Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “performance test”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,621 records · Page 90
All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Reaction Wheel Disturbance Modeling, Jitter Analysis, and Validation Tests for Solar Dynamics Observatory

The Solar Dynamics Observatory (SDO) aims to study the Sun's influence on the Earth by understanding the source, storage, and release of the solar energy, and the interior structure of the Sun. During science observations, the jitter stability at the instrument focal plane must be maintained to less than a fraction of an arcsecond for two of the SDO instruments. To meet these stringent requirements, a significant amount of analysis and test effort has been devoted to predicting the jitter induced from various disturbance sources. One of the largest disturbance sources onboard is the reaction wheel. This paper presents the SDO approach on reaction wheel disturbance modeling and jitter analysis. It describes the verification and calibration of the disturbance model, and ground tests performed for validating the reaction wheel jitter analysis. To mitigate the reaction wheel disturbance effects, the wheels will be limited to operate at low wheel speeds based on the current analysis. An on-orbit jitter test algorithm is also presented in the paper which will identify the true wheel speed limits in order to ensure that the wheel jitter requirements are met.

Liu,Kuo-Chia↗
NASA NTRS2011

Telemetry and Science Data Software System

The Telemetry and Science Data Software System (TSDSS) was designed to validate the operational health of a spacecraft, ease test verification, assist in debugging system anomalies, and provide trending data and advanced science analysis. In doing so, the system parses, processes, and organizes raw data from the Aquarius instrument both on the ground and while in space. In addition, it provides a user-friendly telemetry viewer, and an instant pushbutton test report generator. Existing ground data systems can parse and provide simple data processing, but have limitations in advanced science analysis and instant report generation. The TSDSS functions as an offline data analysis system during I&T (integration and test) and mission operations phases. After raw data are downloaded from an instrument, TSDSS ingests the data files, parses, converts telemetry to engineering units, and applies advanced algorithms to produce science level 0, 1, and 2 data products. Meanwhile, it automatically schedules upload of the raw data to a remote server and archives all intermediate and final values in a MySQL database in time order. All data saved in the system can be straightforwardly retrieved, exported, and migrated. Using TSDSS s interactive data visualization tool, a user can conveniently choose any combination and mathematical computation of interesting telemetry points from a large range of time periods (life cycle of mission ground data and mission operations testing), and display a graphical and statistical view of the data. With this graphical user interface (GUI), the data queried graphs can be exported and saved in multiple formats. This GUI is especially useful in trending data analysis, debugging anomalies, and advanced data analysis. At the request of the user, mission-specific instrument performance assessment reports can be generated with a simple click of a button on the GUI. From instrument level to observatory level, the TSDSS has been operating supporting functional and performance tests and refining system calibration algorithms and coefficients, in sync with the Aquarius/SAC-D spacecraft. At the time of this reporting, it was prepared and set up to perform anomaly investigation for mission operations preceding the Aquarius/SAC-D spacecraft launch on June 10, 2011.

Bates, Lakesha↗
NASA NTRSDate not supplied

Two-Phase Flow in Filters and Orifices: ISS Packed Bed Reactor Experiment Water Recovery Series (PBRE-WRS)

Understanding the hydrodynamics of adiabatic two-phase flows in packed bed reactors offers numerous benefits. It enables the optimization of chemical reactions rates and products which results in more efficient and compact reactors, thus reducing space and resource requirements, crucial for long duration space missions. The Packed Bed Reactor Experiment-Water Recovery Series (PBRE-WRS) is a flight experiment planned for operation on the Microgravity Science Glove box (MSG) facility of the International Space Station (ISS). The objective of the experiment is to validate hydrodynamic models at a range of gas and liquid flow rates, where these models are used in the design of processes for life support systems in microgravity. The microgravity environment allows for measurement and observation of aspects of fluid dynamics that are unique when compared to observations made in full or partial gravity environments. The experiment consists of testing two-phase flow hydrodynamics in three different filters, four (4) orifices and one check valve test articles. The experiment utilizes the hardware of the previously flown PBRE and PBRE-2 with packed beds of different packings materials and sizes. The fluid system of the PBRE-WRS consists of a nitrogen gas delivery and water delivery subsystems. The gas delivery subsystem can accommodate two ranges of gas flow rates, just as for the water delivery system. The nitrogen gas loop is open whereas the water loop is closed. Gas is separated from the water using a gas-liquid phase separator which is located in the water delivery module. Preliminary results from ground testing show the pressure drop across the filters increasing at different rates with the liquid and gas flow rates. In this work, a detailed system description is presented along with a summary of results from ground performance testing of different test sections in an end-to-end preflight testing campaign.

