SEARCH · Search NASA

Results for “DOME”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27

All sources NASA NTRS DOE OSTI

NASA NTRS1975

Mars

The evolution and physical structure of Mars are discussed primarily on the basis of Mariner 9 observations. The Martian atmosphere, density, and iron abundance are compared with those of earth, and it is noted that the planet was probably formed in less than 100,000 years. Stages in Martian differentiation are described together with the atmospheric composition, condensation and dust clouds, and surface winds. The surface is shown to have a wide diversity of geological landforms resulting from a variety of processes, including meteoroid bombardment, volcanic and tectonic activity, sapping, the action of running water, and wind action. Described landforms include impact craters, volcanic plains and domes, shield volcanoes, sinuous channels and gullies apparently formed by running water, and the enormous canyon system. Mechanisms for climatic change are considered, and questions are posed regarding the possibility of life on Mars.

Pollack, J. B.↗

NASA NTRS1975

Propellant reorientation with off-axis accelerations

Reorientation of propellant within a tank is important to the design of many acquisition and vent systems. A drop tower test program was conducted to determine the influence of off-axis accelerations on the motion of the liquid. A series of 39 tests was performed with a spherical tank and a cylindrical tank with hemispherical end domes, varying tank orientation, liquid volume and the magnitude of the acceleration. It was shown that reorientation under the effect of a pure axial acceleration, which has been studied in prior test programs, is a special case. The lateral component of the acceleration caused the liquid to reorient along one side of the tank. The motion of the liquid appeared to be independent of the magnitude of the lateral acceleration for the range of values considered.

Tegart, J.↗

NASA NTRS1975

Pressure Distribution at Subsonic Speeds over the Forepart of Two Blunt Circular Cylinders

A wind tunnel investigation was made at subsonic speeds to determine the pressure distribution over the forward part of a circular cylinder. The cylinder was equipped with interchangeable faces, one having a flat face and one having a dome shaped face. The investigation was made over angle of attack range from -1 deg to 26 deg and a Mach number range from 0.30 to 0.89. Pressure coefficients are presented in tabular form and plotted data are presented for some selected angles of attack about the surface of the cylinder.

Lockwood, V. E.↗

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

A large hemispherical chamber for fire toxicity tests

The paper describes an 84-liter chamber for fire toxicity tests consisting of an upper hemispherical dome section with a diameter of 533 mm, made of clear polymethyl methacrylate and a lower cylindrical base section 190 mm deep, made of cast aluminum. The chamber is designed to expose 36 mice, 8 rats, 4 rabbits or combinations of smaller numbers of two or three species simultaneously to the gaseous products of pyrolysis or combustion. The chamber does not appear to be suitable for screening purposes because its large size introduces operating costs and problems which reduce its cost effectiveness.

Hilado, C. J.↗

NASA NTRS1977

Solar meter with silicon photocell

Instrument for measuring light falling on given spot uses simple silicon photovoltaic cell as sensing element. It measures all light at location: direct, scattered, reflected, or reradiated. Silicon cell is coated with thick antireflecting layer of silicon monoxide and is enclosed in glass dome. Large heat sink reduces temperature fluctuations. Instrument is accurate within few percentage points over angle of Sun's arc across sky.

Yanow, G.↗

NASA NTRS1976

Applicability of ERTS-1 to Montana geology

The author has identified the following significant results. Late autumn imagery provides the advantages of topographic shadow enhancement and low cloud cover. Mapping of rock units was done locally with good results for alluvium, basin fill, volcanics, inclined Paleozoic and Mesozoic beds, and host strata of bentonite beds. Folds, intrusive domes, and even dip directions were mapped where differential erosion was significant. However, mapping was not possible for belt strata, was difficult for granite, and was hindered by conifers compared to grass cover. Expansion of local mapping required geologic control and encountered significant areas unmappable from ERTS imagery. Annotation of lineaments provided much new geologic data. By extrapolating test site comparisons, it is inferred that 27 percent of some 1200 lineaments mapped from western Montana represent unknown faults. The remainder appear to be localized mainly by undiscovered faults and sets of minor faults or joints.

Weidman, R. M.↗

NASA NTRS1977

Method of forming shrink-fit compression seal

A method for making a glass-to-metal seal is described. A domed metal enclosure having a machined seal ring is fitted to a glass post machined to a slight taper and to a desired surface finish. The metal part is then heated by induction in a vacuum. As the metal part heats and expands relative to the glass post, the metal seal ring, possessing a higher coefficient of expansion than the glass post, slides down the tapered post. Upon cooling, the seal ring crushes against the glass post forming the seal. The method results in a glass-to-metal seal possessing extremely good leak resistance, while the parts are kept clean and free of the contaminants.

Podgorski, T. J.↗

NASA NTRS1974

Solid rocket booster performance evaluation model. Volume 3: Sample case

The solid rocket booster performance evaluation model (SRB-11) is used to predict internal ballistics in a sample motor. This motor contains a five segmented grain. The first segment has a 14 pointed star configuration with a web which wraps partially around the forward dome. The other segments are circular in cross-section and are tapered along the interior burning surface. Two of the segments are inhibited on the forward face. The nozzle is not assumed to be submerged. The performance prediction is broken into two simulation parts: the delivered end item specific impulse and the propellant properties which are required as inputs for the internal ballistics module are determined; and the internal ballistics for the entire burn duration of the motor are simulated.

