Results for “Accelerator Applications” — Page 35

NASA NTRS2005

Reliability of Electronics for Cryogenic Space Applications Being Assessed

Many future NASA missions will require electronic parts and circuits that can operate reliably and efficiently in extreme temperature environments below typical device specification temperatures. These missions include the Mars Exploration Laboratory, the James Webb Space Telescope, the Europa Orbiter, surface rovers, and deep-space probes. In addition to NASA, the aerospace and commercial sectors require cryogenic electronics in applications that include advanced satellites, military hardware, medical instrumentation, magnetic levitation, superconducting energy management and distribution, particle confinement and acceleration, and arctic missions. Besides surviving hostile space environments, electronics capable of low-temperature operation would enhance circuit performance, improve system reliability, extend lifetime, and reduce development and launch costs. In addition, cryogenic electronics are expected to result in more efficient systems than those at room temperature.

Patterson, Richard L.↗

NASA NTRS2023

Transient Optimization for the Betterment of Turbine Electrified Energy Management

Gas turbine engine transients are associated with degraded compressor operability, which must be addressed by the engine control system and accounted for in the engine design. Failure to do so may result in events such as compressor stall/surge and combustor blow out. Transient operability concerns constrain the engine design and can result in sacrifices of efficiency and/or thrust responsiveness. The traditional approach to transient operability management is control logic that limits the fuel flow command. A companion paper presents a strategy for optimizing the transient fuel flow control logic taking into consideration transient operability and thrust responsiveness. The study covered here extends this idea to an electrified gas turbine engine that employs a power/energy management concept known as Turbine Electrified Energy Management (TEEM). TEEM uses an electric power system interfaced with the engine (hence the term ‘electrified gas turbine engine’) to further improve transient operability and alleviate associated design constraints. There can be costs associated with implementing TEEM in terms of power and energy requirements that impact the size of the electrical power system. However, the results of this study show that through optimization of the transient limit logic, power and energy requirements needed to implement TEEM can be significantly reduced. Among the conclusions that can be drawn from the results of the illustrative application covered herein are: (1) there is a reduction in the electric machine power requirement to manage operability during accelerations by 200 to 400 hp, and (2) power transfer from the low pressure spool (LPS) to the high pressure spool (HPS) is the most effective option for improving operability during decelerations, followed by the options of only injecting power on the HPS or only extracting power from the LPS.

Turbine Electrified Energy Management↗

NASA NTRSDate not supplied

Transient Optimization for the Betterment of Turbine Electrified Energy Management

Gas turbine engine transients are associated with degraded compressor operability, which must be addressed by the engine control system and accounted for in the engine design. Failure to do so may result in events such as compressor stall/surge and combustor blow out. Transient operability concerns constrain the engine design and can result in sacrifices of efficiency and/or thrust responsiveness. The traditional approach to transient operability management is control logic that limits the fuel flow command. A companion paper presents a strategy for optimizing the transient fuel flow control logic taking into consideration transient operability and thrust responsiveness. The study covered here extends this idea to an electrified gas turbine engine that employs a power/energy management concept known as Turbine Electrified Energy Management (TEEM). TEEM uses an electric power system interfaced with the engine (hence the term ‘electrified gas turbine engine’) to further improve transient operability and alleviate associated design constraints. There can be costs associated with implementing TEEM in terms of power and energy requirements that impact the size of the electrical power system. However, the results of this study show that through optimization of the transient limit logic, power and energy requirements needed to implement TEEM can be significantly reduced. Among the conclusions that can be drawn from the results of the illustrative application covered herein are: (1) there is a reduction in the electric machine power requirement to manage operability during accelerations by 200 to 400 hp, and (2) power transfer from the low pressure spool (LPS) to the high pressure spool (HPS) is the most effective option for improving operability during decelerations, followed by the options of only injecting power on the HPS or only extracting power from the LPS.

