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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 397 records · Page 22

All sources NASA NTRS DOE OSTI

NASA NTRS1978

King 2 2519 ATM residual gyros: Reestablishing 5 year life requirements

The technical expertise required to assess the condition of the residual ATM 2519 Singer gyros is discussed. Past build history records, past performance characteristics, and recommendations for particular tests (which were performed by NASA personnel) are summarized. Test results are analyzed. A study of motor performance data and recommendations concerning gyro spin bearing life was performed. A method of reestablishing potential reliability of the bearing for the 5-year life requirement of the power module is also included.

Kayal, B.↗

NASA NTRS1980

Potential benefits for propfan technology on derivatives of future short- to medium-range transport aircraft

It is noted that several NASA-sponsored studies have identified a substantial potential fuel savings for high subsonic speed aircraft utilizing the propfan concept compared to the equivalent technology turbofan aircraft. Attention is given to a feasibility study for propfan-powered short- to medium-haul commercial transport aircraft conducted to evaluate potential fuel savings and identify critical technology requirements using the latest propfan performance data. An analysis is made of the design and performance characteristics of a wing-mounted and two-aft-mounted derivative propfan aircraft configurations, based on a DC-9 Super 80 airframe, which are compared to the baseline turbofan design. Finally, recommendations for further research efforts are also made.

Goldsmith, I. M.↗

NASA NTRS1982

Influences of horizontal hypokinesia on performance and circadian physiological rhythms in female humans

Eight females from 35-45 yr of age were subjected to seven days of ambulatory control, seven days of bed rest, and a five day recovery period, with 30 min of centrifugation on day seven of bedrest to determine the effects of weightlessness on the circadian rhythms of females in that age group. Heart rate and rectal temperature (RT) were monitored and each subject was tested in a flight simulator twice a day in conditions of varying levels of turbulence. The flight simulations were run during the morning and acrophase of the circadian RT and performance errors wery monitored for 6 min. No significant differences were detected in the group performance data pre-, during, and post-bedrest, although better performance in the simulator was observed after the centrifuge exposure. An RT phase shift was statistically significant between pre- and during bedrest stages.

Winget, C. M.↗

NASA NTRS1983

Air Force Logistics Command (AFLC) solar thermal plant

The plant proved its capability to deliver the desired energy product in a USAF industrial environment. The collector proved capable of energy conversion at insolation levels up to 25% below design minimum. The plant and the project were negatively affected by severe winter weather, with total insolation during the test period 60 percent less than the expected value. Environmental effects reduced plant availability to 55 percent. Only five, minimally good operating days were experienced during the test period. The subsequent lack of performance data prohibits the drawing of general conclusions regarding system performance. System operability was rated generally high. The only inhibiting factor was the difficulty in procuring replacement parts for rapid repair under USAF stockage and procurement policies. No inherently serious system failures were recorded, although a thermostatic valve malfunction in the freeze protection system ultimately took 30 days to repair.

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NASA NTRS1987

Loran-C approach guidance project current status

There are four areas of work in the Loran-C flight test project. Current results provide performance data on the effects of Signal Noise Ratio (SNR) on the dynamic performance of the receiver filters for Loran-C data, and data on Loran-C grid deformation at a microscale of 100 meters. The Loran-C receiver provides a line of position (LOP) Master and Slave transmitter at an angle 0 to magnetic north. No transformation to latitude-longitude reference frame is required since this is the major source of Loran-C navigation errors. A local coordinate frame is established centered at touchdown point on the runway with directions along and across the runway. A Loran-C data collection system was set up. The Loran-C data are sent directly to an Apple II computer with a 12 inch monitor. The effect of SNR on Loran-C precision is shown for two receiver filters of different frequency response. A set of ground level static readings of touchdown was taken around Hanscom Field and transferred to an accurate detailed layout drawing; this showed local distortions of the average touchdown values.

