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At least 73 records · Page 4

Validation & Verification of Electrical Components B2 Test Facility

The research focus of this project is to assist in the closure of Measurement, Monitoring and Control System (MMCS) and other electrical requirements in support of the B2 Space Launch System (SLS) Core Stage Green Run Test Project. Alongside this goal I am to understand project management tools to analyze and control activities/tasks associated with those items. The project I am working on will assist electrical engineers in developing and or identifying closure rationale for the MMCS and electrical requirements. Also as serving the role of a training project manager, I am to develop and maintain a method for tracking progress with estimate completion dates specifically identifying those items during this performance window. The methods I used in order to perform the research consisted of worddocuments, excel sheets, and pdf documents needed for review. For example, documents consisted of: a SLS Core Stage Green Run Facility Requirement Document (FRD) identifying the SSC MMCS and electrical requirements, a Stage Controller to SSC Interface Control Document (ICD) identifying the SSC requirements, and the B2 SLS Core Stage Green Run Test project System Requirements Document (SRD) which identifies the MMCS and electrical requirements. The files were sent to me by both mentors, Mr. Barry Robinson and Ms. Dawn Davis. Overall, the review process for the word documents and excel spreadsheets proved to be successful. The data for the electrical components were accurate and were consistent with the original recorded data. However, the consistency with the pdf documents did not follow up all the way. Attention to this mistake was made and further revisions were done in order for the data to agree with each other. Furthermore, an itinerary was designed using Microsoft Outlook in order to track progress with estimated completion dates. This project contributes to NASA/Center Missions and Goals through the Waterfall Model. The Waterfall Model is a linear system used for engineering design. In the Waterfall Model, the fourth step is Verification and Validation. This involves installation, testing, and debugging of the B2 SLS Core Stage electrical components. For the SLS Core Stage Green Run Test Project, each requirement contained in this approved requirements set will have at least one Verification Item (VI) assigned to it. During the design phase, VIs will mostly consist of Analysis or Inspection types. Design phase VIs and closure information will be documented in Dynamics Data Management System (DDMS) in the form of analysis reports and design documentation.

Bastian, Tyler↗

Remote control circuit breaker evaluation testing

Engineering evaluation tests were performed on several models/types of remote control circuit breakers marketed in an attempt to gain some insight into their potential suitability for use on the space shuttle vehicle. Tests included the measurement of several electrical and operational performance parameters under laboratory ambient, space simulation, acceleration and vibration environmental conditions.

Bemko, L. M.↗

Four-terminal electrical testing device

The invention relates to a four-terminal electrical connector device for testing and measuring unknown resistances of initiators used for starting pyrotechnic events aboard the space shuttle. The testing device minimizes contact resistance degradation effects and so improves the reliability of resistance measurements taken with the device. Separate and independent voltage sensing and current supply circuits each include a pair of socket contacts for mating engagement with the pins of the initiator. The unknown resistance that is measured by the device is the resistance of the bridgewire of the initiator which is required to be between 0.95 and 1.15 ohms.

Robinson, Robert L.↗

Characterization of an Electroanalytical Instrument Suite Searching for Water and Life on Mars

Seeking the existence of life on other planets is an essential part of NASA's research. Our terrestrial experience suggests that water is a mandatory resource for life to exist and thrive. However, instruments capable of detecting water at the levels likely to be present on Mars are lacking. This project tests the possibility of using electrical measurements of soils, at variable frequencies, as a water detector. Generally, the electrical resistance of soils can be described as a combination of resistance and capacitance, which can be described by a vector including a magnitude and (phase) angle. By specifically studying the impedance measurements and phase angles of different types of soil, spiked with varying concentrations of dissolved ions, measurements can be taken to provide an idea of the behavior of dry Martian soils. The presentation will describe the experimental technique, apparatus and procedures, as well as results conducted to calibrate the instrument and to establish sample preparation protocols.

Bostic, Heidi E.↗

Wind 2H2 Project (CRADA Final Report)

The Xcel-NREL Wind Electrolysis R&D Project is designed to gain knowledge and insight about producing hydrogen from electricity for use as a vehicle fuel and as a “stored wind”. The project will analyze producing hydrogen directly from wind as well as from the electric grid. In addition, it will look at storing hydrogen and then using it to put electricity back onto the grid. Modifications were made to the original scope to also include electric vehicles integration with the electric grid. This report addresses Task 8 portion of the CRADA, focused on testing and measuring the attributes of plug-in electric vehicles.

