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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 253 records · Page 14
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NASA NTRS1974

Design of the Skylab MDA window

Description of the optical and structural design requirements, mechanical and thermal response analyses, final design features, and testing procedures employed in the development of a large window mounted on the earth-facing side of the multiple docking adapter (MDA) of the Skylab manned space vehicle. This window was designed for the S190 earth resources multispectral camera and was protected from the space environment during nonuse periods by a hinged cover operated from within the MDA. The camera required a viewing area approximately 43 by 58 cm. A single glass pane 4.1 cm thick was selected to minimize optical distortions. Heaters on the glass and frame were designed to control distortions caused by thermal gradients in the glass.

Trent, D. J.↗
NASA NTRS1974

A study of the Sabatier-methanation reaction kinetics

The kinetics of the Sabatier methanation reaction, the reduction of carbon dioxide with hydrogen to methane and water, was investigated for 58 percent nickel on kieselguhr catalyst and 20 percent ruthenium on alumina catalyst. Differential rate data from an experimental program were correlated with a power function rate equation both for forward and reverse reactions. The kinetic parameters of activation energy, frequency rate constant and reaction order were determined for the rate equation. The values of these parameters were obtained from an Arrhenius plot of the experimental differential rate data. Also the carbon monoxide side reaction effect was measured and included in the correlation of parameters. The reaction was found to fit the rate equation experimentally within the temperature range 421 K, where the reaction effectively begins, the 800 K where the reaction rate drops and departs from the rate equation form.

Verostko, C. E.↗
NASA NTRS1975

The Pioneer 10 radio occultation measurements of the ionosphere of Jupiter

Data from the Pioneer 10 radio occultation measurements are utilized to study the vertical electron number density distribution in the Jovian ionosphere. The immersion measurements were made at 26 North latitude in the late afternoon local time. The solar zenith angle in this region was 81 deg. Emersion measurements were made at 58 North latitude near the morning terminator where the solar zenith angle was 95 deg. The detectable portion of the Jovian ionosphere consists of a number of layers distributed over an altitude range of more than 3000 km. The maximum density appears to be on the order of 30,000 electrons per cu cm. Assuming that H(+) is the principal ion in the upper portion of the ionosphere yields a topside plasma temperature of 900 plus or minus 400 K.

Fjeldbo, G.↗
NASA NTRS1975

Volatile organic components in the Skylab 4 spacecraft atmosphere

The volatile organic components in the spacecraft cabin atmosphere of Skylab 4 were trapped on a solid adsorbent at various times during the mission. In post-flight analyses, more than 300 compounds in concentrations from less than 1 ppb up to 8000 ppb could be detected by high-resolution gas chromatography. In the samples of the 11th, 47th, and 77th day of the mission, approximately 100 components in the molecular weight range from 58 to 592 were identified by mass spectrometry. Besides components known from other environments, such as alkanes, alkenes, and alkylated aromatic hydrocarbons, components typical of the human metabolism, such as ketones and alcohols, were found. Other typical components in the spacecraft atmosphere included fluorocarbons and various silicone compounds, mostly normal and cyclic methylsiloxanes.

Liebich, H. M.↗
NASA NTRS1977

Frame for daylight photocopying

Inexpensive fixture makes quick copy of picture or photograph, film positive or negative, without darkroom. Device holds four-by-five inch instant-developing Polaroid 58 or 55 (or equivalent) film.

Dalton, J. W.↗
NASA NTRS1975

The Noisiness of Low-Frequency One-Third Octave Bands of Noise

This study examined the relative noisiness of low frequency one-third octave bands of noise bounded by the bands centered at 25 Hz and 200 Hz, with intensities ranging from 50 db sound pressure level (SPL) to 95 db SPL. The thirty-two subjects used a method-of-adjustment technique, producing comparison-band intensities as noisy as standard bands centered at 100 Hz and 200 Hz with intensities of 60 db SPL and 72 db SPL. Four contours of equal noisiness were developed for one-third octave bands, extending down to 25 Hz and ranging in intensity from approximately 58 db SPL to 86 db SPL. These curves were compared with the contours of equal noisiness of Kryter and Pearsons. In the region of overlap (between 50 Hz and 200 Hz) the agreement was good.