ISS↗
NASA NTRS2015

NASA's Plan for SDLS Testing

The Space Data Link Security (SDLS) Protocol is a Consultative Committee for Space Data Systems (CCSDS) standard which extends the known Data Link protocols to secure data being sent over a space link by providing confidentiality and integrity services. This plan outlines the approach by National Aeronautics Space Administration (NASA) in performing testing of the SDLS protocol using a prototype based on an existing NASA missions simulator.

Testing↗
NASA NTRS2008

Status of the NEXT Ion Thruster Long-Duration Test After 10,100 hr and 207 kg Demonstrated

The NASA s Evolutionary Xenon Thruster (NEXT) program is developing the next-generation ion propulsion system with significant enhancements beyond the state-of-the-art in ion propulsion to provide future NASA science missions with enhanced mission capabilities at a low total development cost. As part of a comprehensive thruster service life assessment utilizing both testing and analyses, a Long-Duration Test (LDT) was initiated to validate and qualify the NEXT propellant throughput capability to a qualification-level of 450 kg, 1.5 times the mission-derived throughput requirement of 300 kg. This wear test is being conducted with a modified, flight-representative NEXT engineering model ion thruster, designated EM3. As of June 21, 2007, the thruster has accumulated 10,100 hr of operation at the thruster full-input-power of 6.9 kW with 3.52 A beam current and 1800 V beam power supply voltage. The thruster has processed 207 kg of xenon and demonstrated a total impulse of 8.5 106 N-s; the highest total impulse ever demonstrated by an ion thruster in the history of space propulsion. Thruster performance tests are conducted periodically over the entire NEXT throttle table with input power ranging 0.5 to 6.9 kW. Overall ion thruster performance parameters including thrust, input power, specific impulse, and thruster efficiency have been nominal with little variation to date. Lifetime-limiting component erosion rates have been consistent with the NEXT service life assessment, which predicts the earliest failure sometime after 750 kg of xenon propellant throughput; well beyond the mission-derived lifetime requirement. The NEXT wear test data confirm that the erosion of the discharge keeper orifice, enlarging of nominal-current-density accelerator grid aperture cusps, and the decrease in cold grid-gap observed during the NSTAR Extended Life Test have been mitigated. This paper presents the status of the NEXT LDT to date.

Herman, Daniel A.↗
NASA NTRS2001

Baseline Testing of the EV Global E-Bike SX

The NASA John H. Glenn Research Center initiated baseline testing of the EV Global E-Bike SX as an update of the state of the art in hybrid electric bicycles. The E-bike is seen as a way to reduce pollution in urban areas, reduce fossil fuel consumption, and reduce operating costs for transportation systems. The work was done under the Hybrid Power Management (HPM) Program, which includes the Hybrid Electric Transit Bus (HETB). The SX is a high performance, state of the art, ground up, hybrid electric bicycle. Unique features of the SX's 36 V power system include the use of an efficient, 400 W, electric hub motor, and a seven-speed derailleur system that permits operation as fully electric, fully pedal, or a combination of the two. Other innovative features, such as regenerative braking through ultracapacitor energy storage, are planned. Regenerative braking recovers much of the kinetic energy of the vehicle during deceleration. The E-Bike is an inexpensive approach to advance the state of the art in hybrid technology in a practical application. The project transfers space technology to terrestrial use via nontraditional partners, and provides power system data valuable for future space applications. A description of the SX, the results of performance testing, and future vehicle development plans are given in this report. The report concludes that the SX provides excellent performance, and that the implementation of ultracapacitors in the power system can provide significant performance improvements.

