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Technology Focus

Electronics/Computers

Software

Materials

Mechanics/Machinery

Manufacturing

Bio-Medical

Physical Sciences

Information Sciences

Books and Reports

03-14 March 2014

https://ntrs.nasa.gov/search.jsp?R=20140001128 2020-07-20T14:16:05+00:00Z

NASA Tech Briefs, March 2014 1

INTRODUCTIONTech Briefs are short announcements of innovations originating from research and developmentactivities of the National Aeronautics and Space Administration. They emphasize information con-sidered likely to be transferable across industrial, regional, or disciplinary lines and are issued toencourage commercial application.

Additional Information on NASA Tech Briefs and TSPsAdditional information announced herein may be obtained from the NASA Technical Reports Server:http://ntrs.nasa.gov.

Please reference the control numbers appearing at the end of each Tech Brief. Infor mation on NASA’s Innovative Partnerships Program (IPP), its documents, and services is available on the World Wide Webat http://www.ipp.nasa.gov.

Technology Transfer Offices are located at NASA field centers to provide technology-transfer access to in-dustrial users. Inquiries can be made by contacting NASA field centers listed below.

Ames Research CenterSelected technological strengths: InformationTechnology; Biotechnology; Nanotechnology;Aerospace Operations Systems; Rotorcraft; Ther-mal Protection Systems.David Morse(650) [email protected]

Armstrong Flight Research CenterSelected technological strengths: Aerodynamics;Aeronautics Flight Testing; Aeropropulsion; FlightSystems; Thermal Testing; Integrated SystemsTest and Validation.Laura Fobel(661) [email protected]

Glenn Research CenterSelected technological strengths: Aeropropulsion;Communications; Energy Technology; High-Tem-perature Materials Research.Kimberly A. Dalgleish-Miller(216) [email protected]

Goddard Space Flight CenterSelected technological strengths: Earth and Plan-etary Science Missions; LIDAR; Cryogenic Sys-tems; Tracking; Telemetry; Remote Sensing; Com-mand.Nona Cheeks(301) [email protected]

Jet Propulsion LaboratorySelected technological strengths: Near/Deep-Space Mission Engineering; Microspacecraft;Space Communications; Information Systems; Re-mote Sensing; Robotics.Dan Broderick(818) [email protected]

Johnson Space CenterSelected technological strengths: Artificial Intel-ligence and Human Computer Interface; LifeSciences; Human Space Flight Operations;Avionics; Sensors; Communications.

John E. James(281) [email protected] Space CenterSelected technological strengths: Fluids and FluidSystems; Materials Evaluation; Process Engineer-ing; Command, Control, and Monitor Systems;Range Systems; Environmental Engineering andManagement.David R. Makufka(321) [email protected]

Langley Research CenterSelected technological strengths: Aerodynamics;Flight Systems; Materials; Structures; Sensors;Measurements; Information Sciences.Kathy Dezern(757) [email protected]

Marshall Space Flight CenterSelected technological strengths: Materials; Man-ufacturing; Nondestructive Evaluation; Biotech-nology; Space Propulsion; Controls and Dynam-ics; Structures; Microgravity Processing.Terry L. Taylor(256) [email protected]

Stennis Space CenterSelected technological strengths: Propulsion Sys-tems; Test/Monitoring; Remote Sensing; Nonintru-sive Instrumentation.Ramona Travis(228) [email protected]

NASA HEADQUARTERS

Daniel Lockney, Technology TransferProgram Executive

(202) [email protected]

Small Business Innovation Research (SBIR) & SmallBusiness Technology Transfer (STTR) ProgramsRich Leshner, Program Executive(202) [email protected]

NASA Field Centers and Program Offices

5 Technology Focus: Data Acquisi-tion

5 Data Fusion for Global Estimation of Forest Charac-teristics From Sparse Lidar Data

5 Debris & Ice Mapping Analysis Tool — Database6 Data Acquisition and Processing Software — DAPS

7 Manufacturing & Prototyping7 Metal-Assisted Fabrication of Biodegradable Porous

Silicon Nanostructures7 Post-Growth, In Situ Adhesion of Carbon Nanotubes

to a Substrate for Robust CNT Cathodes 8 Integrated PEMFC Flow Field Design for Gravity-Inde-

pendent Passive Water Removal9 Thermal Mechanical Preparation of Glass Spheres

11 Materials & Coatings11 Mechanistic-Based Multiaxial-Stochastic-Strength

Model for Transversely-Isotropic Brittle Materials

13 Electronics/Computers13 Methods for Mitigating Space Radiation Effects, Fault

Detection and Correction, and Processing SensorData

13 Compact Ka-Band Antenna Feed with Double Circu-larly Polarized Capability

14 Dual-Leadframe Transient Liquid Phase BondedPower Semiconductor Module Assembly and Bond-ing Process

15 Quad First Stage Processor: A Four-Channel Digitizerand Digital Beam-Forming Processor

17 Mechanics/Machinery17 Protective Sleeve for a Pyrotechnic Reefing

Line Cutter17 Metabolic Heat Regenerated Temperature

Swing Adsorption 18 CubeSat Deployable Log Periodic Dipole Array18 Re-entry Vehicle Shape for Enhanced Performance

