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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Design and Operation of the Planetary In-Situ Capillary Electrophoresis System (PISCES)

The PISCES instrument is a portable, miniature, modular instrument designed to analyze organic molecular signatures of life. PISCES uses microcapillary electrophoresis (μCE) with laser-induced fluorescence detection (LIFD) to analyze fluorescently-labeled analytes prepared on a multi-layer microfluidic chip. As a modular instrument composed of five independently functioning units, each module can be easily detached from the system and used for subsystem testing in different environments, e.g. low temperature. The pneumatic module contains mechanical and electrical components necessary to control pneumatically-actuated valves for on-chip sample processing. A prototype LabVIEW program and two custom printed circuit boards (PCBs) operate the pneumatics module using an Arduino microcontroller, and a tentative design for the module’s housing has been developed. The high-voltage module contains circuitry required to apply varying electrical potentials to the electrophoretic channel of the microdevice. Work is currently being done to design the circuit and PCB for this module in collaboration with our SBIR partners at Los Gatos Research. The optical electronics module contains the spectrometer, laser, and laser power supply. The mounting components for the electronics and housing for the module have been designed, assembled, and tested. The optical module contains optical components to focus the laser to a 20μm spot in the center of the electrophoretic channel.The housing for this module has been designed and assembled with the aligned optical components inside.

Willis, Peter A.↗
DOE OSTI2020

An Accelerated Creep Testing Program For Nickel Based Superalloys

In order to improve the energy production within the United States, new materials are developed with the goal of increased functionality. These materials are required to perform at extreme pressures and temperatures (up to and beyond 200MPa and 650â??) as well as be sustainable beyond 105 hours. Before developing these materials into components for power generation, mechanical testing is required to better understand the behavior of these materials at various loads and temperatures. The longest of these tests is the conventional creep test which is a real time test that can beyond 105 hours depending on service conditions. Hundreds of specimens must be tested before being approved for use in power generation, but it is extremely difficult to rapidly qualify when each material is required to exceed 105 hours making testing through conventional means unfeasible. While others have designed accelerated testing methods to help qualify materials, many of these experiments use an empirical approach that requires test data to fit already existing creep data. In this study, an accelerated creep test called the stepped isostress method (SSM) is then applied to wrought Inconel 718 (IN 718) specimens. A test matrix is designed using deformation mechanism maps, time-temperature-transformation diagrams, and time-temperature-precipitation diagrams, in order to ensure that microstructurally, the accelerated creep tests fail similarly to the conventional creep tests. The data from the stepped isostress method is then applied to the McVetty and Sin-hyperbolic (Sinh) constitutive models in order to generate a creep master curve. The results from the model fits are then compared to the conventional creep data done from experiments as well as from the NIMS database for Inconel 718. Optical microscopy and scanning electron microscopy are used to compare the evolution of the microstructure from the conventional creep and accelerated creep tests. It is found that using the Sinh model on the accelerated creep data provides reasonable creep rupture predictions when compared to the scatter band of creep tests. It was also observed that the microstructural evolution between the SSM experiments and creep tests were very similar in terms of the volume fraction of precipitates and phases.

Mach, Robert↗
NASA NTRS1979

Preliminary results of the mission profile life test of a 30 cm Hg bombardment thruster

The paper deals with some preliminary results of the Mission Profile Life Test planned to conduct a program of long-term test segments of 30-cm diameter thrusters and power processing units under computer control. Thruster performance data and other operational characteristics taken at various times during a test segment are compared and the results are evaluated in light of the life-timing mechanisms. Thruster control algorithms are also presented. The first test segment completed 2700 hr of a planned 4000 hr test with a J-series 30-cm thruster. The last 1600 hr used a functional model power processing unit (PPU) operated in vacuum. The thruster-PPU was controlled by a computer with software developed to control start-ups, throttling, and variety of off-normal conditions.

