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At least 343 records · Page 19

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NASA NTRS2022

Sub-Scale Adsorption and Compression CO2 Removal System Re-Design

This system is a re-design of NASA’s previously developed Thermally Coupled Temperature Swing Adsorption and Compression (TC-TSAC) systems, providing an air revitalization alternative to assist in the agency’s Moon to Mars exploration objectives. The system consists of two half-cycles whereby packed beds of regenerable bulk sorbents and heat cycles simultaneously adsorb and compress carbon dioxide. The team designed the adsorption and compression beds in a cylindrical shape to maximize airflow. A desiccant bed helps lower humidity and the sorbent Zeolite 13X is used to capture carbon dioxide. Both are monitored by sensors. There is a custom heater within the system that lies in the adsorption bed to regenerate the sorbent, and there is a cooler around the compression bed. The system produced for NASA modeling, experimental test results, and operational results to be able to be scaled up to 4kg CO2 removal per day. The system was found to be 1/16 scale for 1kg of CO2 removal per day. The adsorption and desorption processes were successful, however issues with making the compression bed airtight resulted in an inability to demonstrate full compression. The team provided design suggestions and alternative solutions given these results. This paper describes the final design, fabrication, assembly, and testing of the TC-TSAC re-design.

Joaquin Pesqueira↗

NASA NTRS2021

Instrument Thermal Management for Lunar Night Survival without Radioisotopes

This paper summarizes the technology development progress on two JPL projects focused on developing thermal designs/technologies that enable lunar instrument overnight survival without radioisotopes. Through an internal project known as ARTEMIS, JPL has developed lunar night survivable designs for magnetometer, seismometer, and IR spectrometer science payloads (SPs). These designs incorporate four hyper-isolative thermal management features under development on the NASA GCD-funded PALETTE project: (a) a dual enclosure system with high strength, low k tension cable (TC) supports and a variable conductance thermal link (VCTL) composed of a reverse-operation DTE thermal switch (ROD-TSW) in series with a miniaturized loop heat pipe (mini-LHP); (b) a parabolic reflector radiator (PRR) for low-to-mid latitude lunar sites; (c) ultra-low e* “spacerless” MLI, in which individual layers are hung from the TC supports; and (d) ultra-low G thermal isolators made with polymeric material or polymer/TC assemblies. Each instrument design incorporates solar panels, batteries, telecom, C&DH, and other features necessary for self-sufficient, extended-duration operation on the lunar surface. This paper will provide an overview of the ARTEMIS and PALETTE projects and provide a top-level description of the instrument thermal management approach.

Lin, Ying↗

NASA NTRSDate not supplied

Using Lunar Superconducting Magnetic Energy Storage (LSMES) for NASA Artemis Program

The development of High temperature Superconductors (HTS) with transition temperatures >91K allows for their application in the Permanently Shadowed Regions (PSRs) on the Moon, where temperatures range from ~40K-60K. These are well below the critical temperature, Tc for the YBa2Cu3O7-x HTS material. An HTS coil installed in a PSR would not require cooling to remain below Tc. The coil can be energized with solar panels during daylight and maintain a magnetic field during night. The coil can be loaded and unloaded in millisecond time scales. The long lifetime with minimal losses is an attractive option for NASA’s Artemis program to consider for energy management on the Moon.

High Temperature Superconductivity (HTS)↗

NASA NTRSDate not supplied

Error Sources and Mitigation Strategies for Thermocouples Integrated in Flexible Thermal Protection System Materials

• The flexible thermal protection system (FTPS) on NASA’s Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) vehicle will be instrumented with thermocouples (TCs) to measure the in-depth thermal response during entry into Earth’s atmosphere. Accurate flight temperature measurements are critical for verifying vehicle performance and reducing thermal model uncertainties. • The TC leads are routed from the measurement location to the data acquisition system within the same FTPS layer that they are monitoring the temperature. This approach eliminates the need to put holes in the FTPS layers. However, the insulated TC leads are exposed to high temperatures and large thermal gradients. • The baseline TCs were commercially available 30 AWG Type K TCs with a binder impregnated glass braid insulation. The glass braid is rated to a maximum continuous use temperature of 482°C. LOFTID’s heat pulse will be on the order of minutes and the maximum predicted temperature beneath the outermost FTPS layers is 1350°C.