Elias, A. L.↗

NASA NTRS2003

Performance Evaluation of Electrochem's PEM Fuel Cell Power Plant for NASA's 2nd Generation Reusable Launch Vehicle

NASA's Next Generation Launch Technology (NGLT) program is being developed to meet national needs for civil and commercial space access with goals of reducing the launch costs, increasing the reliability, and reducing the maintenance and operating costs. To this end, NASA is considering an all- electric capability for NGLT vehicles requiring advanced electrical power generation technology at a nominal 20 kW level with peak power capabilities six times the nominal power. The proton exchange membrane (PEM) fuel cell has been identified as a viable candidate to supply this electrical power; however, several technology aspects need to be assessed. Electrochem, Inc., under contract to NASA, has developed a breadboard power generator to address these technical issues with the goal of maximizing the system reliability while minimizing the cost and system complexity. This breadboard generator operates with dry hydrogen and oxygen gas using eductors to recirculate the gases eliminating gas humidification and blowers from the system. Except for a coolant pump, the system design incorporates passive components allowing the fuel cell to readily follow a duty cycle profile and that may operate at high 6:1 peak power levels for 30 second durations. Performance data of the fuel cell stack along with system performance is presented to highlight the benefits of the fuel cell stack design and system design for NGLT vehicles.

Kimble, Michael C.↗

NASA NTRS2004

An Expert System for the Development of Efficient Parallel Code

We have built the prototype of an expert system to assist the user in the development of efficient parallel code. The system was integrated into the parallel programming environment that is currently being developed at NASA Ames. The expert system interfaces to tools for automatic parallelization and performance analysis. It uses static program structure information and performance data in order to automatically determine causes of poor performance and to make suggestions for improvements. In this paper we give an overview of our programming environment, describe the prototype implementation of our expert system, and demonstrate its usefulness with several case studies.

Jost, Gabriele↗

NASA NTRS1996

The Results of Dynamic Data Acquisition During Mars Pathfinder Prototype Airbag Drop Testing

The Mars Pathfinder mission, scheduled for launch in December 1996, will use an airbag system to safely deliver a lander to the Martian surface.The airbag landing system has undergone a comprehensive test program during its evolution from initial design phase to final qualification and acceptance testing. This paper outlines the test approach used in the airbag development program, describes the data acquisition system used to obtain and evaluate airbag performance data, and presents test results.

airbags Mars Mars Pathfinder Mars lander data acqu↗

NASA NTRS2008

Subscale Injector Testing to Support Ares Engines Development

The J-2X and RS-68B rocket engines are being developed for NASA's Ares I and Ares V launch vehicles. In support of the development of these engines, hot-fire testing on subscale coaxial injectors has been performed at NASA s Marshall Space Flight Center (MSFC) to evaluate performance data relative to injector type, liquid oxygen (LOX) post tip design features, element density and various operating conditions. Shear coaxial injectors with element densities of 1.1, 1.6, and 2.3 elements/in2 and a swirl coaxial injector with element density of 1.6 elements/in2 were evaluated at conditions relevant to the Ares applications. Chamber pressures with oxygen/hydrogen propellants ranged from 815-1630 psig with mixture ratios ranging from 4.7-6.9. Fuel manifold inlet temperatures were varied from 90 to 270 R. Shear coaxial LOX post tip thicknesses ranged from 0.006 in. to 0.0175 in. Modular, water cooled, calorimeter chamber assemblies were used to provide heating rate data and evaluate the effects of characteristic length (L*). Performance was evaluated relative to the resulting characteristic velocity (C*) efficiency. Testing with both the 2.3 and 1.1 elements/in2 shear coaxial injectors demonstrated no improvement in performance of the "thin" tip configuration versus the "thick" tip configuration. The loss in chamber pressure and associated performance loss seen in previous testing at low fuel temperatures could not be reliably repeated, indicating that this loss is not the result of a fluidic process in the injector elements. Further, no performance loss could be demonstrated once a faceplate seal specifically designed for operation with low temperature hydrogen was implemented in the 1.1 elements/sq in shear coaxial injector. Results for the 1.6 elements/sq in swirl injector at cold fuel temperatures showed performance higher than both the 1.6 elements/in2 shear coaxial injector and the 2.3 elements/in2 shear coaxial injector.

