Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “SAMS”

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 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Independent Effects of Reynolds and Mach Numbers on the Aerodynamics of an Iced Swept Wing

Aerodynamic assessment of icing effects on swept wings is an important component of a larger effort to improve three-dimensional icing simulation capabilities. An understanding of ice-shape geometric fidelity and Reynolds and Mach number effects on the iced-wing aerodynamics is needed to guide the development and validation of ice-accretion simulation tools. To this end, wind-tunnel testing was carried out for a 13.3%-scale semispan wing based upon the Common Research Model airplane configuration. The wind-tunnel testing was conducted at the ONERA F1 pressurized wind tunnel with Reynolds numbers of 1.6×10(exp 6) to 11.9×10(exp 6) and Mach numbers of 0.09 to 0.34. Five different configurations were investigated using fully 3D, high-fidelity artificial ice shapes that maintain nearly all of the 3D ice accretion features documented in prior icing-wind tunnel tests. These large, leadingedge ice shapes were nominally based upon airplane holding in icing conditions scenarios. For three of these configurations, lower-fidelity simulations were also built and tested. The results presented in this paper show that while Reynolds and Mach number effects are important for quantifying the clean-wing performance, there is very little to no effect for an iced-wing with 3D, high-fidelity artificial ice shapes or 3D smooth ice shapes with grit roughness. These conclusions are consistent with the large volume of past research on icedairfoils. However, some differences were also noted for the associated stalling angle of the iced swept wing and for various lower-fidelity versions of the leading-edge ice accretion. More research is planned to further investigate the key features of ice accretion geometry that must be simulated in lower-fidelity versions in order to capture the essential aerodynamics.

Broeren, Andy P.↗
NASA NTRS2018

Summary of Ice Shape Geometric Fidelity Studies on an Iced Swept Wing

Understanding the aerodynamic impact of swept-wing ice accretions is a crucial component of the design of modern aircraft. Computer-simulation tools are commonly used to approximate ice shapes, so the necessary level of detail or fidelity of those simulated ice shapes must be understood relative to high-fidelity representations of the ice. Previous tests were performed in the NASA Icing Research Tunnel to acquire high-fidelity ice shapes. Some of those ice shapes are based on aircraft certification requirements. From this database, full-span artificial ice shapes were designed and manufactured for both an 8.9%-scale and 13.3%-scale semispan wing model of the CRM65 which has been established as the full-scale baseline for this swept-wing project. These models were tested in the Walter H. Beech wind tunnel at Wichita State University and at the ONERA (Office national d'etudes et de recherches aerospatiales) F1 facility, respectively. The data collected in the Wichita State University wind tunnel provided a low-Reynolds number baseline study while the pressurized F1 facility produced data over a wide range of Reynolds and Mach numbers with the highest Reynolds number studied being approximately Re = 11.9 by 10 (sup 6). Three different fidelity representations were created based on three different icing conditions. Lower-fidelity ice shapes were created by lofting a smooth ice shape between cross-section cuts of the high-fidelity ice shape. Grit roughness was attached to this smooth ice shape as another fidelity variant. The data indicates that the geometric fidelity of the ice shapes resulted in significant differences in lift and drag. These results were similar at both facilities over the wide range of test conditions utilized.

Aerodynamics↗
NASA NTRS2018

The New CCSDS Standard for Low-Complexity Lossless and Near-Lossless Multispectral and Hyperspectral Image Compression

This paper describes the emerging Issue 2 of the CCSDS-123.0-B standard for low-complexity compression of multispectral and hyperspectral imagery, focusing on its new features and capabilities. Most significantly, this new issue incorporates a closed-loop quantization scheme to provide near-lossless compression capability while still supporting lossless compression, and introduces a new entropy coding option that provides better compression of low-entropy data.

