Thermal design and flight experience of the Mars Exploration Rover spacecraft computer-controlled, propulsion line heaters
Explore the source record for details and available documents.
propulsion lines↗
SEARCH · Engineering Papers
Results for “Thermal experience”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Experiments with phase change thermal energy storage canisters for Space Station Freedom
The solar dynamic power module proposed for the Space Station Freedom (SSF) uses the heat of fusion of a phase change material (PCM) to efficiently store thermal energy for use during eclipse periods. The PCM, a LiF-20CaF2 salt, is contained in annular, metal canisters located in a heat receiver at the focus of a solar concentrator. PCM canister ground-based experiments and analytical heat transfer studies are discussed. The hardware, test procedures, and test results from these experiments are discussed. After more than 900 simulated SSF orbital cycles, no canister cracks or leaks were observed and all data were successfully collected. The effect of 1-g test orientation on canister wall temperatures was generally small while void position was strongly dependent on test orientation and canister cooling. In one test orientation, alternating wall temperature data were measured that supports an earlier theory of oscillating vortex flow in the PCM melt. Analytical canister wall temperatures compared very favorably with experimental temperature data. This illustrates that ground-based canister thermal performance can be predicted well by analyses that employ straight-forward, engineering models of void behavior and liquid PCM free convection.
Kerslake, Thomas W.↗
Thermal Gradient and Neutron Irradiation Experiment Design for Fusion Reactor Materials in the Advanced Test Reactor
This work outlines a hypothetical coupled thermal gradient and neutron irradiation experiment in the Advanced Test Reactor (ATR) at the Idaho National Laboratory. Although the ATR is a thermal spectrum test reactor and doesn’t inherently produce a flux spectrum dominated by the high-energy neutrons typical in a fusion reactor, it’s multitude of experiment positions and dynamic flux environment make it a suitable platform for investigating fusion related issues.
36 MATERIALS SCIENCE↗
Thermal design support for the Explorer gamma ray experiment telescope
The results of a thermal design definition study for the GSFC Explorer Gamma Ray Experiment Telescope (EGRET) were documented. A thermal computer model of EGRET with 241 nodes was developed and used to analyze the thermal performance of the experiment for a range of orbits, payload orientations and internal power dissipations. The recommended thermal design utilizes a small radiator with an area of 1.78 square foot on the anti-sun side of the mission adaptor and circumferential heat pipes on the interior of the same adaptor to transfer heat from the electronics compartments to the single radiator. Fifty watts of thermostatically controlled heater power are used to control the temperature level to 10 C + or - 20 C inside the insulated dome structure.
Almgren, D. W.↗
Investigation of Thermal High Cycle and Low Cycle Fatigue Mechanisms of Thick Thermal Barrier Coatings
Thick thermal barrier coating systems in a diesel engine experience severe thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) during engine operation. In this paper, the mechanisms of fatigue crack initiation and propagation in a ZrO2-8wt.% Y2O3 thermal barrier coating, under simulated engine thermal LCF and HCF conditions, are investigated using a high power CO2 laser. Experiments showed that the combined LCF/HCF tests induced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. Lateral crack branching and the ceramic/bond coat interface delaminations were also facilitated by HCF thermal loads, even in the absence of severe interfacial oxidation. Fatigue damages at crack wake surfaces, due to such phenomena as asperity/debris contact induced cracking and splat pull-out bending during cycling, were observed especially for the combined LCF/HCF tests. It is found that the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. The failure associated with HCF process, however, is mainly associated with a surface wedging mechanism. The interaction between the LCF, HCF and ceramic coating creep, and the relative importance of LCF and HCF in crack propagation are also discussed based on the experimental evidence.
Zhu, Dongming↗
Investigation of Thermal High Cycle and Low Cycle Fatigue Mechanisms of Thick Thermal Barrier Coatings
Thick thermal barrier coating systems in a diesel engine experience severe thermal low cycle fatigue (LCF) and high cycle fatigue (HCF) during engine operation. In this paper, the mechanisms of fatigue crack initiation and propagation in a ZrO2-8wt% Y2O3 thermal barrier coating, under simulated engine thermal LCF and HCF conditions, are investigated using a high power CO2 laser. Experiments showed that the combined LCF-HCF tests induced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. Lateral crack branching and the ceramic/bond coat interface delaminations were also facilitated by HCF thermal loads, even in the absence of severe interfacial oxidation. Fatigue damage at crack wake surfaces, due to such phenomena as asperity/debris contact induced cracking and splat pull-out bending during cycling, was observed especially for the combined LCF-HCF tests. It is found that the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. The failure associated with HCF process, however, is mainly associated with a surface wedging mechanism. The interaction between the LCF, HCF and ceramic coating creep, and the relative importance of LCF and HCF in crack propagation are also discussed based on the experimental evidence.
