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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Multiyear On-orbit Calibration and Performance of Terra MODIS Thermal Emissive Bands

Since launch in December 1999, Terra MODIS has been making continuous Earth observations for more than seven years. It has produced a broad range of land, ocean, and atmospheric science data products for improvements in studies of global climate and environmental change. Among its 36 spectral bands, there are 20 reflective solar bands (RSB) and 16 thermal emissive bands (TEB). MODIS thermal emissive bands cover the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions with wavelengths from 3.7 to 14.4pm. They are calibrated on-orbit using an on-board blackbody (BB) with its temperature measured by a set of thermistors on a scan-by-scan basis. This paper will provide a brief overview of MODIS TEB calibration and characterization methodologies and illustrate on-board BB functions and TEB performance over more than seven years of on-orbit operation and calibration. Discussions will be focused on TEB detector short-term stability and noise characterization, and changes in long-term response (or system gain). Results show that Terra MODIS BB operation has been extremely stable since launch. When operated at its nominal controlled temperature of 290K, the BB temperature variation is typically less than +0.30mK on a scan-by-scan basis and there has been no time-dependent temperature drift. In addition to excellent short-term stability, most TEB detectors continue to meet or exceed their specified noise characterization requirements, thus enabling calibration accuracy and science data product quality to be maintained. Excluding the noisy detectors identified pre-launch and those that occurred post-launch, the changes in TEB responses have been less than 0.7% on an annual basis. The optical leak corrections applied to bands 32-36 have been effective and stable over the entire mission

Xiong, Xiaoxiong↗
NASA NTRSDate not supplied

Early Radiometric Performance of Landsat-9 Thermal Infrared Sensor

Landsat-9, launched on September 27, 2021, carries the Thermal Infrared Sensor (TIRS). The Landsat-9 TIRS is a close copy of the Landsat-8 TIRS instrument; it is a two spectral-band, pushbroom sensor with three Sensor Chip Assemblies (SCAs) that cover the 15-degree field-of-view. The primary radiometric change between the instruments is the addition of baffling in the Landsat-9 TIRS telescope to mitigate the stray light issue that has impacted the radiometric quality of Landsat-8 TIRS. The on-orbit radiometric performance is monitored using the on-board variable temperature blackbody and views of deep space. Maneuvers to look at and around the moon have provided an assessment of the stray light. The absolute calibration is monitored by vicarious calibration techniques by teams at NASA/Jet Propulsion Lab and the Rochester Institute of Technology. Landsat-9 completed a three-month commissioning phase in January 2022 and has been operational since February 2022. The instrument has demonstrated excellent radiometric performance, as assessed from the on-orbit measurements. The TIRS instrument is radiometrically stable to 0.1% within a power cycle, and has noise levels below 0.1K. The lunar scans and the vicarious calibration data provide evidence that the stray light has been effectively mitigated.

Landsat-9↗
NASA NTRS1991

Performance impact on nuclear thermal propulsion of piloted Mars missions with short transit times

The requirements of nuclear thermal propulsion (NTP) are examined with respect to a specific mission scenario derived from Stafford Committee recommendations. The recommended mission scenario is a split/sprint opposition mission which includes a piloted vehicle and a cargo vehicle, and the baseline mission is developed from a reference trajectory. Key mision parameters are developed from the baseline mission, including engine-thrust levels, mission opportunity, and engine burn-time requirements. The impact of engine failure is also considered in terms of burn-time requirements, and other mission-performance issues considered include propulsion-technology assumptions, triple-perigee earth-departure burns, and Mars parking-orbit selection. The engine requirements call for a 50-75-klb engine-thrust level, maximum single burn time of 0.6 hours, and a maximum total-mission burn time of 1.7 hours. For a crew of 6, a 475-day total-mission trip with a 90-day stay at Mars is possible.

Wickenheiser, T. J.↗
NASA NTRS2012

Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB

This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under i) different sink temperatures and ii) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies.

Wang, Xiao-Yen, J.↗
NASA NTRSDate not supplied

Balancing Manufacturability with Performance: Achieving Extrudable, High Thermal Conductivity, and Dielectrically Robust Thermoplastic Composites

Improved thermal management solutions for electrical insulation systems are a priority for increasing efficiency. Although polymeric electrical insulation is ubiquitous, it generally exhibits low thermal conductivities (κ ; 0.1 – 0.3 W/mK). High κ electrical insulation systems are desirable for several reasons including improved heat wicking. Polymer-ceramic composites offer a viable path towards increasing κ of electrical insulation systems. However, processing-induced anisotropic particle orientation can result in prohibitively high concentrations of high κ particles being required to achieve impactful improvements. This work evaluates the effectiveness of a double percolation approach and its impacts on extruded polymer composite insulation κ using polyimide (PI), polyphenylsulfone (PPSU), and hexagonal boron nitride (hBN). Thermoplastic composite blends of PI/PPSU exhibited a 15% improvement in composite κ at comparable loading levels of hBN relative to mono-polymer material systems. On the other hand, PI/PPSU/hBN composites exhibited lower dielectric strengths than either neat polymer/hBN composite. A trade-off between maximizing material κ and resultant processing and dielectric performances may exist when using a double percolation approach for thermoplastic composites.