Lawton, B. W.↗
NASA NTRS1975

Thailand National Programme of the Earth Resources Technology Satellite

The author has identified the following significant results. Forest inventory of Thailand was completed in January 1975, using LANDSAT-1 imagery and ground truth survey. Results showed the existing forest covers only 37% of the land area. The last country-wide survey using aerial survey photographs at 1:60,000 scale conducted in 1961 gave the figure of 58%. ERTS-1 imagery showed that Thailand's mangrove forest covers an area of approximately 3130 sq k. The previous aerial survey showed 3681 sq k of mangroves.

Sabhasri, S.↗
NASA NTRS1975

An experimental investigation of the NASA space shuttle external tank at hypersonic Mach numbers

Pressure and heat transfer tests were conducted simulating flight conditions which the space shuttle external tank will experience prior to break-up. The tests were conducted in the Calspan 48-inch Hypersonic Shock Tunnel and simulated entry conditions for nominal, abort-once-around (AOA), and return to launch site (RTLS) launch occurrences. Surface pressure and heat-transfer-rate distributions were obtained with and without various protuberences (or exterior hardware) on the model at Mach numbers from 15.2 to 17.7 at angles of attack from -15 deg to -180 deg and at several roll angles. The tests were conducted over a Reynolds number range from 1300 to 58,000, based on model length.

Wittliff, C. E.↗
NASA NTRS1976

Analysis of six broadband optical filters for measuring chlorophyll alpha and suspended solids in the Patuxent River

Kodak Wratten broadband optical filters numbered 47B (400 to 500 nm), 57 (500 to 600 nm), 58 (500 to 600 nm), 12 (500 to 700 nm), 25 (600 to 700 nm), and 89B (690 to 900 nm) were tested on October 17, 1972, to see whether each spectral band by itself could be used to quantify chlorophyll a and suspended sediment in the Patuxent River. Band 690 to 900 nm showed promise in being able to detect gross changes in chlorophyll a above 28 micrograms/l. None of the broad spectral bands seem capable of measuring chlorophyll a concentrations less than 28 micrograms/l in turbid estuarine water. Except for the 47B spectral band, the bands do show promise for measuring suspended solids.

Ohlhorst, C. W.↗
NASA NTRS1976

High-resolution radio observations of three supernova remnants

The paper presents and discusses radio observations of three supernova remnants (G21.5-0.9, G29.7-0.3, and 3C 391) made at 3.7 and 11.1 centimeters. The supernova remnant G21.5-0.9 has an elliptical brightness distribution and is similar to the Crab Nebula as well as 3C 58 in appearance and spectrum. The two remnants G29.7-0.3 and 3C 391 both show a broken shell structure typical of most galactic supernova remnants.

Becker, R. H.↗
NASA NTRS1976

Flight investigation of the response of a helicopter to the trailing vortex of a fixed-wing aircraft

A flight investigation was conducted to quantitatively determine the response of a medium-weight helicopter to the trailing-vortex system of a fixed-wing aircraft. Flight tests and analytical tools were both utilized in the investigation. The flight tests involved an extensively instrumented UH-1H helicopter and a C-54 aircraft. Penetrations of the vortex system by the UH-1H were made at the following nominal conditions: the C-54 flew at 5500 feet altitude at a nominal gross weight of 58,000 pounds and an indicated airspeed of 115 knots in a cruise configuration. The UH-1H, nominally 7200 pounds gross weight, flew at 60 knots indicated airspeed during the penetrations at separation distances of 6.64 nautical miles to 0.42 nautical mile between aircraft. In general, the data analyzed for the above tests indicated that no unsafe penetration occurred. Further, penetrating vehicle attitude changes and structural loads were nominal. In addition, the response of the helicopter did not change appreciably with decreased separation distance.

Mantay, W. R.↗
NASA NTRS1976

The duration of volcanism in Mare Serenitatis

The crystallization ages of a suite of Apollo 17 basalts from four different stations have been measured using the Ar-39 to Ar-40 stepwise heating technique. The rocks analyzed include all principal petrographic types found at Apollo 17 landing site. A correlation between the ages and the petrographic type exists; plagioclase-poikilitic ilmenite basalts are youngest and olivine porphyritic ilmenite basalts are the oldest. The duration of volcanism in Mare Serenitatis is about 200 million years, the same as observed for Mare Imbrium, and less than observed for Mare Tranquillitatis, 400 million years. A relationship between duration of volcanism and gravity anomalies is noted. The cosmic ray exposure ages (in millions of years) for various locations range as: station 4, 58-315; station 5, 85-440; station 6, 110; station 8, 90-160.