Source record↗

NASA NTRS1976

Crater dimensions from Apollo data and supplemental sources

A catalog of crater dimensions that were compiled mostly from the Apollo-based Lunar Topographic Orthophotomaps is presented in its entirety. Values of crater diameter, depth, rim height, flank width, circularity, and floor diameter (where applicable) are tabulated for a sample of 484 craters on the moon and 22 craters on earth. Systematic techniques of mensuration are detailed. The lunar craters range in size from 400 m to 300 km across and include primary impact craters of the main sequence, secondary impact craters, craterlets atop domes and cones, and dark-halo craters. The terrestrial craters are between 10 m and 22.5 km in diameter and were formed by meteorite impact.

Pike, R. J.↗

NASA NTRS1977

Topography of sinuous rilles in the Harbinger Mountains region of the moon

Five sinuous rilles in mare basalts in the Harbinger Mountains region of the moon are described. Rille length ranges from 12 to 79 km, width from 0.8 to 4.8 km, and depth from 100 to 300 m. The rilles appear to become shallower to the north, while the southern ends are characterized by circular-to-elongate depressions that occur on a 30-km-in-diameter dome of probable volcanic origin. Longitudinal profiles show that the rille floors have a northward slope of less than one deg, consistent with the general slope of the surrounding mare surface. Structural studies indicate that slope, rather than the regional structural pattern, is the dominant factor controlling rill direction. Topographic data support the theory that the rilles were formed as lave channels or tubes.

Strain, P. L.↗

NASA NTRS1977

Stress analysis of pressure vessel assembly

A radome assembly capable of withstanding large hydrostatic pressures was designed with a sapphire hemisperical dome and a plastic housing. These two parts were connected with a stainless steel flange ring. A finite-element stress analysis of this assembly was accomplished and an experimental load test was performed to verify the predicted stresses.

Eppink, R. T.↗

NASA NTRS1977

Thermal surveillance of active volcanoes using the LANDSAT-1 data collection system. Part 3: Heat discharge from Mount St. Helens, Washington

The author has identified the following significant results. Two thermal anomalies, A at 2740 m altitude on the north slope, and B between 2650 and 2750 m altitude on the southwest slope at the contact of the dacite summit dome of Mount St. Helens, Washington were confirmed by aerial infrared scanner surveys between 1971 and 1973. LANDSAT 1 data collection platform 6166, emplaced at site B anomaly, transmitted 482 sets of temperature values in 1973 and 1974, suitable for estimating the differential radiatin emission as 84 W/sq m, approximately equivalent to the Fourier conductive flux of 89 W/sq m in the upper 15 cm below the surface. The differential geothermal flux, including heat loss via evaporation and convection, was estimated at 376 W/sq m. Total energy yield of Mount St. Helens probably ranges between 0.1 and 0.4 x 10 to the 6th power W.

Friedman, J. D.↗

NASA NTRS1979

A closed-loop control-loading system

Langley Differential Maneuvering Simulator (DMS) realistically simulates two aircraft operating in differential mode. It consists of two identical fixed-base cockpits and dome projection systems. Each projection system consists of sky/Earth projector and target-image generator and projector. Although programmable control forces are small part of overall system, they play large role in providing pilot with kinesthetic cues.

Ashworth, B. R.↗

NASA NTRS1979

Pseudocraters on Mars

The morphology and origin of the Martian volcanic-dome like structures are compared to the terrestial pseudocraters.

Frey, H.↗

NASA NTRS1979

Thaumasia - A fossilized early forming Tharsis uplift

The structure of the present-day Valles Marineris rift canyons and related features is a consequence of episodic crustal uplift, dominated by two major events. The first of these occurred near the present-day Thaumasia crustal dome and produced a structural pattern in old plains-forming units which is principally transverse to the main trend of the Valles Marineris canyons. This pattern has provided some structural control over later tectonic and volcanic events. The major crustal deformation in this region is associated with the younger Tharsis uplift, which is responsible for the major trends observed in the Valles Marineris. These two distinct structural patterns are best observed in the resistant, least eroded parts of the canyon walls; linear trends in such resistant points provide a closer approximation to the original bounding scarps of the Martian rifts than do the modern, highly eroded canyon walls. Crustal deformation was dominated by the Tharsis uplift but began much earlier in Martian history.

Frey, H.↗

NASA NTRS1978

Volcanoes on the inner planets - Some preliminary comparisons of gross topography

The paper extends previous numerical work on analogs of planetary landform (Pike, 1974, 1978) by concentrating on volcanic edifices rather than impact craters. Two kinds of extraterrestrial volcanic constructs - domes on the lunar maria and calderas on Mars - are compared with terrestrial volcanoes. According to available data, neither type of landform unequivocally resembles a specific class of terrestrial volcano. The quantitative models of volcanoes presented necessarily are statistical because the shapes of volcanic landforms vary over a wide range of values.

Pike, R. J.↗

NASA NTRS1978

Volcanism in the Noachis-Hellas region of Mars, 2

Mariner 9 and Viking Orbiter imagery has been examined to investigate volcanism in the Noachis-Hellas region of Mars. A wide variety of probable and possible volcanic features, including cinder cones, flood lavas, wrinkel ridges, cratered domes on the floors of impact craters, shield volcanoes, and possible stratovolcanoes has been observed. The flood lavas of ridged plains and broad, low shield volcanoes are indicative of very fluid lavas of ultrabasic or very basic basaltic composition. Evidence for relatively recent pyroclastic volcanism is present in numerous probable cinder cones and some isolated cratered mountains tentatively identified as stratovolcanoes. The volcanic complex and ridged plains at 68 deg S, 323 deg W appear to be relatively young. The occurrence of the five major volcanic centers of the Noachis-Hellas region at the intersections of ancient Hellas impact basin rings with a postulated northeast-trending fracture system suggests that large-scale volcanic activity may have begun soon after formation of the basin.

Peterson, J. E.↗