Zhu, Dongming↗
High Current Cathode Thermal Behavior, Part II: Experiments
Temperature profiles have been measured along the axis of a thoriated tungsten rod cathode in an argon gas discharge at two ambient pressure levels and current levels ranging from 600 to 1400 A.
cathode tip tip temperatures transient thermal beh↗
Thermal surveillance of volcanoes
The author has identified the following significant results. A systematic aircraft program to monitor changes in the thermal emission from volcanoes of the Cascade Range has been initiated and is being carried out in conjunction with ERTS-1 thermal surveillance experiments. Night overflights by aircraft equipped with thermal infrared scanners sensitive to terrestrial emission in the 4-5.5 and 8-14 micron bands are currently being carried out at intervals of a few months. Preliminary results confirm that Mount Rainier, Mount Baker, Mount Saint Helens, Mount Shasta, and the Lassen area continue to be thermally active, although with the exception of Lassen which erupted between 1914 and 1917, and Mount Saint Helens which had a series of eruptions between 1831 and 1834, there has been no recent eruptive activity. Excellent quality infrared images recorded over Mount Rainier, as recently as April, 1972, show similar thermal patterns to those reported in 1964-1966. Infrared images of Mount Baker recorded in November 1970 and again in April 1972 revealed a distinct array of anomalies 1000 feet below the crater rim and associated with fumaroles or structures permitting convective heat transfer to the surface.
Friedman, J. D.↗
The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings: Models and Experiments
The lattice and radiation conductivity of ZrO2-Y2O3 thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the coating apparent thermal conductivity to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature, coating material scattering, and absorption properties. High temperature scattering and absorption of the coating systems can be also derived based on the testing results using the modeling approach. A comparison has been made for the gray and nongray coating models in the plasma-sprayed thermal barrier coatings. The model prediction is found to have a good agreement with experimental observations.
Zhu, Dongming↗
Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control: Validation Results - Part 2
Under NASA s New Millennium Program Space Technology 8 (ST 8) Project, Goddard Space Fight Center has conducted a Thermal Loop experiment to advance the maturity of the Thermal Loop technology from proof of concept to prototype demonstration in a relevant environment , i.e. from a technology readiness level (TRL) of 3 to a level of 6. The thermal Loop is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers designed for future small system applications requiring low mass, low power, and compactness. The MLHP retains all features of state-of-the-art loop heat pipes (LHPs) and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. An MLHP breadboard was built and tested in the laboratory and thermal vacuum environments for the TRL 4 and TRL 5 validations, respectively, and an MLHP proto-flight unit was built and tested in a thermal vacuum chamber for the TRL 6 validation. In addition, an analytical model was developed to simulate the steady state and transient behaviors of the MLHP during various validation tests. The MLHP demonstrated excellent performance during experimental tests and the analytical model predictions agreed very well with experimental data. All success criteria at various TRLs were met. Hence, the Thermal Loop technology has reached a TRL of 6. This paper presents the validation results, both experimental and analytical, of such a technology development effort.
Ku, Jentung↗
A Thermodynamic Paradigm for Studying Disease Vector’s Habitats & Life Cycles Using NASA’s NextGen Remote Sensing Instruments
Global public health is entering a new informational age through the use of spatial models of disease vector/host ecologies driven by the use of remotely sensed data to measure environmental and structural factors critical in determining disease vector habitats, distributions, life cycles, and host interactions. The vector habitat microclimates can be quantified in terms of the surface energy budget measured by satellites. The epidemiological equations (processes) can be adapted and modified to explicitly incorporate environmental factors and interfaces required by a specific disease and its vector/host cycle. Remote sensing can be used to measure or evaluate or estimate both environment (state functions) and interface (process functions). Remote sensing can be used to measure or evaluate or estimate both environment (state functions) and interface (process functions) defining vector habitats. The products of remote sensing can be integrated directly into the epidemiological equations to significantly enhance our understanding of disease vector’s life cycles and habitats. The next generation of NASA’s remote sensing instruments recently operational will provide a significant enhancement in our ability to study disease vector’s life cycles and habitats. Three new instruments have become operational on the International Space Station (ISS) In June 2018, ECOSTRESS (The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station), a five channel, thermal IR instrument with 70 m resolution and approximately 4-5 day repeat cycle of day/night pairs along with DESISa hyperspectral sensor system 235 channels (between 400 and 1000 nanometers), 30 m resolution, and data only being acquired on demand. In November 2018. GEDI (Global Ecosystem Dynamics Investigation). GEDI is a high-resolution laser ranging of Earth’s forests and topography. These instruments set the stage for NASA’s new global designated observables set of remote sensing measurements collecting hyperspectral and multispectral thermal data called SBG (Surface Biology Geology). The SBG is currently in the planning stage. The availability and use of level 1-4 data products generated from these ISS instruments will be discussed.
thermodynamics↗
The JPL isolated application experiment series
A set of small (approximately 60-150 kWe) solar thermal power experiments, each of which is meant to address a separate isolated load application, will employ point focusing distributed receiver technology with emphasis on electric and possibly some thermal power applications. The program will be closely integrated with the technology development element of the thermal power systems project with the objective of utilizing the technologies being developed under that program.
