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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Using Thermal Desktop to Model the Effects of Plume Heating on MLI

Gateway draws on experience from International Space Station (ISS) and geostationary satellites for many aspects of design, including Multilayer Insulation (MLI) material selection. MLI is used on many external surfaces, some of which can be exposed to high plume heating from visiting vehicle during docking and undocking. Due to Gateway’s smaller size and closer proximity of sensitive hardware to plumes from visiting vehicles, the expected and contingency plume heating loads are higher than those experienced by the ISS. Because of MLI’s low mass and thermal conductivity between layers, high plume heating loads can potentially heat MLI past its thermal limits. MLI is typically modeled as a single node of insulation with a given effective emissivity. This method is not adequate for modeling plume heating impacts because the temperature of each individual layer cannot be determined. Modeling MLI is complicated because there are several layers and the conduction between each layer is undefined. It is further complicated by the variety of material options for MLI and their respective mass, optics, transmissivity, and temperature limits. This paper shows modeling of a MLI blanket exposed to solar and plume heating loads using Thermal Desktop. Several sensitivity studies were run including examining distance between layers, varying effective emissivity, effects of different MLI materials, and plume heating loads and durations.

MLI↗
NASA NTRS2024

Post-CDR Thermal Design and Analysis of the Starburst Instrument

The StarBurst Multimessenger Pioneer is a small satellite serving as a wide-field gamma-ray observatory designed to detect the initial emissions of short gamma ray bursts, electromagnetic indicators of neutron star mergers. This paper will detail the thermal design and analysis of the instrument, which includes both the control electronics and crystal detector units (CDUs). The CDUs are a critical component essential to mission success and have the narrowest temperature range, however the CDU thermal model is low fidelity at the time of Critical Design Review (CDR) before a final CDU design is completed. Therefore, a more detailed CDU model is created for post-CDR analysis to update the passive Thermal Control System (TCS) design and efficiently maintain the operational and survival temperature limits with minimal heater power. Including the additional detail is necessary to determine the final Multilayer Insulation (MLI) design, including material selection and coverage, coating selection, and required heater power.

thermal design↗
NASA NTRS2024

Post-CDR Thermal Design and Analysis of the Starburst Instrument

The StarBurst Multimessenger Pioneer is a small satellite serving as a wide-field gamma-ray observatory designed to detect the initial emissions of short gamma ray bursts, electromagnetic indicators of neutron star mergers. This paper will detail the thermal design and analysis of the instrument, which includes both the control electronics and crystal detector units (CDUs). The CDUs are a critical component essential to mission success and have the narrowest temperature range, however the CDU thermal model is low fidelity at the time of Critical Design Review (CDR) before a final CDU design is completed. Therefore, a more detailed CDU model is created for post-CDR analysis to update the passive Thermal Control System (TCS) design and efficiently maintain the operational and survival temperature limits with minimal heater power. Including the additional detail is necessary to determine the final Multilayer Insulation (MLI) design, including material selection and coverage, coating selection, and required heater power.

thermal design↗
NASA NTRS2015

Insulation Resistance Degradation in Ni-BaTiO3 Multilayer Ceramic Capacitors

Insulation resistance (IR) degradation in NiBaTiO3 multilayer ceramic capacitors has been characterized by the measurement of both time to failure (TTF) and direct current leakage current as a function of stress time under highly accelerated life test conditions. The measured leakage current time dependence data fit well to an exponential form, and a characteristic growth time tau (sub SD) can be determined. A greater value of tau (sub SD) represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in NiBaTiO3 capacitors. The reduction of barrier height as a function oftime follows an exponential relation of phi (t ) = phi (0) e (exp -2Kt), where 13 the degradation rate constant K Koe (Ek/kT) is inversely proportional to the mean TTF (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height phi (0) will favor a slow IR degradation process, but a lower phi (0) will also promote electronic carrier conduction across the barrier and decrease the IR. As a result, a moderate barrier height phi (0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant K) will result in a minimized IR degradation process and the most improved reliability in NiBaTiO3 multilayer ceramic capacitors.