Eichenherg, Dennis J.↗
DOE OSTI2024

LCLS-II Helium Refrigeration System Commissioning Results

SLAC National Accelerator Laboratory has upgraded to LCLS-II, featuring a 4 GeV superconducting linear accelerator composed of 37 cryomodules and two large helium refrigeration systems with a cooling capacity of 4 kW at 2.0 K. The LCLS-II Helium Refrigeration System (HRS) consists of two compressor stations, each with a power of approximately 4.5 MW, two 4.5 K cold boxes, each with a power of 18 kW equivalent at 4.5 K, and two sets of cold compressors that can each produce a flow of 230 g/s at 31 mbar (2.0K). Performance tests of the HRS were meticulously planned and successfully carried out, with results demonstrating that it exceeded the process requirements for LCLS-II operations. This paper provides a detailed presentation of the LCLS-II HRS performance and the challenges encountered during the commissioning phase.

42 ENGINEERING↗
NASA NTRS1989

Advanced Hypervelocity Aerophysics Facility Workshop

The primary objective of the workshop was to obtain a critical assessment of a concept for a large, advanced hypervelocity ballistic range test facility powered by an electromagnetic launcher, which was proposed by the Langley Research Center. It was concluded that the subject large-scale facility was feasible and would provide the required ground-based capability for performing tests at entry flight conditions (velocity and density) on large, complex, instrumented models. It was also concluded that advances in remote measurement techniques and particularly onboard model instrumentation, light-weight model construction techniques, and model electromagnetic launcher (EML) systems must be made before any commitment for the construction of such a facility can be made.

Witcofski, Robert D.↗
NASA NTRSDate not supplied

Two-Phase Flow in Filters and Orifices: In preparation for Measurements on ISS Packed Bed Reactor Experiment-Water Recovery Series (PBRE-WRS)

Understanding the hydrodynamics of adiabatic two-phase flows in packed bed reactors offers numerous benefits. It enables the optimization of chemical reactions rates and products, crucial for pharmaceuticals and energy production industries. Additionally, this understanding aids in designing more efficient and compact reactors, reducing space and resource requirements. Insights gained from studying such flows in microgravity contribute to advancements of space technologies and the enhancement of our capabilities for undertaking future long duration safe, and sustainable space exploration missions. The Packed Bed Reactor Experiment-Water Recovery Series (PBRE-WRS) is a flight experiment planned for operation on the Microgravity Science Glove box (MSG) facility of the International Space Station (ISS). The objective of the experiment is to validate hydrodynamic models at a range of gas and liquid flow rates. The microgravity environment allows for measurement and observation of aspects of fluid dynamics that are unique when compared to observations made in full or partial gravity environments. The experiment consists of testing two-phase flow hydrodynamics in three different filters, four (4) orifices and one check valve test articles. The experiment utilizes the hardware of the previously flown PBRE and PBRE-2 with packed beds of different packings materials and sizes. The fluid system of the PBRE-WRS consists of a nitrogen gas delivery and water delivery subsystems. The gas delivery subsystem can accommodate two ranges of gas flow rates, just as for the water delivery system. The nitrogen gas loop is open whereas the water loop is closed. Gas is separated from the water using a gas-liquid phase separator which is located in the water delivery module. Preliminary results from ground testing show the pressure drop increasing at different rates with the liquid and gas flow rates in the Brine filter. In this work, a detailed system description is presented along with a summary of results from ground performance testing of different test sections in an end-to-end preflight testing campaign.