R. A. Miller↗

NASA NTRSDate not supplied

Lightning Flash Behavior and Convective Characteristics in Hurricanes Florence (2018), Dorian (2019), and Laura (2020)

Lightning is a useful tool in forecasting and understanding the behavior of tropical cyclones (TCs). Flash extent density (FED) has been found to be indicative of strength and intensification in TCs, but optical energy is a newer parameter that has not been studied intensively. This presentation analyzes the relationship between convective characteristics, such as updraft speed and updraft size, and Geostationary Lightning Mapper (GLM) optical energy, flash area, and FED in Hurricanes Florence (2018) and Laura (2020). The maximum optical energy values were analyzed for each minute from the innermost 100 kilometers of the eye to determine if there was a relationship between optical energy, flash area, updraft behavior, and intensification. Microwave imagery and tail-doppler radar (TDR) were examined during rapid increases in flash energy to connect updraft size and strength to these spikes. Early results show an increase in size of a moderate updraft occurring just prior to an increase in lightning optical energy and TC intensity, while smaller updrafts coincide with a decrease in intensity or little to no change in intensity. Continuing work aims to investigate the role of moderate updraft size in lightning behavior and TC intensity.

Kiahna Mollette↗

NASA NTRS2023

Two Air Quality Regimes in Total Column NO2 over the Gulf of Mexico in May 2019: Shipboard and Satellite Views

The Satellite Coastal and Oceanic Atmospheric Pollution Experiment (SCOAPE) cruise in the Gulf of Mexico was conducted in May 2019 by NASA and the Bureau of Ocean Energy Management to determine the feasibility of using satellite data to measure air quality in a region of concentrated oil and natural gas (ONG) operations. SCOAPE addressed both technological and scientific issues related to measuring NO2 columns over the Outer Continental Shelf. Featured were nitrogen dioxide (NO 2 ) instruments (Pandora, Teledyne API analyzer) at Cocodrie, LA (29.26°, -90.66°), and on the Research Vessel Point Sur operating off the Louisiana coast with measurements of ozone, carbon monoxide and volatile organic compounds (VOC). The findings: (1) All NO 2 observations revealed two atmospheric regimes over the Gulf, the first influenced by tropical air in 10-14 May, the second influenced by flow from urban areas on 15-17 May; (2) Comparisons of OMI v4 and TROPOMI v1.3 TC (total column) NO 2 data with shipboard Pandora NO 2 column observations averaged 13% agreement with the largest difference during 15-17 May (~20%). At Cocodrie, the satellite-Pandora agreement was ~5%. (3) Three new-model Pandora instruments displayed a TC NO 2 precision of 0.01 Dobson Units (~5%); (4) Regions of smaller, older natural gas operations showed high methane readings from leakage; elevated VOC were also detected. Neither satellite nor spectrometer captured the magnitude of ambient NO 2 variability near ONG platforms. Given an absence of regular air quality monitoring over the Gulf of Mexico, SCOAPE data constitute a baseline against which future observations can be compared.

Nitrogen dioxide↗

NASA NTRSDate not supplied

Implementing Atmospheric Infrared Sounder (AIRS) and Cross-Track Infrared Sounder (CrIS) Cloud-Clearing Algorithm into the NASA GEOS: Focus on the 2017 Atlantic Tropical Cyclone Season