Bechtel, R. T.↗
NASA NTRS2012

The Damper Spring Unit of the Sentinel 1 Solar Array

The Damper Spring Unit (DSU, see Figure 1) has been designed to provide the damping required to control the deployment speed of the spring driven solar array deployment in an ARA Mk3 or FRED based Solar Array in situations where the standard application of a damper at the root-hinge is not feasible. The unit consists of four major parts: a main bracket, an eddy current damper, a spring unit, an actuation pulley which is coupled via Kevlar cables to a synchro-pulley of a hinge. The damper slows down the deployment speed and prevents deployment shocks at deployment completion. The spring unit includes 4 springs which overcome the resistances of the damper and the specific DSU control cable loop. This means it can be added to any spring driven deployment system without major modifications of that system. Engineering models of the Sentinel 1 solar array wing have been built to identify the deployment behavior, and to help to determine the optimal pulley ratios of the solar array and to finalize the DSU design. During the functional tests, the behavior proved to be very sensitive for the alignment of the DSU. This was therefore monitored carefully during the qualification program, especially prior to the TV cold testing. During TV "Cold" testing the measured retarding torque exceeded the max. required value: 284 N-mm versus the required 247 N-mm. Although this requirement was not met, the torque balance analysis shows that the 284 N-mm can be accepted, because the spring unit can provide 1.5 times more torque than required. Some functional tests of the DSU have been performed without the eddy current damper attached. It provided input data for the ADAMS solar array wing model. Simulation of the Sentinel-1 deployment (including DSU) in ADAMS allowed the actual wing deployment tests to be limited in both complexity and number of tests. The DSU for the Sentinel-1 solar array was successfully qualified and the flight models are in production.

Doejaaren, Frans↗
NASA NTRS1975

Comparison between reflectivity statistics at heights of 3 and 6 km and rain rate statistics at ground level

An experiment was conducted to study the relations between the empirical distribution functions of reflectivity at specified locations above the surface and the corresponding functions at the surface. A bistatic radar system was used to measure continuously the scattering cross section per unit volume at heights of 3 and 6 km. A frequency of 3.7 GHz was used in the tests. It was found that the distribution functions for reflectivity may significantly change with height at heights below the level of the melting layer.

Crane, R. K.↗
NASA NTRS1975

Shake test of rotor test apparatus with balance dampers in the 40 by 80 foot wind tunnel

A shake test was conducted to determine the dynamic characteristics of a rotor test apparatus on two strut systems with balance dampers in the Ames 40- by 80-ft wind tunnel. The rotor-off hub transfer function (acceleration per unit force as a function of frequency) was measured in the longitudinal and lateral directions, using a combination of broadband and discrete frequency excitation techniques. The dynamic data are summarized for the configurations tested, giving the following properties for each mode identified: the natural frequency, the hub response at resonance, the fixed system damping, the damping ratio, and the modal mass. The complete transfer functions are presented, and the detailed test results are included as an appendix.

Johnson, W.↗
DOE OSTI2026

Environmental Contributions to Proton Sharing in Protein Low-Barrier Hydrogen Bonds

Hydrogen bonds (H-bonds) are central to biomolecular structure and dynamics. Although H-bonds are typically characterized by well-defined proton positions, proton delocalization has been proposed to play a role in facilitating enzyme catalysis and allostery in some systems. Experimentally locating protons is difficult, hampering the study of proton mobility in H-bonds. We used neutron crystallography, atomic resolution X-ray bond length analysis, and large quantum mechanics/molecular mechanics-Born–Oppenheimer molecular dynamics (QM/MM-BOMD) simulations to comprehensively characterize the shared proton/deuteron in a Glu–Asp low-barrier hydrogen bond (LBHB) in the bacterial protein YajL that is a conventional H-bond in the homologous disease-associated human protein DJ-1. X-ray bond length analysis of protiated and perdeuterated DJ-1 and YajL shows no significant effect of deuteron substitution on these carboxylic acid-carboxylate H-bonds but does reveal an effect at the active site glutamic acid near a cysteine thiolate. Residues in an H-bonded network that might favor LBHB formation in YajL were interrogated by the mutation of homologous residues in DJ-1. A distal DJ-1 substitution increases proton delocalization in the Glu–Asp H-bond, demonstrating that mutations within extended H-bond networks can modulate proton transfer barriers in carboxylic acid-carboxylate H-bonds. In addition, proton mobility in the H-bond is correlated with dimer-spanning motions in the QM/MM-BOMD simulations of YajL and DJ-1. Our results show that proton delocalization can be tuned using combined bioinformatic, structural, and computational information, opening the possibility of using engineered proton delocalization as a probe of H-bonding environments and as a tool to test hypotheses about LBHB function.

