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NASA NTRS2002

A Virtual Mission Operations Center - Collaborative Environment

Development of technologies that enable significant reductions in the cost of space mission operations is critical if constellations, formations, federations and sensor webs, are to be economically feasible. One approach to cost reduction is to infuse automation technologies into mission operations centers so that fewer personnel are needed for mission support. But missions are more culturally and politically adverse to the risks of automation. Reducing the mission risk associated with increased use of automation within a MOC is therefore of great importance. The belief that mission risk increases as more automation is used stems from the fact that there is inherently less direct human oversight to investigate and resolve anomalies in an unattended MOC. The Virtual Missions Operations Center - Collaborative Environment (VMOC-CE) project was launched to address this concern. The goal of the VMOC-CE project is to identify, develop, and infuse technology to enable mission operations between onsite operators and on-call personnel in geographically dispersed locations. VMOC-CE enables missions to more readily adopt automation because off-site operators and engineers can more easily identify, investigate, and resolve anomalies without having to be present in the MOC. The VMOC-CE intent is to have a single access point for all resources used in a collaborative mission operations environment. Team members will be able to interact during spacecraft operations, specifically for resolving anomalies, utilizing a desktop computer and the Internet. Mission operations management can use the VMOC-CE as a tool to participate in and monitor status of anomaly resolution or other mission operations issues. In this paper we present the VMOC-CE project, system capabilities and technologies, operations concept, and results of its pilot in support of the Earth Science Mission Operations System (ESMOS).

Medina, Barbara↗

NASA NTRS2003

Water Ice Albedo Variations on the Martian Northern Polar Cap

The Viking Orbiters determined that the surface of Mars northern residual cap is water ice. Many researchers have related observed atmospheric water vapor abundances to seasonal exchange between reservoirs such as the polar caps, but the extent to which the exchange between the surface and the atmosphere remains uncertain. Early studies of the ice coverage and albedo of the northern residual Martian polar cap using Mariner 9 and Viking images reported that there were substantial internannual differences in ice deposition on the polar cap, a result which suggested a highly variable Martian climate. However, some of the data used in these studies were obtained at differing values of heliocentric solar longitude (L(sub s)). Reevaluation of this dataset indicated that the residual cap undergoes seasonal brightening throughout the summer, and indicated that this process repeats from year to year. In this study we continue to compare Mariner 9 and Viking Orbiter imaging observations and thermal data of the north residual polar cap to data acquired with Mars Global Surveyor s Mars Orbiter Camera (MOC) instrument. In the current study, our goal is to examine all released data from MGS MOC in the northern summer season, along with applicable TES data in order to better understand the albedo variations in the northern summer and their implications on water transport. To date, work has focused primarily on the MOC dataset. In 1999, data acquisition of the northern polar regions began at L(sub s) = 107, although there was little north polar data acquired from L(sub s)= 107 to L(sub s) = 109. We examined a total of 409 images from L(sub s) = 107 to L(sub s)=148. We have also examined data from 2000 from L(sub s)= 93 to L(sub s)= 110; additional progress is ongoing. Here we present a progress report of our observations, and continue to determine their implications for the Martian water cycle.

Hale, A. S.↗

NASA NTRS2005

Characterization of Layered Deposits inside Valles Marineris

This report represents the final progress report on our study of the Melas Chasma region on Mars that was proposed as a landing site for the Mars Exploration Rover mission (MER). During this two-year proposal (which was extended over three years by a no-cost extension), we conducted a thorough study of the layered deposits in western Melas Chasma that had been the location of a high priority MER mission landing ellipse within Valles Marineris. All available data sets from orbiter missions, including MOC, MOLA, THEMIS visible and infrared images were all used to analyze this site. The major outcome of this work was a published paper in the Journal of Geophysics and Research Planets [Weitz et al., 2004]. Our geologic mapping and interpretation of the MOC images suggest the landing ellipse contains three main geomorphologic units: (1) a blocky deposit consisting of bright blocks in a darker matrix (BD); (2) sand sheets composed of dark dunes; and (3) landslide deposits emanating from the wallrock to the west [Weitz et al., 2003]. Furthermore, we propose that the morphology of the BD unit in western Melas is a mass wasting deposit composed of blocks of Interior Layered Deposits (ILDs) mixed in with wallrock material. However, more recent MOC images indicate that in the eastern portion of the ellipse and adjacent to a large hill, there are blocks of material resembling those seen in BD. Hence, we cannot rule out the source of BD was this hill. Unfortunately, sand dunes obscure much of the deposit around this hill, making it impossible to precisely determine the connection between the hill and BD, whereas BD can be traced directly to the southern Melas wallrock. If BD resulted from a mass wasting event in the southern wallrock, then we would expect the material to be concentrated further to the north, as now appears to be the case. In summary, the exact source location for BD continues to remain a mystery, but we favor an origin from either the southern wallrock [Weitz et el., 2002] or the eastern hill.