33 ADVANCED PROPULSION SYSTEMS↗

A 10-Gb/s Driver/Receiver ASIC and Optical Modules for Particle Physics Experiments

We present the design and test results of a Drivers and Limiting AmplifierS ASIC operating at 10 Gbps (DLAS10) and three Miniature Optical Transmitter/Receiver/Transceiver modules (MTx+, MRx+, and MTRx+) based on DLAS10. DLAS10 can drive two Transmitter Optical Sub-Assemblies (TOSAs) of Vertical Cavity Surface Emitting Lasers (VCSELs), receive the signals from two Receiver Optical Sub-Assemblies (ROSAs) that have no embedded limiting amplifiers, or drive a VCSEL TOSA and receive the signal from a ROSA, respectively. Each channel of DLAS10 consists of an input Continuous Time Linear Equalizer (CTLE), a four-stage limiting amplifier (LA), and an output driver. The LA amplifies the signals of variable levels to a stable swing. The output driver drives VCSELs or impedance-controlled traces. DLAS10 is fabricated in a 65 nm CMOS technology. The die is 1 mm x 1 mm. DLAS10 is packaged in a 4 mm x 4 mm 24-pin quad-flat no-leads (QFN) package. DLAS10 has been tested in MTx+, MRx+, and MTRx+ modules. Both measured optical and electrical eye diagrams pass the 10 Gbps eye mask test. Furthermore, the input electrical sensitivity is 40 mVp-p, while the input optical sensitivity is -12 dBm. The total jitter of MRx+ is 29 ps (P-P) with a random jitter of 1.6 ps (RMS) and a deterministic jitter of 9.9 ps. Each MTx+/MTRx+ module consumes 82 mW/ch and 174 mW/ch, respectively.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Guarded Hot Cylinder Apparatus for Characterization of Thermal Insulation Systems and Materials at Liquid Hydrogen Temperatures

As interest in liquid hydrogen (LH2) continues to grow within the energy and mobility sectors, so does the demand for testing capabilities at deep cryogenics temperatures. However, cost-, complexity-, and safety-related challenges associated with handling LH2 effectively limit the landscape of possible options. As an alternative, LH2 temperatures can be accessed via a helium-based cryogenic refrigerator, or “cryocooler”. Recently, NASA and its partners CB&I and Shell began the development of a cryocooler-based calorimeter to characterize the thermal performance of insulations and other materials down to 20 K. Deemed the Guarded Hot Cylinder (GHC), the apparatus utilizes a small vacuum chamber in conjunction with a GM cryocooler and trim heater to control the cold boundary temperature. A sealed, cylindrical copper cup bolts to the cryocooler and houses the material specimen, with an internal, cylindrical test heater assembly to maintain the warm boundary. The steady-state heat load, traveling radially through the specimen, is measured via the electrical input power to the test heater and then used to evaluate the material’s absolute thermal performance. Initial checkout and validation of the GHC using a common bulk-fill insulation material showed close agreement with published data from standardized LN2 boiloff calorimetry testing. The instrument is now considered a lab standard, with the goal of incorporating it into the ASTM C1774 standard in the future, and it is in continuous use, examining insulation materials for next-generation LH2 applications.

Swanger, Adam (ORCID:000000021487592X)↗

Application of a Virtual Reactivity Feedback Control Loop in Non-Nuclear Testing of a Fast Spectrum Reactor

For a compact, fast-spectrum reactor, reactivity feedback is dominated by core deformation at elevated temperature. Given the use of accurate deformation measurement techniques, it is possible to simulate nuclear feedback in non-nuclear electrically heated reactor tests. Implementation of simulated reactivity feedback in response to measured deflection is being tested at the NASA Marshall Space Flight Center Early Flight Fission Test Facility (EFF-TF). During tests of the SAFE-100 reactor prototype, core deflection was monitored using a high resolution camera. "virtual" reactivity feedback was accomplished by applying the results of Monte Carlo calculations (MCNPX) to core deflection measurements; the computational analysis was used to establish the reactivity worth of van'ous core deformations. The power delivered to the SAFE-100 prototype was then dusted accordingly via kinetics calculations, The work presented in this paper will demonstrate virtual reactivity feedback as core power was increased from 1 kilowatt(sub t), to 10 kilowatts(sub t), held approximately constant at 10 kilowatts (sub t), and then allowed to decrease based on the negative thermal reactivity coefficient.