Lin, Jiusheng [University of Nebraska, Lincoln, NE↗
NASA NTRS1990

NASA Shuttle Logistics Depot (NSLD) - The application of ATE

The concept of the NASA Shuttle Logistics Depot (NSLD) developed for the Space Shuttle Orbiter Program is described. The function of the NSLD at Cape Canaveral is to perform the acceptance and diagnostic testing of the Shuttle's space-rated line-replaceable units and shop-replaceable units (SRUs). The NSLD includes a comprehensive electronic automatic test station, program development stations, and assorted manufacturing support equipment (including thermal and vibration test equipment, special test equipment, and a card SRU test system). The depot activities also include the establishment of the functions for manufacturing of mechanical parts, soldering, welding, painting, clean room operation, procurement, and subcontract management.

Simpkins, Lorenz G.↗
NASA NTRS1976

Data management system DIU test system

An operational and functional description is given of the data management system. Descriptions are included for the test control unit, analog stimulus panel, discrete stimulus panel, and the precision source. The mechanical configuration is defined and illustrated to provide card and component location for modification or repair. The unit level interfaces are mirror images of the DIU interfaces and are described in the Final Technical Report for NASA-MSFC contract NAS8-29155.

Source record↗
NASA NTRS1981

Results of the Mission Profile Life Test first test segment - Thruster J1

A series of long term test segments of 30 cm diameter mercury bombardment thrusters is being conducted as the Mission Profile Life Test. The first 4000 hour segment has been completed with the J series thruster, J1. Thruster and power processing units were controlled by computer with software algorithms governing normal functions of startup, throttle, and shutdown as well as automatically handling a variety of off-normal conditions. Thruster operation includes a discussion of the test chronology describing notable events and their significance. Post-test examination provides insight into thruster lifetime. Results are consistent with mission requirements of 15,000 hours at 2A

James, E. L.↗
NASA NTRS2013

Countermeasures and Functional Testing in Head-Down Tilt Bed Rest (CFT 70)

This 70‐day bed rest campaign was comprised of 6 integrated studies and conducted at the NASA Flight Analogs Research Unit (FARU). The FARU is located at the University of Texas Medical Branch, Galveston, Texas and is a satellite unit of the Institute for Translational Sciences - Clinical Research Center. This presentation will describe the FARU, discuss the utility of the bed rest platform for use in these studies, and introduce the studies that participated in the CFT 70 bed rest campaign. Information in this presentation will serve as the background for subsequent talks from each individual study. Individual study presentations will discuss preliminary results from completed subjects. Studies included in CFT70 were:  Physiological Factors Contributing to Post Flight Changes in Functional Performance. J. Bloomberg, NASA  Integrated Resistance and Aerobic Training Study. L. Ploutz‐Snyder, USRA  Testosterone Supplementation as a Countermeasure Against Musculoskeletal losses during Space Exploration. R. Urban, University of Texas Medical Branch  Effects of Retronasal Smelling, Variety and Choice on Appetite & Satiety. J. Hunter, Cornell University  AD ASTRA: Automated Detection of Attitudes and States through Transaction Recordings Analysis. C. Miller, Smart Information Flow Technologies, LLC  Bed Rest as a Spaceflight Analog to Study Neuro‐cognitive Changes: Extent, Longevity, and Neural Bases. R. Seidler, University of Michigan

Cromwell, Ronita L.↗
NASA NTRS1998

Integrated Advanced Microwave Sounding Unit-A(AMSU-A). Performance Verification Report, METSAT Phase Locked Oscillator Assembly, P/N 1348360-1, S/N's F07 and F08

Two Flight Model AMSU-A Phase Locked Oscillators (PIN 1348360-1, S/N F07 and F08) have been tested per AES Test Procedure AE-26758 Rev. B, which include full functional testing, vibration testing, thermal testing, and AM/FM Noise testing. Both assemblies satisfactorily passed all performance requirements of the AE-26633 Product Specification. During the thermal cycling of both units, spurs developed 1 MHz from the carrier when the units were cold, and TARs were written to document the anomaly. The symptoms observed in both cases were consistent with inadequate tuning. The units were successfully re-tuned. In the case of F08, re-tuning required a design change which allowed a greater range of possible values for tuning resisters. Both units completed thermal cycling without further delay. The results of the required tests are presented in the following section as test data. As indicated on the test data sheets, all measured data passed all requirements.

