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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Aeroservoelastic wind-tunnel investigations using the active flexible wing model - Status and recent accomplishments

This paper describes the status of the joint NASA/Rockwell Active Flexible Wing Wind-Tunnel Test Program. The objectives of the program are to develop and validate the analysis, design and test methodologies required to apply multifunction active control technology for improving aircraft performance and stability. Major tasks of the program include designing digital multiinput/multioutput flutter-suppression and rolling-maneuver-load-alleviation concepts for a flexible full-span wind-tunnel model, obtaining an experimental data base for the basic model and each control concept, and providing comparisons between experimental and analytical results to validate the methodologies. This program is also providing the opportunity to improve real-time simulation techniques and to gain practical experience with digital control law implementation procedures.

Noll, Thomas↗
DOE OSTI2022

SAS4A/SASSYS-1 Validation with the FFTF LOFWOS Tests #10-12

The FFTF liquid sodium cooled test reactor was built to assist the development and testing of advanced fuels and material for fast reactors. The goals of the FFTF Passive Safety Testing program included confirming the safety margins of FFTF as a liquid metal reactor, providing data for computer code validation, and demonstrating the inherent and passive safety benefits of its specific design features. The program included thirteen unprotected loss of flow without scram tests. The results of modeling and simulation of LOFWOS Tests #10, #11, and #12 are presented in this report to support validation of Argonne’s SAS4A/SASSYS-1 fast reactor safety analysis code. These three tests did not use the primary loop pony motors and thus transitioned to natural circulation flow rates from varying initial power levels. This validation activity leverages modeling and simulation efforts that originated under an International Atomic Energy Agency Coordinated Research Project (CRP) for benchmark analysis of the FFTF LOFWOS Test #13. The SAS4A/SASSYS-1 model originally developed for the CRP has been extended to include LOFWOS Tests #10-12 and modernized to utilize new code features and modeling practices. Predicted results from SAS4A/SASSYS-1 were compared to measured test data and differences were investigated. Overall, it was concluded that, for LOFWOS Tests #10-12, there was good agreement between the flow, power, and temperature predictions and the measured data.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1972

Apollo lunar orbital sciences program alpha and X-ray spectrometers

The development of the alpha and X-ray spectrometers which were used on the Apollo 15 and 16 flights is discussed. Specific subjects presented are: (1) lunar program management, (2) scientific and technical approach, (3) major test programs, (4) reliability, quality assurance, and safety, and (5) subcontract management.

Source record↗
NASA NTRS1973

Analysis and testing of two-dimensional slot nozzle ejectors with variable area mixing sections

Finite difference computer techniques have been used to calculate the detailed performance of air to air two-dimensional ejectors with symmetric variable area mixing sections and coaxial coverging primary nozzles. The analysis of the primary nozzle assumed correct expansion of the flow and is suitable for subsonic and slightly supersonic velocity levels. The variation of the mixing section channel walls is assumed to be gradual so that the static pressure can be assumed uniform on planes perpendicular to the axis. A test program was run to provide two-dimensional ejector test data for verification of the computer analysis. A primary converging nozzle with a discharge geometry of 0.125 inch x 8.0 inch was supplied with 600 SCFM of air at about 35 psia and 180 F. This nozzle was combined with two mixing section geometries with throat sizes of 1.25 inch x 8.0 inch and 1.875 inch x 8.0 inch and was tested at a total of 11 operating points.

Gilbert, G. B.↗
NASA NTRS1973

Flight-measured X-24A lifting body control surface hinge moments and correlation with wind tunnel predictions

Control-surface hinge-moment measurements obtained in the X-24A lifting body flight-test program are compared with results from wind-tunnel tests. The effects of variations in angle of attack, angle of sideslip, rudder bias, rudder deflection, upper-flap deflection, lower-flap deflection, Mach number, and rocket-engine operation on the control-surface hinge moments are presented. In-flight motion pictures of tufts attached to the inboard side of the right fin and the rudder and upper-flap surfaces are discussed.