Bragg-Sitton, Shannon M.↗

Static Measurements on HTS Coils of Fully Superconducting AC Electric Machines for Aircraft Electric Propulsion System

The NASA Glenn Research Center (GRC) has been developing the high efficiency and high-power density superconducting (SC) electric machines in full support of electrified aircraft propulsion (EAP) systems for a future electric aircraft. A SC coil test rig has been designed and built to perform static and AC measurements on BSCCO, (RE)BCO, and YBCO high temperature superconducting (HTS) wire and coils at liquid nitrogen (LN2) temperature. In this paper, DC measurements on five SC coil configurations of various geometry in zero external magnetic field are measured to develop good measurement technique and to determine the critical current (Ic) and the sharpness (n value) of the super-to-normal transition. Also, standard procedures for coil design, fabrication, coil mounting, micro-volt measurement, cryogenic testing, current control, and data acquisition technique were established. Experimentally measured critical currents are compared with theoretical predicted values based on an electric-field criterion (Ec). Data here are essential to quantify the SC electric machine operation limits where the SC begins to exhibit non-zero resistance. All test data will be utilized to assess the feasibility of using HTS coils for the fully superconducting AC electric machine development for an aircraft electric propulsion system.

superconducting motor↗

Standard Practices for Usage of Inductive Magnetic Field Probes with Application to Electric Propulsion Testing

Inductive magnetic field probes (also known as B-dot probes and sometimes as B-probes or magnetic probes) are useful for performing measurements in electric space thrusters and various plasma accelerator applications where a time-varying magnetic field is present. Magnetic field probes have proven to be a mainstay in diagnosing plasma thrusters where changes occur rapidly with respect to time, providing the means to measure the magnetic fields produced by time-varying currents and even an indirect measure of the plasma current density through the application of Ampère's law. Examples of applications where this measurement technique has been employed include pulsed plasma thrusters and quasi-steady magnetoplasmadynamic thrusters. The Electric Propulsion Technical Committee (EPTC) of the American Institute of Aeronautics and Astronautics (AIAA) was asked to assemble a Committee on Standards (CoS) for Electric Propulsion Testing. The assembled CoS was tasked with developing Standards and Recommended Practices for various diagnostic techniques used in the evaluation of plasma thrusters. These include measurements that can yield either global information related to a thruster and its performance or detailed, local data related to the specific physical processes occurring in the plasma. This paper presents a summary of the standard, describing the preferred methods for fabrication, calibration, and usage of inductive magnetic field probes for use in diagnosing plasma thrusters. Inductive magnetic field probes (also called B-dot probes throughout this document) are commonly used in electric propulsion (EP) research and testing to measure unsteady magnetic fields produced by time-varying currents. The B-dot probe is relatively simple in construction, and requires minimal cost, making it a low-cost technique that is readily accessible to most researchers. While relatively simple, the design of a B-dot probe is not trivial and there are many opportunities for errors in probe construction, calibration, and usage, and in the post-processing of data that is produced by the probe. There are typically several ways in which each of these steps can be approached, and different applications may require more or less vigorous attention to various issues.

Polzin, Kurt A.↗

TEAMER – Enhanced Flow Measurement for Aquantis Tidal Turbine Test

The AQ10 is a floating, two-bladed, passive yawing tidal turbine developed by Aquantis that has a 10-meterrotor diameter, 160 kW rating, and employs reliable off-the-shelf powertrain and power conversion hardware. Aquantis is planning on-water turbine power performance and loads (blade loading and thrust)testing, where the turbine will be pushed through still water up to 4 knots and placed in a ‘station keeping’ tow in a tidal race up to its rated speed. On-water testing will be conducted using vessels and floating platforms on the sea surface to improve ease of testing and reduce disturbance to the environment. In this TEAMER project, Pacific Northwest National Laboratory (PNNL) will conduct water velocity and turbulence measurements in front of the turbine during on-water testing using acoustic Doppler instrumentation. By measuring both the tidal current flowing past the turbine and the resulting electrical power output, test results will provide a power curve (power vs flow speed) for the turbine up to rated power. Measurements of turbulence and velocity shear in front of the rotor will also provide information to assess the structural response of the rotor blades. With this analysis, Aquantis can use the performance and loads data to validate Tidal Bladed and OpenFAST simulations of the measured operating conditions. Measuring the power performance of a prototype turbine is a valuable step to improving device development and conducting a complete power performance assessment to IEC/TS 62600-200 standards in the future.

