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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 289 records · Page 16

Non-Toxic Dual Thrust Reaction Control Engine Development for On-Orbit APS Applications

A non-toxic dual thrust proof-of-concept demonstration engine was successfully tested at the Aerojet Sacramento facility under a technology contract sponsored by the National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC). The goals of the NASA MSFC contract (NAS8-01109) were to develop and expand the technical maturity of a non-toxic, on-orbit auxiliary propulsion system (APS) thruster under the Next Generation Launch Technology (NGLT) program. The demonstration engine utilized the existing Kistler K-1 870 lbf LOX/Ethanol orbital maneuvering engine ( O m ) coupled with some special test equipment (STE) that enabled engine operation at 870 lbf in the primary mode and 25 lbf in the vernier mode. Ambient testing in primary mode varied mixture ratio (MR) from 1.28 to 1.71 and chamber pressure (P(c) from 110 to 181 psia, and evaluated electrical pulse widths (EPW) of 0.080, 0.100 and 0.250 seconds. Altitude testing in vernier mode explored igniter and thruster pulsing characteristics, long duration steady state operation (greater than 420 sec) and the impact of varying the percent fuel film cooling on vernier performance and chamber thermal response at low PC (4 psia). Data produced from the testing provided calibration of the performance and thermal models used in the design of the next version of the dual thrust Reaction Control Engine (RCE).

Robinson, Philip J.↗

Media Controller For Receiving Data From A TAXI(TM) Link

TAXI(TM) media controller (TMC) is interface circuit that supports operation of test equipment in diagnosis of telemetry system in which data communicated via TAXI(TM) links. TMC designed specifically for use with TAXI(TM) test adapter for monitoring and testing telemetry data signals generated by payloads and other subsystems of Space Station Freedom. Overall, TMC characterized as providing interface between output part of a TAXI(TM) receiving chip and input port of memory system in test adapter. TMC detects some abnormalities in received data stream and resynchronizes stream to locally generated clock signal.

Stauffer, David R.↗

Rapid-Rate Compression Testing of Sheet Materials at High Temperatures

This Report describes the test equipment that was developed and the procedures that were used to evaluate structural sheet-material compression properties at preselected constant strain rates and/or loads. Electrical self-resistance was used to achieve a rapid heating rate of 200 F/sec. Four materials were tested at maximum temperatures which ranged from 600 F for the aluminum alloy to 2000 F for the Ni-Cr-Co iron-base alloy. Tests at 0.1, 0.001, and 0.00001 in./in./sec showed that strain rate has a major effect on the measured strength, especially at the high temperatures. The tests, under conditions of constant temperature and constant compression stress, showed that creep deformation can be a critical factor even when the time involved is on the order of a few seconds or less. The theoretical and practical aspects of rapid-rate compression testing are presented, and suggestions are made regarding possible modifications of the equipment which would improve the over-all capabilities.

Bernett, E. C.↗

Spacecraft factory-to-pad testing concept

It is noted that the concept of factory-to-pad testing is based on the shipment of a flight-ready spacecraft to the launch base and can be achieved by thorough and comprehensive factory testing of the spacecraft. The principal objectives and results of this approach are shown to be significant cost reductions, increased test effectiveness, and fewer flight problems. Key elements for this concept's success are discussed, including factory-to-pad commonality of support equipment, test requirements and procedures, test teams, and computer programs. Applications of this approach in the space-shuttle era are considered, and a preliminary factory-to-pad concept for the Large Space Telescope spacecraft is presented.

Jones, R. H.↗

Some new results concerning the dynamic behavior of annular turbulent seals

The dynamic characteristics of annular turbulent seals applied in high pressure turbopumps can be described by stiffness, damping, and inertia coefficients. An improved procedure is presented for determining these parameters by using measurements made with newly developed test equipment. The dynamic system seal, consisting of the fluid between the cylindrical surfaces of the rotating shaft and the housing, is excited by test forces (input), and the relative motion between the surfaces (output) is measured. Transformation of the input and output time signals into the frequency domain leads to frequency response functions. An analytical model, depending on the seal parameters, is fitted to the measured data in order to identify the dynamic coefficients. Some new results are reported that show the dependencies of these coefficients with respect to the axial and radial Reynolds numbers and the geometrical data of the seal.

