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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

The Role of Magnetograms in Testing Models of Coronal Mass Ejections

A general review of current and future magnetographic capabilities is presented with emphasis on how they address observational predictions of CME models (e.g., the model/observation matrix developed in the SHINE 2000 workshop). Existing line-of-sight magnetographs can observe certain structural and kinematic properties of CME source regions when they are on the visible disk. These include polarity configuration, location and structure of the magnetic inversion line, proper motions of magnetic elements, and time variation of flux. Additional chromospheric magnetograms provide information on how the field spreads with height and, if properly sequenced with photospheric magnetograms, can determine whether flux is emerging or submerging. Vector magnetographs can provide information about currents and magnetic shear but will only begin to attain the spatial and temporal coverage appropriate to CMEs with the advent of the SOLIS vector spectromagnetograph and, hopefully, its copies at several widely spaced longitudes. Important additions to the SHINE 2000 matrix are required to define an observational program. These include spatial and temporal resolutions and extents as well as needed sensitivity.

Jones, Harrison P.↗
NASA NTRS1998

Testing Models for Perceptual Discrimination Using Repeatable Noise

Adding noise to stimuli to be discriminated allows estimation of observer classification functions based on the correlation between observer responses and relevant features of the noisy stimuli. Examples will be presented of stimulus features that are found in auditory tone detection and visual Vernier acuity. Using the standard signal detection model (Thurstone scaling), we derive formulas to estimate the proportion of the observer's decision variable variance that is controlled by the added noise. One is based on the probability of agreement of the observer with him/herself on trials with the same noise sample. Another is based on the relative performance of the observer and the model. When these do not agree, the model can be rejected. A second derivation gives the probability of agreement of observer and model when the observer follows the model except for internal noise. Agreement significantly less than this amount allows rejection of the model.

Ahumada, Albert J., Jr.↗
NASA NTRS2006

Fabrication of 0.0075-Scale Orbiter Phosphor Thermography Test Models for Shuttle RTF Aeroheating Studies

This report details the techniques and fidelity associated with aeroheating models constructed in support of the return-to-flight boundary layer transition (BLT) activity for STS-114. This report provides technical descriptions of the methods, materials, and equipment used, as well as the surface quality results obtained with the cast ceramic phosphor thermography models.

Buck, Gregory M.↗
NASA NTRS2012

Frequency-Based Spatial Correlation Assessments of the Ares I Subscale Acoustic Model Test Firings

The Marshall Space Flight Center has performed a series of test firings to simulate and understand the acoustic environments generated for the Ares I liftoff profiles. Part of the instrumentation package had special sensor groups to assess the acoustic field spatial correlation features for the various test configurations. The spatial correlation characteristics were evaluated for all of the test firings, inclusive of understanding the diffuse to propagating wave amplitude ratios, the acoustic wave decays, and the incident angle of propagating waves across the sensor groups. These parameters were evaluated across the measured frequency spectra and the associated uncertainties for each parameter were estimated.

Kenny, R. Jeremy↗
NASA NTRS2018

Overview of Recent EAST Testing, Modeling & Analysis

Shock Layer Radiation at NASA Ames - Background: Complex aerothermal and thermochemical phenomena of planetary entry define convective and radiative heating. A spacecraft's TPS (Thermal Protective System) mitigates heat transfer to substructure. Successful TPS design relies on verifiable characterization of these phenomena in the anticipated flight environment. - Approach: EAST (Electric Arc Shock Tube) [facility at Ames] simulates high-enthalpy, real-gas phenomena encountered by hypersonic vehicles entering planetary atmospheres by spectrally imaging the flow behind a moving shock wave. - Goal: Validate aerothermal models (DPLR (Data Parallel Line Relaxation Code) and NEQAIR (Nonequilibrium Radiative Transport and Spectra Program)), inform model improvements, reduce uncertainty and quantify design uncertainties. - Recent Relevant Projects: MSL (Mars Science Laboratory) & Mars 2020, InSight, OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer), Orion EFT-1 (Exploration Flight-1) and EM-1 (Exploration Mission-1) and New Frontiers.

Brandis, Aaron↗
NASA NTRS2016

Dynamic CFD Simulations of the MEADS II Ballistic Range Test Model

Dynamic, viscous, free-to-oscillate simulations of the Mars Entry Atmospheric Data System (MEADS) ballistic range model are performed using two different ow solvers, OVERFLOW and US3D. At the time of publication, data from the ballistic range experiment was not yet available, so the current work serves as a code-to-code exercise. Results from the analysis show good agreement between the predicted static aerodynamic coefficients for each solver. Both codes predict damped pitch oscillations for Mach 3:0 with initial amplitudes of 5⁰ and 30⁰, as well as for Mach 1:5 with initial amplitude of 30⁰. The two solvers predict undamped pitch oscillations for Mach 1:5 with initial amplitude of 5⁰. For most cases, US3D predicts less damping than OVERFLOW. The difference is attributed to higher pressures in the separated region of the wake, and the resultant effect on the backshell contribution to the pitching moment.

Stern, Eric C.↗
NASA NTRS2017

Mars ISRU Pathfinder Atmospheric Processing and Regolith Operations Modeling, Testing, and Optimization

The Mars Pathfinder project sought to increase the technology readiness level of Mars ISRU technologies being developed at KSC. The ultimate goal of these technologies is to produce propellant on Mars from the carbon dioxide found in the atmosphere and water found in the regolith. This overall system requires many components to collect the resources, prepare them for processing and ultimately to produce methane and oxygen.