Weitz, Catherine↗

NASA NTRS2008

Microgravity Flame Spread in Exploration Atmospheres: Pressure, Oxygen, and Velocity Effects on Opposed and Concurrent Flame Spread

Microgravity tests of flammability and flame spread were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows. Three thin fuels were tested for flammability (Ultem 1000 (General Electric Company), 10 mil film, Nomex (Dupont) HT90-40, and Mylar G (Dupont) and one fuel for flame spread testing (Kimwipes (Kimberly-Clark Worldwide, Inc.). The 1g Upward Limiting Oxygen Index (ULOI) and 1g Maximum Oxygen Concentration (MOC) are found to be greater than those in 0g, by up to 4% oxygen mole fraction, meaning that the fuels burned in 0g at lower oxygen concentrations than they did using the NASA Standard 6001 Test 1 protocol. Flame spread tests with Kimwipes were used to develop correlations that capture the effects of flow velocity, oxygen concentration, and pressure on flame spread rate. These correlations were used to determine that over virtually the entire range of spacecraft atmospheres and flow conditions, the opposed spread is faster, especially for normoxic atmospheres. The correlations were also compared with 1g MOC for various materials as a function of pressure and oxygen. The lines of constant opposed flow agreed best with the 1g MOC trends, which indicates that Test 1 limits are essentially dictated by the critical heat flux for ignition. Further evaluation of these and other materials is continuing to better understand the 0g flammability of materials and its effect on the oxygen margin of safety.

Olson, Sandra L.↗

NASA NTRS2008

Geologic Mapping of Athabasca Valles

Two factors drive us to map the Athabasca Valles area in unusual detail: (1) the extremely well-preserved and exposed surface morphologies and (2) the extensive high resolution imaging. In particular, the near-complete CTX coverage of Athabasca Valles proper and the extensive coverage of its surroundings have been invaluable. The mapping has been done exclusively in ArcGIS, using individual CTX, THEMIS VIS, and MOC frames overlying the THEMIS IR daytime basemap. MOLA shot points and gridded DTMs are also included. It was found that CTX images processed through ISIS are almost always within 300 m of the MOLA derived locations, and usually within tens of meters, with no adjustments to camera pointing. THEMIS VIS images appear to be systematically shifted to the southwest of their correct positions and MOC images are often kilometers off. The good SNR and minimal artifacts make the CTX images vastly more useful than the THEMIS VIS or MOC images. The bulk of the mapping was done at 1:50,000 scale on CTX images. In more complex areas, mapping at 1:24,000 proved necessary. The CTX images were usually simultaneously viewed on a second monitor using the ISIS3 qview program to display the full dynamic range of the CTX data. Where CTX data was not available, mapping was often done at 1:100,000 and most contacts are mapped as approximate.

Keszthelyi, L. P.↗

NASA NTRS2012

Data Distribution System (DDS) and Solar Dynamic Observatory Ground Station (SDOGS) Integration Manager

The DDS SDOGS Integration Manager (DSIM) provides translation between native control and status formats for systems within DDS and SDOGS, and the ASIST (Advanced Spacecraft Integration and System Test) control environment in the SDO MOC (Solar Dynamics Observatory Mission Operations Center). This system was created in response for a need to centralize remote monitor and control of SDO Ground Station equipments using ASIST control environment in SDO MOC, and to have configurable table definition for equipment. It provides translation of status and monitoring information from the native systems into ASIST-readable format to display on pages in the MOC. The manager is lightweight, user friendly, and efficient. It allows data trending, correlation, and storing. It allows using ASIST as common interface for remote monitor and control of heterogeneous equipments. It also provides failover capability to back up machines.