transient↗

NASA NTRSDate not supplied

Accelerating TEMPO Air Quality Science Through STAQS

Soon after the launch of Tropospheric Emissions: Monitoring of Pollution (TEMPO) mission, NASA is supporting the Synergistic TEMPO Air Quality Science field study (STAQS) in summer 2023. This study’s main objective is to accelerate science with geostationary air quality observations from TEMPO to better understand its use in air pollution research and applications. Science objectives include, but are not limited to, TEMPO L2 product evaluation, the interpretation of the spatiotemporal evolution of TEMPO data during air quality events, assessment of anthropogenic emissions, contributions to chemical transport modeling, and environmental justice applications. These objectives can be accomplished through the integration of satellite data with systematically repeated high-resolution aircraft- and ground-based measurements in multiple urban environments. The primary urban cities considered include Los Angeles, New York City, and Chicago in June-August 2023. Measurements consist of airborne remote sensing observations of air quality constituents of nitrogen dioxide (NO2), formaldehyde (HCHO), ozone, and aerosols using the GeoCape Airborne Simulator and High-Spectral Resolution Lidar 2/Differential Absorption Lidar (HSRL2/DIAL) on the NASA JSC G-V aircraft, greenhouse gas observations from Airborne Visible InfraRed Imaging Spectrometer - Next Generation (AVIRIS-NG) and High Altitude Lidar Observatory (HALO) on the NASA LaRC G-III aircraft, and ground-based remote sensing and in situ observations of ozone, NO2, and HCHO from the Tropospheric Ozone Lidar Network (TOLNet), Pandora spectrometers, and ground-based monitoring networks. Key partnership studies providing in situ airborne observations include the NOAA Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas (AEROMMA) field study on the NASA DC-8 in the same primary target areas as STAQS and Greater New York Oxidant, Tropospheric Halogens, and Aerosol Measurements and Modeling (GOTHAMM) field study on the NSF C-130 near New York City. This presentation will include a current status update of the STAQS mission and an overview of its measurement strategies and science objectives with the goal of promoting continued discussions for building and strengthening collaborations prior to the mission.

Laura Judd↗

NASA NTRSDate not supplied

Transient Optimization for the Betterment of Turbine Electrified Energy Management

Gas turbine engine transients are associated with degraded compressor operability, which must be addressed by the engine control system and accounted for in the engine design. Failure to do so may result in events such as compressor stall/surge and combustor blow out. Transient operability concerns constrain the engine design and can result in sacrifices of efficiency and/or thrust responsiveness. The traditional approach to transient operability management is control logic that limits the fuel flow command. A companion paper presents a strategy for optimizing the transient fuel flow control logic taking into consideration transient operability and thrust responsiveness. The study covered here extends this idea to an electrified gas turbine engine that employs a power/energy management concept known as Turbine Electrified Energy Management (TEEM). TEEM uses an electric power system interfaced with the engine (hence the term ‘electrified gas turbine engine’) to further improve transient operability and alleviate associated design constraints. There can be costs associated with implementing TEEM in terms of power and energy requirements that impact the size of the electrical power system. However, the results of this study show that through optimization of the transient limit logic, power and energy requirements needed to implement TEEM can be significantly reduced. Among the conclusions that can be drawn from the results of the illustrative application covered herein are: (1) there is a reduction in the electric machine power requirement to manage operability during accelerations by 200 to 400 hp, and (2) power transfer from the low pressure spool (LPS) to the high pressure spool (HPS) is the most effective option for improving operability during decelerations, followed by the options of only injecting power on the HPS or only extracting power from the LPS.

transient↗

NASA NTRS1973

A low-cost inertial smoothing system for landing approach guidance

Accurate position and velocity information with low noise content for instrument approaches and landings is required for both control and display applications. In a current VTOL automatic instrument approach and landing research program, radar-derived landing guidance position reference signals, which are noisy, have been mixed with acceleration information derived from low-cost onboard sensors to provide high-quality position and velocity information. An in-flight comparison of signal quality and accuracy has shown good agreement between the low-cost inertial smoothing system and an aided inertial navigation system. Furthermore, the low-cost inertial smoothing system has been proven to be satisfactory in control and display system applications for both automatic and pilot-in-the-loop instrument approaches and landings.

