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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 1,729 records · Page 96
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Long term evaluation of grease type lubricants in selected environments

The operating life of grease-type lubricants in various environments is evaluated. The test equipment and procedures are described. The lubricants were placed in the rolling element bearings of hysteresis synchronous motors and exposed to environments of a vacuum at 60 C, a vacuum at 93.3 C, 10 psia oxygen at 90 percent relative humidity at 60 C, 14.7 psia air at 90 percent relative humidity at 60 C, start-stop operation, and low temperature start capability for one or five years. The weights of the bearings were measured before and after lubrication; the weight data for each environment are analyzed. The data reveal that the high viscosity index perfluoroalkypolyether grease performs the best in a vacuum at moderate and high temperature, in low temperature start capability, and in start-stop steps; however, the grease does not work well in oxidizing and high relative humidity environments.

Dolan, F. J.↗
NASA NTRS1986

Development of Space Station strut design

Candidate Space Station struts exhibiting high stiffness (38-40 msi modulus of elasticity) were manufactured and experimentally evaluated. One and two inch diameter aluminum-clad evaluation specimens were manufactured using a unique dry fiber resin injection process. Preliminary tests were performed on strut elements having 80 percent high-modulus graphite epoxy and 20 percent aluminum. Performed tests included modulus of elasticity, thermal cycling, and coefficient of thermal expansion. The paper describes the design approach, including an analytical assessment of strut thermal deformation behavior. The major thrust of this paper is the manufacturing process which produces aluminum-clad struts with precisely controlled properties which can be fine-tuned after fabrication. An impact test and evaluation procedure for evaluating toughness is described.

Johnson, R. R.↗
NASA NTRS1987

First flight of the ATMOS instrument during the Spacelab 3 Mission, April 29 through May 6, 1985

The underlying rationale and the implementation of the Atmospheric Trace Molecule Spectroscopy (ATMOS) investigation are discussed, a description of the sensor is given, and the ground tests and integration procedures leading to the Spacelab 3 flight are described. The data reduction and analysis procedures used after the flight are discussed, a number of examples of the spectra obtained are shown, and the concentration profiles as a function of altitude for the minor and trace gases measured during the mission are presented. On the basis of the instrument's ability to survive both the launch and the reentry of the shuttle and its flawless performance while on orbit, the concepts involved in the investigation have been proved by the Spacelab 3 flight, and an extended series of reflights is currently being planned as a part of the Atmospheric Laboratory for Applications and Science (ATLAS) Missions. The goals for the investigation during these missions are also discussed.

Farmer, Crofton B.↗
NASA NTRS1988

Payload bay atmospheric vent airflow testing at the Vibration and Acoustic Test Facility

Several concerns related to venting the Space Shuttle Orbiter payload bay during launch led to laboratory experiments with a flight-type vent box installed in the wall of a subsonic wind tunnel. This report describes the test setups and procedures used to acquire data for characterization of airflow through the vent box and acoustic tones radiated from the vent-box cavity. A flexible boundary-layer spoiler which reduced the vent-tone amplitude is described.

Johnston, James D., Jr.↗
NASA NTRS1987

External noise evaluation of the XV-15 TiltRotor aircraft

The noise emission of the XV-15 in both helicopter and airplane operation and in level and constant-slope descending flight is measured (as sound exposure levels) in a series of test flights over a ground microphone array. The aircraft characteristics, test facility, and procedures are described, and the results are presented in extensive graphs and characterized in detail. Consideration is given to engine-rpm and nacelle-tilt effects, noise duration, sideline radiation, altitude effects, acoustic waveforms, and variations with glideslope. The XV-15 is found to produce less noise in its airplane mode than in the helicopter mode, where the noise levels are similar to those of other helicopters.

Brieger, John T.↗
NASA NTRS1987

Cockpit readiness for night vision goggles

The introduction of night vision goggles into the cockpit environment may produce incompatibility with existing cockpit optoelectronic instrumentation. The methodology used to identify the origin of the spurious signal is demonstrated with the example of an electronic display. The amount of radiation emitted by a gray body in the wavelength region of goggle sensitivity is calculated. A simple procedure for preflight testing of cockpit instrumentation using a commercially available infrared camera is recommended. Other recommendations include the specification of cocklpit instrumentation for compatibility with night vision devices.

Scholl, Marija S.↗
NASA NTRS1986

The testability of Ada programs

Software development for NASA's Space Station poses a significant problem; considered the most difficult by some. The difficulty is the magnitude and complexity of the required software. The concerns raised by consideration of the requirements for testing and checkout procedures for the Space Station software are addressed. In particular, it addresses the use of Ada in the development of widely distributed yet closely coordinated processing.

Auty, David↗
NASA NTRS1989

Practices in Adequate Structural Design

Structural design and verification of space vehicles and space systems is a very tricky and awe inspiring business, particularly for manned missions. Failures in the missions with loss of life is devastating personally and nationally. The scope of the problem is driven by high performance requirements which push state-of-the-art technologies, creating high sensitivites to small variations and uncertainties. Insurance of safe, reliable flight dictates the use of sound principles, procedures, analysis, and testing. Many of those principles which were refocused by the Space Shuttle Challenger (51-L) accident on January 26, 1986, and the activities conducted to insure safe shuttle reflights are discussed. The emphasis will be focused on engineering, while recognizing that project and project management are also key to success.

