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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Dude Where's My Stars: A Novel Topologically Justified Approach to Star Tracking

In this paper, we consider two novel approaches to celestial navigation for spacecraft. Determining attitude without any prior knowledge using star tracking is known to be a difficult task, particularly given the computational complexity and the many potential sources of misinformation. We consider localization by optimizing matching parameters without explicit star identification in a computationally tractable manner. This is achieved using the mathematical tools of topological data analysis (TDA) and cellular sheaves to study the geometry and distribution of cataloged stars. A framework is gained that enhances the statistical approach to noise handling and false star detection, and heterogeneous sensor fusion. Finally, we discuss confidence bounds and minimum information requirements for successful operation.

Sheaf theory↗
NASA NTRS2021

Modeling Laminar-to-Turbulent Transition in the Panel Test Facility Arcjet

A computational fluid dynamics (CFD) laminar-to-turbulence transition model was developed for the NASA Ames Research Center’s 20 MW Panel Test Facility (PTF). Surface pressure, heat flux to a water-cooled plate, and surface temperature on a tile plate coated with reaction-cured glass were measured across several conditions in the facility and compared with laminar and fully-turbulent CFD simulations. The potential for bypass transition in the PTF nozzle was assessed via application of the Langtry-Menter four-equation transitional shear-stress transport (SST) model. Results from the transition model were inconsistent with measurements. Flow interaction with a boundary conditioning plate feature inside the nozzle was also investigated as a potential source of laminar-to-turbulent transition using two turbulence models with specified transition locations. The Baldwin-Lomax turbulence model was configured to simulate a transition at the upstream edge of the boundary conditioning plate and produced results consistent with the surface pressure measurements but not the cold-wall heat flux. Finally, the SST turbulence model was calibrated to transition at the upstream edge of the boundary conditioning plate and produced results consistent with both the surface pressure and cold-wall heat flux measurements. The SST-based model demonstrated reasonable agreement with surface temperature measurements on the reaction-cured glass tile, albeit with some discrepancies.

Computational Fluid Dynamics↗
NASA NTRS2020

Comprehensive Investigation of Mars Methane and Organics with ExoMars/NOMAD

Methane (CH4) on Mars has attracted a great deal of attention since it was first detected in January 2003. As methane is considered a potential marker for past/present biological or geological activity, any possible detection would require evidence with strong statistical significance. Ethane (C2H6) and ethylene (C2H4) are also relevant chemical species as their shorter lifetimes in the Martian atmosphere make them excellent tracers for recent and ongoing releases. If detected, a CH4/C2Hn ratio could aid in constraining the potential source of organic production. Here we present the results of an extensive search for hydrocarbons in the Martian atmosphere in 240,000 solar occultation measurements performed by the ExoMars Trace Gas Orbiter/NOMAD instrument from April 2018 to April 2019. The observations are global, covering all longitudes and latitudes from 85°N to 85°S, and sampled from 6-100 km altitude with a typical vertical resolution of 2km. There were no statistically significant detections of organics and new stringent upper limits for global ethane and ethylene were set at 0.1 ppbv and 130.7 ppbv, respectively. No global background level of methane was observed, obtaining an upper limit of 0.06 ppbv, in agreement with early results from ExoMars (Korablev et al., 2019). Dedicated searches for localized plumes at more than 2000 locations provided no positive detections, implying that if methane were released in strong and rapid events, the process would have to be sporadic.

Elise W Knutsen↗
NASA NTRS2004

Optical state estimation using wavefront data

The use of wavefront measurements to deduce the state of multiple optics in a telescope beam train - their misalignments and figure errors — can be confused by the fact that there are multiple potential sources for the same measured error. This talk applies Kalman filtering techniques as a tool for separating true telescope errors from artifactual testing errors in the alignment and testing of NASA’s James Webb Space Telescope, a large segmented-aperture cryogenic telescope to be launched after 2010.

Whitman, Tony↗
NASA NTRS2004

Model validation of SIM external metrology at the sub-nanometer level

In order to achieve micro-arcsecond astrometry, SIM must make measurements of various optical path lengths at the picometer level. In this regime of precision, nearly every simplifying assumption in optics must be reexamined as a potential source of systematic error. SIM makes extensive use of physics-based models to predict the form and level of systematic errors affecting instrument performance. Since many of the modeling areas represent new frontiers in optical modeling, the validation of these physical models is a significant challenge that SIM must meet. In the case of the external metrology truss, the model must account for the imperfections in the corner cubes as well as the distance measuring interferometers ("beam launchers"). This model is being validated using the Kite testbed, a 2-D metrology truss with picometer-level accuracy in displacement measurements. We present the model and the results of the model validation tests on the Kite testbed.

