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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Opportunities for development of advanced large cargo aircraft

A critical review of the history, current state of the art, and future prospects for cargo aircraft systems indicates that three of the major advantages of air cargo are rapid delivery, ability to bridge geographical boundaries, and capability to provide a flexible market response. Foreseeable advances in large aircraft development offer even greater profit potential by increasing the payload ton-miles per pound of fuel. Intermodal containers and handling systems and computerized control and billing may be key ingredients. Details of a NASA program for large aircraft systems technology are outlined, which includes systems studies, research and technology investigations, and determination of the need for critical flight experiments. Innovative advanced technologies and configuration concepts are discussed. Numerous illustrations supplement the text.

Whitehead, A. H., Jr.↗
NASA NTRS1977

Graphite fiber reinforced thermoplastic resins

The results of a program designed to optimize the fabrication procedures for graphite thermoplastic composites are described. The properties of the composites as a function of temperature were measured and graphite thermoplastic fan exit guide vanes were fabricated and tested. Three thermoplastics were included in the investigation: polysulfone, polyethersulfone, and polyarylsulfone. Type HMS graphite was used as the reinforcement. Bending fatigue tests of HMS graphite/polyethersulfone demonstrated a gradual shear failure mode which resulted in a loss of stiffness in the specimens. Preliminary curves were generated to show the loss in stiffness as a function of stress and number of cycles. Fan exit guide vanes of HMS graphite polyethersulfone were satisfactorily fabricated in the final phase of the program. These were found to have stiffness and better fatigue behavior than graphite epoxy vanes which were formerly bill of material.

Navak, R. C.↗
NASA NTRS1978

Food packages for Space Shuttle

The paper reviews food packaging techniques used in space flight missions and describes the system developed for the Space Shuttle. Attention is directed to bite-size food cubes used in Gemini, Gemini rehydratable food packages, Apollo spoon-bowl rehydratable packages, thermostabilized flex pouch for Apollo, tear-top commercial food cans used in Skylab, polyethylene beverage containers, Skylab rehydratable food package, Space Shuttle food package configuration, duck-bill septum rehydration device, and a drinking/dispensing nozzle for Space Shuttle liquids. Constraints and testing of packaging is considered, a comparison of food package materials is presented, and typical Shuttle foods and beverages are listed.

Fohey, M. F.↗
NASA NTRS1981

JT8D high pressure compressor performance improvement

An improved performance high pressure compressor with potential application to all models of the JT8D engine was designed. The concept consisted of a trenched abradable rubstrip which mates with the blade tips for each of the even rotor stages. This feature allows tip clearances to be set so blade tips run at or near the optimum radius relative to the flowpath wall, without the danger of damaging the blades during transients and maneuvers. The improved compressor demonstrated thrust specific fuel consumption and exhaust gas temperature improvements of 1.0 percent and at least 10 C over the takeoff and climb power range at sea level static conditions, compared to a bill-of-material high pressure compressor. Surge margin also improved 4 percentage points over the high power operating range. A thrust specific fuel consumption improvement of 0.7 percent at typical cruise conditions was calculated based on the sea level test results.

Gaffin, W. O.↗
NASA NTRS1982

The use of LANDSAT data to monitor the urban growth of Sao Paulo Metropolitan area

Urban growth from 1977 to 1979 of the region between Billings and the Guarapiranga reservoir was mapped and the problematic urban areas identified using several LANDSAT products. Visual and automatic interpretation techniques were applied to the data. Computer compatible tapes of LANDSAT multispectral scanner data were analyzed through the maximum likelihood Gaussian algorithm. The feasibility of monitoring fast urban growth by remote sensing techniques for efficient urban planning and control is demonstrated.

Dejesusparada, N.↗
NASA NTRS1983

User interface to administrative DRMS within a distributed environment

The implementation of a data base management system (DBMS) into a communications office to control and report on communication leased service contracts is discussed. The system user executes online programs to update five files residing on a UNIVAC 1100/82, through the forms mode features of the Tektronix 4025 terminal and IMSAI 8080 microcomputer. This user can select the appropriate form to the Tektronix 4025 screen, and enter new data, update existing data, or discontinue service. Selective online printing of 40 reports is accomplished by the system user to satisfy management, budget, and bill payment reporting requirements.