Tang, M. H.↗
NASA NTRS1975

Analysis and testing of two-dimensional slot nozzle ejectors with variable area mixing sections

Finite difference computer techniques have been used to calculate the detailed performance of air-to-air two-dimensional ejectors with symmetric variable area mixing sections and coaxial converging primary nozzles. The analysis of the primary nozzle assumed correct expansion of the flow and is suitable for subsonic and slightly supersonic velocity levels. The variation of the mixing section channel walls is assumed to be gradual so that the static pressure can be assumed uniform on planes perpendicular to the axis. A test program was run to provide two-dimensional ejector test data for verification of the computer analysis. A primary converging nozzle with a discharge geometry of 3.18 mm x 203 mm was supplied with 0.340 kg/sec of air at about 2.43 bar and 356 K. This nozzle was combined with two mixing section geometries with throat sizes of 31.8 mm x 203 mm and 47.6 mm x 203 mm and was tested at a total of 11 operating points.

Gilbert, G. B.↗
NASA NTRS1982

An advanced tracker design for pointing and control of space vehicles using the charge injection device

The use of charge transfer devices (CTD) in pointing and control of space vehicles is examined, with emphasis on the use of charge injection devices (CID). The selection of CTD type and CID operation, including CID signal and noise analysis and signal improvement, are discussed. Star tracking operational advantages of the CTD are pointed out, and the tracking optical concept is discussed and graphically depicted. The position interpolation procedure and the effects of rate of stellar motion on position interpolation are considered, and error analysis is examined. Finally, the breadboard and test program are discussed in detail, coarse and fine acquisition, test for star, track pattern, test procedure and results. An overall accuracy performance of approximately 0.02 pixels or approximately 0.8 arcsec for the test equipment and tracker was obtained.

Jones, C.↗
NASA NTRS1989

Space shuttle solid rocket booster redesign and testing

The redesigned solid rocket motor of the Space Shuttle is described. Improvements over the model that led to the loss of the Space Shuttle Challenger are outlined. Scale and full-size tests carried out to verify the quality of the redesign are described. A unique feature of the test program is the introduction of deliberate flaws into some test articles. Post-flight evaluation of the redesigned boosters show excellent results.

R. E. Mitchell↗
NASA NTRS1990

Detailed modal testing of a solid rocket motor using a portable test system

Modern analytical techniques have expended the ability to evaluate solid rocket motors used in launch vehicles. As more detailed models of solid rocket motors were developed, testing methods were required to verify the models. Experimental modal analysis (modal testing) of space structures and launch vehicles has been a requirement for model validation for many years. However, previous testing of solid rocket motors has not typically involved dynamic modal testing of full scale motors for verification of solid propellant or system assembly properties. Innovative approaches to the testing of solid rocket motors were developed and modal testing of a full scale, two segment Titan 34D Solid Rocket Motor (SRM) was performed to validate detailed computer modeling. Special modifications were made to convert an existing facility into a temporary modal test facility which would accommodate the test article. The assembly of conventional data acquisition equipment into a multiple channel count portable system has made modal testing in the field feasible. Special purpose hydraulic exciters were configured to apply the dynamic driving forces required. All instrumentation and data collection equipment were installed at the test site for the duration of the test program and removed upon completion. Conversion of an existing test facility into a temporary modal test facility, and use of a multiple channel count portable test data acquisition system allowed all test objectives to be met and resulted in validation of the computer model in a minimum time.

Glozman, Vladimir↗
NASA NTRS1992

High pressure turbomachinery ground test facility

Turbomachinery test facilities are at present scarce to non-existent world-wide. The turbomachinery test facility at Stennis Space Center will provide for advanced development and research and development capabilities for liquid hydrogen/liquid oxygen propellant rocket engine components. The facility will provide ultra-high pressure via gas generators to deliver the needed turbine drive on various turbomachinery. State of the art process control systems will provide the vital pressure, temperature and flow requirements during tests. These systems will better control adverse transient conditions during start-up and shutdown, and by using advanced control theory, as well as incorporate test article health monitoring. Also, digital data acquisition systems will obtain high frequency (up to 20 KHz) and low frequency (up to 1 KHz) data during the test. Pressures of up to 15,000 psi will be generated to pressurize high pressure tanks supplying cryogens to various test article inlets thus pushing turbopump materials and manufacturing processes to their limits. By planning for future projects the test facility will be easily adaptable to multi-program test configurations over a range of thermodynamic positions.

