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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 NTRS2010

Recent Stirling Conversion Technology Developments and Operational Measurements at NASA Glenn Research Center

In support of the Advanced Stirling Radioisotope Generator (ASRG) project and other potential applications, NASA Glenn Research Center (GRC) has initiated convertor technology development efforts in the areas of acoustic emission, electromagnetic field mitigation, thermoacoustic Stirling conversion, and multiple-cylinder alpha arrangements of Stirling machines. The acoustic emission measurement effort was developed as a health monitoring metric for several Stirling convertors undergoing life testing. While accelerometers have been used in the past to monitor dynamic signature, the acoustic sensors were chosen to monitor cycle events, such gas bearing operation. Several electromagnetic interference (EMI) experiments were performed on a pair of Advanced Stirling Convertors (ASC). These tests demonstrated that a simple bucking coil was capable of reducing the alternating current (ac) magnetic field below the ASRG system specification. The thermoacoustic Stirling concept eliminates the displacer typically found in Stirling machines by making use of the pressure oscillations of a traveling acoustic wave. A 100 W-class thermoacoustic Stirling prototype manufactured by Northrop Grumman Space and Technology was received and tested. Another thermoacoustic prototype designed and fabricated by Sunpower, Inc., will be tested in the near future. A four cylinder free piston alpha prototype convertor was received from Sunpower, Inc. and has been tested at GRC. This hardware was used as a proof of concept to validate thermodynamic models and demonstrate stable operation of multiple-cylinder free-piston Stirling conversion. This paper will discuss each of these activities and the results they produced.

Oriti, Salvatore M.↗
NASA NTRS2012

Control Algorithms Charge Batteries Faster

On March 29, 2011, NASA s Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft beamed a milestone image to Earth: the first photo of Mercury taken from orbit around the solar system s innermost planet. (MESSENGER is also the first spacecraft to orbit Mercury.) Like most of NASA s deep space probes, MESSENGER is enabled by a complex power system that allows its science instruments and communications to function continuously as it travels millions of miles from Earth. "Typically, there isn't one particular power source that can support the entire mission," says Linda Taylor, electrical engineer in Glenn Research Center s Power Systems Analysis Branch. "If you have solar arrays and you are in orbit, at some point you re going to be in eclipse." Because of this, Taylor explains, spacecraft like MESSENGER feature hybrid power systems. MESSENGER is powered by a two-panel solar array coupled with a nickel hydrogen battery. The solar arrays provide energy to the probe and charge the battery; when the spacecraft s orbit carries it behind Mercury and out of the Sun s light, the spacecraft switches to battery power to continue operations. Typically, hybrid systems with multiple power inputs and a battery acting alternately as storage and a power source require multiple converters to handle the power flow between the devices, Taylor says. (Power converters change the qualities of electrical energy, such as from alternating current to direct current, or between different levels of voltage or frequency.) This contributes to a pair of major concerns for spacecraft design. "Weight and size are big drivers for any space application," Taylor says, noting that every pound added to a space vehicle incurs significant costs. For an innovative solution to managing power flows in a lightweight, cost-effective manner, NASA turned to a private industry partner.

Source record↗
NASA NTRS2013

Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments

Fission fragment direct energy conversion has been considered in the past for the purpose of increasing nuclear power plant efficiency and for advanced space propulsion. Since the fragments carry electric charge (typically in the order of 20 e) and have 100 MeV-range kinetic energy, techniques utilizing very high-voltage DC electrodes have been considered. This study is focused on a different approach: the kinetic energy of the charged fission fragments is converted into alternating current by means of a traveling wave coupling scheme (Traveling Wave Direct Energy Converter, TWDEC), thereby not requiring the utilization of high voltage technology. A preliminary feasibility analysis of the concept is introduced based on a conceptual level study and on a particle simulation model of the beam dynamics.