Kiely, Aaron B.↗
NASA NTRS2018

Comparison of Iced Aerodynamic Measurements on a Swept Wing from Two Wind Tunnels

Artificial ice shapes of various geometric fidelity were tested on a wing model based on the Common Research Model. Low Reynolds number tests were conducted at Wichita State University's Beech Memorial Wind Tunnel, and high Reynolds number tests were conducted at ONERA's F1 wind tunnel. The aerodynamic performance data from the two facilities were compared at matched or similar Reynolds and Mach number to ensure that the results and trends observed at low Reynolds number could be applied and continued to high Reynolds number. For both clean and iced configurations, the data from Wichita State University and F1 agreed well at matched or similar Reynolds and Mach numbers. The lift and pitching moment curves agreed very well for most configurations. There appeared to be 0.2-0.3deg offset in the angle of attack between the Wichita State University and F1 data, possibly due to different flow angularities in the test sections of the two facilities. There was also an offset in the drag values between the two facilities from an unknown cause. Overall, the data compared very well between the low Reynolds number test at Wichita State University tunnel and the high Reynolds number test at F1. This indicated that data from the low Reynolds number tests could be used to understand iced-swept-wing aerodynamics at high Reynolds number.

Federal Aviation Administration↗
NASA NTRS2018

Power Processing and Flow Control for a 100 kW Hall Thruster System

Aerojet Rocketdyne's NextSTEP program is developing and demonstrating a 100 kW Electric Propulsion (EP) system, the XR-100, which includes a modular power processing unit and modular xenon feed system to operate a Nested Hall Thruster (NHT) designed for powers up to 200 kW. The NextSTEP system is intended for use on large scale cargo transportation to support human missions to the Moon and Mars, which require very high-power Solar Electric Propulsion (SEP) systems operating between 200 and 400 kW. The three-year program objective is to operate the integrated EP system continuously at 100 kW for 100 hours, advancing this very high-power EP system to Technology Readiness Level (TRL) 5. In order to process the power and control propellant flow for this high-power system, Aerojet Rocketdyne has developed a modular concept for the Power Processing Units (PPUs) and Xenon feed system. The program has completed testing of critical elements of the PPU and feed system with a thruster simulator. Design upgrades to demonstrate the TRL 5 capabilities are underway. This paper will present an overview of the program and system design approach, the high power XR-100 capabilities of the PPU and feed system, and the latest test results for the 100 kW EP system demonstration program. In order to successfully execute this contract, there is a close collaboration between the teammates at Aerojet Rocketdyne (AR), the University of Michigan (UM), the NASA Jet Propulsion Laboratory (JPL), and the NASA Glenn Research Center (GRC).

Hablitzel, Sam↗
NASA NTRS2019

Rapid Development of the Seeker Free-Flying Inspector Guidance, Navigation, and Control System

Seeker is an automated extravehicular free-flying inspector CubeSat designed and built in-house at the Johnson Space Center (JSC). As a Class 1E project funded by the International Space Station (ISS) Program, Seeker had a stream-lined process to flight certification, but the vehicle had to be designed, developed, tested, and delivered within approximately one year after authority to proceed (ATP) and within a $1.8 million budget. These constraints necessitated an expedited Guidance, Navigation, and Control (GNC) development schedule. Development began with a navigation sensor trade study using Linear Covariance (LinCov) analysis and a rapid sensor down-selection process, resulting in the use of commercial off-the-shelf (COTS) sensors which could be procured quickly and subjected to in-house environmental testing to qualify them for flight. A neural network was used to enable a COTS camera to provide bearing measure-ments for visual navigation. The GNC flight software (FSW) algorithms utilized lean development practices and leveraged the Core Flight Software (CFS) architecture to rapidly develop the GNC system, tune the system parameters, and verify performance in simulation. This pace was anchored by several Hardware-Software Integration (HSI) milestones, which forced the Seeker GNC team to develop the interfaces both between hardware and software and between the GNC domains early in the project and to enable a timely delivery.

Sullivan, Jake↗
NASA NTRS2018

Re-evaluation of IIH as the Ideal Terrestrial Analog for Sans: Is There a Better Model to Consider?

While astronauts are returning from long duration spaceflight with multiple ocular signs that mimic those seen in terrestrial patients with elevated intracranial pressure (ICP), evidence has yet to prove a clinically significant increase in ICP during space.1 Preliminary research evidence may even suggest that ICP decreases in microgravity. Idiopathic intracranial hypertension (IIH) has long been considered the ideal terrestrial analogue to Spaceflight Associated Neuro-ocular Syndrome (SANS).1 However, there are several critical features of SANS that do not complement any reported case of IIH on Earth. These findings mandate a closer look at the accuracy of IIH as a terrestrial SANS analog.

