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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1961

THE DENSITIES OF SATURATED LIQUID HYDROGEN

This laboratory is engaged in a programme for the determination of thermostatic, thermodynamic, and transport properties of para-hydrogen, emphasizing high densities. Reported here are new data for the density of saturated liquid pura-hydrogen from boiling point to critical point. A review of hydrogen properties includes densities of normal hydrogen from triple to critical points and of pura-hydrogen up to the boiling point? More recent determinations of vapour pressures and critical constants have been made for both hydrogen modification.

LIQUID HYDROGEN↗
NASA NTRS1971

Fire retardancy using applied materials

An example of advanced technology transfer from the Little Joe, Surveyor, Comsat, re-entry and Apollo age to everyday fire protection needs is presented. Utilizing the principle of sublimation cooling for thermostatic temperature control, the material meets a wide range of fire retardancy and heat transmission control requirements. Properties vary from flexible tape for conduits and electrical cables to rigid coatings for column protection, with a broad spectrum of sublimation temperatures available. The material can be applied in the field or in the factory, utilizing mass production techniques, yielding a product that is reliable, effective, widely available and low in cost.

Feldman, R.↗
NASA NTRS1972

Pioneer F/G feed movement mechanism

The Pioneer F/G spacecraft achieves the desired earth-pointing direction through a system requiring the shifting of the main antenna feed 1 in. off axis. The feed is pivoted to this position by an electrically heated thermal actuator consisting of an electroless nickel bellows in a copper housing and filled with Freon 21. The actuator overtravels and maintains the feed in the offset position in a thermostatic limit cycle operation mode until commanded off. The mechanism is expected to operate in a -240 F environment near Jupiter and was successfully tested at such temperatures.

R. M. Acker↗
NASA NTRS1971

Compressibility measurements of gases using externally heated pressure vessels.

Most of the data collected under conditions of high temperature and pressure have been determined using a thick-walled bomb of carefully measured and fixed volume which is externally heated by an electric furnace or a thermostatically controlled bath. There are numerous variations on the basic method depending on the pressure-temperature range of interest, and the particular gas or gas mixture being studied. The construction and calibration of the apparatus is discussed, giving attention to the pressure vessel, the volume of the bomb, the measurement of pressure, the control and measurement of temperature, and the measurement of the amount and composition of gas in the bomb.

Presnall, D. C.↗
NASA NTRS1973

Thermally responsive mechanical actuator

Device built for use in heat control, heat measurement, and mechanical actuation by heat include thermometers, thermostats, safety switches, circuit breakers, and mechanical actuators. Silicon rubber has highest coefficient of expansion of any known material and seems suitable for most of these devices.

Madey, J. M.↗
NASA NTRS1973

Velocity control propulsion subsystem of the Radio Astronomy Explorer satellite for Goddard Space Flight Center

The Velocity Control Propulsion Subsystem (VCPS) was designed the propulsion required for trajectory and lunar orbit corrections of the spacecraft. A GFE clamp assembly physically attaches the VCPS to the spacecraft and the unit is ejected after completing the required corrections. The VCPS is physically and functionally separated from the spacecraft except for the electrical and telemetry interfaces. A GFE transtage provides the superstructure on which the VCPS is assembled. The subsystem consists of two 5 foot pound rocket engine assemblies, 4 propellant tanks, 2 latching valves, 2 fill and drain valves, a system filter, pressure transducer, gas and propellant manifolds and electrical heaters and thermostats. The RAE-B VCPS program covered the design, manufacture and qualification of one subsystem. This subsystem was to be manufactured, subjected to qualification tests; and refurbished, if necessary, prior to flight. The VCPS design and test program precluded the need for refurbishing the subsystem and the unit was delivered to GSFC at the conclusion of the program.

Braught, W.↗
NASA NTRS1973

Thermal control of the solar electric propulsion stage

The thermal control requirements consist of functional requirements related to the various mission phase natural environments, operational requirements of induced power loadings by the solar electric propulsion stage subsystems, and design temperature limits for performance and reliability. The design approach utilizes passive thermal control techniques combining insulation, surface coatings, and sunshields with thermostatically controlled louvers. Heaters are used to regulate certain temperatures for extreme conditions. Details regarding the thruster array thermal control design are discussed, giving attention to the parameters used in the mathematical model, questions of conductive coupling, and thruster estimated power distribution.