Martin, L. D.↗
NASA NTRS1983

Land mobile satellite system requirements

A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

Kiesling, J. D.↗
NASA NTRS1985

Space Shuttle security policies and programs

The Space Shuttle vehicle consists of the orbiter, external tank, and two solid rocket boosters. In dealing with security two major protective categories are considered, taking into account resource protection and information protection. A review is provided of four basic programs which have to be satisfied. Aspects of science and technology transfer are discussed. The restrictions for the transfer of science and technology information are covered under various NASA Management Instructions (NMI's). There were two major events which influenced the protection of sensitive and private information on the Space Shuttle program. The first event was a manned space flight accident, while the second was the enactment of a congressional bill to establish the rights of privacy. Attention is also given to national resource protection and national defense classified operations.

Keith, E. L.↗
NASA NTRS1984

Introduction to life modeling of thermal barrier coatings

Thermal barrier coatings may be applied to air-cooled turbine section airfoils to insulate such components from hot gases in the engine. The coatings, which typically consist of about 0.01 to 0.04 cm of zirconia-yttria ceramic over about 0.01 cm of NiCrAlY or NiCrAlZr alloy bond coat, allow increased gas temperatures or reduced cooling air flows. This, in turn, leads to marked improvements in engine efficiency and performance. However, certain risks are associated with designing for maximum benefits, and eventually a point is reached where coating loss would immediately jeopardize the underlying component. Therefore, designers must be able to accurately predict the life of a given bill-of-material coating in any particular design. The results of an in-house aeronautics, base research and technology program which is designed to provide the first steps towards developing mission-capable life-prediction models are outlined.

Miller, R. A.↗
NASA NTRS1986

Measurement of atmospheric HO by a chemical method

The parameters for a chemical technique can be outlined from the following set of desirable goals: (1) sufficient conversion of tracer species A to product B that B can be measured quantitatively in the presence of A and a great excess of air; (2) specificity of reaction such that A is converted to B only by reaction with HO; and (3) sufficient sensitivity for detection that the ambient concentration of HO is not seriously perturbed by the presence of A and B. This proposed study involves finding a chemical reaction specific enough for OH, and a measurement of the product formed. What one wants is a rate constant of about 10 to the -10th power cu cm/s, so that 0.1 percent of the OH will be converted in 100 s. Laboratory studies are needed to find a reaction which will fill this bill, yielding a product in quantity sufficient for precise measurement. This is an extremely fast constant and the search may be difficult. Again there is a question of perturbing the local environment, while still providing a sensitive measurement. Also the temperature and pressure dependence of the reaction rate is a complicated function for many of these species (that is, one must use a RRKM or Troe-based picture), and must be taken into account.

Iyer, R. Subramonia↗
NASA NTRS1988

Current status and future trends in turbine application of thermal barrier coatings

This paper provides an overview of the current status and future trends in application of thermal barrier coatings (TBC) to turbine components, and in particular to high turbine airfoils. Included are descriptions of the favorable results achieved to date with bill-of-material applications of plasma deposited TBC, and recent experience with developmental coatings applied by electron beam-physical vapor deposition.

Sheffler, Keith D.↗
NASA NTRS1985

Mechanisms of thermal barrier coating degradation and failure

The objectives and initial results of a Thermal Barrier Coating (TBC) Life Prediction Model Development Program are described. The goals of this program are to: identify and understand TBC failure modes; generate quantitative TBC life data; and develop and verify a TBC life prediction model. The coating being studied is a two layer thermal barrier system incorporating a nominal ten mil outer layer of seven percent yttria partially stabilized zirconia plasma deposited over an inner layer of highly oxidation resistant low pressure plasma sprayed NiCrAlY bond coating. This coating currently is in flight service on turbine vane platforms in the JT-9D and PW2037 engines and is bill-of- material on turbine vane airfoils in the advanced PW4000 and IAE V2500 engines. Effort currently is in progress on the first task, which involves the identification and understanding of TBC failures. Five modes of coating damage were considered: thermomechanical ceramic failure; oxidative bond coat failure; hot corrosion; foreign object damage (FOD); and erosion.

Demasi, J. T.↗
NASA NTRS1988

MATE (Materials for Advanced Turbine Engines) Program, Project 3. Volume 2: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner

The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Two yttria (Y2O3) dispersion strengthened alloys were evaluated; Incoloy MA956 and Haynes Development Alloy (HDA) 8077 (NiCrAl base). Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. MA956 was selected as the final alloy based on manufacturing reproducibility for evaluation as a burner liner. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components and using a louvered configuration was designed and constructed. The louvered configuration was chosen because of field experience and compatibility with the bill of material PW2037 design. The simulated flight cycle for the ground based engine tests consisted of 4.5 min idle, 1.5 min takeoff and intermediate conditions in a PW2037 engine with average uncorrected combustor exit temperature of 1527 C. Post test evaluation consisting of visual observations and fluorescent penetrant inspections was conducted after 500 cycles of testing. No loss of integrity in the burner liner was shown.

