities. The current fastest computers are considerably beyond human brain speed. Machine intelligence is developing well after decades of inadequate machine capability, now no longer the case, and a detour into expert systems. Researchers in machine intelligence are now pursuing deep learning approaches using neural nets, which are proving to be extremely useful. Some believe the frontier of potential human-level machine intelligence may be found in biomimetics and brain-emulation approaches. There is even a possibility of “emergence”—i.e., when the machine intelligence is complex enough that it “wakes up,” as when human intelligence emerged via evolution during the million-plus years of the hunter-gatherer epoch [ Ref 4]. In fact, some posit that human intelligence can be improved upon and is only a cul-de-sac of what is conceivable. The IT revolution has produced massive changes in human society and economics—from the Internet, enabling the rapid expansion of knowledgeability (and even what is knowable), to an increasingly pervasive trend of “tele-everything.” The extraordinary compilation, storage, and availability of truly massive amounts of information could, when combined with AI and under the mantra of “big data,” greatly improve many of our technical and commercial processes and their content including elucidating new heuristic governing laws.

Dennis M. Bushnell↗

NASA NTRS2010

Ares I-X Flight Test Development Challenges and Success Factors

The NASA Constellation Program's Ares I-X rocket launched successfully on October 28, 2009 collecting valuable data and providing risk reduction for the Ares I project. The Ares I-X mission was formulated and implemented in less than four years commencing with the Exploration Systems Architecture Study in 2005. The test configuration was founded upon assets and processes from other rocket programs including Space Shuttle, Atlas, and Peacekeeper. For example, the test vehicle's propulsion element was a Shuttle Solid Rocket Motor. The Ares I-X rocket comprised a motor assembly, mass and outer mold line simulators of the Ares I Upper Stage, Orion Spacecraft and Launch Abort System, a roll control system, avionics, and other miscellaneous components. The vehicle was 327 feet tall and weighed approximately 1,800,000 pounds. During flight the rocket reached a maximum speed of Mach 4.8 and an altitude of 150,000 feet. The vehicle demonstrated staging at 130,000 feet, tested parachutes for recovery of the motor, and utilized approximately 900 sensors for data collection. Developing a new launch system and preparing for a safe flight presented many challenges. Specific challenges included designing a system to withstand the environments, manufacturing large structures, and re-qualifying heritage hardware. These and other challenges, if not mitigated, may have resulted in test cancellation. Ares I-X succeeded because the mission was founded on carefully derived objectives, led by decisive and flexible management, implemented by an exceptionally talented and dedicated workforce, and supported by a thorough independent review team. Other major success factors include the use of proven heritage hardware, a robust System Integration Laboratory, multi-NASA center and contractor team, concurrent operations, efficient vehicle assembly, effective risk management, and decentralized element development with a centralized control board. Ares I-X was a technically complex test that required creative thinking, risk taking, and a passion to succeed.

Askins, Bruce↗

NASA NTRSDate not supplied

Material Property Estimation in Thin Battery Components Using Guided Wave Measurement, Experimental Dispersion Curve Extraction and Finite Element Modeling

At NASA, we are investigating nondestructive evaluation (NDE) and structural health monitoring (SHM) techniques to detect precursors of thermal runaway failure in lithium metal based lithium ion batteries (LIB). The approach is centered on computational simulation models to guide inspection and aid in interpretation of results. Since lithium metal LIBs have combinations of solid and fluid-filled porous materials, obtaining accurate material properties is both challenging and critical for successful simulation of battery inspection. To this end, we investigated a multi-verification approach for material characterization of thin battery components. First, a laser Doppler vibrometer (LDV) was used to measure guided wave fields in thin (microns-thick) battery components subject to broadband excitation. The time-space wavefield data was converted to frequency-wave number data to extract guided wave dispersion curves. A data visualization and post processing graphics user interface (GUI) was developed at NASA to aid the data exploration and analysis. Due to the thinness of the samples, low frequency-thickness-product plate wave approximations allowed for the calculation of closed-form solutions for material elastic property estimation. These approximations were then verified by calculating the Lamb wave solutions using the previously obtained material properties. Finally, the estimated elastic material properties were implemented in a COMSOL simulation model, and dispersion curves were extracted from simulation results. The dispersion curves and derived material properties were then compared to the analysis results from the experimental data. These comparisons informed on the accuracy of the measured material properties and helped demonstrate the accuracy of the finite element analysis (FEA) computational models. This assessment will prove vital when we start simulating more complex multi-layer components and poroelastic media. This paper gives a brief background of the problem space, outlines the workflow for data analysis and verification, shows results from the workflow, and gives an overview of future plans for simulation of lithium metal LIB inspection.