Scheuermann, Patrick E.↗
NASA NTRS1995

Post-launch data analysis for the cosmic ray isotope experiment ONR-604 in the Combined Release and Radiation Effects Satellite (CRRES)

Research was continued on the origins, acceleration mechanisms, and the propagation modes of the hierarchy of energetic charged particles found in a wide range of astrophysical settings, extending from the cosmic rays arriving from the depth of the galaxy to the energetic particles in the heliosphere and in the near earth environment. In particular this grant has been a vital support in the investigation of the particle radiations in the earth's magnetosphere. The ONR-604 instrument was launched in July 1990 aboard the CRRES spacecraft. The CRRES mission has been a joint program of NASA and the U.S. Air Force Space Test Program which has provided launch support and telemetry coverage. The spacecraft was placed into a low-inclination eccentric orbit with a period of approximately 10 hours, and thus measured charged particle fluxes in both interplanetary space and in the earth's trapped radiation. ONR-604 performed extremely well, both in interplanetary space and in the intense radiation belt environment. We were able to make detailed measurements of interplanetary fluxes and composition into L=4, or for more than 50% of the orbital period. Thus the experiment produced two valuable datasets, one set outside of L=4 for interplanetary studies, and one set inside of L=4 for radiation belt studies. The data returned by the University of Chicago ONR-604 instrument has been the base for 10 papers on magnetospheric and galactic energetic-particle research.

Simpson, John A.↗
NASA NTRS1997

The New Heavy Gas Testing Capability in the NASA Langley Transonic Dynamics Tunnel

The NASA Langley Transonic Dynamics Tunnel (TDT) has provided a unique capability for aeroelastic testing for over thirty-five years. The facility has a rich history of significant contributions to the design of many United States commercial transports and military aircraft. The facility has many features which contribute to its uniqueness for aeroelasticity testing; however, perhaps the most important facility capability is the use of a heavy gas test medium to achieve higher test densities. Higher test medium densities substantially improve model building requirements and therefore simplify the fabrication process for building aeroelastically scaled wind-tunnel models. The heavy gas also provides other testing benefits, including reduction in the power requirements to operate the facility during testing. Unfortunately, the use of the original heavy gas has been curtailed due to environmental concerns. A new gas, referred to as R-134a, has been identified as a suitable replacement for the former TDT heavy gas. The TDT is currently undergoing a facility upgrade to allow testing in R-134a heavy gas. This replacement gas will result in an operational test envelope, model scaling advantages, and general testing capabilities similar to those available with the former TDT heavy gas. As such, the TDT is expected to remain a viable facility for aeroelasticity research and aircraft dynamic clearance testing well into the 21st century. This paper describes the anticipated advantages and facility calibration plans for the new heavy gas and briefly reviews several past test programs that exemplify the possible benefits of heavy gas testing.

Cole, Stanley R.↗
NASA NTRS1995

A Conversion of Wheatstone Bridge to Current-Loop Signal Conditioning for Strain Gages

Current loop circuitry replaced Wheatstone bridge circuitry to signal-condition strain gage transducers in more than 350 data channels for two different test programs at NASA Dryden Flight Research Center. The uncorrected test data from current loop circuitry had a lower noise level than data from comparable Wheatstone bridge circuitry, were linear with respect to gage-resistance change, and were uninfluenced by varying lead-wire resistance. The current loop channels were easier for the technicians to set up, verify, and operate than equivalent Wheatstone bridge channels. Design choices and circuit details are presented in this paper in addition to operational experience.