Numerical Weather Prediction (NWP) centers assimilate cloud-free infrared (IR) radiances because the assimilation of all-sky IR radiances is not yet operationally achievable. The cloud-clearing procedure offers a simpler, but effective strategy that produces cloud-affected radiances suitable for assimilation in partially cloudy regions. Several studies conducted by this team have demonstrated that IR Cloud-Cleared Radiances (CCRs), if thinned more aggressively than clear-sky radiances, can improve analysis and forecasts, particularly in meteorologically active areas. However, CCRs are not used by operational centers due partly to the thought that the process of cloud-clearing may affect latency and introduce difficult-to-control external dependencies. This study presents the results of implementing an Atmospheric Infrared Sounder (AIRS) and Cross-Track Infrared Sounder (CrIS) cloud-clearing procedure into the NASA Goddard Earth Observing System (GEOS) to demonstrate the portability of the procedure. The AIRS and CrIS cloud-clearing algorithms have been deprived of external dependencies, made customizable to any specific model, and the computational efficiency has been improved via parallelization. The revised AIRS and CrIS cloud-clearing algorithms allow a customized choice of channel selection, the use of a user-specified model's fields as first guess, and can perform in real time. Data assimilation experiments with the hybrid 4DEnVar GEOS system were successfully performed for the 2017 tropical cyclones (TC) season with a focus on three major hurricanes (Harvey, Irma, and Maria). This study shows that assimilation of locally-generated CCRs have a positive impact on both global skill and TC representation, compared to the assimilation of AIRS and CrIS clear-sky radiances, and a comparable or slightly improved impact compared to assimilation of CCRs produced by external sources, such as NASA's Distributed Active Archive Centers and NOAA’s Comprehensive Large Array-data Stewardship System. The customization and computational efficiency of the revised procedure would enable its usability in a real-time forecast context.

Niama Boukachaba↗

NASA NTRS2024

Tropical Cyclones in the GEOS-S2S-2 Subseasonal Forecasts

This paper analyzes the climatology, prediction skill, and predictability of tropical cyclones (TCs) in NASA’s Global Earth Observing System Subseasonal to Seasonal (GEOS-S2S) forecast system version 2. GEOS reasonably simulates the number and spatial distribution of TCs compared to observations except in the Atlantic where the model simulates too few TCs due to low genesis rates in the Caribbean Sea and Gulf of Mexico. The environmental conditions, diagnosed through a genesis potential index, do not clearly explain model biases in the genesis rates, especially in the Atlantic. At the storm-scale, GEOS reforecasts replicate several key aspects of the thermodynamic and dynamic structure of observed TCs, such as a warm core and the secondary circulation. The model, however, fails to simulate an off-center eyewall when evaluating vertical velocity, precipitation and moisture. The analysis of prediction skill of TC genesis and occurrence shows that GEOS has comparable skill to other global models in WMO S2S archive and that its skill could be further improved by increasing the ensemble size. After calibration, GEOS forecasts are skillful in the Western North Pacific and Southern Indian Ocean up to 20 days in advance. A model-based predictability analysis demonstrates the importance of the Madden-Julian Oscillation (MJO) as a source of predictability of TC occurrence beyond the 14 day lead-time. Forecasts initialized under strong MJO conditions show evidence of predictability beyond week 3. However, due to model biases in the forecast distribution there are notable gaps between MJO-related prediction skill and predictability which require further study.

Jorge L. Garcia-Franco↗

NASA NTRSDate not supplied

Thermal Vacuum Testing Strategy and Thermal Desktop Model Correlation for the Moon to Mars Planetary Autonomous Construction Technologies (MMPACT) Robotic Terrestrial Arm

This paper discusses the initial thermal vacuum testing of the MMPACT robotic terrestrial arm. The robotic arm is part of a construction system designed for the lunar south pole surface. The first thermal vacuum test was a risk mitigation test to ensure the arm could operate in vacuum, with all other data collection as secondary priorities. 44 thermocouples (TCs) were attached to the arm. Installation was done with additional care to account for both the extra wiring harness weight on the arm with the TC wires and increased focus on stabilizing the TC attachments to the moving components. Thermal steady state of <= 0.01°C/hour was reached for the hot set of testing conditions. This data was used to correlate the Thermal Desktop (TD) model to the test results within +/- 5°C.