Massmann, H.↗

Stabilizer flutter investigated by flight test

Flight flutter tests were conducted on an experimental airplane which resulted in the successful prediction of a limited amplitude stabilizer flutter at supersonic speeds. The flutter obtained was unusual in that fore and aft bending of the stabilizer carry-through structure contributed to the flutter condition. During flight tests the impending flutter condition was observed from force per unit amplitude, damping coefficient, and frequency measurements. A description is given of the physical and operational characteristics of the test equipment and telemetering facilities. A flutter analysis using measured modes and incompressible two-dimensional strip air forces yielded a conservative flutter speed. Sled tests of a similar stabilizer configuration had lead to the conclusion that flutter would not be encountered. Certain overall conclusions are reached regarding this particular flight flutter testing program and the need for a concerted research effort in this field.

Baird, E. F.↗

Timing and frequency considerations in the worldwide testing of a spread spectrum communication system

During 1978 and 1979, an Air Force C-135 test aircraft was flown to various locations in the North and South Atlantic and Pacific Oceans for satellite communications experiments. A part of the equipment tested on the aircraft was the SEACOM spread spectrum modem. The SEACOM modem operated at X band frequency from the aircraft via the DSCS II satellite to a ground station. For data to be phased successfully, it was necessary to maintain independent time and frequency accuracy over relatively long periods of time (up to two weeks) on the aircraft and at the ground station. To achieve this goal, two Efratom atomic frequency standards were used. The performance of these frequency standards as used in the spread spectrum modem is discussed, including the effects of high relative velocity, synchronization and the effects of the frequency standards on data performance is discussed. The aircraft environment, which includes extremes of temperature, as well as long periods of shutdown followed by rapid warmup requirements, is also discussed.

Woodring, D. G.↗

Automatic arc welding of propulsion system tubing in close proximity to sensitive electronic devices

The planned final assembly of the Galileo spacecraft propulsion system tubing, which involves welding in close proximity to sensitive electronics, raised significant concerns about the effects of electromagnetic coupling of weld energy on CMOS and other sensitive integrated circuits. A test program was established to assess the potential of an orbital arc welder and an RF-induction brazing machine to damage sensitive electronic equipment. Test parameters were varied to assess the effectiveness of typical transient suppression practices such as grounding, bonding, and shielding. A technique was developed to calibrate the hazard levels at the victim-circuit location; this technique is described along with the results and conclusions of the test program.

Lumsden, J. M.↗

David Florida Laboratory: Support for mobile satellite communications

The comprehensive integration and environmental (including RF) test facilities of the Canadian Space Agency's David Florida Laboratory (CSA)(DFL) were used extensively for the MSAT Program. Following a description of the facilities, the paper outlines their application to the qualification of the two MSAT satellites following an overview of the test plan. Particular emphasis is given to passive intermodulation measurement (PIM) demands, which for the MSAT satellites, contributed to the need to extend the anechoic chamber. The extended chamber was also used for an EMC test and SAR signature test of the RADARSAT satellite. The DFL's facilities are being used for additional aspects of mobile satellite communications. One shielded anechoic Extra High Frequency (EHF) chamber and associated test equipment are employed predominantly for measuring the performance of the IRIDIUM satellites' Engineering Model Gateway Moveable Antennas (EM)(GMA). Other chambers are used for testing aeronautical antennas on behalf of Inmarsat. Still others combine thermal and PIM testing. The paper concludes with a review of the test requirements of evolving satcom missions such as Inmarsat Aero-1.