Anderson, Karl F.↗
NASA NTRS2011

Human-in-the-Loop Integrated Life Support Systems Ground Testing

Human exploration missions beyond low earth orbit will be long duration with abort scenarios of days to months. This necessitates provisioning the crew with all the things they will need to sustain themselves while carrying out mission objectives. Systems engineering and integration is critical to the point where extensive integrated testing of life support systems on the ground is required to identify and mitigate risks. Ground test facilities (human-rated altitude chamber) at the Johnson Space Center are being readied to integrate all the systems for a mission along with a human test crew. The relevant environment will include deep space habitat human accommodations, sealed atmosphere of 8 psi total pressure and 32% oxygen concentration, life support systems (food, air, water), communications, crew accommodations, medical, EVA, tools, etc. Testing periods will approximate those of the expected missions (such as a near Earth asteroid, Earth-Moon L2 or L1, the moon). This type of integrated testing is needed for research and technology development as well as later during the mission design, development, test, and evaluation (DDT&E) phases of an approved program. Testing will evolve to be carried out at the mission level fly the mission on the ground . Mission testing will also serve to inform the public and provide the opportunity for active participation by international partners.

Henninger, Donald L.↗
NASA NTRS2012

Human in the Loop Integrated Life Support Systems Ground Testing

Human exploration missions beyond low earth orbit will be long duration with abort scenarios of days to months. This necessitates provisioning the crew with all the things they will need to sustain themselves while carrying out mission objectives. Systems engineering and integration is critical to the point where extensive integrated testing of life support systems on the ground is required to identify and mitigate risks. Ground test facilities (human-rated altitude chambers) at the Johnson Space Center are being readied to integrate all the systems for a mission along with a human test crew. The relevant environment will include deep space habitat human accommodations, sealed atmosphere capable of 14.7 to 8 psi total pressure and 21 to 32% oxygen concentration, life support systems (food, air, and water), communications, crew accommodations, medical, EVA, tools, etc. Testing periods will approximate those of the expected missions (such as a near Earth asteroid, Earth-Moon L2 or L1, the moon, Mars). This type of integrated testing is needed for research and technology development as well as later during the mission design, development, test, and evaluation (DDT&E) phases of an approved program. Testing will evolve to be carried out at the mission level fly the mission on the ground . Mission testing will also serve to inform the public and provide the opportunity for active participation by international, industrial and academic partners.

Henninger, Donald L.↗
NASA NTRS2012

Development and Calibration of a System-Integrated Rotorcraft Finite Element Model for Impact Scenarios

Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber (DEA) under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. The presence of this energy absorbing device reduced the peak impact acceleration levels by a factor of three. Accelerations and kinematic data collected from the crash tests were compared to a system-integrated finite element model of the test article developed in parallel with the test program. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests were conducted to evaluate the impact performances of various components and subsystems, including new crush tubes and the DEA blocks. Parameters defined for the system-integrated finite element model were determined from these tests. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the full-scale crash test without the DEA. This combination of heuristic and quantitative methods identified modeling deficiencies, evaluated parameter importance, and proposed required model changes. The multidimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and copilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. One lesson learned was that this approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and pretest predictions. Complete crash simulations with validated finite element models can be used to satisfy crash certification requirements, potentially reducing overall development costs.

Annett, Martin S.↗
NASA NTRS2017

Characterization of Volatiles Loss from Soil Samples at Lunar Environments

Resource Prospector Integrated Thermal Vacuum Test Program A series of ground based dirty thermal vacuum tests are being conducted to better understand the subsurface sampling operations for RP Volatiles loss during sampling operations Hardware performance Sample removal and transfer Concept of operationsInstrumentation5 test campaigns over 5 years have been conducted with RP hardware with advancing hardware designs and additional RP subsystems Volatiles sampling 4 years Using flight-forward regolith sampling hardware, empirically determine volatile retention at lunar-relevant conditions Use data to improve theoretical predictions Determine driving variables for retention Bound water loss potential to define measurement uncertainties. The main goal of this talk is to introduce you to our approach to characterizing volatiles loss for RP. Introduce the facility and its capabilities Overview of the RP hardware used in integrated testing (most recent iteration) Summarize the test variables used thus farReview a sample of the results.

In Situ Resource Utilization↗