Tarditi, A. G.↗
NASA NTRS2013

A DC Transformer

A component level dc transformer is described in which no alternating currents or voltages are present. It operates by combining features of a homopolar motor and a homopolar generator, both de devices, such that the output voltage of a de power supply can be stepped up (or down) with a corresponding step down (or up) in current. The basic theory for this device is developed, performance predictions are made, and the results from a small prototype are presented. Based on demonstrated technology in the literature, this de transformer should be scalable to low megawatt levels, but it is more suited to high current than high voltage applications. Significant development would be required before it could achieve the kilovolt levels needed for de power transmission.

Youngquist, Robert C.↗
NASA NTRS2013

Innovations for ISS Plug-In Plan (IPiP) Operations

Limited resources and increasing requirements will continue to influence decisions on ISS. The ISS Plug-In Plan (IPiP) supports power and data for utilization, systems, and daily operations through the Electrical Power System (EPS) Secondary Power/Data Subsystem. Given the fluid launch schedule, the focus of the Plug-In Plan has evolved to anticipate future requirements by judicious development and delivery of power supplies, power strips, Alternating Current (AC) power inverters, along with innovative deployment strategies. A partnership of ISS Program Office, Engineering Directorate, Mission Operations, and International Partners poses unique solutions with existing on-board equipment and resources.

Moore, Kevin D.↗
NASA NTRS2013

Testing of the Advanced Stirling Radioisotope Generator Engineering Unit at NASA Glenn Research Center

The Advanced Stirling Radioisotope Generator (ASRG) is a high-efficiency generator being developed for potential use on a Discovery 12 space mission. Lockheed Martin designed and fabricated the ASRG Engineering Unit (EU) under contract to the Department of Energy. This unit was delivered to NASA Glenn Research Center in 2008 and has been undergoing extended operation testing to generate long-term performance data for an integrated system. It has also been used for tests to characterize generator operation while varying control parameters and system inputs, both when controlled with an alternating current (AC) bus and with a digital controller. The ASRG EU currently has over 27,000 hours of operation. This paper summarizes all of the tests that have been conducted on the ASRG EU over the past 3 years and provides an overview of the test results and what was learned.

Lewandowski, Edward J.↗
NASA NTRS2014

Direct Energy Conversion for Nuclear Propulsion at Low Specific Mass

The project will continue the FY13 JSC IR&D (October-2012 to September-2013) effort in Travelling Wave Direct Energy Conversion (TWDEC) in order to demonstrate its potential as the core of a high potential, game-changing, in-space propulsion technology. The TWDEC concept converts particle beam energy into radio frequency (RF) alternating current electrical power, such as can be used to heat the propellant in a plasma thruster. In a more advanced concept (explored in the Phase 1 NIAC project), the TWDEC could also be utilized to condition the particle beam such that it may transfer directed kinetic energy to a target propellant plasma for the purpose of increasing thrust and optimizing the specific impulse. The overall scope of the FY13 first-year effort was to build on both the 2012 Phase 1 NIAC research and the analysis and test results produced by Japanese researchers over the past twenty years to assess the potential for spacecraft propulsion applications. The primary objective of the FY13 effort was to create particle-in-cell computer simulations of a TWDEC. Other objectives included construction of a breadboard TWDEC test article, preliminary test calibration of the simulations, and construction of first order power system models to feed into mission architecture analyses with COPERNICUS tools. Due to funding cuts resulting from the FY13 sequestration, only the computer simulations and assembly of the breadboard test article were completed. The simulations, however, are of unprecedented flexibility and precision and were presented at the 2013 AIAA Joint Propulsion Conference. Also, the assembled test article will provide an ion current density two orders of magnitude above that available in previous Japanese experiments, thus enabling the first direct measurements of power generation from a TWDEC for FY14. The proposed FY14 effort will use the test article for experimental validation of the computer simulations and thus complete to a greater fidelity the mission analysis products originally conceived for FY13.

