Radiative heat exchange and equilibrium surface temperature in a space environment.
Radiative heat exchange and equilibrium surface temperature in space environment
Hering, R. G.↗
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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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High-power-level temperature controller for space flight applications
High power level solid state temperature controller for space environment
SEMICONDUCTOR DEVICE↗
A Summary of the Temperature Control Problems of Interplanetary Space-Crafts
Temperature control in interplanetary spacecraft
CONTROL↗
Development of a low temperature battery for space probe applications first quarterly report
Low temperature liquid ammonia battery for space probe application
LIQUID AMMONIA↗
A mosaic infrared sensor for space astronomy
The objectives were to give a theoretical and/or experimental evaluation of HgCdTe detector arrays (1 to 5 micron) for space astronomy applications; to analyze low background HgCdTe/CCD coupling schemes for low temperature space astronomy; and to test and evaluate existing silicon CCDs at temperatures below 77 K. The accomplishments are the theoretical tradeoffs for PV-HgCdTe detectors completed at low temperatures; the characterization of existing PV-HgCdTe detector arrays (1 to 5 Micron) at low temperatures (low temperature performance exceeds measurement capability, preamplifier designed and built, and limiting detector current mechanisms analyzed); various detector/CCD coupling approaches were evaluated (resettable gate coupled approach chosen for low background); and low temperature CCD performance at 50 K shows compatibility with astronomical requirements.
Sood, Ashok K.↗
High temperature power electronics for space
A high temperature electronics program at NASA Lewis Research Center focuses on dielectric and insulating materials research, development and testing of high temperature power components, and integration of the developed components and devices into a demonstrable 200 C power system, such as inverter. An overview of the program and a description of the in-house high temperature facilities along with experimental data obtained on high temperature materials are presented.
Hammoud, Ahmad N.↗
A solid-state digital temperature recorder for space use
A solid-state, digital, temperature recorder has been developed for use in space experiments. The recorder is completely self-contained and includes a temperature sensor; all necessary electronics for signal conditioning, processing, storing, control and timing; and a battery power supply. No electrical interfacing with the particular spacecraft on which the unit is used is required. The recorder is small, light, and sturdy, and has no moving parts. It uses only biocompatible materials and has passed vibration and shock spaceflight qualification tests. The unit is capable of storing 2048, -10 to +45 C, 8-bit temperature measurements taken at intervals selectable by factors of 2 from 1.875 to 240 min; data can be retained for at least 6 months. The basic recorder can be simplified to accommodate a variety of applications by adding memory to allow more data to be recorded, by changing the front end to permit measurements other than temperature to be made, and by using different batteries to realize various operating periods. Stored flight data are read out from the recorder by means of a ground read-out unit.
Westbrook, R. M.↗
Antiferromagnetic inclusions in lunar glass
The magnetic susceptibility of eleven glass spherules from the Apollo 15, 16, and 17 fines and two specimens of a relatively large glass spherical shell were studied as a function of temperature from room temperature to liquid helium temperatures. All but one specimen showed the presence of antiferromagnetic inclusions. Closely spaced temperature measurements of the magnetic susceptibility below 77 K on five of the specimens showed antiferromagnetic temperature transitions (Neel transitions). With the exception of ilmenite in one specimen, these transitions did not correspond to any transitions in known antiferromagnetic compounds.
Thorpe, A. N.↗
Development and testing of a low-temperature hydraulic system. Volume II - Hydraulic system analysis and test program Final report
Hydraulic actuation systems analysis and design, and simulated space temperature and pressure environmental testing
ENVIRONMENTAL TESTING↗
Investigation of high temperature antennas for space shuttle
The design and development of high temperature antennas for the space shuttle orbiter are discussed. The antenna designs were based on three antenna types, an annular slot (L-Band), a linear slot (C-Band), and a horn (C-Band). The design approach was based on combining an RF window, which provides thermal protection, with an off-the-shelf antenna. Available antenna window materials were reviewed and compared, and the materials most compatible with the design requirements were selected. Two antenna window design approaches were considered: one employed a high temperature dielectric material and a low density insulation material, and the other an insulation material usable for the orbiter thermal protection system. Preliminary designs were formulated and integrated into the orbiter structure. Simple electrical models, with a series of window configurations, were constructed and tested. The results of tests and analyses for the final antenna system designs are given and show that high temperature antenna systems consisting of off-the-shelf antennas thermally protected by RF windows can be designed for the Space Shuttle Orbiter.
Kuhlman, E. A.↗
Valve Packing
"S Glass" yarn was originally developed by NASA for high temperature space and aeronautical applications. When John Crane, Inc. required material that would withstand temperatures higher than 1,200 degrees Fahrenheit, they contacted Owens-Corning, which had developed a number of applications for the material. John Crane combines the yarn with other components to make Style 287-I packing. The product can be used in chemical processing operations, nuclear power stations, petroleum products, etc. Advantages include increased service life and reduced maintenance costs.