Thermal analysis↗

NASA NTRSDate not supplied

Thermal Vacuum Testing Strategy and Thermal Desktop Model Correlation for the Moon to Mars Planetary Autonomous Construction Technologies (MMPACT) Robotic Terrestrial Arm

Thermal analysis↗

NASA NTRS2024

Assessment of Some IASMS-relevant Data Sources for Aviation Safety

An In-time Aviation Safety Management System (IASMS) [1,2] is a set of services, functions, and capabilities (SFCs) necessary for monitoring known hazards and emergent risks, assessing safety data for anomalies, precursors, and trends, mitigating hazards that reach safety thresholds, and assuring efficacy of controls in mitigating hazards. An IASMS will continually monitor the NAS to collect data on the status of aircraft, air traffic management systems, weather, and airports. Within the NASA Aeronautics Research Mission Directorate (ARMD) System-Wide Safety (SWS) project’s technical challenge called In-time Aviation Safety Management Systems (IASMS) for Commercial Aviation Operations, which we often refer to as Technical Challenge 6 (TC-6), we have performed an assessment of several aviation data sources we have found that are relevant to assessing the safety of the National Airspace System (NAS) in the context of an IASMS. This assessment includes understanding the nature of the data themselves and using some data analytics tools on these data to show how they can be used to identify potential safety issues. We also describe how the data and analytics are part of a system that can allow for other data and analytics to be performed and for the results to be visualized for use by appropriate operators to identify potential safety issues and develop mitigations. This report is a step toward the ultimate goal of TC-6, which is to develop a prototype IASMS system that demonstrates the potential of an IASMS and inspire operators to build analogous systems to make the best possible use of the significant investments that they make in collecting, storing, and managingdata related to their operations.

aviation safety↗

NASA NTRS1974

The electrical properties of zero-gravity processed immiscibles

When dispersed or mixed immiscibles are solidified on earth, a large amount of separation of the constituents takes place due to differences in densities. However, when the immiscibles are dispersed and solidified in zero-gravity, density separation does not occur, and unique composite solids can be formed with many new and promising electrical properties. By measuring the electrical resistivity and superconducting critical temperature, Tc, of zero-g processed Ga-Bi samples, it has been found that the electrical properties of such materials are entirely different from the basic constituents and the ground control samples. Our results indicate that space processed immiscible materials may form an entirely new class of electronic materials.

Lacy, L. L.↗

NASA NTRS1973

Multivariable system synthesis with step disturbance rejection

The primary objective of this paper is to present a constructive procedure for the synthesis of linear multivariable systems whose entire internal state and output are corrupted by unknown step disturbances. It is assumed that the dynamical behavior of the system is expressed in any one of three equivalent ways - i.e., the state space representation, the controllable and observable differential operator representation, and the transfer matrix representation. In terms of the transfer matrix representation, T(s), the synthesis procedure is shown to be capable of producing any stable, desired closed loop transfer matrix, Td(s), which can be expressed as the product of T(s) and any proper rational matrix, Tc(s), while simultaneously eliminating the steady-state effect of step disturbances at the output of the system. Furthermore, the synthesis scheme outlined employes only the known, directly measurable input and output signals.

Wolovich, W. A.↗

NASA NTRS1975

Titan/Centaur T/C-1 post flight evaluation report

The first Titan/Centaur launch vehicle, TC-1, was launched from the Eastern Test Range Complex 41 at 09:48:01.46 hours Eastern Daylight Time on February 11, 1974. The vehicle carried a dynamic mass model of the Viking spacecraft and a SPHINX spacecraft, intended to study high voltage interactions in space. This launch was a Proof Flight of a vehicle con- figuration integrating the Air Force Titan booster and the NASA Centaur upper stage. It also was the first flight of the Centaur Standard Shroud developed for the Titan/Centaur. The countdown for the launch proceeded normally except for an additional 45 minute hold which was required to resolve a question concerning interpretation of booster hydraulic system data. The launch window opened at 09:03:00 hours Eastern Daylight Time. The vehicle was launched o on a flight azimuth of 105°. The Titan boost phase of flight was satisfactory. Solid Motor operation, Stage I and Stage II operation were normal. Venting of the Centaur Standard Shroud during ascent was successful and shroud separation and jettison was accomplished without incident. At the completion of the Titan Stage II burn, the Centaur successfully separated from the Titan. At this time, the Centaur main engines were sequenced through the first planned starting cycle but failed to achieve steady state operation. The vehicle flight control system, not sensing vehicle acceleration, commanded engine shutdown, and recycled, as programmed, through a back-up engine start attempt. The second engine start attempt was also unsuccessful. The flight control system then placed the vehicle in a coast-phase mode and the vehicle continued downrange in free fall. The vehicle was destroyed by Range Safety when the impact point was approximately 2200 nautical miles downrange, 12 minutes, 28.5 seconds after liftoff.