Witold K. Fuchs↗
NASA NTRS1984

The importance of thermal-vacuum testing in achieving high reliability of spacecraft mechanisms

The work performed on thermal vacuum testing of complex mechanisms is described. The objective of these tests is to assess the mechanism reliability by monitoring performance in an environment that closely resembles the environment that will occur during flight. To be both valid and cost effective, these tests are performed in a detailed, formally controlled manner. A review of the major test observations is given, during which time some failure modes are detected. Full confidence now exists in many mechanism and component designs, and much valuable data obtained.

Parker, K.↗
NASA NTRS1977

Atmospheric cloud physics thermal systems analysis

Engineering analyses performed on the Atmospheric Cloud Physics (ACPL) Science Simulator expansion chamber and associated thermal control/conditioning system are reported. Analyses were made to develop a verified thermal model and to perform parametric thermal investigations to evaluate systems performance characteristics. Thermal network representations of solid components and the complete fluid conditioning system were solved simultaneously using the Systems Improved Numerical Differencing Analyzer (SINDA) computer program.

Source record↗
NASA NTRS1976

Solar thermal electric power plants - Their performance characteristics and total social costs

The central receiver (power tower) concept as a thermal conversion approach to the conversion of solar energy into electricity is compared to other solar power plant designs which feature distributed solar collection and use other types of solar collector configurations. A variety of solar thermal storage concepts are discussed and their impacts on system performance are assessed. Although a good deal of quantification is possible in a comparative study, the subjective judgments carry enormous weight in a socio-economic decision, the ultimate choice of central power plant being more a social than an economic or technical decision. Major elements of the total social cost of each type of central plant are identified as utility economic costs, R&D funds, health costs, and other relevant social impacts.

Caputo, R. S.↗
NASA NTRS2014

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

This paper presents recent thermal model results of the Advanced Stirling Radioisotope Generator (ASRG). The three-dimensional (3D) ASRG thermal power model was built using the Thermal Desktop(trademark) thermal analyzer. The model was correlated with ASRG engineering unit test data and ASRG flight unit predictions from Lockheed Martin's (LM's) I-deas(trademark) TMG thermal model. The auxiliary cooling system (ACS) of the ASRG is also included in the ASRG thermal model. The ACS is designed to remove waste heat from the ASRG so that it can be used to heat spacecraft components. The performance of the ACS is reported under nominal conditions and during a Venus flyby scenario. The results for the nominal case are validated with data from Lockheed Martin. Transient thermal analysis results of ASRG for a Venus flyby with a representative trajectory are also presented. In addition, model results of an ASRG mounted on a Cassini-like spacecraft with a sunshade are presented to show a way to mitigate the high temperatures of a Venus flyby. It was predicted that the sunshade can lower the temperature of the ASRG alternator by 20 C for the representative Venus flyby trajectory. The 3D model also was modified to predict generator performance after a single Advanced Stirling Convertor failure. The geometry of the Microtherm HT insulation block on the outboard side was modified to match deformation and shrinkage observed during testing of a prototypic ASRG test fixture by LM. Test conditions and test data were used to correlate the model by adjusting the thermal conductivity of the deformed insulation to match the post-heat-dump steady state temperatures. Results for these conditions showed that the performance of the still-functioning inboard ACS was unaffected.

radioisotope power system↗
NASA NTRS1996

International Research Project on the Effects of Chemical Ageing of Polymers on Performance Properties: Chemical and Thermal Analysis

Work during the past six months has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted small changes in the molecular weight distribution. Again these changes may result in variations in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Ultra- Violet Scanning Analysis, GC/Mass Spectrometry, Differential Scanning Calorimetry and Thermomechanical Analysis. In the ultra-violet analysis we noted the presence of an absorption band indicative of triene formation. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We also cast films at SWT and subjected these films to a refluxing methanol 1% ethylene diamine solution. An updated literature search was conducted using Dialog and DROLLS to identify any new papers that may have been published in the open literature since the start of this project. The updated literature search and abstracts are contained in the Appendix section of this report.