Source record↗
Comprehensive Evaluation of Power Supplies at Cryogenic Temperatures for Deep Space Applications
The operation of power electronic systems at cryogenic temperatures is anticipated in many future space missions such as planetary exploration and deep space probes. In addition to surviving the space hostile environments, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing development and launch costs. DC/DC converters are widely used in space power systems in the areas of power management, conditioning, and control. As part of the on-going Low Temperature Electronics Program at NASA, several commercial-off-the-shelf (COTS) DC/DC converters, with specifications that might fit the requirements of specific future space missions have been selected for investigation at cryogenic temperatures. The converters have been characterized in terms of their performance as a function of temperature in the range of 20 C to - 180 C. These converters ranged in electrical power from 8 W to 13 W, input voltage from 9 V to 72 V and an output voltage of 3.3 V. The experimental set-up and procedures along with the results obtained on the converters' steady state and dynamic characteristics are presented and discussed.
Patterson, Richard L.↗
The brightness temperature of a half-space random medium with nonuniform temperature profile
The problem of microwave thermal emission from a half-space random medium is solved. We consider a laminar structure which has a nonuniform temperature distribution in the vertical direction. A radiative transfer approach is applied. For constant absorption and scattering coefficients, the brightness temperature is determined by a simple closed-form formula. Physical interpretations and numerical results are illustrated and discussed for the various cases.
Tsang, L.↗
A Computational Fluid Dynamic and Heat Transfer Model for Gaseous Core and Gas Cooled Space Power and Propulsion Reactors
A computational model based on the axisymmetric, thin-layer Navier-Stokes equations is developed to predict the convective, radiation and conductive heat transfer in high temperature space nuclear reactors. An implicit-explicit, finite volume, MacCormack method in conjunction with the Gauss-Seidel line iteration procedure is utilized to solve the thermal and fluid governing equations. Simulation of coolant and propellant flows in these reactors involves the subsonic and supersonic flows of hydrogen, helium and uranium tetrafluoride under variable boundary conditions. An enthalpy-rebalancing scheme is developed and implemented to enhance and accelerate the rate of convergence when a wall heat flux boundary condition is used. The model also incorporated the Baldwin and Lomax two-layer algebraic turbulence scheme for the calculation of the turbulent kinetic energy and eddy diffusivity of energy. The Rosseland diffusion approximation is used to simulate the radiative energy transfer in the optically thick environment of gas core reactors. The computational model is benchmarked with experimental data on flow separation angle and drag force acting on a suspended sphere in a cylindrical tube. The heat transfer is validated by comparing the computed results with the standard heat transfer correlations predictions. The model is used to simulate flow and heat transfer under a variety of design conditions. The effect of internal heat generation on the heat transfer in the gas core reactors is examined for a variety of power densities, 100 W/cc, 500 W/cc and 1000 W/cc. The maximum temperature, corresponding with the heat generation rates, are 2150 K, 2750 K and 3550 K, respectively. This analysis shows that the maximum temperature is strongly dependent on the value of heat generation rate. It also indicates that a heat generation rate higher than 1000 W/cc is necessary to maintain the gas temperature at about 3500 K, which is typical design temperature required to achieve high efficiency in the gas core reactors. The model is also used to predict the convective and radiation heat fluxes for the gas core reactors. The maximum value of heat flux occurs at the exit of the reactor core. Radiation heat flux increases with higher wall temperature. This behavior is due to the fact that the radiative heat flux is strongly dependent on wall temperature. This study also found that at temperature close to 3500 K the radiative heat flux is comparable with the convective heat flux in a uranium fluoride failed gas core reactor.
Anghaie, S.↗
Development of a low temperature battery for space probe applications second quarterly report, 24 sep. - 23 dec. 1964
Low temperature battery for space probe
SPACE PROBE↗
Net Shaped Component Fabrication of Refractory Metal Alloys using Vacuum Plasma Spraying
The vacuum plasma spraying (VPS) technique was employed to produce dense and net shaped components of a new tungsten-rhenium (W-Re) refractory metal alloy. The fine grain size obtained using this technique enhanced the mechanical properties of the alloy at elevated temperatures. The alloy development also included incorporation of thermodynamically stable dispersion phases to pin down grain boundaries at elevated temperatures and thereby circumventing the inherent problem of recrystallization of refractory alloys at elevated temperatures. Requirements for such alloys as related to high temperature space propulsion components will be discussed. Grain size distribution as a function of cooling rate and dispersion phase loading will be presented. Mechanical testing and grain growth results as a function of temperature will also be discussed.
Sen, S.↗
Temperature Stratification in a Cryogenic Fuel Tank
A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.
stratification↗
Detector Assembly and the Ultralow-Temperature Refrigerator for XRS
The X-ray spectrometer (XRS) on the Japanese Astro-E Spacecraft is the first ultra low temperature space borne instrument. The system utilizes a 900g Ferric Ammonium Alum (FAA) Adiabatic Demagnetization Refrigerator (ADR) with a helium-3 gas gap heat switch to cool the detector assembly to 0.060K. The system operates in a "single shot" configuration allowing the system to remain at its operating temperature for about 40 hours in the lab. The on-orbit performance is expected to be about 35 hours with a 97% duty cycle. The detector assembly for XRS consists of a 32 channel microcalorimeter array bias electronics, thermometry, and an anti-coincidence detector that are attached to the cold stage of the ADR. To thermally Isolate the detector system from the superfluid helium reservoir, the detector system is suspended by Kevlar cords and electrical connection in made by L30, 17-micron diameter, tensioned NbTi leads. The detectors are read out in a source-follower arrangement using FET amplifiers operating at 130K mounted in multiply-thermally-isolated assemblies that also use Kevlar and stainless steel wiring. The design and thermal performance of this system will be discussed and compared to the theoretical limits.
Porter, F. S.↗