reliability↗
NASA NTRS2015

Insulation Resistance Degradation in Ni-BaTiO3 Multilayer Ceramic Capacitors

Insulation resistance (IR) degradation in Ni-BaTiO3 multilayer ceramic capacitors has been characterized by the measurement of both time to failure and direct-current (DC) leakage current as a function of stress time under highly accelerated life test conditions. The measured leakage current-time dependence data fit well to an exponential form, and a characteristic growth time SD can be determined. A greater value of tau(sub SD) represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in Ni-BaTiO3 capacitors. The reduction of barrier height as a function of time follows an exponential relation of phi (𝑡)=phi (0)e(exp -2Κt), where the degradation rate constant 𝐾=𝐾o𝑒(𝐸𝑘/𝑘𝑇) is inversely proportional to the mean time to failure (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height phi(0) will favor a slow IR degradation process, but a lower phi(0) will also promote electronic carrier conduction across the barrier and decrease the insulation resistance. As a result, a moderate barrier height phi(0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant 𝐾) will result in a minimized IR degradation process and the most improved reliability in Ni-BaTiO3 multilayer ceramic capacitors.

dielectric degradation↗
NASA NTRS2002

A Multilayered Thin Film Insulator for Harsh Environments

The status of work to develop a reliable high temperature dielectric thin film for use with thin film sensors is presented. The use of thin films to electrically insulate thin film sensors on engine components minimizes the intrusiveness of the sensor and allows a more accurate measurement of the environment. A variety of insulating films were investigated for preventing electrical shorting caused by insulator failure between the sensor and the component. By alternating layers of sputtered high temperature ceramics, a sequence of insulating layers was devised that prevents pinholes from forming completely through the insulator and maintains high electrical resistivity at high temperatures. The major technical challenge remaining is to optimize the fabrication of the insulator with respect to composition to achieve a reliable high temperature insulating film. Data from the testing of various potentially insulating thin film systems is presented and their application to thin film sensors is also discussed.

Wrbanek, John D.↗
NASA NTRS2017

Thermal Insulation System for Non-Vacuum Applications Including a Multilayer Composite

The thermal insulation system of the present invention is for non-vacuum applications and is specifically tailored to the ambient pressure environment with any level of humidity or moisture. The thermal insulation system includes a multilayered composite including i) at least one thermal insulation layer and at least one compressible barrier layer provided as alternating, successive layers, and ii) at least one reflective film provided on at least one surface of the thermal insulation layer and/or said compressible barrier layer. The different layers and materials and their combinations are designed to provide low effective thermal conductivity for the system by managing all modes of heat transfer. The thermal insulation system includes an optional outer casing surrounding the multilayered composite. The thermal insulation system is particularly suited for use in any sub-ambient temperature environment where moisture or its adverse effects are a concern. The thermal insulation system provides physical resilience against damaging mechanical effects including compression, flexure, impact, vibration, and thermal expansion/contraction.

Fesmire, James E.↗
NASA NTRS1976

Improved insulation material

Multilayer material consisting of embossed, silver-coated Mylar, nylon net, and silk net is useful for thermal-protection systems and cryogenic containers. Embossing serves two purposes: helps separate radiation barriers and controls radiant energy diffusion. Insulation requires no maintenance after installation.

Source record↗
NASA NTRS1972

Superior cryogenic insulation developed

Multilayer composite consisting of alternate spunbond nylon layers and doubly aluminized mylar layers is used primarily in cryogenic thermal protection systems.