Bulluck, J. W.↗
NASA NTRS2009

Ballistic Performance of Porous Ceramic Thermal Protection Systems at 9 km/s

Porous-ceramic, thermal-protection-systems are used heavily in current reentry vehicles like the Orbiter, and they are currently being proposed for the next generation of manned spacecraft, Orion. These materials insulate the structural components and sensitive electronic components of a spacecraft against the intense thermal environments of atmospheric reentry. Furthermore, these materials are also highly exposed to space environmental hazards like meteoroid and orbital debris impacts. This paper discusses recent impact testing up to 9 km/s on ceramic tiles similar to those used on the Orbiter. These tiles have a porous-batting of nominally 8 lb/cubic ft alumina-fiber-enhanced-thermal-barrier (AETB8) insulating material coated with a damage-resistant, toughened-unipiece-fibrous-insulation (TUFI) layer.

Miller, Joshua E.↗
NASA NTRS2017

Ultra-Stable Segmented Telescope Sensing and Control Architecture

The LUVOIR team is conducting two full architecture studies Architecture A 15 meter telescope that folds up in an 8.4m SLS Block 2 shroud is nearly complete. Architecture B 9.2 meter that uses an existing fairing size will begin study this Fall. This talk will summarize the ultra-stable architecture of the 15m segmented telescope including the basic requirements, the basic rationale for the architecture, the technologies employed, and the expected performance. This work builds on several dynamics and thermal studies performed for ATLAST segmented telescope configurations. The most important new element was an approach to actively control segments for segment to segment motions which will be discussed later.

Telescope↗
NASA NTRS2017

Ultra-Stable Segmented Telescope Sensing and Control Architecture

The LUVOIR team is conducting two full architecture studies. Architecture A - 15 meter telescope that folds up in an 8.4m SLS Block 2 shroud is nearly complete. Architecture B - 9.2 meter that uses an existing fairing size will begin study this Fall. This talk will summarize the ultra-stable architecture of the 15m segmented telescope including the basic requirements, the basic rationale for the architecture, the technologies employed, and the expected performance. This work builds on several dynamics and thermal studies performed for ATLAST segmented telescope configurations. The most important new element was an approach to actively control segments for segment to segment motions which will be discussed later.

Telescope↗
NASA NTRSDate not supplied

Evaluation of High-Temperature Fabrics for Improved Performance of Seals and Thermal Barriers

Hypersonic and space flight applications continue to push material demands of component-level technologies such as high-temperature seals and thermal barriers. NASA Glenn Research Center continues to develop and evaluate materials and coatings as well as thermal barrier designs for these applications. Experimental test data is presented for two different sheath fabrics that were evaluated in full thermal barrier assemblies through compression and wear testing at elevated temperatures, as well as flow testing at ambient temperature.

Seals↗
NASA NTRS1993

Numerical study of nozzle wall cooling for nuclear thermal rockets

The flowfields and performance of nuclear thermal rockets, which utilize radiation and film-cooling to cool the nozzle extension, are studied by solving the Navier-Stokes equations and species equations. The thrust level of the rocket for the present study is about 75,000 lb(f) for a chamber pressure of 68 atm(l,000 psi) and a chamber temperature of 2700 K. The throat radius of the nozzle is 0.0936 m and the area ratios of the nozzles are 300 and 500. It is assumed that the flow is chemically frozen and the turbulence is simulated by the modified Baldwin-Lomax turbulence model. The calculated results for various area ratios and film mass-flow rates are presented as Mach number contours, variations of nozzle wall temperature, exit profiles, and vacuum specific impulses. The present study shows that by selecting the flow rate of the film-cooling hydrogen and area ratio of the nozzle correctly, high area ratio nozzle extensions can be cooled effectively with radiation and film-cooling without significant penalty in performance.

Kim, Suk C.↗
NASA NTRS2004

Heat Shielding Characteristics and Thermostructural Performance of a Superalloy Honeycomb Sandwich Thermal Protection System (TPS)

Heat-transfer, thermal bending, and mechanical buckling analyses have been performed on a superalloy "honeycomb" thermal protection system (TPS) for future hypersonic flight vehicles. The studies focus on the effect of honeycomb cell geometry on the TPS heat-shielding performance, honeycomb cell wall buckling characteristics, and the effect of boundary conditions on the TPS thermal bending behavior. The results of the study show that the heat-shielding performance of a TPS panel is very sensitive to change in honeycomb core depth, but insensitive to change in honeycomb cell cross-sectional shape. The thermal deformations and thermal stresses in the TPS panel are found to be very sensitive to the edge support conditions. Slight corrugation of the honeycomb cell walls can greatly increase their buckling strength.

Ko, William L.↗