S. V. Szabo, Jr.↗

NASA NTRS1976

Titan/Centaur D-1TTC-5 Helios B flight data report

The fourth operational flight of the newest NASA unmanned launch vehicle is reported. The spacecraft was the Helios B, the second of two solar probes designed and built by the Federal Republic of Germany. The primary mission objective, to place the Helios spacecraft on a heliocentric orbit in the ecliptic plane with a perihelion distance of 0.29 AU, was successfully accomplished. After successful injection of the Helios spacecraft, a series of experiments were performed with the Centaur stage to demonstrate its operational capabilities. All objectives of the extended mission phase were successfully met. This report presents the analysis of the launch vehicle flight data for the primary mission phase of the TC-5 flight.

Adams, K. A.↗

NASA NTRS1976

Titian/Centaur D-1TTC-4 Viking A flight data report

Titan/Centaur TC-4 was launched from the Eastern Test Range, Complex 41, at 05:22 PM EDT on Wednesday, August 20, 1975. This was the second operational flight of the newest NASA unmanned launch vehicle. The spacecraft was the Viking A, the first of two orbiting and landing missions to Mars planned for the 1975 Martian launch opportunity. The objective of the launch phase of the mission, to inject the Viking spacecraft onto the planned transfer orbit to Mars, was successfully accomplished. This report presents a review of the launch vehicle system flight data.

Source record↗

NASA NTRS1976

Shuttle model tailcone pressure distribution at low subsonic speeds of a 0.03614-scale model in the NASA/LaRC low-turbulence pressure tunnel (LA81), volume 1

An investigation was conducted in the NASA/LaRC Low-Turbulence Pressure Tunnel on a 0.03614-scale orbiter model of a 089B configuration with a 139B configuration nose forward of F.S. 500. The tailcone was the TC sub 4 design and was instrumented with eighty-nine pressure orifices. Control surfaces were deflected and three wind tunnel mounting techniques were investigated over an angle-of-attack range from -2 deg to a maximum of 18 deg. In order to determine the sensitivity of the tailcone to changes in Reynolds number, most of the test was made at a Mach number of 0.20 over a Reynolds number range of 2.0 to 10 million per foot. A few runs were made at a Mach number of 0.30 at Reynolds numbers of 4.0, 6.0, and 8 million per foot.

Ball, J. W.↗

NASA NTRS1976

Centaur boost pump turbine icing investigation

An investigation was conducted to determine if ice formation in the Centaur vehicle liquid oxygen boost pump turbine could prevent rotation of the pump and whether or not this phenomenon could have been the failure mechanism for the Titan/Centaur vehicle TC-1. The investigation consisted of a series of tests done in the LeRC Space Power Chamber Facility to evaluate evaporative cooling behavior patterns in a turbine as a function of the quantity of water trapped in the turbine and as a function of the vehicle ascent pressure profile. It was found that evaporative freezing of water in the turbine housing, due to rapid depressurization within the turbine during vehicle ascent, could result in the formation of ice that would block the turbine and prevent rotation of the boost pump. But for such icing conditions to exist it would be necessary to have significant quantities of water in the turbine and/or its components, and the turbine housing temperature would have to be colder than 40 F at vehicle liftoff.

Rollbuhler, R. J.↗