Protz, Christopher↗

NASA NTRS2015

ER-2 High Altitude Solar Cell Calibration Flights

Evaluation of space photovoltaics using ground-based simulators requires primary standard cells which have been characterized in a space or near-space environment. Due to the high cost inherent in testing cells in space, most primary standards are tested on high altitude fixed wing aircraft or balloons. The ER-2 test platform is the latest system developed by the Glenn Research Center (GRC) for near-space photovoltaic characterization. This system offers several improvements over GRC's current Learjet platform including higher altitude, larger testing area, onboard spectrometers, and longer flight season. The ER-2 system was developed by GRC in cooperation with NASA's Armstrong Flight Research Center (AFRC) as well as partners at the Naval Research Laboratory and Air Force Research Laboratory. The system was designed and built between June and September of 2014, with the integration and first flights taking place at AFRC's Palmdale facility in October of 2014. Three flights were made testing cells from GRC as well as commercial industry partners. Cell performance data was successfully collected on all three flights as well as solar spectra. The data was processed using a Langley extrapolation method, and performance results showed a less than half a percent variation between flights, and less than a percent variation from GRC's current Learjet test platform.

ER-2↗

NASA NTRS2003

Characterization of Space Shuttle Reusable Rocket Motor Static Test Stand Thrust Measurements

Space Shuttle Reusable Solid Rocket Motors (RSRM) are static tested at two ATK Thiokol Propulsion facilities in Utah, T-24 and T-97. The newer T-97 static test facility was recently upgraded to allow thrust measurement capability. All previous static test motor thrust measurements have been taken at T-24; data from these tests were used to characterize thrust parameters and requirement limits for flight motors. Validation of the new T-97 thrust measurement system is required prior to use for official RSRM performance assessments. Since thrust cannot be measured on RSRM flight motors, flight motor measured chamber pressure and a nominal thrust-to-pressure relationship (based on static test motor thrust and pressure measurements) are used to reconstruct flight motor performance. Historical static test and flight motor performance data are used in conjunction with production subscale test data to predict RSRM performance. The predicted motor performance is provided to support Space Shuttle trajectory and system loads analyses. Therefore, an accurate nominal thrust-to-pressure (F/P) relationship is critical for accurate RSRM flight motor performance and Space Shuttle analyses. Flight Support Motors (FSM) 7, 8, and 9 provided thrust data for the validation of the T-97 thrust measurement system. The T-97 thrust data were analyzed and compared to thrust previously measured at T-24 to verify measured thrust data and identify any test-stand bias. The T-97 FIP data were consistent and within the T-24 static test statistical family expectation. The FSMs 7-9 thrust data met all NASA contract requirements, and the test stand is now verified for future thrust measurements.

Mart L. Cook↗

NASA NTRS2015

Conflict Detection Performance Analysis for Function Allocation Using Time-Shifted Recorded Traffic Data

The performance of the conflict detection function in a separation assurance system is dependent on the content and quality of the data available to perform that function. Specifically, data quality and data content available to the conflict detection function have a direct impact on the accuracy of the prediction of an aircraft's future state or trajectory, which, in turn, impacts the ability to successfully anticipate potential losses of separation (detect future conflicts). Consequently, other separation assurance functions that rely on the conflict detection function - namely, conflict resolution - are prone to negative performance impacts. The many possible allocations and implementations of the conflict detection function between centralized and distributed systems drive the need to understand the key relationships that impact conflict detection performance, with respect to differences in data available. This paper presents the preliminary results of an analysis technique developed to investigate the impacts of data quality and data content on conflict detection performance. Flight track data recorded from a day of the National Airspace System is time-shifted to create conflicts not present in the un-shifted data. A methodology is used to smooth and filter the recorded data to eliminate sensor fusion noise, data drop-outs and other anomalies in the data. The metrics used to characterize conflict detection performance are presented and a set of preliminary results is discussed.