Anthony Muscatello↗
NASA NTRS2022

NESC Peer Review of Exploration Systems Development (ESD) Integrated Vehicle Modal Test, Model Correlation, Development Flight Instrumentation (DFI) and Flight Loads Readiness; Uncertainty Propagation for Model Validation Sub-task

This report details a sub-task (regarding Uncertainty Propagation for Model Validation) from a NASA Engineering and Safety Center assessment that is a multi-year activity spanning the complete development of the Space Launch System integrated vehicle structural dynamic models, and the development of the certification of flight readiness for the Artemis 1 and Artemis 2 vehicles and their variants.

Exploration Systems Development; Development Fligh↗
NASA NTRS1965

Thermal scale modeling.

Test models of spacecraft to investigate thermal behavior, particularly Mariner temperature control model

SPACECRAFT MODEL↗
NASA NTRS1983

Annular Momentum Control Device (AMCD)

The Annular Momentum Control Device (AMCD) concept, applications, and advantages as a momentum storage device are discussed. A laboratory test model AMCD was designed and built. The laboratory model AMCD is described and the results of the laboratory model test phase are presented. The efforts required to complete the AMCD laboratory model test phase are outlined.

Groom, N. J.↗
NASA NTRS1978

Pioneer Venus probe models instrumented prop tests

Models of both the small and large Pioneer Venus probes were dropped from a helicopter to simulate the conditions of Mach and Reynolds numbers to be encountered by the probes upon entry into the Venus atmosphere. The models were dropped at an average Mach number of .10 and at an average Reynolds number of 2.84 million for the small probe and 2.90 million for the large probe. After the large amplitude launching oscillations were damped, the small probe oscillations in angle of attack and in sideslip were generally less than 2 degrees. The large probe oscillations were generally less than 10 degrees. Both exhibited distinct frequencies. The motion of the small probe in a place perpendicular to the z axis was random while the large probe rotated (corkscrewed) at 1.1 cycles per second about the z axis. The average drag coefficients of the probe models were .714 for the small probe and .663 for the large probe.

Muirhead, V. U.↗
NASA NTRS1984

Space Shuttle AFRSI OMS pod environment test using model 81-0 test fixture in the Ames Research Center 9x7-foot supersonic wind tunnel (OS-314A/B/C)

A test was conducted in the NASA/Ames Research Center 9x7-foot Supersonic Wind Tunnel to help resolve an anomaly that developed during the STS-6 orbiter flight wherein sections of the Advanced Flexible Reusable Surface Insulation (AFRSI) covering the OMS pods suffered some damage. A one-third scale two-dimensional shell structure model of an OMS pod cross-section was employed to support the test articles. These consisted of 15 AFRSI blanket panels form-fitted over the shell structures for exposure to simulated flight conditions. Of six baseline blankets, two were treated with special surface coatings. Two other panels were configured with AFRSI sections removed from the OV099 orbiter vehicle after the STS-6 flight. Seven additional specimens incorporated alternative designs and repairs. Following a series of surface pressure calibration runs, the specimens were exposed to simulated ascent and entry dynamic pressure profiles. Entry conditions included the use of a vortex generator to evaluate the effect of shed vortices on the AFRSI located in the area of concern.

Collette, J. G. R.↗
NASA NTRS1991

Description and evaluation of an interference assessment for a slotted-wall wind tunnel

A wind-tunnel interference assessment method applicable to test sections with discrete finite-length wall slots is described. The method is based on high order panel method technology and uses mixed boundary conditions to satisfy both the tunnel geometry and wall pressure distributions measured in the slotted-wall region. Both the test model and its sting support system are represented by distributed singularities. The method yields interference corrections to the model test data as well as surveys through the interference field at arbitrary locations. These results include the equivalent of tunnel Mach calibration, longitudinal pressure gradient, tunnel flow angularity, wall interference, and an inviscid form of sting interference. Alternative results which omit the direct contribution of the sting are also produced. The method was applied to the National Transonic Facility at NASA Langley Research Center for both tunnel calibration tests and tests of two models of subsonic transport configurations.

Kemp, William B., Jr.↗
NASA NTRS1995

A hybrid electronically scanned pressure module for cryogenic environments

Pressure is one of the most important parameters measured when testing models in wind tunnels. For models tested in the cryogenic environment of the National Transonic Facility at NASA Langley Research Center, the technique of utilizing commercially available multichannel pressure modules inside the models is difficult due to the small internal volume of the models and the requirement of keeping the pressure transducer modules within an acceptable temperature range well above the -173 degrees C tunnel temperature. A prototype multichannel pressure transducer module has been designed and fabricated with stable, repeatable sensors and materials optimized for reliable performance in the cryogenic environment. The module has 16 single crystal silicon piezoresistive pressure sensors electrostatically bonded to a metalized Pyrex substrate for sensing the wind tunnel model pressures. An integral temperature sensor mounted on each silicon micromachined pressure sensor senses real-time temperature fluctuations to within 0.1 degrees C to correct for thermally induced non-random sensor drift. The data presented here are from a prototype sensor module tested in the 0.3 M cryogenic tunnel and thermal equilibrium conditions in an environmental chamber which approximates the thermal environment (-173 degrees C to +60 degrees C) of the National Transonic Facility.

Chapman, J. J.↗