Schaeffer, O. A.↗
NASA NTRS1976

Effect of Low Velocity Impact Damage on the Compressive Strength of Graphite/Epoxy Hat-Stiffened Panels

Low velocity impact damage on the compressive strength of graphite/epoxy hat stiffened panels is studied. Fourteen panels, representative of minimum-mass designs for two compression load levels were tested. Eight panels were damaged by impact and the effect on compressive strength was evaluated by comparing the results with data for undamaged panels. The impact tests consisted of firing 1.27 cm diameter aluminum projectiles normal to the plane of the panel at a velocity of approximately 55 m/sec to simulate impact from runway debris. The results of this investigation indicate that impact damage in the panels designed for 0.53 MN/m was contained locally and the damaged panels were capable of carrying the design load. The panels designed for 1.58 MN/m failed between 50 and 58 percent of the design load due to impact damage in the high axial stiffness region. The extent of damage in the high axial stiffness region of both panel designs increased with the magnitude of applied axial load. Damage in this region was the most significant factor in reducing panel strength. Limited damage that was not visually detectable reduced ultimate strength as much as extensive visible damage.

Rhodes, M. D.↗
NASA NTRS1977

Helicopter sling load accident/incident survey: 1968 - 1974

During the period considered a mean of eleven accidents per year occurred and a mean of eleven persons were killed or seriously injured per year. Forty-one percent of the accidents occurred during hover, and 63 percent of the accidents had pilot error listed as a cause/factor. Many accidents involved pilots losing control of the helicopter or allowing a collision with obstructions to occur. There was a mean of 58 incidents each year and 51 percent of these occurred during cruise.

Shaughnessy, J. D.↗
NASA NTRS1977

A Directionally Solidified Iron-chromium-aluminum-tantalum Carbide Eutectic Alloy

A eutectic alloy, Fe-13.6CR-3.7Al+9TaC, was directionally solidified in a high gradient furnace, producing a microstructure of alined TaC fibers in an oxidation resistant alpha-iron matrix. Tensile and stress rupture properties, thermal cycling resistance, and microstructures were evaluated. The alloy displays at 1000 C an ultimate tensile strength of 58 MPa and a 100-hour rupture life at a stress of 21 MPa. Thermal cycling to 1100 C induces faceting in the TaC fibers.

Harf, F. H.↗
NASA NTRS1977

Thailand national programme of the earth resources technology satellite

The author has identified the following significant results. Accomplishments include the identification of a series of active alluvial fans along the margins of the Central Plain, the compilation of crop resources maps of central and eastern Thailand, and evaluation of the Purdue/LARS printout using unsupervised mode of an area near Bangkok. Results from LANDSAT 1 imagery and ground truth survey showed that Thailand existing forest in 1973 covered an area of approximately 37% of total land area. The last countrywide survey using aerial photographs at 1:60,000 scale conducted in 1961 gave the figure of 58%. Experience has shown many advantages of LANDSAT imagery over the conventional aerial photography in locating faults and fractures in the preparation of tectonic maps. Several rock types can also be identified from LANDSAT imagery.

Sabhasri, S.↗
NASA NTRS1977

Experimental clean combustor program, phase 3

A two-stage vortex burning and mixing combustor and associated fuel system components were successfully tested at steady state and transient operating conditions. The combustor exceeded the program goals for all three emissions species, with oxides of nitrogen 10 percent below the goal, carbon monoxide 26 percent below the goal, and total unburned hydrocarbons 75 percent below the goal. Relative to the JT9D-7 combustor, the oxides of nitrogen were reduced by 58 percent, carbon monoxide emissions were reduced by 69 percent, and total unburned hydrocarbons were reduced by 9 percent. The combustor efficiency and exit temperature profiles were comparable to those of production combustor. Acceleration and starting characteristics were deficient relative to the production engine.

Roberts, R.↗
NASA NTRS1976

The effective temperature of Uranus

Uranus was observed in the spectral region from 40 to 250 microns with a 102-cm balloon-borne telescope, and the results were interpreted in terms of model atmosphere calculations to yield an effective temperature of 58 plus or minus 3 K; this sets an upper limit of about 28 per cent on the relative contribution of an internal heat source to the total thermal radiation. On the same flight, the brightness temperatures of Venus (215 plus or minus 13 K) and Jupiter (135 plus or minus 6 K) were also measured, thus reconfirming the existence of an internal heat source for Jupiter.

Fazio, G. G.↗