Niessen, F. R.↗

NASA NTRS2009

Atomic References for Measuring Small Accelerations

Accelerometer systems that would combine the best features of both conventional (e.g., mechanical) accelerometers and atom interferometer accelerometers (AIAs) have been proposed. These systems are intended mainly for use in scientific research aboard spacecraft but may also be useful on Earth in special military, geological, and civil-engineering applications. Conventional accelerometers can be sensitive, can have high dynamic range, and can have high frequency response, but they lack accuracy and long-term stability. AIAs have low frequency response, but they offer high sensitivity, and high accuracy for measuring small accelerations. In a system according to the proposal, a conventional accelerometer would be used to perform short-term measurements of higher-frequency components of acceleration, while an AIA would be used to provide consistent calibration of, and correction of errors in, the measurements of the conventional accelerometer in the lower-frequency range over the long term. A brief description of an AIA is prerequisite to a meaningful description of a system according to the proposal. An AIA includes a retroreflector next to one end of a cell that contains a cold cloud of atoms in an ultrahigh vacuum. The atoms in the cloud are in free fall. The retroreflector is mounted on the object, the acceleration of which is to be measured. Raman laser beams are directed through the cell from the end opposite the retroreflector, then pass back through the cell after striking the retroreflector. The Raman laser beams together with the cold atoms measure the relative acceleration, through the readout of the AIA, between the cold atoms and the retroreflector.

Maleki, Lute↗

NASA NTRS2006

Electrodynamic Tether as a Thruster for LEO Mission Applications

Electrodynamic tether propulsion has a number of attractive features and has been widely discussed for different low earth orbit applications. Despite the commonality of application, the choice of the proper design for any particular mission is a unique problem. The flight trajectory, duration, available power and voltage, and drag force should be taken into consideration with other mission requirements. Characteristics of tether performance such as system acceleration and electrical efficiency should be calculated and assessed based on the system's capability to collect electrical current. We discuss the choice of parameters for circular, tape, and grid-sphere tether anodes and their applicability to International Space Station (ISS) reboost and Momentum Exchange Electrodynamic Reboost (MXER) applications.

Khazanov, G. V↗

NASA NTRS1978

Design and performance verification of a passive propellant management system

This paper describes the design and verification testing of a reusable passive propellant management system. The system was designed to acquire propellant in low- or zero-g environments and also retain this propellant under high axially directed accelerations that may be experienced during launch and orbit-to-orbit transfer. The system design requirements were established to satisfy generally the requirements for a large number of potential NASA and military applications, such as orbit-to-orbit shuttles and satellite vehicles. The resulting concept was a multicompartmented tank with independent surface tension acquisition channels in each compartment. The tank was designed to provide a minimum expulsion efficiency of 98 percent when subjected to the simultaneous conditions of acceleration, vibration, and outflow. The system design has the unique capability to demonstrate low-g performance in a 1-g test environment, and the test program summarized was structured around this capability.

Hess, D. A.↗

NASA NTRS1966

A Torque Motor Servorotator for Vestibular Application

Torque motor servorotator for vestibular application

VESTIBULAR APPARATUS↗

NASA NTRS1971

Accelerated battery-life testing - A concept

Test program, employing empirical, statistical and physical methods, determines service life and failure probabilities of electrochemical cells and batteries, and is applicable to testing mechanical, electrical, and chemical devices. Data obtained aids long-term performance prediction of battery or cell.

Mccallum, J.↗

NASA NTRS1995

Magnetic reconnection in the presence of sheared flow and density asymmetry: Applications to the Earth's magnetopause

Classical models of magnetic reconnection consist of a small diffusion region bounded by two symmetric slow shocks, across which the plasma is accelerated. Asymmetries often present in space plasmas are sheared plasma flow and dissimilar plasma densities on the two sides of current sheets. In this paper, we investigate magnetic reconnection in the presence of a shear flow and an asymmetric density across the current sheet using two-dimensional magnetohydrodynamic (MHD) simulations. The results demonstrate that magnetic reconnection can occur only for a plasma flow velocity (in the frame of the X line) which is below the Alfven speed in each inflow region. This limits the velocity of the X line to a certain range for a given flow shear and provides an upper limit to the total velocity shear at which reconnection ceases to operate. Depending on the direction of the flow in the adjacent inflow region, the effects from the sheared flow and from the density asymmetry will compete with or enhance each other in respect to the magnitude and location of the currents which bound the outflow regions. The results are applied to the dayside and flank regions of the magnetosphere. For the dayside region where the magnetosheath flow is slow, the magnetic field transition region is thin and the accelerated flow is earthward of the sharp current layer (magnetopause). At the flanks tailward of the X line, shear flow and density asymmetry effects compete making the magnetic field transition layer broad with the high-speed flow contained within the transition region which explains corresponding observations. At the flanks sunward of the X line, shear flow and density asymmetry effects enhance each other and lead to a strong current sheet on the magnetosheath side of the accelerated flow. The total volume affected by magnetic reconnection is much larger than the steady state region. A large bulge region precedes the steady state region. Qualitatively, the bulge and the steady state region have similar signatures and both can explain observations. We provide criteria in order to distinguish between the bulge and the steady state region in observations.