Batliwala, Shehzad↗
NASA NTRS2014

An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development

This final technical report describes the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable solution to the most probable impact threat of an asteroid or comet with short warning time (less than 5 years). The technical materials contained in this final report are based on numerous technical papers, which have been previously published by the project team of the NIAC Phase 1 and 2 studies during the past three years. Those technical papers as well as a NIAC Phase 2 Executive Summary report can be downloaded from the ADRC website (www.adrc.iastate.edu).

NEO↗
NASA NTRS2018

Compact Mid-Wave Imaging System (CMIS) for Retrieval of Cloud Motion Vectors and Cloud Geometric Heights

The Johns Hopkins University Applied Physics Laboratory (JHU/APL) is developing a compact, light-weight, and low power midwave-infrared (MWIR) imager called the Compact Midwave Imaging Sensor (CMIS), under the support of the NASA Earth Science Technology Office Instrument Incubator Program. The goal of this CMIS instrument development and demonstration project is to increase the technical readiness of CMIS, a multi-spectral sensor capable of retrieving 3D winds and cloud heights 24/7, for a space mission. The CMIS instrument employs an advanced MWIR detector that requires less cooling than traditional technologies and thus permits a compact, low-power design, which enables accommodation on small spacecraft such as CubeSats. CMIS provides the critical midwave component of a multi-spectral sensor suite that includes a high-resolution Day-Night Band and a longwave infrared (LWIR) imager to provide global cloud characterization and theater weather imagery. In this presentation, an overview of the CMIS project, including the high-level sensor design, the concept of operations, and measurement capability will be presented. System performance for a variety of different scenes generated by a cloud resolving model (CRM) will also be discussed.

midwave↗
NASA NTRS2019

A Three-Dimensional Thermodynamically Based Function for the Progressive Failure of Unidirectional Composites

A thermodynamically-based work potential theory for modeling progressive damage for laminated, unidirectional composites assuming plane stress (2D Schaperystheory) is extended to three dimensioanl (3D). An internal state variable, S, is defined to account for the dissipated energy due to damage evolution in the form of microstructure changes in the matrix. With the stationary of the total work potential with respect to the internal state variable, a thermodynamically-consistent set of evolution equationsis derived. The internal state variable is related to the transverse and shear modulithrough microdamage functions. In the first part of this work, coupon specimensare prepared to conduct experiments to characterize the relations between the internalstate variable and the transverse modulus as well as shear modulus. The informationis subsequent used for the prediction of three point bending test. In the second partof this work, objectivity is studied. Three separate methods utilizing different definitions of a reduced internal state variable or of the order of the polynomials are used to represent the matrix micro-damage functions are employed. The three methods are implemented in a user defined subroutine within a commercial finite element method software package. Results from numerical simulations of a center-notched composites panel are compared. The agreement in the maximum stress predictions among the three methods indicates that objectivity, with respect to the functional form of themicrodamage functions, is satisfied.

carbon fiber reinforced polymer composites↗
NASA NTRS2019

GeneLab Metadata & Processed Data

An overview of the organization and structure of the metadata and data in the GeneLab Data Repository. This presentaiton provides examples of how the data is presented and what data can be download from the GLDS Repository.

Gebre, Sam↗
NASA NTRS2019

Safe, High Power/Voltage Battery Module Design Challenges

NASA seeks to demonstrate a path for achieving safe, high power, and high performing Li-ion battery designs for the purpose of establishing design guidelines for our aeronautic and spacecraft applications. Safe means passively resistant to thermal runaway propagation of any single cell catastrophic thermal runaway. High power means capable of 3C continuous discharge without overheating. High performing means achieving > 160 Wh/kg, 200 Wh/L. The biggest challenge has been balancing a high flux light weight path for cell heat dissipation during the high rate discharge that minimizes thermal gradients between cells and also protects adjacent cells from the heat load of thermal runaway cell. Our solution includes an oscillating heat pipe spine that contacts every 18650 cell in the pack and careful cell design selection to maximize the range of initial temperatures conditions where the battery can safely complete the 3C discharge.

