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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 37 records · Page 2
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NASA NTRS1960

III. Supersonic cruise aircraft

The aviation world is on the threshold of sustained supersonic flight at a level of efficiency approaching the best of our subsonic aircraft. This potential has been recognized in the concept of the B-70. Now the supersonic transport is on the horizon. The supersonic transport represents a great technical challenge. Not only must this vehicle have the aerodynamic efficiency of the subsonic bomber, but it must also embrace: (a) the overriding element of passenger safety, (b) the problem of community acceptance (noise), and (c) economy of operation. This paper will be devoted primarily to the aerodynamic problems of large supersonic aircraft as related to performance. Smaller vehicles have been considered in part II of this compilation. The stability and control problems are of equal importance but are not discussed herein.

Supersonic aircraft↗
NASA NTRS1972

Artic and subarctic environmental analyses utilizing ERTS-1 imagery. Cold regions environmental analysis based on ERTS-1 imagery (preprint)

There are no author-identified significant results in this report. An overriding problem in arctic and subarctic environmental research has been the absence of long-term observational data and the sparseness of geographical coverage of existing data. A first look report is presented on the use of ERTS-1 imagery as a major tool in two large area environmental studies: (1) investigation of sedimentation and other nearshore marine processes in Cook Inlet, Alaska; and (2) a regional study of permafrost regimes in the discontinuous permafrost zone of Alaska. These studies incorporate ground truth acquisition techniques that are probably similar to most ERTS investigations. Studies of oceanographic processes in Cook Inlet will be focused on seasonal changes in nearshore bathymetry, tidal and major current circulation patterns, and coastal sedimentation processes, applicable to navigation, construction, and maintenance of harbors. Analyses will be made of the regional permafrost distribution and regimes in the Upper Koyukuk-Kobuk River area located in NW Alaska.

Anderson, D. M.↗
NASA NTRS1973

Steady-state simulation program for attitude control propulsion systems

The formulation and the engineering equations employed in the steady state attitude control propulsion system simulation program are presented. The objective of this program is to aid in the preliminary design and development of propulsion systems used for spacecraft attitude control. The program simulates the integrated operation of the many interdependent components typically comprising an attitude control propulsion system. Flexibility, generality, ease of operation, and speed consistent with adequate accuracy were overriding considerations during the development of this program. Simulation modules were developed representing the various types of fluid components typically encountered in an attitude control propulsion system. These modules are basically self-contained and may be arranged by the program user into desired configuration through the program input data.

Heinmiller, P. J.↗
NASA NTRS1973

Competition between cutaneous vasodilator and vasoconstrictor reflexes in man

A two-part experiment was carried out on seven men to determine whether skin will respond to increased neurogenic vasoconstrictor activity during heating. The latter was induced by lower body negative pressure of -50 mm Hg applied for 5 of each 15 min in 12 studies with constant, neutral skin temperature (32.2-34.4 C) in a 40-min control period and with skin temperature held at 38 C for 40-70 min. We conclude that during heating, skin retains the ability to vasoconstrict but that this vasoconstriction cannot completely override heat-induced vasodilatation.

Johnson, J. M.↗
NASA NTRS1974

Evaluation of soft rubber goods

The performance of rubber goods suitable for use as O-rings, seals, gaskets, bladders and diaphragms under conditions simulating those of the space shuttle were studied. High reliability throughout the 100 flight missions planned for the space shuttle was considered of overriding importance. Accordingly, in addition to a rank ordering of the selected candidate materials based on prolonged fluid compatibility and sealability behavior, basic rheological parameters (such as cyclic hysteresis, stress relaxation, indicated modulus, etc.) were determined to develop methods capable of predicting the cumulative effect of these multiple reuse cycles.

Merz, P. L.↗
NASA NTRS1975

Space tug/shuttle interface compatibility study. Volume 1: Executive summary

Shuttle interfaces required for space tug accommodation are primarily involved with supporting and servicing the tug during launch countdown, flight, and postlanding; deploying and retrieving the tug on orbit; and maintaining control over the tug when it is in or near the orbiter. Each of these interface areas was investigated to determine the best physical and operational method of accomplishing the required functions, with an overriding goal of establishing simple and flexible orbiter interface requirements suitable for tug, tug payloads, IUS and other cargo. It is concluded the orbiter payload accommodations and the MSFC baseline tug are generally interface compatible. Specific minor changes to tug and orbiter interfaces were identified to provide full compatibility. A system concept for supporting and deploying tug from orbiter is described.