Guerreiro, Nelson M.↗

NASA NTRS1988

InP homojunction solar cell performance on the LIPS 3 flight experiment

Performance data for the NASA Lewis Research Center indium phosphide n+p homojunction solar cell module on the LIPS 3 Flight Experiment is presented. The objective of the experiment is to measure the performance of InP cells in the natural radiation environment of the 1100 km altitude, 60+ deg inclination orbit. Analysis of flight data indicates that the performance of the four cells throughout the first year is near expected values. No degradation in short-circuit current was seen, as was expected from radiation tolerance studies of similar cells. Details of the cell structure and flight module design are discussed. The results of the temperature dependency and radiation tolerance studies necessary for normalization and analysis of the data are included.

Brinker, David J.↗

NASA NTRS1988

InP homojunction solar cell performance on the LIPS III flight experiment

Performance data for the NASA Lewis Research Center indium phosphide n+p homojunction solar cell module on the LIPS 3 flight experiment is presented. The objective of the experiment is to measure the performance of InP cells in the natural radiation environment of the 1100 km altitude, 60+ deg inclination orbit. Analysis of flight data indicates that the performance of the four cells throughout the first year is near expected values. No degradation in short-circuit current was seen, as was expected from radiation tolerance studies of similar cells. Details of the cell structure and flight module design are discussed. The results of the temperature dependency and radiation tolerance studies necessary for normalization and analysis of the data are included.

Brinker, David J.↗

NASA NTRS2007

Advanced Stirling Convertor Testing at NASA Glenn Research Center

The U.S. Department of Energy (DOE), Lockheed Martin Space Systems (LMSS), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science and exploration missions. This generator will make use of the free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. The ASRG will utilize two Advanced Stirling Convertors (ASC) to convert thermal energy from a radioisotope heat source to electricity. NASA GRC has initiated several experiments to demonstrate the functionality of the ASC, including: in-air extended operation, thermal vacuum extended operation, and ASRG simulation for mobile applications. The in-air and thermal vacuum test articles are intended to provide convertor performance data over an extended operating time. These test articles mimic some features of the ASRG without the requirement of low system mass. Operation in thermal vacuum adds the element of simulating deep space. This test article is being used to gather convertor performance and thermal data in a relevant environment. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto devices powered directly by the convertors, such as a rover. This paper discusses the design, fabrication, and implementation of these experiments.

Oriti, Salvatore↗

NASA NTRS2007

Advanced Stirling Convertor Testing at NASA Glenn Research Center

Oriti, Salvatore M.↗

NASA NTRS1992

Automated screening of propulsion system test data by neural networks, phase 1

The evaluation of propulsion system test and flight performance data involves reviewing an extremely large volume of sensor data generated by each test. An automated system that screens large volumes of data and identifies propulsion system parameters which appear unusual or anomalous will increase the productivity of data analysis. Data analysts may then focus on a smaller subset of anomalous data for further evaluation of propulsion system tests. Such an automated data screening system would give NASA the benefit of a reduction in the manpower and time required to complete a propulsion system data evaluation. A phase 1 effort to develop a prototype data screening system is reported. Neural networks will detect anomalies based on nominal propulsion system data only. It appears that a reasonable goal for an operational system would be to screen out 95 pct. of the nominal data, leaving less than 5 pct. needing further analysis by human experts.

Hoyt, W. Andes↗

NASA NTRS1972

Long life assurance study for manned spacecraft long life hardware. Volume 1: Summary of long life assurance guidelines

A long life assurance program for the development of design, process, test, and application guidelines for achieving reliable spacecraft hardware was conducted. The study approach consisted of a review of technical data performed concurrently with a survey of the aerospace industry. The data reviewed included design and operating characteristics, failure histories and solutions, and similar documents. The topics covered by the guidelines are reported. It is concluded that long life hardware is achieved through meticulous attention to many details and no simple set of rules can suffice.

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