21 Physical Sciences21 NanoRacks-Scale MEMS Gas Chromatograph System21 Variable Camber Aerodynamic Control Surfaces and

Active Wing Shaping Control 22 Spacecraft Line-of-Sight Stabilization Using

LWIR Earth Signature23 Technique for Finding Retro-Reflectors in Flash

LIDAR Imagery23 Novel Hemispherical Dynamic Camera for EVAs

25 Software25 360° Visual Detection and Object Tracking on

an Autonomous Surface Vehicle25 Simulation of Charge Carrier Mobility in

Conducting Polymers25 Observational Data Formatter Using CMOR

for CMIP5

27 Information Technology27 Propellant Loading Physics Model for Fault Detection

Isolation and Recovery 27 Probabilistic Guidance for Swarms of

Autonomous Agents28 Reducing Drift in Stereo Visual Odometry 28 Future Air-Traffic Management Concepts

Evaluation Tool 29 Examination and A Priori Analysis of a Direct

Numerical Simulation Database for High-Pressure Turbulent Flows

30 Resource-Constrained Application of Support Vector Machines to Imagery


This document was prepared under the sponsorship of the National Aeronautics and Space Administration. Neither the United States Government nor any person acting on behalf of the United States Government assumes any liability resulting from the use of the information con-tained in this document, or warrants that such use will be free from privately owned rights.

03-14 March 2014


Technology Focus: Data Acquisition

The Debris & ICE Mapping AnalysisTool (DIMAT) system is a Web-based sys-tem that supports communication, dataintegration, data sharing, and problemdefinition/resolution through use of anintegrated presentation framework forice and debris description and analysis.It provides an integrated engineeringproblem description, visualizationanalysis, and resolution presentationframework for ice and debris issues.These include, but are not limited to:pre-launch debris walk-downs; ice for-mation during tanking, pre-launch,and launch; debris hits on Orbiteridentified on-orbit or post-landing; and

external tank (ET) foam damage/tex-ture mapping. The DIMAT systemleverages the EMaps application andmodels, as well as Design VisualizationGroup (DVG) models to provide high-fidelity 3D models of the Orbiter, ET,Solid Rocket Boosters (SRB), and Pad.Proposed solutions generated byDIMAT integrate these models withice/frost/debris location data, and caninclude 3D visualizations and digitalphotographs of ice and/or orbiter TPS(thermal protection system) debrishits. Ice/debris displayed on theEMaps model will represent actual sizeand location. The user will be able to

access data and photograph displays byselecting the ice on the EMaps model.The DIMAT analysis component al-

lows the user to enter ice/debris datainto the system from the Web, and tolink to program-related databases anddocuments. The DIMAT inspector com-ponent is a laptop-based system that theice/debris team uses to enter data, in-cluding digital photographs, in realtime. It incorporates the diverse datarepositories into a single database. The software is simple for engineers

and management to use, and automatesdata input into a repetitive report. Thesoftware easily adapts to another database

Debris & Ice Mapping Analysis Tool — DatabaseThe software is simple for engineers and management to use.Lyndon B. Johnson Space Center, Houston, Texas

This lidar data fusion approach isbased on associating samples fromsparse lidar data with groups of regionobjects determined by a unique imagesegmentation approach, HSeg (Hierar -chical Segmentation). This segmenta-tion approach, which was previously de-veloped by co-innovator James Tilton, isideal for this application because HSegautomatically produces a hierarchicalset of image segmentations, i.e., a set ofseveral image segmentations of the sameimage at different levels of detail inwhich the segmentations at coarser lev-els of detail can be produced from sim-ple merges of regions at finer levels ofdetail. This enables a simple approachfor selecting an appropriate level of seg-mentation detail. HSeg also automati-cally classifies the spatially continuousregion objects into region classes,through a tight intertwining of regiongrowing segmentation, which producesspatially connected region objects, withnon-adjacent region object aggregation,

which groups sets of region objects to-gether into region classes. No otherpractical, operational image segmenta-tion approach has this tight integrationof region growing, object finding withnon-adjacent region aggregation. HSegproduces image segmentations withhigh spatial fidelity — enabled by thetight intertwining of region growing seg-mentation with non-adjacent region ob-ject aggregation. Also, Hseg controls the importance of

spatially adjacent region merging rela-tive to spatially non-adjacent regionmerging (aggregation) through theSwght parameter, which can vary from 0.0to 1.0. At Swght = 0.0 no non-adjacent re-gion object aggregation is performed,and with Swght = 1.0, equal weighting isgiven to spatially adjacent and spatiallynon-adjacent region merging. The initial tests were performed using