Hale, D. V.↗
NASA NTRS2012

Arcjet Testing and Thermal Model Development for Multilayer Felt Reusable Surface Insulation

Felt Reusable Surface Insulation was used extensively on leeward external surfaces of the Shuttle Orbiter, where the material is reusable for temperatures up to 670 K. For application on leeward surfaces of the Orion Multi-Purpose Crew Vehicle, where predicted temperatures reach 1620 K, the material functions as a pyrolyzing conformal ablator. An arcjet test series was conducted to assess the performance of multilayer Felt Reusable Surface Insulation at high temperatures, and a thermal-response, pyrolysis, and ablation model was developed. Model predictions compare favorably with the arcjet test data

Milos, Frank S.↗
NASA NTRS1995

(abstract) Cassini MLI Balnkets High-Temperature Exposure Tests

The trajectory required for the Cassini spacecraft to reach Saturn will subject the spacecraft to a 0.61 AU temperature environment at perihelion. Temperatures on some sunlit blanket surfaces at 0.61 AU can reach levels that are beyond the service capability of the conventional Mylar/Dacron net MLI. The majority of the blanket surfaces, however, will experience temperatures with an upper bound of 250(deg) C. The maximum allowable temperature for Mylar/Dacron net is determined to be 220(deg)C. Kapton can withstand temperatures in excess of 400(deg) C; however, the high cost of embossed Kapton relative to Mylar/Dacron net requires a baseline design which includes a standard layup and a high-temperature layup. The high-temperature layup is utilized at a limited number of locations, while at least 90% of the blankets are of the standard layup. The verification of both layups' capability to meet all temperature requirements has been accomplished by a comprehensive test program which addressed their high-temperature survivability, effective emittance, and optical and electrical properties. This paper focuses on the high-temperature exposure tests which helped define the hybrid standard layup, and which demonstrated the adequacy of both layups in withstanding their respective thermal environments.

temperature control insulation Cassini↗
NASA NTRS2002

Refractive Secondary Solar Concentrator Demonstrated High-Temperature Operation

Space applications that utilize solar thermal energy--such as electric power conversion systems, thermal propulsion systems, and furnaces--require highly efficient solar concentration systems. The NASA Glenn Research Center is developing the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, such as inflatable thin films, the refractive secondary concentrator enables very high system concentration ratios and very high temperatures. Last year, Glenn successfully demonstrated a secondary concentrator throughput efficiency of 87 percent, with a projected efficiency of 93 percent using an antireflective coating. Building on this achievement, Glenn recently successfully demonstrated high-temperature operation of the secondary concentrator when it was used to heat a rhenium receiver to 2330 F. The high-temperature demonstration of the concentrator was conducted in Glenn's 68-ft long Tank 6 thermal vacuum facility equipped with a solar simulator. The facility has a rigid panel primary concentrator that was used to concentrate the light from the solar simulator onto the refractive secondary concentrator. NASA Marshall Space Flight Center provided a rhenium cavity, part of a solar thermal propulsion engine, to serve as the high-temperature receiver. The prototype refractive secondary concentrator, measuring 3.5 in. in diameter and 11.2 in. long, is made of single-crystal sapphire. A water-cooled splash shield absorbs spillage light outside of the 3.5-in. concentrator aperture. Multilayer foil insulation composed of tungsten, molybdenum, and niobium is used to minimize heat loss from the hightemperature receiver. A liquid-cooled canister calorimeter is used to measure the heat loss through the multilayer foil insulation.

Wong, Wayne A.↗
NASA NTRS2007

Multilayer Impregnated Fibrous Thermal Insulation Tiles

The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

Tran, Huy K.↗
NASA NTRS2018

Lightweight, Durable, and Multifunctional Electrical Insulation Material Systems for High Voltage Applications