Pham, Kim↗

NASA NTRS2021

A Study into Validating a Coupled Method of Characteristics and Direct Simulation Monte Carlo Method Against Empirical Data

The following will outline the methodology and results of validating a coupled Method of Characteristics (MOC) and Direct Simulation Monte Carlo (DSMC) method. This research focused specifically on modeling plume impingement, induced by Reaction Control System (RCS) thrusters that flew on the National Aeronautics and Space Administration’s (NASA’s) space shuttle Discovery. For each simulation, the continuum portion of the RCS thruster was simulated using MOC for solving hyperbolic Partial Differential Equations (PDEs) and computed with the NASA code, Reacting and Multi-phase Program (RAMP). The solution was then implemented as a starting condition into the NASA DSMC code, Direct Simulation and Monte Carlo Analysis Code (DAC). Typically, DSMC models rely on code-to-code validation for fidelity. The significance of this research is in its ability to validate its models against empirical data. Prior to computing solutions for these simulations, the mesh size and structure were optimized and many variants of DSMC input parameters were iterated on in order to acquire a reliable, mesh-independent, fully optimized numerical solution. This research will discuss the mathematical formulation of MOC for nozzle flow and DSMC for rarefied gases. Additionally, it will provide an explanation of how to implement these mathematical concepts into the two solvers: RAMP and DAC. Ultimately, this research will demonstrate that the overall process illustrated produces results in good agreement with empirical data. As a consequence, the methodology presented is granted an increased level of confidence and will greatly contribute to the aerospace industry and its effort in understanding and predicting rarefied flow fields.

Direct Simulation Monte Carlo Analysis Code↗

NASA NTRS2021

A Study into Validating A Coupled Method of Characteristics And Direct Simulation Monte Carlo Method Against Empirical Data

DAC↗

NASA NTRS2023

X-57 Maxwell Airworthiness Validation Plan

This report is a Final Airworthiness Validation Plan (AVP) and describes how an aircraft like X-57 does (and does not) meet current airworthiness standards. The objective of this report is to create an example certification basis, associated means of compliance (MoC), and method of compliance for a distributed electric propulsion airplane under 14 Code of Federal Regulations (CFR) Part 21, “Certification Procedures for Products and Articles,” and its associated relevant sections of 14 CFR for “Airworthiness Standards” of Part 23, “Normal Category Airplanes,” Part 33 “Aircraft Engines,” and Part 35 “Propellers.” The approach to meet the objective is to use NASA’s X-57 Modification (Mod) IV flight demonstrator as an example and categorize its applicability to the regulations and standards according to the following three conditions: 1. Identify, where applicable, that the MoC and methods of compliance can be associated with existing Standard Specifications and Standard Practices of (ASTM) Committee F39 on Aircraft Systems and ASTM Committee F44 on General Aviation Aircraft; 2. If relevant ASTM standards do not exist, identify means and-or methods of compliance from appropriate Federal Aviation Administration (FAA) Advisory Circulars and other sources to use for the X-57 Mod IV vehicle; or 3. If no relevant certification rule, MoC, or method of compliance exists, highlight this omission and provide recommendations.

Herbert W Schlickenmaier↗

DOE OSTI2023

Impact of Mg on Pd-based Methane Oxidation Catalysts for Lean-burn Natural Gas Emissions Control

More efficient lean-burn, natural gas engines are limited by greenhouse gas emissions due to methane oxidation catalysts (MOC) that suffer from water inhibition and high temperature activation. Herein, we report that the addition of Mg to supported 1 wt.% Pd MOCs improved hydrothermal stability even after severe hydrothermal aging. The superior methane oxidation activity compared to the corresponding Mg-free catalyst was attributed to (1) influence of Mg during surface roughening and restructuring at 700 °C on metal-support interaction, (2) reducibility of PdOx sites and (3) preferential stabilization of active Pd (1 0 0) facets in the sample as was evidenced by H 2 TPR and CO TPD characterization experiments. Methane conversion under synthetic exhaust conditions relevant to natural gas, lean-burn engines were investigated. In conclusion, BET, TPR, CO pulse chemisorption followed by TPD provided valuable insights into the surface area, pore volume, reducibility, Pd dispersion and Pd particle size of the selected catalyst samples.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2017

XTCE (XML Telemetric and Command Exchange) Standard Making It Work at NASA. Can It Work For You?

The XML Telemetric and Command Exchange (XTCE) standard is intended as a way to describe telemetry and command databases to be exchanged across centers and space agencies. XTCE usage has the potential to lead to consolidation of the Mission Operations Center (MOC) Monitor and Control displays for mission cross-support, reducing equipment and configuration costs, as well as a decrease in the turnaround time for telemetry and command modifications during all the mission phases. The adoption of XTCE will reduce software maintenance costs by reducing the variation between our existing mission dictionaries. The main objective of this poster is to show how powerful XTCE is in terms of interoperability across centers and missions. We will provide results for a use case where two centers can use their local tools to process and display the same mission telemetry in their MOC independently of one another. In our use case we have first quantified the ability for XTCE to capture the telemetry definitions of the mission by use of our suite of support tools (Conversion, Validation, and Compliance measurement). The next step was to show processing and monitoring of the same telemetry in two mission centers. Once the database was converted to XTCE using our tool, the XTCE file became our primary database and was shared among the various tool chains through their XTCE importers and ultimately configured to ingest the telemetry stream and display or capture the telemetered information in similar ways.Summary results include the ability to take a real mission database and real mission telemetry and display them on various tools from two centers, as well as using commercially free COTS.

