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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 163 records · Page 9

Temperature control of silica mirrors for cryogenically-cooled telescopes in space

The SIRTF (Space Infrared Telescope Facility) optical subsystem, including the primary mirror, has been modeled using lumped-parameter techniques and a thermal and cryogenic transient analysis program developed previously. Since silica mirrors have been shown to have significantly less distortion due to cryogenic cooldown, a silica primary mirror of approximately 1 m diameter is being considered. Thermal responses to variations in aperture heat load and heat sink temperature have been explored. Calculations have been made of system noise components from primary mirror spatial and temporal temperature variations. Background-limited infrared observations can be made at wavelengths out to 200 micrometers. Mirror thermal performance with and without copper wires for cooling is also considered.

Melugin, R. K.↗

Evaluation of commercially supplied silver coated Teflon for spacecraft temperature control usage

A series of tests are described which were performed to evaluate the acceptability of a commercially supplied silver backed teflon thermal control coating relative to teflon previously coated at GSFC. Optical measurements made on numerous samples indicate that the commercial material possesses an average solar absorptance of 0.085, an emittance of 0.76 and an average alpha/epsilon equal to 0.112, all of which are equivalent to the GSFC coated teflon. The emittance of the protective inconel backing was found to be 0.037. The coating is shown to have good adhesion at the Ag-teflon interface and exposure to UV irradiation uncovered no coating irregularities. Temperature cycling over the range -135 C to +200 C produced crazing in the evaporated Ag layer as expected but no delamination was observed. The suitability of Mystik no. 7366 and 3M no. 467 adhesives as bonding agents for the metallized polymer is demonstrated. Various problems associated with production reproducibility and selection of a proper bonding process are discussed.

Heaney, J. B.↗

Closed fluid system without moving parts controls temperature

Closed fluid system maintains a constant temperature in an insulated region without the use of any moving parts. Within the system, the energy for thermodynamic cycling of two-phase heat transfer fluid and a hydraulic fluid is entirely supplied by the heat generated in the thermally insulated region.

Stenger, F. J.↗

Temperature-controlled resistor

Electrical resistance of a carbon-pile resistor is controlled by the compression or relaxation of a pile of carbon disks by a thermally actuated bimetallic spring. The concept is advantageous in that it is direct-acting, can cover a wide range of controllable characteristics, and can handle considerable power directly.

Perkins, T. G.↗

Temperature control of a cryogenic bath

Foreign gas introduced into vapor phase above liquid region cools cryogenic baths. Equipment consists of gas tank and cover of styrofoam. Helium is considered the best choice to produce cooling, though any gas with boiling point lower than that of bath liquid may be used.

Asher, I. M.↗

Temperature control of the Mariner Mars 1971 spacecraft

The Mariner Mars 1971 orbiter mission was a part of the ongoing program of unmanned planetary exploration. The spacecraft design was based on that of Mariner Mars 1969, with changes as necessary to achieve mission objectives. The thermal design for Mariner Mars 1971 is described herein, with emphasis on those areas in which significant changes were implemented. Developmental tasks are summarized and discussed, and initial flight data are presented.

Source record↗

Balloon-borne package temperature controller

Simple, inexpensive, lightweight enclosure traps upward long wave radiation of earth while reflecting harsh solar radiation in upper atmosphere. It warms enclosed instruments in cold regions and protects them from overheating during the day. Device can be attached to balloon system without any changes in experimental design.

Schach, M.↗

Cryogenic temperature control by means of energy storage materials

An investigation was conducted to study the concept of thermal control by means of physical or chemical reaction heats for applications involving the storage of cryogens during long-term space voyages. The investigation included some preliminary experimental tests of energy storage material (ESM) effectiveness. The materials considered can store and liberate large amounts of thermal energy by means of mechanisms such as sensible heat, heat of fusion, and physical or chemical reaction heat. A differential thermal analysis was utilized in the laboratory tests. Attention is given to the evaluation of cryogenic ESM thermal control concepts, the experimental determination of phase change materials characteristics, and adsorption ESMs. It is found that an ESM shield surrounded by multiple layer insulation provides the best protection for a cryogen store.

Grodzka, P. G.↗

Improved temperature-control garment

Multilayer fabric containing polyurethane tubing is used in fabrication of liquid cooled garments. Cooling helmets may be assembled from material and various garments used for heating can be developed.

Cox, R. L.↗

Temperature controller for crystal resonators

Controller operates on less than 5W prime power and heats crystal from -10 C to 75 C in less than 45s. Unit is faster and more accurate (to within 0.7 C) than other inexpensive controllers and faster and less expensive than very precise controllers in vacuum flasks.

Turlington, T. R.↗

Multichannel temperature controller for hot air solar house

This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

Currie, J. R.↗

High-Temperature Controlled Redox Crystallization Studies

The crystallization of silicates containing redox sensitive ions (e.g., Fe, Ti, Ce) must be performed under controlled and known redox conditions in order to obtain the maximum scientific benefit from experimental study. Furthermore, many compositions crystallize dense phases which settle during ground-based experiments. This settling influences the texture and chemical evolution of the crystallizing system. The purpose of this investigation is to develop a test system in which controlled redox experiments can be performed in the microgravity environment. The system will use solid ceramic oxygen electrolyte cells for control, measurements, and production of the required redox conditions. A preliminary design for a prototype is developed, the electrolyte and furnace tested, and a tentative protocol for experiment developed. The control parameter is to be established and a laboratory prototype built.

Williams, R. J.↗

Three-Zone Programmable Temperature Controller

Microprocessor-based controller regulates electrical power supplied to heater in each zone of three-zone directional-solidification furnace. Intended primarily for use in microgravity experiments aboard KC-135 airplane, controller also used on ground. Offers advantage of low electrical noise and consequent minimal interference with low-level signals put out by thermocouples and other sensors used in experiments. Achieved by heating with direct (instead of alternating) current and not pulsing heating current.

Smith, Guy A.↗