Scott, John H.↗
NASA NTRS2011

Semi-Supervised Novelty Detection with Adaptive Eigenbases, and Application to Radio Transients

We present a semi-supervised online method for novelty detection and evaluate its performance for radio astronomy time series data. Our approach uses adaptive eigenbases to combine 1) prior knowledge about uninteresting signals with 2) online estimation of the current data properties to enable highly sensitive and precise detection of novel signals. We apply the method to the problem of detecting fast transient radio anomalies and compare it to current alternative algorithms. Tests based on observations from the Parkes Multibeam Survey show both effective detection of interesting rare events and robustness to known false alarm anomalies.

anomaly detection↗
NASA NTRS2015

Fine-Filament MgB2 Superconductor Wire

Hyper Tech Research, Inc., has developed fine-filament magnesium diboride (MgB2) superconductor wire for motors and generators used in turboelectric aircraft propulsion systems. In Phase I of the project, Hyper Tech demonstrated that MgB2 multifilament wires (<10 micrometers) could reduce alternating current (AC) losses that occur due to hysteresis, eddy currents, and coupling losses. The company refined a manufacturing method that incorporates a magnesium-infiltration process and provides a tenfold enhancement in critical current density over wire made by a conventional method involving magnesium-boron powder mixtures. Hyper Tech also improved its wire-drawing capability to fabricate fine multifilament strands. In Phase II, the company developed, manufactured, and tested the wire for superconductor and engineering current density and AC losses. Hyper Tech also fabricated MgB2 rotor coil packs for a superconducting generator. The ultimate goal is to enable low-cost, round, lightweight, low-AC-loss superconductors for motor and generator stator coils operating at 25 K in next-generation turboelectric aircraft propulsion systems.

Cantu, Sherrie↗
NASA NTRS2017

Get the Power You Need, When and Where You Need It Aboard the International Space Station (ISS) Using the ISS Plug-In Plan (IPiP) Requirement Request Process

Trying to get your experiment aboard ISS? You likely will need power. Many enditem providers do. ISS Plug-In Plan (IPiP) supports power and data for science, Payloads (or Utilization), vehicle systems, and daily operations through the Electrical Power System (EPS) Secondary Power/Data Subsystem. Yet limited resources and increasing requirements continue to influence decisions on deployment of ISS end items. Given the fluid launch schedule and the rapidly- increasing number of end item providers requiring power support, the focus of the Plug-In Plan has evolved from a simple FIFO recommendation to provide power to end item users, to anticipating future requirements by judicious development and delivery of support equipment (cables, power supplies, power strips, and alternating current (AC) power inverters), employing innovative deployment strategies, and collaborating on end item development. This paper describes the evolution of the ISS Program Office, Engineering Directorate, Flight Operations Directorate (FOD), International Partners and the end item provider relationship and how collaboration successfully leverages unique requirements with limited on- board equipment and resources, tools and processes which result in more agile integration, and describes the process designed for the new ISS end item provider to assure that their power requirements will be met.

Moore, Kevin D.↗
NASA NTRS2018

Systems and Methods for Ejection of Ions from an Ion Trap

The invention generally relates to systems and methods for ejection of ions from an ion trap. In certain embodiments, systems and methods of the invention sum two different frequency signals into a single summed signal that is applied to an ion trap. In other embodiments, an amplitude of a single frequency signal is modulated as the single frequency signal is being applied to the ion trap. In other embodiments, a first alternating current (AC) signal is applied to an ion trap that varies as a function of time, while a constant radio frequency (RF) signal is applied to the ion trap.

Cooks, Robert Graham↗
NASA NTRS2020

Control Demonstration of Multiple Doubly Fed Induction Motors for Hybrid Electric Propulsion

The Convergent Aeronautics Solutions (CAS) High Voltage Hybrid Electric Propulsion (HVHEP) activity was formulated to support the move into future hybrid-electric aircraft. The goal of this high-voltage activity is to develop a new alternating current (AC) power architecture to support the needs of higher efficiency and lower emissions aircraft. This proposed architecture will adopt the use of the doubly fed induction machine (DFIM) for propulsor drive motor application. The DFIMs are attractive for several reasons, including but not limited to, the ability to self-start, the ability to operate subsynchronously and supersynchronously, and the requirement for power converters rated at a fraction of those required in a corresponding direct current system, dependent on the range of operation. The focus of this report is based specifically on the presentation and analysis of a novel strategy, which allows for independent operation of multiple doubly fed induction motors from a common AC bus