Kuan, Gary M.↗
NASA NTRS2019

Subsurface Cl-bearing salts as potential contributors to recurring slope lineae (RSL) on Mars

We report laboratory experimental results that support a brine-related hypothesis for the recurring slope lineae (RSL) on Mars in which the subsurface Cl-salts, i.e., hydrous chlorides and oxychlorine salts (HyCOS) are the potential source materials. Our experiments revealed that within the observed RSL temperature window TRSL (250–300 K), the deliquescence of HyCOS could occur in relative humidity ranges (RH≥22%–46%) much lower than those for hydrous (Mg, Fe)-sulfates (RH≥75%–96%). In addition, we demonstrated that the RH values kept by common HyCOS and hydrous sulfates in enclosures have a general trend as RH(sulfates) > RH(perchlorates) > RH(chlorides) (with same type of cation) in wide T range. It means that the required RH range for a Cl-bearing salt to deliquescence can be satisfied by a co-existing salt of different type, e.g., in the subsurface layers of mixed salts on Mars. Furthermore, we found a strong temperature dependence of the deliquescence rates for all tested HyCOS, e.g., a duration of 1–5 sols for all HyCOS at the high end (300 K) of TRSL, and of 20–70 sols for all tested HyCOS (except NaClO4·H2O) at the low end (250 K) of TRSL, which is consistent with the observed seasonal behavior of RSL on Mars. From a mass-balance point of view, the currently observed evidences on Mars do not support a fully-brine-wetted track model, thus we suggest a brine-triggered granular-flow model for the most RSL. Considering the recurrence of RSL in consecutive martian years, our experimental results support the rehydration of remnant HyCOS layers during a martian cold season through H2O vapor-to-salt direct interaction. We found that the evidences of HyCOS rehydration under Mars relevant P-T-RH conditions are detectable in a few minutes by in situ Raman spectroscopy. This rehydration would facilitate the recharge of H2O back into subsurface HyCOS, which could serve as the source material to trigger RSL in a subsequent warm season. The major limiting factor for this rehydration is the H2O supply, i.e., the H2O vapor density carried by current Mars atmospheric circulation and the diffusion rate of H2O vapor into the salt-rich subsurface in a cold season. In a worst-case scenario, these H2O supplies can support a maximum increase of hydration degrees of two for totally dehydrated HyCOS, whereas the full rehydration of subsurface HyCOS layers can be easily reached during a>30° obliquity period that has H2O vapor density 10× to 20× times the value of current obliquity. Overall, our results imply the existence of a large amount of Cl-bearing salts in the subsurface at RSL sites.

Alian Wang↗
NASA NTRSDate not supplied

Government Astronaut Participation In Suborbital Spaceflight

In 2020, NASA issued a Request for Information (RFI) from potential sources for Suborbital Crew (SubC) Space Transportation Services. NASA recognizes the advancement of the commercial suborbital spaceflight industry and is currently working to develop suborbital transportation for Government personnel, that could fly on commercially available suborbital vehicles and determine a systems qualification approach for flight risk acceptance.

Suborbital↗
NASA NTRS2019

Tropospheric Ozone Assessment Report: Tropospheric Ozone From 1877 to 2016, Observed Levels, Trends and Uncertainties