Bose, S.↗
NASA NTRS1990

Reliability of equivalent sphere model in blood-forming organ dose estimation

The radiation dose equivalents to blood-forming organs (BFO's) of the astronauts at the Martian surface due to major solar flare events are calculated using the detailed body geometry of Langley and Billings. The solar flare spectra of February 1956, November 1960, and August 1972 events are employed instead of the idealized Webber form. The detailed geometry results are compared with those based on the 5-cm sphere model which was used often in the past to approximate BFO dose or dose equivalent. Larger discrepancies are found for the later two events possibly due to the lower numbers of highly penetrating protons. It is concluded that the 5-cm sphere model is not suitable for quantitative use in connection with future NASA deep-space, long-duration mission shield design studies.

Shinn, Judy L.↗
NASA NTRS1990

Procedural error monitoring and smart checklists

Human beings make and usually detect errors routinely. The same mental processes that allow humans to cope with novel problems can also lead to error. Bill Rouse has argued that errors are not inherently bad but their consequences may be. He proposes the development of error-tolerant systems that detect errors and take steps to prevent the consequences of the error from occurring. Research should be done on self and automatic detection of random and unanticipated errors. For self detection, displays should be developed that make the consequences of errors immediately apparent. For example, electronic map displays graphically show the consequences of horizontal flight plan entry errors. Vertical profile displays should be developed to make apparent vertical flight planning errors. Other concepts such as energy circles could also help the crew detect gross flight planning errors. For automatic detection, systems should be developed that can track pilot activity, infer pilot intent and inform the crew of potential errors before their consequences are realized. Systems that perform a reasonableness check on flight plan modifications by checking route length and magnitude of course changes are simple examples. Another example would be a system that checked the aircraft's planned altitude against a data base of world terrain elevations. Information is given in viewgraph form.

Palmer, Everett↗
NASA NTRS1991

Finding and utilizing lunar lava tubes

Horz describes the evidence for lava tubes associated with rills in lunar photoimaging. These tubes have terrestrial counterparts as described by Billings, et al., and Gillet. The widths of these tubes range from 10s to 100s of meters. Their roof thickness are at least 0.125 to 0.25 times their widths and stand unsupported on the Moon. To confine one atmosphere of internal pressure, static roof thickness must be at least 16 m. Favorable locations of lava tubes may be surveyed using roving gravity meters on Doodle Bugs, which consist of platforms containing equipment for communication with Earth-based control stations. The stable -20 C temperature of the lava tubes should provide a workable habitat environment. The greater than 16 m of basalt in the roof should give adequate radiation and impact protection. Typically, after clearing entries and grading ramps, habitats might be placed in tubes and inflated. Later, larger habitats might be built by enclosing tube sections with compacted-regolith dams. The interior can then be sealed to hold an atmosphere. The huge lava tubes inferred from the photographs are capable of providing habitats hundreds of meters wide, in lengths of kilometers.

Kuck, David L.↗
NASA NTRS1992

Software For Monitoring A Computer Network

SNMAT is rule-based expert-system computer program designed to assist personnel in monitoring status of computer network and identifying defective computers, workstations, and other components of network. Also assists in training network operators. Network for SNMAT located at Space Flight Operations Center (SFOC) at NASA's Jet Propulsion Laboratory. Intended to serve as data-reduction system providing windows, menus, and graphs, enabling users to focus on relevant information. SNMAT expected to be adaptable to other computer networks; for example in management of repair, maintenance, and security, or in administration of planning systems, billing systems, or archives.

Lee, Young H.↗
NASA NTRS1992

Early aerospaceplane propulsion research: Marquardt Corporation: ca 1956-1963

A brief summary is presented of the very early days of aerospaceplane propulsion and concept research, from a viewpoint based in the Astro Division of Marquardt Aircraft Co. in the years listed, with some view into later times that were on Bill Escher's watch and others. Other groups who were pursuing the same goals by various routes are discussed by some following speakers. The chief purpose is to bring out background information that may be of value to members of the workshop and future workers in the field. The state of engine and airframe technology at those times must be understood to make sense of the effort. Operational kerosene fueled ramjets were routinely flying Mach 2 to 3 in the Bomarc and Talos interceptors. One Marquardt ramjet had accelerated a Lockheed X-7 test vehicle to about Mach 4.7 in an all-out test, holding it at nearly 1 'G' until the fuel ran out. Development of further research at Marquardt is outlined.

Lindley, Charles A.↗