Source record↗
NASA NTRS1975

Direct observation of small cluster mobility and ripening

Direct evidence is reported for the simultaneous occurrence of Ostwald ripening and short-distance cluster mobility during annealing of discontinuous metal films on clean amorphous substrates. The annealing characteristics of very thin particulate deposits of silver on amorphized clean surfaces of single crystalline thin graphite substrates were studied by in-situ transmission electron microscopy (TEM) under controlled environmental conditions (residual gas pressure of 10 to the minus 9th power torr) in the temperature range from 25 to 450 C. Sputter cleaning of the substrate surface, metal deposition, and annealing were monitored by TEM observation. Pseudostereographic presentation of micrographs in different annealing stages, the observation of the annealing behavior at cast shadow edges, and measurements with an electronic image analyzing system were employed to aid the visual perception and the analysis of changes in deposit structure recorded during annealing. Slow Ostwald ripening was found to occur in the entire temperature range, but the overriding surface transport mechanism was short-distance cluster mobility.

Heinemann, K.↗
NASA NTRS1977

Safety brake for tape reels

All-mechanical device senses end of tape and stops reel, even in event of electronic system failure. Assembly includes stop to prevent brake from overriding tape. Recentering mechanism returns brake to neutral position after torque is removed from reels.

Carle, C. E.↗
NASA NTRS1975

The role of toxicology in the Apollo space program

Some of the major considerations are presented which governed the formation and application of the toxicology program employed in support of the Apollo program. The overriding concern of the program was the safety of crews exposed to trace contaminant gases for extended periods of time. The materials screening program employed, in conjunction with a well designed spacecraft environmental control system, helped to attain the goals set forth for the Apollo program. The knowledge gained from working with the toxicity problems and the identification of compounds in the space cabin atmosphere are of importance for continued efforts in manned space flight. Tabular data of spacecraft contaminants are presented.

Wayland J. Rippstein, Jr↗
NASA NTRS1975

Tug and payload-to-Orbiter interface requirements

This paper presents results of a study to identify, evaluate, and develop Tug plus payload-to-Orbiter accommodation requirements. Interface areas include structural, mechanical, fluids, environmental, avionics, and safety. Each interface area was investigated to determine the best physical and operational method of accomplishing the required functions with an overriding goal of establishing sample and flexible interface requirements suitable for Tug, Tug payloads, and other cargo. The recommended system for supporting the Tug and its payload from the Orbiter employs a cylindrical load-carrying structure called a deployment adapter that has a rotational capability for Tug deployment. The design and operation of the deployment adapter and other peripheral interface equipment such as crew compartment monitor and control panels and cargo bay fluid and electrical interface panels are discussed.

Bock, E. H.↗
NASA NTRS1976

Direct observation of small cluster mobility and ripening

Direct evidence is reported for the simultaneous occurrence of Ostwald ripening and short-distance cluster mobility during annealing of discontinuous metal films on clean amorphous substrates. The annealing characteristics of very thin particulate deposits of silver on amorphized clean surfaces of single-crystalline thin graphite substrates have been studied by in situ transmission electron microscopy (TEM) under controlled environmental conditions in the temperature range from 25 to 450 C. It was possible to monitor all stages of the experiments by TEM observation of the same specimen area. Slow Ostwald ripening was found to occur over the entire temperature range, but the overriding surface transport mechanism was short-distance cluster mobility. This was concluded from in situ observations of individual particles during annealing and from measurements of cluster size distributions, cluster number densities, area coverages, and mean cluster diameters.