Landsat TM data transformed intobrightness, greenness, and wetness tas-seled cap features in an area where there

is “wall-to-wall” lidar data from the LaserVegetation Imaging Sensor, LVIS. ThisLandsat TM data was collected on Sept.5, 2007 from over central Maine, and theLVIS data was collected in August 2009.The spaceborne lidar (SSL) data wassimulated by selecting tracks out of theLVIS data at an appropriate density. TheLVIS data served as the ground refer-ence data for the evaluation of the re-sults. Later, additional tests were per-

formed using UAV SAR data with threepolarizations: HH, HV, and VV. Theoriginal SAR data was at 5-meter pixelresolution, but 6×6 blocks of pixels wereaveraged of this data to produce 30-meter pixel resolution SAR data to bet-ter compare the results with the testswith the 30-meter transformed LandsatTM data.

This work was done by James Tilton, BruceCook, and Paul Montesano for Goddard SpaceFlight Center. Further information is con-tained in a TSP (see page 1).GSC-16535-1

Data Fusion for Global Estimation of Forest CharacteristicsFrom Sparse Lidar DataA new approach automatically produces a hierarchical set of image segmentations for detailedanalysis of forest data.Goddard Space Flight Center, Greenbelt, Maryland

6 NASA Tech Briefs, March 2014

and is comparative to system architec-ture. The model will be capable of beingutilized for engineering analysis, and in-tegrates and displays CAD-based draw-ings. The model can display integratedviews/JPEGS from NSTS documents.DIMAT can display and translate be-

tween any of the element coordinatesystems, and has the ability to calculatex,y,z from manual/visual user input.Using x,y,z coordinates provides relative

distances or clearances between points.It visually locates ice/debris on themodel and determines x,y,z location. Ithas the ability to provide accuratesize/geometry of reported ice/debris,and can isolate specific zones for identi-fying locations of ice/debris and sur-rounding hardware.The model will contain locations,

type, field of view, and simulated cam-era view for specified OTVs (Orbital

Transfer Vehicles), and has the capabil-ity to link OTV to the application to dis-play real-time status/picture of reportedice/debris. The model will have the ca-pability to accept live feed from a se-lected OTV and overlay on the model.

This work was done by Robert Lueckingand Cindy Nguyen of The Boeing Companyfor Johnson Space Center. Further informationis contained in a TSP (see page 1). MSC-25030-1

DAPS was designed to support theDAWN-AIR project participating in theGenesis and Rapid IntensificationProcesses (GRIP) hurricane campaign.It controls the data acquisition systemconsisting of a scanner that directs thelidar beam, an inertial navigation sys-tem/GPS (INS/GPS) unit for monitor-ing aircraft motion, a DSP module,and serial and video modules while ac-quiring and processing lidar data inreal time. DAPS was optimized to meetthe project requirement: acquiringand processing more than 550,000samples per second. DAPS was capableof managing such extensive computa-tional loads without experiencing asingle incident of crash or system fail-ure during the entire 130 flight hoursof the GRIP mission.

The latest wind profiling algorithm ac-curately estimates the horizontal windspeed and direction. It is robust enoughto identify abrupt changes in the hori-zontal wind parameters that are difficultto be detected by other conventionalmethods. Some of the unique features ofDAPS and the latest data processing al-gorithm are as follows:1. DAPS can operate both in realtime and offline while performingfull tasks faster than 10 Hz of exe-cution rate.

2. DAPS has informative data displayssuch as the Doppler shift and thepower distribution of line of sights,horizontal and vertical wind profiles,and color-coded history displays ofwind profiles. It also displays importantuser inputs and real-time GPS data.

3. DAPS is smart software that is capa-ble of automatic error correctionand calibration of the scanner andthe digitizer.

4. DAPS is robust and is capable of long-haul operations without an incidentof system error or crash.

5. The latest wind profiling algorithmcan produce robust horizontal windparameters.

6. The algorithm has smart routines toincrease the signal-to-noise ratio andeffective INS/GPS data interpretationand application.