Packed Bed Reactor Experiment↗
NASA NTRS2015

Aeroelastic Airworthiness Assesment of the Adaptive Compliant Trailing Edge Flaps

The Adaptive Compliant Trailing Edge (ACTE) demonstrator is a joint task under the National Aeronautics and Space Administration Environmentally Responsible Aviation Project in partnership with the Air Force Research Laboratory and FlexSys, Inc. (Ann Arbor, Michigan). The project goal is to develop advanced technologies that enable environmentally friendly aircraft, such as adaptive compliant technologies. The ACTE demonstrator flight-test program encompassed replacing the Fowler flaps on the SubsoniC Aircraft Testbed, a modified Gulfstream III (Gulfstream Aerospace, Savannah, Georgia) aircraft, with control surfaces developed by FlexSys. The control surfaces developed by FlexSys are a pair of uniquely-designed unconventional flaps to be used as lifting surfaces during flight-testing to validate their structural effectiveness. The unconventional flaps required a multidisciplinary airworthiness assessment to prove they could withstand the prescribed flight envelope. Several challenges were posed due to the large deflections experienced by the structure, requiring non-linear analysis methods. The aeroelastic assessment necessitated both conventional and extensive testing and analysis methods. A series of ground vibration tests (GVTs) were conducted to provide modal characteristics to validate and update finite element models (FEMs) used for the flutter analyses for a subset of the various flight configurations. Numerous FEMs were developed using data from FlexSys and the ground tests. The flap FEMs were then attached to the aircraft model to generate a combined FEM that could be analyzed for aeroelastic instabilities. The aeroelastic analysis results showed the combined system of aircraft and flaps were predicted to have the required flutter margin to successfully demonstrate the adaptive compliant technology. This paper documents the details of the aeroelastic airworthiness assessment described, including the ground testing and analyses, and subsequent flight-testing performed on the unconventional ACTE flaps.

aeroelasticity↗
NASA NTRS1996

Mars global surveyor

The design and performance of a highly reliable, 20 volt nickel hydrogen battery compatible with existing NiCad Mars observer based spacecraft components and an 800 psi, zirconium wall wick Common Pressure Vessel (CPV) are discussed. The objectives of the design process are: to meet or exceed all PD requirements by using existing technologies; to have high reliability hardware and parallel fabrication of components; and low schedule risk configurations. This paper discusses the tests performed on the batteries (capacity, charge retention, random vib., pyro shock, energy density, and packing factor) and the results of the tests. In addition to the design discussion, a brief introduction on Mars Global Surveyor (MGS) Satellite objectives (NASA's next interplanetary mission) is also presented.

Source record↗
NASA NTRS1972

Development of a carbon cloth heat post module for thermal vacuum testing of a spinning spacecraft

Development of a high temperature, high power density, isothermal, rapid transient, infrared thermal module is described. The investigation of various alternative approaches is discussed, as well as the rationale leading to the choice of a carbon cloth concept. Evolution of module design configurations and a summary of the development test results are included, along with a detailed description of the final design, which incorporated a black plate emitter radiantly heated by the carbon cloth. The final module configuration met design criteria during a 200-hour thermal vacuum performance test at 1000 F operating temperature without contaminating a solar cell array.

Levine, M. B.↗
NASA NTRS1983

The development of a power spectral density processor for C and L band airborne radar scatterometer sensor systems

A real-time signal processor was developed for the NASA/JSC L-and C-band airborne radar scatterometer sensor systems. The purpose of the effort was to reduce ground data processing costs. Conversion of two quadrature channels of data (like and cross polarized) was made to obtain Power Spectral Density (PSD) values. A chirp-z transform (CZT) approach was used to filter the Doppler return signal and improved high frequency and angular resolution was realized. The processors have been tested with record signals and excellent results were obtained. CZT filtering can be readily applied to scatterometers operating at other wavelengths by altering the sample frequency. The design of the hardware and software and the results of the performance tests are described in detail.