Levin, R. R.↗
Mercury Abundances and Isotopic Compositions in the Murchison (CM) and Allende (CV)Carbonaceous Chondrites
The abundance and isotopic composition of Hg was determined in bulk samples of both the Murchison (CM) and Allende (CV) carbonaceous chondrites using single- and multi-collector inductively coupled plasma mass spectrometry (ICP-MS). The bulk abundances of Hg are 294 6 15 ng/g in Murchison and 30.0 6 1.5 ng/g in Allende. These values are within the range of previous measurements of bulk Hg abundances by neutron activation analysis (NAA). Prior studies suggested that both meteorites contain isotopically anomalous Hg, with d l 96/202Hg values for the anomalous, thermal-release components from bulk samples ranging from 2260 %o to 1440 9/00 in Murchison and from 2620 9/00 to 1540 9/00 in Allende (Jovanovic and Reed, 1976a; 1976b; Kumar and Goel, 1992). Our multi-collector ICP-MS measurements suggest that the relative abundances of all seven stable Hg isotopes in both meteorites are identical to terrestrial values within 0.2 to 0.5 9/00m. On-line thermal-release experiments were performed by coupling a programmable oven with the singlecollector ICP-MS. Powdered aliquots of each meteorite were linearly heated from room temperature to 900 C over twenty-five minutes under an Ar atmosphere to measure the isotopic composition of Hg released fiom the meteorites as a h c t i o n of temperature. In separate experiments, the release profiles of S and Se were determined simultaneously with Hg to constrain the Hg distribution within the meteorites and to evaluate the possibility of Se interferences in previous NAA studies. The Hg-release patterns differ between Allende and Murchison. The Hg-release profile for Allende contains two distinct peaks, at 225" and 343"C, whereas the profile for Murchison has only one peak, at 344 C. No isotopically anomalous Hg was detected in the thermal-release experiments at a precision level of 5 to 30 9/00, depending on the isotope ratio. In both meteorites the Hg peak at ;340"C correlates with a peak in the S-release profile. This correlation suggests that Hg is associated with S-bearing phases and, thus, that HgS is a major Hg-bearing phase in both meteorites. The Hg peak at 225 C for Allende is similar to release patterns of physically adsorbed Hg on silicate and metal grains.
Lauretta, D. S.↗
Thermal control paints on LDEF: Results of sub-experiment 802-18
Several thermal control paints were flown on the LDEF, including the white paints Chemglaze A276, S13GLo, and YB-71, and the black paint D-111. The effects of low earth orbit, which includes UV radiation and atomic oxygen, varied significantly with each paint and its location on LDEF. This paper will examine the performance of these paints as determined by changes in their optical and physical properties, including solar absorptance, surface chemical changes, and changes in surface morphology. It will also provide a correlation of these optical and physical property changes to the physical phenomena that occurred in these materials during the LDEF mission.
Jaggers, Christopher H.↗
IER-520 and IER-553: Final Design for Follow-on Plutonium TEX Configurations [Slides]
This presentation discusses final designs for Plutonium Thermal Epithermal eXperiments (TEX) configurations. The goal of the experiments is to produce Pu critical benchmarks to address the nuclear data and validations needs for criticality safety.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap
A dual-membrane gas trap is currently used to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the NCG. The inner hydrophobic fiber allows the trapped NCG to pass through and vent to the ambient atmosphere in the cabin. The purpose of the gas trap is to prevent gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump, and the current gas trap has performed flawlessly in this regard. However, because of actual operational conditions on-orbit, its gas removal performance and operational lifetime have been affected. This paper discusses experiences with several of these dual- membrane gas traps, including on-orbit gas venting rate, effects due to the presence of nickel in the ITCS coolant, and subsequent refurbishing to remove the nickel from the gas trap.
Leimkuehler, Thomas O.↗
A preliminary thermal distortion analysis of the proposed A0S0 experiment support structure
Mathematical model for calculating thermal distortion of AOSO experiment support structure and equations for expressing interaction loads and rotational deflections
DISTORTION↗
Influence of High Cycle Thermal Loads on Thermal Fatigue Behavior of Thick Thermal Barrier Coatings
Thick thermal barrier coating systems in a diesel engine experience severe thermal Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) during engine operation. In the present study, the mechanisms of fatigue crack initiation and propagation, as well as of coating failure, under thermal loads which simulate engine conditions, are investigated using a high power CO2 laser. In general, surface vertical cracks initiate early and grow continuously under LCF and HCF cyclic stresses. It is found that in the absence of interfacial oxidation, the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. Experiments show that the HCF cycles are very damaging to the coating systems. The combined LCF and HCF tests produced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. It is suggested that the HCF component cannot only accelerate the surface crack initiation, but also interact with the LCF by contributing to the crack growth at high temperatures. The increased LCF stress intensity at the crack tip due to the HCF component enhances the subsequent LCF crack growth. Conversely, since a faster HCF crack growth rate will be expected with lower effective compressive stresses in the coating, the LCF cycles also facilitate the HCF crack growth at high temperatures by stress relaxation process. A surface wedging model has been proposed to account for the HCF crack growth in the coating system. This mechanism predicts that HCF damage effect increases with increasing temperature swing, the thermal expansion coefficient and the elastic modulus of the ceramic coating, as well as the HCF interacting depth. A good agreement has been found between the analysis and experimental evidence.
Zhu, Dongming↗