Newly developed multilayer structures of well-known polymer insulation materials significantly improved dielectric breakdown voltage, VB, or dielectric strength, K, if well-bonded, when compared to those of single material insulations or the commercial SOA systems, such as Teflon-Kapton-Teflon (TKT), at the same overall thickness. To date, the greatest improvement of the new structures from a few candidate materials, including various types of Kapton PIs and PFA or PET as bond layer (BL), was about 61% higher than that of the Kapton PI alone films, 40.1 vs. 24.9 kV, which was translated to 86.3% decrease in insulation thickness, thus significant volume and weight reduction of the final system. However, it was of interest to note that most improvements of the multilayer structures occurred at thicker overall thicknesses, above ~ 0.15 mm. Extensive analyses also showed that K of the multilayer structures increased with (i) decreasing individual layer thickness regardless of material type, (ii) increasing total accumulated thickness of PI or overall PI/BL ratio, and (iii) increasing number of interface or total number of layers, but only above the aforementioned overall thickness limit. Increases in VB of the multilayer structures were directly correlated with damage evolution and failure mode. With further material-design-process optimizations of the multilayer structures, it was expected to achieve other multifunctionalities, such as high partial discharge (PD) resistance, improved durability, EMI shielding, and high thermal dissipation in addition to high dielectric strength. These new structures can be used in various high voltage and high temperature applications, such as future hybrid or all electric aircraft wiring and power transmission as well as many other non-aerospace high power cables, electronic parts and components, printed circuit board, and so forth. The multilayer insulation system can be easily processed and manufactured with various conductor types via calendaring, compression-molding, stamping, laminating, vacuum-bagging and autoclaving, or 3D printing, even for complex 3-D components. Based on their unique structural configurations and potential capabilities, the new insulation system was identified as micro-multilayer multifunctional electrical insulation (MMEI). Patent application of the MMEI concept and current design configurations was filed for a 1-year provisional application (OAI-58834, Serial No.: 62/659,234), pending conversion to a U.S. utility application. This paper presents details of the MMEI structures, their dielectric performance analyses, potential mechanisms, and commercial scaleup feasibility assessment.

Electric aircrafts↗
NASA NTRS2018

Lightweight, Durable, and Multifunctional Electrical Insulation Material Systems for High Voltage Applications

Newly developed multilayer structures of well-known polymer insulation materials significantly improved dielectric breakdown voltage, VB, or dielectric strength, K, if well-bonded, when compared to those of single material insulations or the commercial SOA systems, such as Teflon-Kapton-Teflon (TKT), at the same overall thickness. To date, the greatest improvement of the new structures from a few candidate materials, including various types of Kapton PIs and PFA or PET as bond layer (BL), was about 61% higher than that of the Kapton PI alone films, 40.1 vs. 24.9 kV, which was translated to 86.3% decrease in insulation thickness, thus significant volume and weight reduction of the final system. However, it was of interest to note that most improvements of the multilayer structures occurred at thicker overall thicknesses, above ~ 0.15 mm. Extensive analyses also showed that K of the multilayer structures increased with (i) decreasing individual layer thickness regardless of material type, (ii) increasing total accumulated thickness of PI or overall PI/BL ratio, and (iii) increasing number of interface or total number of layers, but only above the aforementioned overall thickness limit. Increases in VB of the multilayer structures were directly correlated with damage evolution and failure mode. With further material-design-process optimizations of the multilayer structures, it was expected to achieve other multifunctionalities, such as high partial discharge (PD) resistance, improved durability, EMI shielding, and high thermal dissipation in addition to high dielectric strength. These new structures can be used in various high voltage and high temperature applications, such as future hybrid or all electric aircraft wiring and power transmission as well as many other non-aerospace high power cables, electronic parts and components, printed circuit board, and so forth. The multilayer insulation system can be easily processed and manufactured with various conductor types via calendaring, compression-molding, stamping, laminating, vacuum-bagging and autoclaving, or 3D printing, even for complex 3-D components. Based on their unique structural configurations and potential capabilities, the new insulation system was identified as micro-multilayer multifunctional electrical insulation (MMEI). Patent application of the MMEI concept and current design configurations was filed for a 1-year provisional application (OAI-58834, Serial No.: 62/659,234), pending conversion to a U.S. utility application. This paper presents details of the MMEI structures, their dielectric performance analyses, potential mechanisms, and commercial scaleup feasibility assessment.

Multifunctional↗
NASA NTRS1968

Cryogenic insulation system Patent

Prefabricated multilayered self-evacuating insulation panels using gas with low vapor pressure at cryogenic temperatures for application to storage of cryogens

Perkins, P. J., Jr.↗