Ryan, Robert S.↗
NASA NTRS1988

Dexterity analysis and robot hand design

Understanding about a dexterous robot hand's motion ranges is important to the precision grasping and precision manipulation. A planar robot hand is studied for object orientation, including ranges of motion, measures with respect to the palm, position reaching of a point in the grasped object, and rotation of the object about the reference point. The rotational dexterity index and dexterity chart are introduced and an analysis procedure is developed for calculating these quantities. A design procedure for determining the hand kinematic parameters based on a desired partial or complete dexterity chart is also developed. These procedures have been tested in detail for a planar robot hand with two 2- or 3-link fingers. The derived results are shown to be useful to performance evaluation, kinematic parameter design, and grasping motion planning for a planar robot hand.

Li, LU↗
NASA NTRS1989

Radiation durability of polymeric matrix composites

The combined effects of thermal cycling and high-dose electron irradiation on the mechanical properties of laminated graphite/polymeric CFRPs are investigated experimentally. The test apparatus and procedures are briefly described, and the results are presented in extensive tables and graphs. It is found that electron radiation produces similar significant reductions in the glass transition temperatures of the neat resins and CFRPs. The radiation-induced degradation products tend to plasticize the matrix at high temperature but embrittle it at low temperature.

Tenney, Darrel R.↗
NASA NTRS1988

Bioisolation on the Space Station

Animal research on the Space Station presents the need for bioisolation, which is here defined as instrumental and operational provisions, which will prevent the exchange of particles greater than 0.3-micron size and microorganisms between crew and animals. Current design principles for the Biological Research Project thus call for: (1) use of specific pathogen-free animals; (2) keeping animals at all times in enclosed habitats, provided with microbial filters and a waste collection system; (3) placing habitats in a holding rack, centrifuge, and workbench, all equipped with particulate and odor filters, (4) washing dirty cage units in an equipment cleaner, with treatment and recycling of the water; (5) designing components and facilities so as to ensure maximal accessibility for cleaning; and (6) defining suitable operational procedures. Limited ground tests of prototype components indicate that proper bioisolation can thus be achieved.

Bonting, Sjoerd L.↗
NASA NTRS1989

Development testing of TSS-1 Deployer tether control system mechanisms

Successful tether deployment and retrieval, consistent with established control laws, is predicated upon statusing real time tether dynamic conditions. This paper reports on the initial phase of engineering tests performed on various components and subassemblies integral to the TSS-1 tether control system as part of the TSS Deployer. The tests were conducted as part of the tether control system development and verification plan to confirm the functionality and map the performance of the hardware in both ambient and environmental test conditions. The result of this development effort is a lessons-learned list and design upgrades to both the flight and test hardware and to the test methods and procedures.

Bentley, D. P.↗
NASA NTRS1989

Recent aerodynamic measurements with Magnetic Suspension Systems

This paper reviews recent aerodynamic tests of a family of slanted-base ogive-cylinders using the NASA Langley 13-inch Magnetic Suspension and Balance System. Results include drag, lift, pitching moment, support interference and base pressure measurements. Mach numbers were in the range 0.04 to 0.2. Drag results are shown to be in satisfactory agreement with previous measurements. Significant support interferences were found at all test conditions. Comparison is made between interference free base pressures, obtained using remote telemetry, and sting cavity pressures. Test results and procedures are briefly discussed in the context of the proposed helium flow facility.

Britcher, Colin P.↗
NASA NTRS1990

Fatigue testing of plasma-sprayed thermal barrier coatings, volume 2

A plasma sprayed thermal barrier coating for diesel engines were fatigue tested. Candidate thermal barrier coating materials were fatigue screened and a data base was generated for the selected candidate material. Specimen configurations are given for the bend fatigue tests, along with test setup, specimen preparation, test matrix and procedure, and data analysis.

Cruse, T. A.↗
NASA NTRS1990

Performance of multiplexed Ge:Ga detector arrays in the far infrared

The performance of two multi-element, multiplexed Ge:Ga linear arrays under low-background conditions was investigated. The on-focal switching is accomplished by MOSFET switches, and the integrated charge is made available through MOSFET source followers. The tests were conducted at 106 microns, and the radiation on the detectors was confined to a spectral window 1.25 microns wide using a stack of cold filters. At 4.2 K, the highest responsivity was 584 A/W, the noise equivalent power was 1.0 x 10(exp -16) W/square root of Hz, and the read noise was 6100 electrons/sample. A detailed description of the test setup and procedure is presented.

Farhoomand, Jam↗
NASA NTRS1990

In-orbit experimentation with the Small Expendable-Tether Deployment System

The Small Expendable-Tether Deployment System (SEDS) is a light-weight deployer capable of deploying instrumented packages and other tethered payloads up to a distance of 20 km. The system is simple and inexpensive because it does not retrieve the tethered payloads. The deployer is attached to the second stage of a Delta II which acts as a stabilized platform for the deployment of tethered payloads. SEDS is particularly suitable for complementing the Tethered Satellite missions by providing a flexible system for experimenting with the tether-in-space technology. SEDS can also provide a convenient way for testing instruments and/or procedures which require the use of long tethers.

Lorenzini, Enrico C.↗
NASA NTRS1989

En route noise test preliminary results

Preliminary results are reported from ground measurements of noise emitted by a full-scale advanced single-rotation turbofan model mounted on the wing of the NASA Lewis Propfan Test Assessment aircraft during test flights in October 1987. The procedures and instruments employed in the test program are described, and the data are presented in tables. The repeatability of the measurements is shown to be good within one test day, with day-to-day variations attributed to cross-wind convection. Fair agreement is found between these measurements and the predictions of ray-tracing models.

Willshire, William L., Jr.↗