CCSDS↗

DOE OSTI2021

In Situ Synthesis of Molybdenum Carbide Nanoparticles Incorporated into Laser‐Patterned Nitrogen‐Doped Carbon for Room Temperature VOC Sensing

Abstract Carbon laser‐patterning (CLaP) is emerging as a new tool for the precise and selective synthesis of functional carbon‐based materials for on‐chip applications. The aim of this work is to demonstrate the applicability of laser‐patterned nitrogen‐doped carbon (LP‐NC) for resistive gas‐sensing applications. Films of pre‐carbonized organic nanoparticles on polyethylenetherephthalate are carbonized with a CO 2 ‐laser. Upon laser‐irradiation a compositional and morphological gradient in the films is generated with a carbon content of 92% near the top surface. The specific surface areas of the LP‐NC are increased by introducing sodium iodide (NaI) as a porogen. Electronic conductivity and surface area measurements corroborate the deeper penetration of the laser‐energy into the film in the presence of NaI. Furthermore, impregnation of LP‐NC with MoC 1− x (<10 nm) nanoparticles is achieved by addition of ammonium heptamolybdate into the precursor film. The resulting doping‐sensitive nano‐grain boundaries between p‐type carbon and metallic MoC 1− x lead to an improvement of the volatile organic compounds sensing response of Δ R / R 0 = −3.7% or −0.8% for 1250 ppm acetone or 900 ppm toluene at room temperature, respectively, which is competitive with carbon‐based sensor materials. Further advances in sensitivity and in situ functionalization are expected to make CLaP a useful method for printing selective sensor arrays.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Science of the Van Allen Probes Science Operations Centers

The Van Allen Probes mission operations materialized through a distributed model in which operational responsibility was divided between the Mission Operations Center (MOC) and separate instrument specific SOCs. The sole MOC handled all aspects of telemetering and receiving tasks as well as certain scientifically relevant ancillary tasks. Each instrument science team developed individual instrument specific SOCs proficient in unique capabilities in support of science data acquisition, data processing, instrument performance, and tools for the instrument team scientists. In parallel activities, project scientists took on the task of providing a significant modeling tool base usable by the instrument science teams and the larger scientific community. With a mission as complex as Van Allen Probes, scientific inquiry occurred due to constant and significant collaboration between the SOCs and in concert with the project science team. Planned cross-instrument coordinated observations resulted in critical discoveries during the seven-year mission. Instrument cross-calibration activities elucidated a more seamless set of data products. Specific topics include post-launch changes and enhancements to the SOCs, discussion of coordination activities between the SOCs, SOC specific analysis software, modeling software provided by the Van Allen Probes project, and a section on lessons learned. One of the most significant lessons learned was the importance of the original decision to implement individual team SOCs providing timely and well-documented instrument data for the NASA Van Allen Probes Mission scientists and the larger magnetospheric and radiation belt scientific community.

47 OTHER INSTRUMENTATION↗

DOE OSTI2020

Supported Molybdenum Carbide Nanoparticles as Hot Hydrogen Reservoirs for Catalytic Applications

Transition metal carbides have been long proposed as replacements for expensive Pt-group transition metals as heterogeneous catalysts for hydrogenation reactions, featuring similar to superior activities and selectivities. Combining experimental observations and theoretical calculations, we show that the hydrogenating capabilities of molybdenum carbide can be further improved by nanostructuring, as seen on MoC y nanoclusters anchored on an inert Au(111) support, revealing a more prominent role of Mo active sites in the easier H 2 adsorption, dissociation, H adatom diffusion, and elongated chemisorbed H 2 Kubas moieties formation when compared to the bulk δ-MoC(001) surface, thus explaining the observed stronger H 2 interaction and the larger formation of CH x species, making these systems ideal to catalyse hydrogenation reactions

36 MATERIALS SCIENCE↗

DOE OSTI2025

Modulation of the Electronic and Vibrational Landscape in Lead Organic Chalcogenides