Thermal runaway↗
NASA NTRS2016

Radiation Tolerance Studies of Long Wavelength Infrared InAs/GaSb Detectors

In this work we investigated the effect of proton irradiation on the performance of long wavelength infrared (LWIR) InAs/GaSb photodiodes (λ(sub c) = 10.2µm) based on the complementary barrier infrared detector (CBIRD) design. We found that irradiation with 68MeV protons up to the total ionizing dose TID = 200 kRad results in only small (about 15%) decrease of the Quantum Efficiency and does not increase the operational bias of the photodiodes. However, the irradiation causes a significant increase of the dark current from j(sub d) = 5x10(exp -5) A/sq cm at V(sub b) = 0.1V and T = 80K to j(sub d) = 6x10(exp -3) A/sq cm at TID = 200 kRad. This change in the dark current mechanism can be attributed to the onset of surface leakage current, generated by the trap assisted tunneling processes in the proton displacement damage areas near the device sidewalls.

InAs/GaSb photodiodes↗
NASA NTRS2019

FOXSI-2 Solar Microflares: Multi-Instrument Differential Emission Measure Analysis

Outline: Overview of FOXSI-2 (Focusing Optics X-ray Solar Imager) coordinated microflare observations with Hinode/XRT (X-Ray Telescope) and SDO/AIA (Solar Dynamics Observatory/Atmospheric Imaging Assembly); Temperature response functions for FOXSI-2, XRT and AIA; Combined Differential Emission Measure (DEM) analysis - to determine the amount of plasma in the line of sight that emits the radiation as a function of temperature; Thermal energy released during the microflares; Summary.

Athiray, P. S.↗
NASA NTRS2019

Biomarker and Geochemical Assay Validation in Mars Analog Sites: Lessons from the FELDSPAR (Field Exploration and Life Detection Sampling for Planetary Analog Research) Project

Missions looking for signs of life on other worlds can often only take a few samples once they arrive. Making sense of these "few and far between" observations is easier if we know what a "normal" level of variation for that kind of planet is. Recent eruption sites in Iceland are good places to learn about this, because they have very little life present and the same types of rocks as many places on Mars. We have visited several of these sites in Iceland and tested many different kinds of measurements: the energy available for life, the amount of DNA (an important biological molecule) present, the relative amounts of different kinds of micro-organisms, and the specific minerals that make up the rocks and ground. In addition to recommendations for future expeditions, we have also shown that using early on-site measurements to choose later on-site sample sites is very helpful in reducing the number of sample sites needed.

Geochemical Assay Validation↗
NASA NTRS2016

Performance and Radiation Tolerance of InAs/GaSb LWIR Detectors Based on CBIRD Design

We report our recent developments of antimonide based infrared photodetectors utilizing a complementary barrier infrared detector (CBIRD) design. The new generation of devices can operate close to zero bias with the same quantum efficiency as the initial design. 320x256 pixel long-wavelength infrared focal plane arrays utilizing optimized design have been demonstrated with 8.8 µm cutoff wavelength and noise equivalent differential temperature of 26 mK at operating temperature of 80 K for 300 K background and f/2 optics. As CBIRD detectors became valuable candidates for space-based instruments, question of their radiation tolerance became important. Here, we report our investigations of the proton irradiation effects on the photodetector performance.

heterostructure↗
NASA NTRS2017

Extended Cut-Off Wavelength nBn Detector Utilizing InAsSb/InSb Digital Alloy Absorber

We investigated a novel approach to extend a cut -off wavelength of Sb-based nBn detectors. We incorporated a series of single InSb monolayer into InAsSb bulk that allowed to realize a digital alloy absorber with an extended cut-off wavelength of λ = 4.6 μm at T = 200 K. The cut-off wavelength extension to 4.6μm is technologically important for realization of detectors covering CO2 absorption line at 4.26μm

InAsSb/InSb photodiodes↗