From the earliest observations of ozone in the lower atmosphere in the 19th century, both measurement methods and the portion of the globe observed have evolved and changed. These methods have different uncertainties and biases, and the data records differ with respect to coverage (space and time), information content, and representativeness. In this study, various ozone measurement methods and ozone datasets are reviewed and selected for inclusion in the historical record of background ozone levels, based on relationship of the measurement technique to the modern UV absorption standard, absence of interfering pollutants, representativeness of the well-mixed boundary layer and expert judgement of their credibility. There are significant uncertainties with the 19th and early 20th-century measurements related to interference of other gases. Spectroscopic methods applied before 1960 have likely underestimated ozone by as much as 11% at the surface and by about 24% in the free troposphere, due to the use of differing ozone absorption coefficients. There is no unambiguous evidence in the measurement record back to 1896 that typical mid-latitude background surface ozone values were below about 20 nmol mol–1, but there is robust evidence for increases in the temperate and polar regions of the northern hemisphere of 30–70%, with large uncertainty, between the period of historic observations, 1896–1975, and the modern period (1990–2014). Independent historical observations from balloons and aircraft indicate similar changes in the free troposphere. Changes in the southern hemisphere are much less. Regional representativeness of the available observations remains a potential source of large errors, which are difficult to quantify. The great majority of validation and intercomparison studies of free tropospheric ozone measurement methods use ECC ozonesondes as reference. Compared to UV-absorption measurements they show a modest (~1–5% ±5%) high bias in the troposphere, but no evidence of a change with time. Umkehr, lidar, and FTIR methods all show modest low biases relative to ECCs, and so, using ECC sondes as a transfer standard, all appear to agree to within one standard deviation with the modern UV-absorption standard. Other sonde types show an increase of 5–20% in sensitivity to tropospheric ozone from 1970–1995. Biases and standard deviations of satellite retrieval comparisons are often 2–3 times larger than those of other free tropospheric measurements. The lack of information on temporal changes of bias for satellite measurements of tropospheric ozone is an area of concern for long-term trend studies.

UV absorption standard↗
NASA NTRSDate not supplied

Government Personnel Participation in Suborbital Space Flight

In 2020, NASA issued a Request for Information (RFI) from potential sources for Suborbital Crew (SubC) space transportation services. NASA recognizes the advancement of the commercial suborbital space flight industry and is currently working to develop suborbital transportation for Government personnel that could fly on commercially available suborbital vehicles and determine a systems qualification approach for flight risk acceptance. Prior examples of risk assessment such as the purchase of Soyuz missions serve as a foundation for how the US Government’s best technical experts can partner with a successfully flying industry provider to understand risks. More recently, NASA, the FAA, and industry have successfully demonstrated that a company-owned operation with government oversight can successfully launch Government Astronauts safely. This paper explores the challenges and opportunities presented with the use of suborbital vehicles by Government personnel and how industry might leverage the Government’s efforts to maximize the success of the suborbital space industry.

Risk Management↗
NASA NTRSDate not supplied

Evaluation of Near Singular Integrals for Computational Electromagnetics by Dimensionality Reduction

With the need for ever faster codes, a limiting factor that must be dealt with is the accurate yet efficient evaluation of interaction integrals between the more problematic near-field elements. Several recent works have together shown that all evaluations of source potential integrals and their derivatives for the most common bases and elements can be reduced to the evaluation of boundary line integrals; these can be evaluated by Gauss-Legendre quadrature, though integrand-smoothing transforms are often needed to accelerate their computation. In this paper, we modify the reported approach to eliminate cancellation errors in the line integral integrand, reinterpret the integral as a vertex function, and study the scalar potential integral form under the sinh transform and static subtraction acceleration methods.

D R Wilton↗
NASA NTRS2020

Investigation Of Prandtl-Ishlinskii Hysteresis Compensation for Deep Space Optical Communications Pointing Control

This paper studies the simulated performance of the Deep Space Optical Communication (DSOC) laser downlink pointing control system that has a pointing requirement at the sub-microradian scale. To achieve the required pointing precision, the DSOC Flight Laser Transceiver (FLT) point-ahead mirror (PAM) employs piezoelectric actuators, which are widely used in precision applications due to their high motion resolution, rapid response, and high output forces. However, a piezoelectric actuator's performance is often limited by nonlinearities in their response, most significantly hysteresis. To study the effect of hysteresis on our simulated pointing performance, an invertible hysteresis model is developed using the Classical Prantdl-Ishlinskii (CPI) method. The simulation includes models of DSOC hardware and electronic system components based on key parameters (bias, frequency response, noise), with the hysteresis modeled in the PAM piezo actuator dynamics. A Proportional-Integral controller provides feedback with measurements from two potential sources: strain gauge sensors or a photon-counting camera. To compensate for hysteresis behavior, a feedforward inverse CPI hysteresis model is implemented in the control system. Two CPI models are built using different sampling methods (uniform sampling and cosine spacing) and controller performance is compared. For the maximum command range of ±400 μrad at 1 mHz, results show that the feedforward combined with feedback control reduces output tracking error by 50% or 58% (to 0.20 or 0.38 μrad) compared to feedback control alone (from 0.40 or 0.90 μrad), corresponding to the uniform-sampled and cosine-sampled CPI models, respectively.