Dumoulin, Jean-Guy↗

Soil experiment

An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

Hutcheson, Linton↗

Millimeter wave experiment for ATS-F

A detailed description of spaceborne equipment is provided. The equipment consists of two transmitters radiating signals at 20 and 30 GHz from either U.S. coverage horn antennas or a narrow beam parabolic antenna. Three modes of operation are provided: a continuous wave mode, a multitone mode in which nine spectral lines having 180 MHz separation and spaced symmetrically about each carrier, and a communications mode in which communications signals from the main spacecraft transponder are modulated on the two carriers. Detailed performance attained in the flight/prototype model of the equipment is presented both under laboratory conditions and under environmental extremes. Provisions made for ensuring reliability in space operation are described. Also described the bench test equipment developed for use with the experiment, and a summary of the new technology is included.

Green, J. S.↗

The Preflight Calibration of the Thermal Infrared Sensor (TIRS) on the Landsat Data Continuity Mission

The preflight calibration testing of TIRS evaluates the performance of the instrument at the component, subsystem and system level, The overall objective is to provide an instrument that is well calibrated and well characterized with specification compliant data that will ensure the data continuity of Landsat from the previous missions to the LDCM, The TIRS flight build unit and the flight instrument were assessed through a series of calibration tests at NASA Goddard Space Flight Center. Instrument-level requirements played a strong role in defining the test equipment and procedures used for the calibration in the thermal/vacuum chamber. The calibration ground support equipment (CGSE), manufactured by MEI and ATK Corporation, was used to measure the optical, radiometric and geometric characteristics of TIRS, The CGSE operates in three test configurations: GeoRad (geometric, radiometric and spatial), flood source and spectral, TIRS was evaluated though the following tests: bright target recovery, radiometry, spectral response, spatial shape, scatter, stray light, focus, and uniformity, Data were obtained for the instrument and various subsystems under conditions simulating those on orbit In the spectral configuration, a monochromator system with a blackbody source is used for in-band and out-of-band relative spectral response characterization, In the flood source configuration the entire focal plane array is illuminated simultaneously to investigate pixel-to-pixel uniformity and dead or inoperable pixels, The remaining tests were executed in the GeoRad configuration and use a NIST calibrated cavity blackbody source, The NIST calibration is transferred to the TIRS sensor and to the blackbody source on-board TIRS, The onboard calibrator will be the primary calibration source for the TIRS sensor on orbit.

Smith, Ramsey↗

Backplane Design Considerations for High Speed SpaceWire Networks

SpaceWire is becoming a preferred protocol for board to board communication over a backplane in addition to its existing use over cabled interfaces, replacing other protocols due to its simplicity and readily available flight quality physical layer devices, IP cores and test equipment. However, without specific guidelines for implementing SpaceWire over a backplane, designers are left to make trade decisions regarding connector selection, layout design rules and test accessibility issues. This paper will discuss NASA's Goddard Space Flight Center s implementation of high speed SpaceWire over backplane on James Webb Space Telescope and other missions.

Pagen, Shahana Aziz↗

Good Enough for the X-38, but Made for Commercial Aircraft

Aircraft Belts, Inc. (ABI), of Kemah, Texas, was looking for a way to ensure the safety of its customers by developing a thorough test system for aviation restraint systems. Previous safety restraint test methods did not properly measure the load distribution placed on the restraints, leaving an unknown factor in meeting safety standards. ABI needed to improve its testing methods and update its test equipment. Through a partnership with NASA's Johnson Space Center Technical Outreach Program, the need was met. With the assistance of NASA engineers, ABI developed a hydraulic test system that provides the consumer with in-depth data about the load placed on the restraint system throughout the duration of the test. The old systems were only able to detect if the belts could sustain the applied force and could not target the problem of providing load data. In comparison, the new system modeled after the one used by NASA, can collect data that tells exactly what went wrong with belts that break and why. Depending on the test requirements of various restraint components, the system can exert a subjected force ranging from merely a few pounds to thousands. The test force can be applied to an entire safety restraint system or to its individual parts, including, stitching, webbing, and hardware.

