52,910 research outputs found

    A radiant heating test facility for space shuttle orbiter thermal protection system certification

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    A large scale radiant heating test facility was constructed so that thermal certification tests can be performed on the new generation of thermal protection systems developed for the space shuttle orbiter. This facility simulates surface thermal gradients, onorbit cold-soak temperatures down to 200 K, entry heating temperatures to 1710 K in an oxidizing environment, and the dynamic entry pressure environment. The capabilities of the facility and the development of new test equipment are presented

    Initial development of an ablative leading edge for the space shuttle orbiter

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    A state-of-the-art preliminary design for typical wing areas is developed. Seven medium-density ablators (with/without honeycomb, flown on Apollo, Prime, X15A2) are evaluated. The screening tests include: (1) leading-edge models sequentially subjected to ascent heating, cold soak, entry heating, post-entry pressure fluctuations, and touchdown shock, and (2) virgin/charred models subjected to bondline strains. Two honeycomb reinforced 30 pcf elastomeric ablators were selected. Roughness/recession degradation of low speed aerodynamics appears acceptable. The design, including attachments, substructure and joints, is presented

    Design, fabrication, and structural testing of a lightweight shadow shield for deep-space application

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    Two full-scale, lightweight, double-sheeted shadow shields were developed as the primary element of a deep-space thermal protection system for liquid-hydrogen propellant tankage. The thermal and mechanical considerations used in s, the method of fabrication, and the environmental testing results on a prototype shield are discussed. Testing consisted of a transient cooldown period, a prolonged cold soak, and a transient warmup. The mechanical and thermal analyses used in the shield design are sufficient to produce a lightweight rugged shadow shield assembly that is structurally adequate for its intended application

    Surface tension induced convection in encapsulated liquid metals in microgravity: Apollo-Soyuz test project experiment no. MA-041

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    This experiment was designed to determine the extent of surface tension induced convection caused by a steplike compositional variation in a liquid metal. Preliminary results are presented

    Lightweight tire concept for space shuttle

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    Various tests were conducted on a 49x17/26 PR aircraft tire that had been designed as a lightweight tire for use on the C-5A military transport. This tire is approximately 25 per cent lighter than a tire of the same size and ply rating that would be used in commercial airline service. The tires were tested at 40 per cent, 37 per cent, and 35 per cent deflections. These deflections were obtained by adjusting the inflation pressure while the load on the tire remained constant at 60,000 pounds. It was determined that the tire would operate successfully under the test conditions at 35% deflection. Prior to testing, the tires were subjected to conditions of high vacuum and low temperature. It was determined that the tires were not adversely affected by these conditions

    Factors influencing online banking adoption: the case of academicians in Malaysian technical University network (MTUN)

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    Advancement of technology saw the evolution of how banking activities being conducted. Online banking for example, has created new approach of banking activities around the globe. This study was conducted to investigate and determine factors influencing online banking adoption among academicians in Malaysia. The selection of factors was developed based on extended Technology Acceptance Model (TAM). TAM is the most widely applied model in the field of technology adoption. TAM investigates the adoption of technology based on its Perceived Usefulness and Perceived Ease of Use. Government support was included as an extension of the original model mainly because of its direct influence on the existence of the online banking itself. These factors were categorized as the independent variables in this study while online banking adoption as the dependent variable. Data for this research were collected from survey questionnaires, distributed to the target population of academicians at four higher education institutions listed under Malaysian Technical University Network (MTUN) in Malaysia. Data collected were analyzed using Statistical Package for Social Science (SPSS) software. Correlation and regression technique was employed to study factors influencing online banking adoption among respondents, Results of the analysis shows that Perceived Usefulness and Perceived Ease of Use found to be significant factors while Government Support is found to be not a significant factor in influencing the adoption of online banking among the respondents. This study has shed new knowledge for the research in the area of technology adoption particularly in Malaysia

    General purpose rocket furnace

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    A multipurpose furnace for space vehicles used for material processing experiments in an outer space environment is described. The furnace contains three separate cavities designed to process samples of the widest possible range of materials and thermal requirements. Each cavity contains three heating elements capable of independent function under the direction of an automatic and programmable control system. A heat removable mechanism is also provided for each cavity which operates in conjunction with the control system for establishing an isothermally heated cavity or a wide range of thermal gradients and cool down rates. A monitoring system compatible with the rocket telemetry provides furnace performance and sample growth rate data throughout the processing cycle

    Evaluation of the micro-carburetor

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    A prototype sonic, variable-venturi automotive carburetor was evaluated for its effects on vehicle performance, fuel economy, and exhaust emissions. A 350 CID Chevrolet Impala vehicle was tested on a chassis dynamometer over the 1975 Federal Test Procedure, urban driving cycle. The Micro-carburetor was tested and compared with stock and modified-stock engine configurations. Subsequently, the test vehicle's performance characteristics were examined with the stock carburetor and again with the Micro-carburetor in a series of on-road driveability tests. The test engine was then removed from the vehicle and installed on an engine dynamometer. Engine tests were conducted to compare the fuel economy, thermal efficiency, and cylinder-to-cylinder mixture distribution of the Micro-carburetor to that of the stock configuration. Test results show increases in thermal efficiency and improvements in fuel economy at all test conditions. Improve fuel/air mixture preparation is implied from the information presented. Further improvements in fuel economy and exhaust emissions are possible through a detailed recalibration of the Micro-carburetor

    Ground test program for a full-size solar dynamic heat receiver

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    Test hardware, facilities, and procedures were developed to conduct ground testing of a full size, solar dynamic heat receiver in a partially simulated, low Earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment were designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed Brayton cycle engine simulator to circulate and condition the helium xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described
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