Ruttner, L. E.↗
NASA NTRS1975

Heater improves cold-temperature capacity of silver-cadmium batteries

Eight heaters are included in 14-cell package to provide 14-Vdc. Each heater is 11-ohm self-adhesive strip placed across broad face of each pair of cells. They are installed before cells are wired. Heaters are in series and are connected through pair of redundant thermostats.

Webster, W. H., Jr.↗
NASA NTRS1977

Low-voltage motor heater

Heater has stepdown transformer for low voltage range, variable transformer for holding within 0-to-28 volt range, and voltmeters and ammeters to monitor load and wattage. Regulated thermostat controls contactor, permitting heater to cycle.

Bezant, K. R.↗
NASA NTRS1975

The photon gas formulation of thermal radiation

A statistical consideration of the energy, the linear momentum, and the angular momentum of the photons that make up a thermal radiation field was presented. A general nonequilibrium statistical thermodynamics approach toward a macroscopic description of thermal radiation transport was developed and then applied to the restricted equilibrium statistical thermostatics derivation of the energy, linear momentum, and intrinsic angular momentum equations for an isotropic photon gas. A brief treatment of a nonisotropic photon gas, as an example of the results produced by the nonequilibrium statistical thermodynamics approach, was given. The relativistic variation of temperature and the invariance of entropy were illustrated.

Ried, R. C., Jr.↗
NASA NTRS1975

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.↗
NASA NTRS1976

The preliminary design of an orbiting observatory - The Space Telescope

The systems and subsystems of the Space Telescope proposed for an orbiting observatory to be launched by the Space Shuttle in the 1980s are described. The structural design is simple and based on existing technologies for high reliability. Provisions are made for on-orbit servicing and maintenance. All deployable appendages are designed for manual override to insure retrieval and return of the Space Telescope to earth for major refurbishing, which should occur at intervals of not less than six years. Low performance risk, passive techniques are used in the thermal control subsystem to provide a cold-biased design with thermostatically controlled heaters to adjust temperature. The electrical power system utilizes NASA Standard Hardware - 50 ampere hour nickel-cadmium battery cells, a standard power regulator unit, and a flight-proven flexible rollup solar array with high-efficiency (12.5 per cent) silicon solar cells. The communication subsystem is designed for compatibility with the Tracking and Data Relay Satellite System. The pointing control system will have a maximum line of sight variation of 0.007 arc seconds. The telescope optics are a Ritchey-Chretien version of the Cassegrain configuration.

Timmons, K. P.↗
NASA NTRS1977

Window-mounted auxiliary solar heater

System uses hot-air collectors, no thermal storage, and fan with thermostat switches. At cost of heating efficiency, unit could be manufactured and sold at price allowing immediate entry to market as auxiliary heating system. Its simplicity allows homeowner installation, and maintenance is minimal.

Anthony, K. G.↗
NASA NTRS1976

Energy conservation and analysis and evaluation

The survey assembled and made recommendations directed at conserving utilities and reducing the use of energy at the Slidell Computer Complex. Specific items included were: (1) scheduling and controlling the use of gas and electricity, (2) building modifications to reduce energy, (3) replacement of old, inefficient equipment, (4) modifications to control systems, (5) evaluations of economizer cycles in HVAC systems, and (6) corrective settings for thermostats, ductstats, and other temperature and pressure control devices.

Source record↗
NASA NTRS1978

Thermal-control canister

Use of variable-conductance heat-pipe link together with fixed-conductance system allows canister temperature to vary over wide range, yet hold stable to + or - 1 degree Centigrade. System has fewer parts and requires considerably less power than conventional heaters and thermostats.

Ollendorf, S.↗
NASA NTRS1977

Modular control subsystems for use in solar heating systems for multi-family dwellings

Progress in the development of solar heating modular control subsystems is reported. Circuit design, circuit drawings, and printed circuit board layout are discussed along with maintenance manuals, installation instructions, and verification and acceptance tests. Calculations made to determine the predicted performance of the differential thermostat are given including details and results of tests for the offset temperature, and boil and freeze protect points.

Source record↗
NASA NTRS1979

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.↗