Peter Juarez↗

NASA NTRS2008

Using Piezoelectric Devices to Transmit Power through Walls

A method denoted wireless acoustic-electric feed-through (WAEF) has been conceived for transmitting power and/or data signals through walls or other solid objects made of a variety of elastic materials that could be electrically conductive or nonconductive. WAEF would make it unnecessary to use wires, optical fibers, tubes, or other discrete wall-penetrating signal-transmitting components, thereby eliminating the potential for structural weakening or leakage at such penetrations. Avoidance of such penetrations could be essential in some applications in which maintenance of pressure, vacuum, or chemical or biological isolation is required. In a basic WAEF setup, a transmitting piezoelectric transducer on one side of a wall would be driven at resonance to excite ultrasonic vibrations in the wall. A receiving piezoelectric transducer on the opposite side of the wall would convert the vibrations back to an ultrasonic AC electric signal, which would then be detected and otherwise processed in a manner that would depend on the modulation (if any) applied to the signal and whether the signal was used to transmit power, data, or both. An electromechanical-network model has been derived as a computationally efficient means of analyzing and designing a WAEF system. This model is a variant of a prior model, known in the piezoelectric-transducer art as Mason's equivalent-circuit model, in which the electrical and mechanical dynamics, including electromechanical couplings, are expressed as electrical circuit elements that can include inductors, capacitors, and lumped-parameter complex impedances. The real parts of the complex impedances are used to account for dielectric, mechanical, and coupling losses in all components (including all piezoelectric-transducer, wall, and intermediate material layers). In an application to a three-layer piezoelectric structure, this model was shown to yield the same results as do solutions of the wave equations of piezoelectricity and acoustic propagation in their full complexity.

Sherrit, Stewart↗

NASA NTRS2001

Method Improvements in Thermal Analysis of Mach 10 Leading Edges

Several improvements have recently been made in the thermal analysis methods for leading edges of a hypersonic vehicle. The leading edges of this vehicle undergo exceptionally high heat loads that incorporate extreme spatial gradients as well as severe transients. Due to the varying flight conditions, complex geometry, and need for thermal loads at many points along the trajectory, full computational fluid dynamics (CFD) analysis of the aeroheating; loads is not feasible. Thus, engineering methods must be used to determine the aeroheating on the vehicle surfaces, and that must be utilized in the thermal analysis. Over the last year, the thermal analysis of a hypersonic vehicle has been enhanced in several ways. Two different engineering codes are used to predict aeroheating loads: one over the curve near the stagnation point, and the other on flat surfaces downstream of the leading edge. These two are matched together at the intersection point using a method that allows closer approximation of CFD results. User-developed FORTRAN, which is part of the thermal solver PATRAN Thermal, is used to accomplish this. The customizable FORTRAN code also allows use of many different time- and space-dependent factors, interpolation of the heat load in time and space, and inclusion of both highly swept and unswept grid structures. This FORTRAN is available to other PATRAN users who may want to accomplish a similar objective in analysis. Flux, rather than convective coefficient, is used to define heat loads, which allows more accurate analysis as well as better application of margins. Improvements have also been made in more efficient utilization of imported CAD geometry, by creating faces on solids to facilitate load application.

Amundsen, Ruth M.↗

NASA NTRS1994

STS-59 Space Shuttle mission report

The STS-59 Space Shuttle Program Mission Report summarizes the Payload activities as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Redesigned Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the sixty-second flight of the Space Shuttle Program and sixth flight of the Orbiter vehicle Endeavor (OV-105). In addition to the Orbiter, the flight vehicle consisted of an ET designated as ET-63; three SSME's which were designated as serial numbers 2028, 2033, and 2018 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-065. The RSRM's that were installed in each SRB were designated as 360W037A (welterweight) for the left SRB, and 360H037B (heavyweight) for the right SRB. This STS-59 Space Shuttle Program Mission Report fulfills the Space Shuttle Program requirement as documented in NSTS 07700, Volume 8, Appendix E. That document requires that each major organizational element supporting the Program report the results of its hardware evaluation and mission performance plus identify all related in-flight anomalies. The primary objective of the STS-59 mission was to successfully perform the operations of the Space Radar Laboratory-1 (SRL-1). The secondary objectives of this flight were to perform the operations of the Space Tissue Loss-A (STL-A) and STL-B payloads, the Visual Function Tester-4 (VFT-4) payload, the Shuttle Amateur Radio Experiment-2 (SAREX-2) experiment, the Consortium for Materials Development in Space Complex Autonomous Payload-4 (CONCAP-4), and the three Get-Away Special (GAS) payloads.

Fricke, Robert W., Jr.↗