Marinello, Lindsey A.↗
NASA NTRSDate not supplied

Organic Carbon Concentrations in 3-Billion-Year-Old Lacustrine Mudstones of Mars

Understanding the inventory of carbon on Mars is relevant to the question of whether Mars was ever habitable. While the Mars atmosphere represents a large reservoir of carbon, in situ pyrolysis performed on Mars and meteorite analyses indicate that another significant reservoir of carbon is the rocks themselves. Complex organic carbon was discovered in 3.5 Ga mudstones sampled at Cumberland (CB) in the Yellowknife Bay Formation in Gale Crater by the Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) using a thermal decomposition technique called evolved gas analysis (EGA). Other simple organics have also been detected in these same CB materials. Low temperature co-evolution of CO and CO2 (~200°C – 500°C) has been detected in many samples from Gale Crater where SAM EGA has been performed, and potential sources include combustion of terrestrial organics from SAM, as well as combustion and/or decarboxylation of either indigenous martian or exogenous organic carbon.

J. C. Stern↗
NASA NTRS2022

Developing High Performance Space Networking Capabilities for the International Space Station and Beyond

A performance optimized implementation of Delay Tolerant Networking (DTN) with the capacity of gigabit-per second rates is developed for the International Space Station (ISS) and missions demanding large amounts of communications bandwidth. An overview of the High-rate Delay Tolerant Networking (HDTN) architecture and support for different convergence layers is provided. This paper then presents an overview of the testing and integration efforts to evaluate interoperability and capability in relevant environments. The first was interoperability testing with DTN Marshall Enterprise (DTNME) which resulted in near-gigabit per second data rates. This was followed by ISS emulation testing with the Software Development and Integration Laboratory (SDIL) at the Lyndon B. Johnson Space Center (JSC) and local testing based on the ISS DTN network topology. The local tests resulted in the discovery of potential sources of performance loss in the network and demonstrated near-gigabit rates between HDTN and DTNME.

Daniel Raible↗
NASA NTRS2022

Electrodeionization Salt Removal from Water

This project developed a method to selectively extract sodium (Na) from complex, mission-relevant wastewaters using electricity as a driving force. The team investigated capacitive deionization (CDI), which has been used for general desalination but not for selective removal of Na. Three tasks supported this overall aim: designing and building a reactor and electrodes, engineering absorption and desorption parameters, and investigating varying water compositions and sources. Potential benefits of this approach include integrating into existing Environmental Control & Life Support Systems (ECLSS) treatment trains, reducing salinity for hydroponic installations, and producing food preservatives. Significant accomplishments, including building new reactors and characterizing their optimal operations and applications, advance the frontier of in-situ resource utilization for planetary habitation.

Luke Roberson↗
NASA NTRS2023

Fire Station #3 Area, Solid Waste Management Unit (SWMU) 106 Per- and Polyfluoroalkyl Substances (PFAS) Site Assessment Progress Report Kennedy Space Center, Florida

This Per-and Polyfluoroalkyl Substances (PFAS) Site Assessment (SA) Progress Report (SAPR) presents the activities and results associated with PFAS investigation in the Fire Station #3 (FS3) Area located at Kennedy Space Center (KSC), Florida. FS3 (formerly known as Fire Station #6) was previously designated as Solid Waste Management Unit (SWMU) 106 for legacy contaminants that were investigated and still being managed under KSC’s Resource Conservation and Recovery Act (RCRA) Corrective Action Program. This PFAS SA is being managed under SWMU 106 as the fire station was also identified as the potential source of PFAS to the environment in this area.