Heinemann, K.↗
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 NTRS1976

Observations of fallibility in applications of modern programming methodologies

Errors, inconsistencies, or confusing points are noted in a variety of published algorithms, many of which are being used as examples in formulating or teaching principles of such modern programming methodologies as formal specification, systematic construction, and correctness proving. Common properties of these points of contention are abstracted. These properties are then used to pinpoint possible causes of the errors and to formulate general guidelines which might help to avoid further errors. The common characteristic of mathematical rigor and reasoning in these examples is noted, leading to some discussion about fallibility in mathematics, and its relationship to fallibility in these programming methodologies. The overriding goal is to cast a more realistic perspective on the methodologies, particularly with respect to older methodologies, such as testing, and to provide constructive recommendations for their improvement.

Gerhart, S. L.↗
NASA NTRS1977

Investigation of real-gas and viscous effects on the aerodynamic characteristics of a 40 deg half-cone with suggested correlations for the shuttle orbiter

Parameters were evaluated that might be used to correlate shuttle orbiter aerodynamic data to be used in extrapolating from wind-tunnel to flight conditions. Preliminary calculations indicate that the lee-side forces will have an insignificant influence on the aerodynamic characteristics of the orbiter for moderate angle-of-attack entries; therefore, this work is focused on phenomena which have an overriding influence on windward forces, namely, real-gas (equilibrium and nonequilibrium) and viscous-interaction effects. Analytically determined flow fields previously obtained on 40 deg blunted cones were used as a data source to evaluate various correlation parameters. Inviscid effects were found to be the dominant contributor to the aerodynamic coefficients in the altitude range of 64 to 76.2 km. The most suitable correlation of the aerodynamic forces on these cones is based on local dynamic pressure and local Mach number.

Hunt, J. L.↗
NASA NTRS1977

Solar influence on meteor rates and atmospheric density variations at meteor heights

Lindblad (1967) has concluded that there was an inverse relation between meteor rates and the solar cycle brought about by an increase in atmospheric density gradient at the height of meteor ionization. The present paper investigates Lindblad's conclusion more fully by using three long series of continuous radar meteor data from New Zealand and Canada. The results confirm a clear variation of total rate from year to year, inversely correlated with the annual sunspot number. Although meteor rates call for a density gradient variation inversely related to the solar cycle, direct evidence for such a variation remains nonexistant. Possibly the effect is being obscured by other density changes occurring at these heights. Analysis of meteor rates within the same one-year period in the two hemispheres has established that seasonal rate changes brought about by the variation of the angle between the latitude of the observing station and the apex of the earth's way override change of density gradient in at least one of the hemispheres and possibly both in controlling meteor rates within the year.

Ellyett, C.↗
NASA NTRS1978

DSN command system Mark III-78

The Deep Space Network command Mark III-78 data processing system includes a capability for a store-and-forward handling method. The functions of (1) storing the command files at a Deep Space station; (2) attaching the files to a queue; and (3) radiating the commands to the spacecraft are straightforward. However, the total data processing capability is a result of assuming worst case, failure-recovery, or nonnominal operating conditions. Optional data processing functions include: file erase, clearing the queue, suspend radiation, command abort, resume command radiation, and close window time override.

Stinnett, W. G.↗
NASA NTRS1978

Aerothermodynamic assessment of corrugated panel thermal protection systems

The results of an analysis of wind-tunnel data for the effect of wave shape on local boundary layer flows and heat transfer are used to assess the feasibility of using corrugated panels on a Single-Stage-To-Orbit (SSTO) vehicle. In the flight assessment, available engineering design procedures are used to compute the inviscid and boundary layer flow for a given flight trajectory. The flight vehicle flow field calculations are then used in conjunction with wind-tunnel corrugated panel heating data correlations to examine the heating penalties associated with using corrugated panels at a number of locations on the vehicle. Severe heating penalties, as a result of the corrugations, were found over large areas of the windward surface. Maximum surface temperature penalties ranged from 100K to 500K and very large structural advantages for the corrugations would be required to override the heating penalties. Computed peak corrugation temperatures were within allowable limits of the equivalent smooth wall material for most leeward and side fuselage locations and corrugated panels will be most likely limited to these locations.

Brandon, H. J.↗
NASA NTRS1978

An analysis of short haul air passenger demand, volume 2

Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose.

Blumer, T. P.↗