David J Sadey↗
NASA NTRSDate not supplied

The Impact of Transition-Edge Sensor Design on Internal Thermal Fluctuation Noise and Thermal Conductance

The measured noise in transition-edge sensor (TES) microcalorimeters with a Mo/Au bilayer has been shown to have a significant contribution from internal thermal fluctuation noise (ITFN) between the absorber and the TES. Previous measurements showed the relevant thermal link leading to the noise was the thermal conductance of the TES bilayer, and ITFN has been shown to correlate with the sheet resistance of the TES. As a result, ITFN is particularly significant in devices with a large bilayer sheet resistance. However, because of more favorable transition shapes, such high resistance devices have recently been shown to be preferable under alternating current bias, which is required for the frequency division multiplexed readout baselined for the X-ray Integral Field Unit (X-IFU) instrument on the ATHENA satellite. Therefore, it is important to investigate how else to minimize the ITFN beyond changes to the sheet resistance. In this presentation, we will discuss our investigation of how changes to the TES design can affect ITFN for a fixed sheet resistance. We will present how ITFN is altered by changes to the aspect ratio of the TES, the addition of normal metal banks parallel to the TES current direction, and the size and position of the connections between the absorber and the TES. We will also discuss how these design changes impact the superconducting transition shape, and the thermal conductance from the TES to the thermal bath. These results may provide routes for further improvements of TES performance, and a deeper understanding of the physics of the thermal network in a TES microcalorimeter.

Nicholas A Wakeham↗
NASA NTRS2020

Progress in the Development of Frequency-Domain Multiplexing for the X-ray Integral Field Unit on Board the Athena Mission

Frequency-domain multiplexing (FDM) is the baseline readout system for the X-ray Integral Field Unit on board the Athena mission. Under the FDM scheme, TESs are coupled to a passive LC filter and biased with alternating current (AC bias) at MHz frequencies. Using high-quality-factor LC filters and room-temperature electronics developed at SRON and low-noise two-stage SQUID amplifiers provided by VTT, we have recently demonstrated good performance with the FDM readout of Mo/Au TES calorimeters with Au/Bi absorbers. We have achieved a performance requested for the demonstration model with the single-pixel AC bias ( ΔE = 1.8 eV ) and nine-pixel multiplexing ( ΔE = 2.6 eV ) modes. We have also demonstrated 14-pixel multiplexing with an average energy resolution of 3.3 eV, which is limited by nonfundamental issues related to FDM readout in our laboratory setup.

H. Akamatsu↗
NASA NTRSDate not supplied

A Study on Effect of Tuning Capacitor in Dynamic Radioisotope Power Systems

This study presents the effect of tuning capacitors on the power factor and power output of a gas spring-based free-piston Stirling convertor—Advanced Stirling convertor—when the convertor runs on a forced-oscillation type controller. More specifically, this paper studies how off-nominal tuning capacitance values affects the Stirling convertor in terms of the piston stability and electrical power output, when the convertor is operated by forced-oscillation type controller, such as an alternating current bus controller, and operating conditions of the convertor are unchanged. It has been widely known that tuning capacitors are important circuit components to stabilize the piston amplitude of the free-piston Stirling convertors and correct the power factor for high electrical power output. Recent modeling analysis conducted by NASA Glenn Research Center, however, suggests that while the stability of the convertor is affected by the tuning capacitor value, the power factor and the electrical power output are not affected by the tuning capacitor value, as long as the convertor is controlled by a forced-oscillation controller and the convertor operating conditions, such as the hot-end/cold-end temperatures, piston amplitude, and operating frequency, are unchanged. To verify the modeling analysis results, a test setup is devised where the convertor is controlled by a forced-oscillation controller and the piston amplitude, hot-end temperature, and charge pressure are controlled to 4mm, 760˚C, and 485psig, respectively, while the tuning capacitor value is changed from its nominal value, 840μF to 1040μF and 1240μF. Furthermore, the vibration test results of the same convertor with the three tuning capacitor values are also presented in this paper to show the effect of the tuning capacitor value on the convertor stability. The test results suggest that when the convertor is controlled by a forced-oscillation, the tuning capacitor value determines the convertor stability but not the power factor nor electrical power output. Therefore, the tuning capacitance value in forced-oscillation controllers should be determined based on the convertor stability, system mass, and volume.