Pines, D.↗
NASA NTRS1990

X-wing fly-by-wire vehicle management system

A complete, computer based, vehicle management system (VMS) for X-Wing aircraft using digital fly-by-wire technology controlling many subsystems and providing functions beyond the classical aircraft flight control system. The vehicle management system receives input signals from a multiplicity of sensors and provides commands to a large number of actuators controlling many subsystems. The VMS includes--segregating flight critical and mission critical factors and providing a greater level of back-up or redundancy for the former; centralizing the computation of functions utilized by several subsystems (e.g. air data, rotor speed, etc.); integrating the control of the flight control functions, the compressor control, the rotor conversion control, vibration alleviation by higher harmonic control, engine power anticipation and self-test, all in the same flight control computer (FCC) hardware units. The VMS uses equivalent redundancy techniques to attain quadruple equivalency levels; includes alternate modes of operation and recovery means to back-up any functions which fail; and uses back-up control software for software redundancy.

Fischer, Jr., William C.↗
NASA NTRS2021

The Effect of Transfer Line Length and Heat Rejection Temperature Distribution on the Thales Linear Pulse Tube (LPT) Cryocoolers

Four Thales LPT9310 and four Thales LPT9510 commercial off-the-shelf (COTS) cryocoolers were parametrically performance tested. The LPT9310 coolers had transfer lines of various lengths while the LPT9510 coolers all had the same transfer line geometry. The LPT9510 test results revealed unit-tounit thermodynamic performance variation, quantified the effect of compressor temperature on thermodynamic performance and quantified the heat flow distribution between the compressor and expander as a function of their temperature distribution. The LPT9310 test results revealed the optimal drive frequency as a function of transfer line length, quantified the effect of heat rejection temperature distribution on thermodynamic performance and enabled the development and verification of a thermodynamic performance prediction tool that accounted for cold tip temperature, heat lift, heat rejection temperature and transfer line length.

Rodriguez, J.I.↗
NASA NTRS1979

Aerodynamic characteristics at low Reynolds numbers of several heat-exchanger configurations for wind-tunnel use

In response to design requirements of the National Transonic Facility, aerodynamic tests were conducted to determine the pressure-drop, flow-uniformity, and turbulence characteristics of various heat-exchanger configurations as a function of Reynolds number. Data were obtained in air with an indraft flow apparatus operated at ambient temperature and pressure. The unit Reynolds number of the tests varied from about 0.06 x 10 to 6th power to about 1.3 x 10 to 6th power per meter. The test models were designed to represent segments of full-scale tube bundles and included bundles of round tubes with plate fins in both staggered and inline tube arrays, round tubes with spiral fins, elliptical tubes with plate fins, and an inline grouping of tubes with segmented fins.

Johnson, W. G., Jr.↗
NASA NTRS1989

On the development of the power sources for the Ulysses and Galileo missions

The technically challenging European Space Agency Ulysses mission to explore the polar regions of the Sun and the NASA Galileo mission to explore Jupiter have prompted the development of the most powerful radioisotope thermoelectric generator (RTG) yet built for space use. This RTG, which was designed to provide a minimum of 285 We at beginning of mission builds upon the successful thermoelectric technology developed for the RTGs now in operation on the Voyager 1 and 2 spacecraft. A total of four flight RTGs, one ground qualification RTG, and one Engineering Unit have been built and tested for the Galileo and Ulysses missions. The tests have included measurements of functional performance, vibration response, magnetic signature, mass properties, nuclear radiation, and vacuum performance. The RTGs are fully flight qualified for both missions and are ready for launch.

Gary L. Bennett↗