Metal organic chalcogenides (MOCs) are an emerging class of two-dimensional (2D) materials featuring tunable band gaps and strong light-matter interactions with great potential for optical and polaritonic applications. Lead organic chalcogenides (LOCs) stand out among MOCs for sustaining long-lived coherent optical phonons despite their distorted lattices. However, the strong electron–phonon coupling also leads to rapid charge carrier self-trapping, hindering carrier transport. Herein, we demonstrate that charge carrier self-trapping is suppressed in Se- and Te-based LOCs. Specifically, the expansive Se and Te orbitals give rise to more dispersive conduction bands and reduced electron effective masses, thereby mitigating carrier self-trapping. As a result of reduced carrier self-trapping, the Se- and Te-based LOCs exhibit enhanced band-to-band photoluminescence and improved charge transport performance. Furthermore, our results provide a synthetic route to Se- and Te-based LOC single crystals and demonstrate the potential of orbital engineering to tune their electronic and phononic properties.

Chalcogenides↗

DOE OSTI2023

Revisiting Interior Water Mass Responses to Surface Forcing Changes and the Subsequent Effects on Overturning in the Southern Ocean

Abstract Two coupled climate models, differing primarily in horizontal resolution and treatment of mesoscale eddies, were used to assess the impact of perturbations in wind stress and Antarctic ice sheet (AIS) melting on the Southern Ocean meridional overturning circulation (SO MOC), which plays an important role in global climate regulation. The largest impact is found in the SO MOC lower limb, associated with the formation of Antarctic Bottom Water (AABW), which in both models is enhanced by wind and weakened by AIS meltwater perturbations. Even though both models under the AIS melting perturbation show similar AABW transport reductions of 4–5 Sv (50%–60%), the volume deflation of AABW south of 30°S is four times greater in the higher resolution simulation (−20 vs. −5 Sv). Water mass transformation (WMT) analysis reveals that surface‐forced dense water formation on the Antarctic shelf is absent in the higher resolution and reduced by half in the lower resolution model in response to the increased AIS melting. However, the decline of the AABW volume (and its inter‐model difference) far exceeds the surface‐forced WMT changes alone, which indicates that the divergent model responses arise from interactions between changes in surface forcing and interior mixing processes. This model divergence demonstrates an important source of uncertainty in climate modeling, and indicates that accurate shelf processes together with scenarios accounting for AIS melting are necessary for robust projections of the deep ocean's response to anthropogenic forcing.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2022

Effect of nanostructuring on the interaction of CO 2 with molybdenum carbide nanoparticles

Transition metal carbides are increasingly used as catalysts for the transformation of CO 2 into useful chemicals. Recently, the effect of nanostructuring of such carbides has started to gain relevance in tailoring their catalytic capabilities. Catalytic materials based on molybdenum carbide nanoparticles (MoC y ) have shown a remarkable ability to bind CO 2 at room temperature and to hydrogenate it into oxygenates or light alkanes. However, the involved chemistry is largely unknown. In the present work, a systematic computational study is presented aiming to elucidate the chemistry behind the bonding of CO 2 with a representative set of MoC y nanoparticles of increasing size, including stoichiometric and non-stoichiometric cases. Furthermore, the obtained results provide clear trends to tune the catalytic activity of these systems and to move towards more efficient CO 2 transformation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Demonstration of MOOSE-based Griffin reactor physics, code for heterogeneous lead-cooled fast reactor analysis

The MOOSE-based reactor physics code Griffin was assessed on a heterogeneous pin-resolved model of a prototype lead-cooled fast reactor assembly. This model was developed in preparation for future use in MOOSE-based multiphysics calculations for computing hot channel factors. Heterogeneous multigroup cross sections were prepared using the fast reactor multi-group cross section processing code MC{sup 2}-3 using a two-step method. Griffin simulations were performed using the DFEM-SN solver on 576 cores on Argonne's LCRC cluster. Diffusion-based acceleration methods were applied (NDA and CMFD). Reference solutions were generated with continuous energy MCNP and the hybrid MOC/finite element solver PROTEUS-MOC for code-to-code comparison. Space-angle convergence studies were conducted to observe convergence in k-eigenvalue and axial pin power distributions. The fully resolved Griffin calculation was within 68 pcm of the MCNP eigenvalue and exhibited max 1.2% relative error in the axial pin power distribution. Griffin produced nearly identical results to PROTEUS-MOC when using the same 9-group multigroup cross-section set. Griffin demonstrated favorable scaling in wall-clock time and memory usage when using diffusion-based acceleration methods. Griffin is capable of simulating the pin-resolved heterogeneous LFR assembly with good accuracy and performance, and is suitable for future use in coupled high-fidelity hot channel factor simulations. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