Free-Piston Stirling Convertor Controller↗
NASA NTRS2023

Assessment of Gaseous Helium Cooling in a Superconducting Coil Test Rig

An experimental rig was designed and constructed at the NASA Glenn Research Center to measure the alternating current (AC) losses of round, multifilament, superconducting (SC), magnesium diboride (MgB2) wire in the temperature range from 20 to 30 K. The rig resembles a permanent magnet (PM) motor with the stator windings omitted. Experiment packs containing the superconductor samples will be placed in the annular space between the rotor and the stator back iron. The original plan was to measure the AC losses by calorimetry using nonboiling liquid hydrogen as the cooling fluid. The present plan is to use helium gas (GHe) under a few bar pressure instead. This report summarizes the calculations that indicate that reasonable results can be obtained, even though the mass density of the GHe will be only a fraction of that of liquid hydrogen. It is necessary to show that the heat transfer coefficient from SC wire to GHe can be high enough, that the temperature rise of the He between the experiment inlet and outlet can be small enough, and that sufficient He flow can be driven by a commercially available He fan. Both straight wire samples to validate loss models and coils to simulate motor stator coils can be tested in the rig. The lowest superconductor temperature that is feasible to reach in the rig is estimated. The temperature range available for samples will be wider with the gaseous He system than it would have been with liquid hydrogen.

supeconductors↗
NASA NTRS2004

Construction and Analysis of Electronic circuits

The Aviation Environmental Technical Branch produces many various types of aeronautical research that benefits the NASA mission for space exploration and in turn, produces new technology for our nation. One of the present goals of the Aviation Environmental Technical Branch is to create better engines for airplanes by testing supersonic jet propulsion and safe fuel combustion. During the summer of 2004, I was hired by Vincent Sattenvhite Chief executive of the Aviation Environmental Technical Branch to Assist Yves Lamothe with a fuel igniter circuit. Yves Lamothe is an electrical engineer who is currently working on safe fuel combustion testing. This testing is planned to determine the minimum ignition energy for fuel and air vapors of current and alternative fuels under simulated flight conditions. An air temperature bath will provide simulated flight profile temperatures and the heat fluxes to the test chamber. I was assigned with Yves to help complete the igniter circuit which consists of a 36k voltage supply an oscilloscope, and a high voltage transistor switch. During my tenure in the L.E.C.I.R.P. program I studied the basics of electricity and circuitry along with two other projects that I completed. In the beginning of my internship, I devote all of my time to research the aspects of circuitry so that I would be prepared for the projects that I was assigned to do. I read about lessons on; the basic physical concepts of electronics, Electrical units, Basic dc circuits, direct current circuit analysis, resistance and cell batteries, various types of magnetism , Alternating current basics, inductance, and power supplies. I received work sheets and math equations from my Mentor so that I could be able to apply these concepts into my work. After I complete my studies, I went on to construct a LED chaser circuit which displays a series of light patterns using a 555 timer. I incorporated a switch and motion detector into the circuit to create basic alarm system. This project challenged my ability to interpret a schematic and expand it. While I was still completing the LED chaser circuit I Also was given A Basic Stamp Toddler Robot to build and program. The Toddler robot can walk in 36 various styles using advanced robotics. I used many different programs to create movement and direction of the robot. Also the Toddler can use infrared vision to sense objects. This enables the robot to maneuver indefinitely without running into objects. During my tenure at the NASA Glen Research Center I definite utilized the NASA mission to educate. I learned valuable information to help in my up coming year as a freshman in college.

Thomas, Ashley N.↗