La Belle-Hamer, A. L.↗

NASA NTRS1973

New motor shaft angular accelerometer concept

Concept permits measurement of the acceleration of continuously rotating shafts without use of slip rings or telemetry and with little additional inertial load. Concept has application in servomotor control circuits and easy-to-fly airplane controls.

Smetana, F. O.↗

NASA NTRS1979

The energetics of resistive magnetic tearing

A new treatment of the energetics of resistive magnetic tearing is presented. This instability is the only known field-reconnection mechanism which develops in time, and is thus a primary candidate for a number of astrophysical 'flare' processes occurring in stressed magnetic fields. The tearing process is elucidated by a subdivision into magnetic regions of different characteristics: first, as dominated by resistive or highly conductive dynamics, and then by function as a source or sink of the energy flux. Matching conditions between these zones provide a determination of the growth rate and its physical-parameter dependence. The observable plasma energy outputs, due mainly to two distinct magnetically driven acceleration mechanisms, are estimated and their directive spatial properties shown. Finally, the generality of resistive tearing is demonstrated by an application of the previous considerations to realistic sheared-field configurations, including the case of a solar coronal loop, for which flare-instability thresholds and energy-deposition sites are described.

Van Hoven, G.↗

NASA NTRS1997

Crystal Growth of Solid Solution HgCdTe Alloys

The growth of homogenous crystals of HgCdTe alloys is complicated by the large separation between their liquidus and solidus temperatures. Hg(1-x)Cd(x)Te is representative of several alloys which have electrical and optical properties that can be compositionally tuned for a number of applications. Limitations imposed by gravity during growth and results from growth under reduced conditions are described. The importance of residual accelerations was demonstrated by dramatic differences in compositional distribution observed for different attitudes of the space shuttle that resulted in different steady acceleration components.

Lehoczky, Sandor L.↗

NASA NTRS2005

A Parallel Trade Study Architecture for Design Optimization of Complex Systems

Design of a successful product requires evaluating many design alternatives in a limited design cycle time. This can be achieved through leveraging design space exploration tools and available computing resources on the network. This paper presents a parallel trade study architecture to integrate trade study clients and computing resources on a network using Web services. The parallel trade study solution is demonstrated to accelerate design of experiments, genetic algorithm optimization, and a cost as an independent variable (CAIV) study for a space system application.

Kim, Hongman↗

NASA NTRS2005

Review of high-throughput techniques for detecting solid phase Transformation from material libraries produced by combinatorial methods

High-throughput measurement techniques are reviewed for solid phase transformation from materials produced by combinatorial methods, which are highly efficient concepts to fabricate large variety of material libraries with different compositional gradients on a single wafer. Combinatorial methods hold high potential for reducing the time and costs associated with the development of new materials, as compared to time-consuming and labor-intensive conventional methods that test large batches of material, one- composition at a time. These high-throughput techniques can be automated to rapidly capture and analyze data, using the entire material library on a single wafer, thereby accelerating the pace of materials discovery and knowledge generation for solid phase transformations. The review covers experimental techniques that are applicable to inorganic materials such as shape memory alloys, graded materials, metal hydrides, ferric materials, semiconductors and industrial alloys.

Lee, Jonathan A.↗

NASA NTRSDate not supplied

Atmospheric Structure Investigation: Planetary in Situ Measurements of Atmospheric State Including Clouds/Aerosols.

The Atmospheric Structure Investigation (ASI) is a sensor suite designed for descent probes into planetary atmospheres, primarily aimed at Giant planets like Saturn and Uranus, and applicable to Venus, Titan, and Earth-specific missions. ASI aims to provide essential measurements of atmospheric structure, including probe acceleration, rotation, pressure, temperature, vertical winds, aerosol properties, and hydrogen and helium composition, crucial for contextualizing other probe data.

V Jha↗