16 TIDAL AND WAVE POWER↗

Early Burn-In Parasitic Conduction in 500 °C Durable SiC JFET ICs

All prior reports of long-term 500 °C operation of SiC JFET-R ICs have noted the existence of an initial “burn-in” period of changes in measured electrical characteristics for the first few hundred hours oven-testing. This work reports measurements of “burn-in parasitic MOSFET conduction” that can substantially impact the performance of some circuits during initial heat-up of JFET ICs, but then subsequently disappears after a few hours of operation at 500 °C. The behavior appears generally consistent with the known MOS phenomenon of bias-temperature driven redistribution of mobile ionic contamination. Approaches for further mitigating this initial burn-in conduction mechanism are discussed.

silicon carbide↗

Early Burn-In Parasitic Conduction in 500 °C Durable SiC JFET ICs

All prior reports of long-term 500 °C operation of SiC JFET-R ICs have noted the existence of an initial “burn-in” period of changes in measured electrical characteristics for the first few hundred hours oven-testing. This work reports measurements of “burn-in parasitic MOSFET conduction” that can substantially impact the performance of some circuits during initial heat-up of JFET ICs, but then subsequently disappears after a few hours of operation at 500 °C.

silicon carbide↗

Measurement of volt/meter vertical electric fields in the middle atmosphere

A test flight for a series of middle atmosphere electrodynamics rockets was launched from Wallops Island, Virginia, at 7:18 EST on July 31, 1980. The mother-daughter configuration contained a three axis symmetric double probe electric field instrument and a blunt probe on the daughter payload, and a Gerdien condenser and a single axis (vertical) asymmetric double probe electric field instrument on the mother payload. The payloads reached an apogee of 111 km, and data were gathered from all instruments on the downleg. A downward vertical electric field with a maximum amplitude of about 4 V/m was observed in a layer between about 57 and 67 km. The integrated potential across this layer was approximately 20 kV. Conductivity measurements indicated that free electrons were absent from the region of large electric fields; however, the decrease in conductivity was insufficient to maintain vertical current continuity through the layer. These results establish the existence of large mesospheric electric fields, supporting previous results from single axis measurements.

Maynard, N. C.↗

Hall Thruster Plume Measurements On-Board the Russian Express Satellites

The operation of North-South and East-West station-keeping Hall thruster propulsion systems on-board two Russian Express-A geosynchronous communication satellites were investigated through a collaborative effort with the manufacturer of the spacecraft. Over 435 firings of 16 different thrusters with a cumulative run time of over 550 hr were reported with no thruster failures. Momentum transfer due to plume impingement was evaluated based on reductions in the effective thrust of the SPT-100 thrusters and induced disturbance torques determined based on attitude control system data and range data. Hall thruster plasma plume effects on the transmission of C-band and Ku-band communication signals were shown to be negligible. On-orbit ion current density measurements were made and subsequently compared to predictions and ground test data. Ion energy, total pressure, and electric field strength measurements were also measured on-orbit. The effect of Hall thruster operation on solar array performance over several months was investigated. A subset of these data is presented.

Manzella, David↗

Acoustic Measurements for the Moog S-250 Vehicle in Hover

Acoustic measurements for hover conditions and electric motor noise tests were conducted for the Moog S-250 research aircraft, an RPM-controlled quadcopter-type Urban Air Mobility (UAM) vehicle with four sets of contra-rotating rotors. The objectives of the study included determining the minimum far-field distance, the noise characteristics, and the potential for electric motor noise to contribute to the overall acoustic radiation for the full-scale UAM vehicle. Acoustic data for full-scale aircraft are critical for determining the impact of these vehicles on the surrounding communities. The results showed the far-field was reached by 8.1 single rotor diameters or 2.7 vehicle diameters as defined by the longest tip-to-tip rotor dimension for the vehicle. In hover, the peak acoustic radiation occurred at a declination angle of roughly 29° below the midplane between the upper and lower rotors. The lowest acoustic levels occurred below the aircraft. The electric motor noise studies, conducted with the rotors removed, showed motor noise radiated at shaft orders 17 – 20, whereas rotor noise covered the range of 2 – 24 shaft orders. There was some evidence that electric motor noise was present in previous ground run-up measurements.

Urban Air Mobility Noise↗