Harrison, D. A., III↗
NASA NTRS1984

Optical fibers and components experiment (A0138-7)

Fiber optics permanent damages induced by ionizing radiation after a long exposure in space and after laboratory tests were examined. Irradiation tests performed with radioactive sources (Sr90 - Y90) were validataed, computer coses used for the fluence and dose profile were verified. The performance of fiber optics waveguides in a low altitude orbit, and the origin of transmission losses in the material were dtermined. High sensitivity to ionizing radiations, however, may be a restriction for optic fiber use on satellites. Irradiation tests on these components using neutrons, gamma rays, and X-rays are carried out. Radiation damage on opticao materials, however, is strongly linked to the test conditions.

Bourrieau, J.↗
NASA NTRS2003

Microgravity Emissions Laboratory Testing of the Light Microscopy Module Control Box Fan

The Microgravity Emissions Laboratory (MEL) was developed at the NASA Glenn Research Center for the characterization, simulation, and verification of the International Space Station (ISS) microgravity environment. This Glenn lab was developed in support of the Fluids and Combustion Facility (FCF). The MEL is a six-degrees-of-freedom inertial measurement system that can characterize the inertial response forces (emissions) of components, subrack payloads, or rack-level payloads down to 10 7g. The inertial force output data generated from the steady-state or transient operations of the test article are used with finite element analysis, statistical energy analysis, and other analysis tools to predict the on-orbit environment at specific science or rack interface locations. Customers of the MEL have used benefits in isolation performance testing in defining available attenuation during the engineering hardware design phase of their experiment s development. The Light Microscopy Module (LMM) Control Box (LCB) fan was tested in the MEL in June and July of 2002. The LMM is planned as a remotely controllable on-orbit microscope subrack facility that will be accommodated in an FCF Fluids Integrated Rack on the ISS. The disturbances measured in the MEL test resulted from operation of the air-circulation fan within the LCB. The objectives of the testing were (1) to identify an isolator to be added to the LCB fan assembly to reduce fan-speed harmonics and (2) to identify the fan-disturbance forcing functions for use in rack-response analysis of the LMM and Fluids Integrated Rack facility. This report describes the MEL, the testing process, and the results from ground-based MEL LCB fan testing.

McNelis, Anne M.↗
NASA NTRS2014

Design Improvements and X-Ray Performance of a Time Projection Chamber Polarimeter for Persistent Astronomical Sources

The design of the Time-Projection Chamber (TPC) Polarimeter for the Gravity and Extreme Magnetism Small Explorer (GEMS) was demonstrated to Technology Readiness Level 6 (TRL-6)3 and the flight detectors fabricated, assembled and performance tested. A single flight detector was characterized at the Brookhaven National Laboratory Synchrotron Light Source with polarized X-rays at 10 energies from 2.3-8.0 keV at five detector positions. The detector met all of the GEMS performance requirements. Lifetime measurements have shown that the existing flight design has 23 years of lifetime4, opening up the possibility of relaxing material requirements, in particular the consideration of the use of epoxy, to reduce risk elsewhere. We report on design improvements to the GEMS detector to enable a narrower transfer gap that, when operated with a lower transfer field, reduces asymmetries in the detector response. In addition, the new design reduces cost and risk by simplifying the assembly and reducing production time. Finally, we report on the performance of the narrow-gap detector in response to polarized and unpolarized X-rays.

GEMS↗
NASA NTRS1993

Performance results of a digital test signal generator

Performance results of a digital test signal-generator hardware-demonstration unit are reported. Capabilities available include baseband and intermediate frequency (IF) spectrum generation, for which test results are provided. Repeatability in the setting of a given signal-to-noise ratio (SNR) when a baseband or an IF spectrum is being generated ranges from 0.01 dB at high SNR's or high data rates to 0.3 dB at low data rates or low SNR's. Baseband symbol SNR and carrier SNR (Pc/No) accuracies of 0.1 dB were verified with the built-in statistics circuitry. At low SNR's that accuracy remains to be fully verified. These results were confirmed with measurements from a demodulator synchronizer assembly for the baseband spectrum generation, and with a digital receiver (Pioneer 10 receiver) for the IF spectrum generation.

Gutierrez-Luaces, B. O.↗