Sarah Damphouse↗
NASA NTRS2023

Fire Station #1 Area, SWMU 116 Per- and Polyfluoroalkyl Substances (PFAS) Site Assessment Progress Report Kennedy Space Center, Florida

This Per- and Polyfluoroalkyl Substances (PFAS) Site Assessment (SA) Progress Report (SAPR) discusses the investigation activities and findings for the Fire Station #1 (FS1) Area (formerly known as Fire Station #4) located at Kennedy Space Center (KSC), Florida (Figure 1-1). This site has been designated Solid Waste Management Unit (SWMU) 116 under KSC’s Resource Conservation and Recovery Act (RCRA) Corrective Action Program. This PFAS SA is being managed under SWMU 116 as the fire station was identified as a potential source of PFAS to the environment. This PFAS SAPR was prepared by Tetra Tech, Inc., for the National Aeronautics and Space Administration (NASA) under Indefinite Delivery Indefinite Quantity Contract 80KSC019D0011-80KSC019F0070. This is the first progress report to document on-going SA activities; supplemental progress reports will be provided as additional data is collected. During the SA, a total of six soil, 48 groundwater direct push technology (DPT), eight groundwater monitoring well, and one surface water sample were collected between October 2021 and March 2022. The samples were analyzed for 28 PFAS compounds using the Department of Defense Quality Systems Manual-compliant Method. SA sample results were used along with historical results to evaluate the extent of PFAS impacts to the environment in the FS1 Area. Data generated to date and prior results were screened against the United States Environmental Protection Agency (USEPA) May 2022 Tap Water Regional Screening Levels (RSLs) for groundwater and residential RSLs for soil (hazard quotient of 0.1). Surface water results were screened against the State of Florida Human Health Surface Water Screening Levels (SWSLs). Overall, results from the SA showed exceedances of the applicable screening criteria for soil, groundwater and surface water. Considering the current and historical dataset, perfluorooctanesulfonic acid (PFOS) is the prevalent PFAS compound, which is indicative of AFFF releases. Based on results of the SA, additional groundwater DPT and surface water sampling should be considered, focused on evaluating surface water bodies in the southeast portion of the Industrial Area, which discharge into the Banana River. Additionally, installation of monitoring wells should be considered to evaluate the interaction between groundwater and surface water in the FS1 Area.

PFAS↗
NASA NTRS2023

Development of Solar Energetic Particle Prediction Portal (SEP3)

Robust prediction of Solar Energetic Particle (SEP) events is among the key priorities of the space weather community. In the framework of NASA’s Early Stage Innovation Program, we develop the Solar Energetic Particle Prediction Portal (SEP3: https://sun.njit.edu/SEP3), which hosts web applications that allow the users to retrieve the database records. In particular, SEP3 lists the API examples to query each data source potentially important for the SEP prediction. The Portal has a search page for browsing the events from the most widely used catalogs (https://sun.njit.edu/SEP3/search.php) and a dedicated space to share the most recent achievements of the team. In addition, we have added a CDAW SEP catalog and a LASCO/SOHO CME catalog and introduced the possibility of displaying the properties of the connected events (parental solar flares and CMEs for SEPs) on the search page. The interactive widget has the capability to display GOES soft X-ray and proton flux time series from different satellites with the GOES flare records on top of them. The data portal has been used to evaluate the forecasts of the solar proton events based on the statistical properties of the GOES soft X-ray and proton fluxes and investigate machine-learning approaches to the SEP prediction.

SMD↗
NASA NTRSDate not supplied

Analysis of Igniter/Promoter Material Effects on Burn Length Variability in Astm G124 Standard Testing

ASTM G124 refers to the “Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen Enriched Atmospheres”. Major test parameters are well defined in the standard and a detailed description of how to set up and conduct the test is also included. However, one variable - the igniter/promoter system - is not clearly restricted or specified. Due to the fact that this igniter/promoter system is not definitively specified, multiple materials have been used. This lack of specificity in igniter/promoter material was identified as a potential source of variability in test results, and as such has been selected for this study as a parameter to analyze and identify if the igniters/promoters should be standardized. For that purpose, several igniter/promoter systems have been selected (that were currently in use at various laboratories) which would be tested via ASTM G124 with Inconel 718 test rods. Testing was conducted over two phases – the first for screening promoter effects in the transition region of the material, and the second for comparing measured flammability thresholds identified through testing by each igniter/promoter type. The results of this study have found that igniter/promoter material is not a statistically significant factor in the variability of burn length in test samples. Initial results showing variability was likely due to small sample size, as the issue became less pronounced once more samples were tested and more data generated. Each of the igniter/promoter systems tested were effective at determining flammability thresholds and so it is concluded that no specific igniter/promoter needs to be identified in the ASTM G124 test standard.

oxygen compatibility↗