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Model Rotor Hover Performance at Low Reynolds Number

Hover performance data from four key experiments has been analyzed in detail to shed some light on model rotor hover performance at low Reynolds number. Each experiment used the simplest blade geometry. The blades were constant chord and untwisted. Three experiments used blades with the NACA 0012 airfoil from root to tip. The NACA 0015 was used in the earliest test. The four experiments provide data spanning a Reynolds number range of 136,500 to 548,700. The specific objective of this report is to ask and answer two questions: 1. Does blade aspect ratio influence hover performance or is rotor solidity the fundamental rotor geometry parameter for practical engineering purposes? ANSWER: Rotor solidity is the fundamental rotor geometry parameter for practical engineering purposes. Any effect of blade aspect ratio appears to be such a secondary variable that its effect lies within the range of experimental error. 2. Is Reynolds number a significant factor in scaling up hover performance to full-scale rotor performance? The answer is twofold. ANSWER: (a) Reynolds number effects on the increase of power with thrust do not appear to be a significant factor for practical engineering purposes, and (b) Reynolds number effects on minimum profile power at or very near zero rotor thrust could not be clearly established primarily because the low torque levels could not be accurately measured with the test equipment used. This has led to significant data scatter. A number of other observations can be made based on the analysis provided herein. For instance: 1. The test matrices used in the four key references contained far too few data points. A collective pitch variation of four or five data points is insufficient to establish experimental accuracy and data repeatability. 2. A common property of the power-versus-thrust (raised to the 3/2 exponent) graphs was that this curve was linear below the onset of blade stall. 3. The blade-to-blade interference at or near zero thrust may, in fact, be creating a turbulent flow field such that the effective Reynolds number at a blade element is considerably greater than what theories using two-dimensional (2D) airfoil properties at a blade element would calculate. 4. Definitive experiments answering the two key questions have yet to be made.

Model Rotor Hover Performance↗

NASA Li/CF(x) cell problem analysis: Anion exchange chromatography analysis

An analysis was made of wiper samples used to wipe down lithium/chlorine fluorine battery components and production equipment. These components and equipment were potentially exposed to thionyl chloride vapors. In the presence of moisture, thionyl chloride decomposes to sulfur dioxide and hydrogen chloride. The wiper samples were analyzed for soluble chlorides and fluorides by anion exchange chromatography. During the examination of the test chromatographs, fluoride contamination was discovered in wiper samples from the test equipment. An analytical method to determine fluoride was developed. The first 3 extracts from the potentially exposed and clean wiper samples were tested, and the total fluoride from both groups determined. A comparison of the results from both groups was made to determine the extent of fluoride contamination.

Bytella, Joseph↗

Apollo experience report: Ground-support equipment

The experience gained in management of the ground-support-equipment and site-readiness activity for the Apollo Program is summarized. The design of equipment and facilities are examined as well as some operational aspects. The organization for ensuring site readiness and the maintenance of ground-support equipment are discussed. Recommendations for use in future programs are given in the areas of design considerations, cleanliness requirements, periodic evaluation of changing requirements, maintenance and overhaul, special test equipment, site-activation schedule coordination, and schematics for ground-support equipment.

Cooper, J. S.↗

NASA Metrology and Calibration, 1980

The proceedings of the fourth annual NASA Metrology and Calibration Workshop are presented. This workshop covered (1) review and assessment of NASA metrology and calibration activities by NASA Headquarters, (2) results of audits by the Office of Inspector General, (3) review of a proposed NASA Equipment Management System, (4) current and planned field center activities, (5) National Bureau of Standards (NBS) calibration services for NASA, (6) review of NBS's Precision Measurement and Test Equipment Project activities, (7) NASA instrument loan pool operations at two centers, (8) mobile cart calibration systems at two centers, (9) calibration intervals and decals, (10) NASA Calibration Capabilities Catalog, and (11) development of plans and objectives for FY 1981. Several papers in this proceedings are slide presentations only.

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