7. The algorithm runs at the minimalerror resolution of 1 m/s in windspeed with 512-FFT.This work was done by Jeffrey Beyon of Lang-

ley Research Center. Further information is con-tained in a TSP (see page 1). LAR-18033-1

Data Acquisition and Processing Software — DAPSLangley Research Center, Hampton, Virginia


Manufacturing & Prototyping

Post-Growth, In Situ Adhesion of Carbon Nanotubes to aSubstrate for Robust CNT Cathodes This technology can be used down-hole in oil wells, and in high-temperature, high-pressure,corrosive environments in the automotive industry. NASA’s Jet Propulsion Laboratory, Pasadena, California

The field emission electron sourcesusing carbon nanotubes (CNTs) arebeing targeted for low-power vacuum mi-croelectronic applications for harsh-envi-ronment operation (high temperature,pressure, and corrosive atmosphere).While CNTs have demonstrated excel-lent properties in terms of low thresholdfield, low-power operation, and high cur-rent densities, one problem with vacuum

electronic applications is poor adhesionof CNTs to the substrate on which theyare synthesized. The chemical vapor dep-osition (CVD) process used to growCNTs on silicon or other metallic sub-strates using an iron catalyst with a thinoxide diffusion barrier layer has consis-tently provided reproducible growth.The CNTs are only surface-adhering inthese cases, and are easily removed from

the surface with the application of minorforces — typically pressures of 20 to 60kPa. This causes catastrophic failures ofCNT field emitters since the appliedfield could exceed the adhesion strengthof CNTs to the substrate. An in situ process was developed that

allows welding of CNT bundles to thesupport substrate. An efficient fieldemission architecture of CNTs has been

Metal-Assisted Fabrication of Biodegradable Porous Silicon NanostructuresSilicon nanostructures are fabricated from single-crystal silicon by an electroless chemical etch process.Lyndon B. Johnson Space Center, Houston, Texas

Porous silicon nanowires are fabri-cated by two-step, metal-assisted electro-less chemical etching of p-type or n-typesilicon wafers. This method, in combi-nation with nanolithography ornanopatterning, can be applied to fabri-cate porous silicon nanostructures ofdifferent shapes and sizes, such asnanorods, nanobelts, nano strips, andnanochains. The specific resistivity ofthe silicon substrate, and compositionof the etching solution, determine theporosity and pore size or lack thereof ofthe resulting nanostructures. Silicondoping, type of metal catalyst, concen-trations of H2O2, and solvent all affectthe formation of porous nanostructuresat various resistivity ranges of silicon. Aphase diagram summarizing the rela-tion of porosification and doping,metal, concentrations of H2O2, and sol-vent can be generated.In this innovation, high-aspect-ratio

porous silicon nanostructures, such asthose previously mentioned, were fab-ricated from single-crystal silicon by anelectroless chemical etch process. Ametal film, metal nanofeatures, or

metal nanoparticles were coated onthe silicon substrate first, and a solu-tion of HF and hydrogen peroxide wasthen used to anisotropically etch thesilicon to form the porous siliconnanostructures. Up to hundreds of mi-cron-long high-aspect-ratio porous sili-con nanostructures can be fabricated,and the patterns of the cross-section ofporous silicon structures can be con-trolled by photolithography, nanolith-ography, or nanoparticle-assisted pat-terning. The porosity is related to theresistivity range of the silicon sub-strate, the metal catalysts, the chemicalconcentration, and the additive sol-vent. The fabricated porous siliconnanostructure is biodegradable, andthe degradation time can be con-trolled by surface treatments. Porous silicon nanowires can be fab-

ricated with a two-step process. A nano -structured metal layer can be depositedon a silicon substrate by an electrolesschemical deposition or electrochemi-cal deposition. This step determinesthe shape of the final nanowires. Alter-natively, metal nanoparticles can be

spun on the silicon surface to form ametal layer, or a metal layer can bephysically or chemically deposited onthe silicon through a nanopatternedmask. The metal-coated silicon can beetched in a solution of HF, water, andH2O2 to produce porous siliconnanowires. Solvent can be added to thesolution to modulate the features ofthe porous silicon nanowires.

This work was done by Mauro Ferrari,Xuewu Liu, and Ciro Chappini of the Uni-versity of Texas Health Science Center atHouston for Johnson Space Center. For fur-ther information, contact the JSC InnovationPartnerships Office at (281) 483-3809.

In accordance with Public Law 96-517,the contractor has elected to retain title to thisinvention. Inquiries concerning rights for itscommercial use should be addressed to:

The University of TexasHealth and Science Center at HoustonOffice of Technology Management7000 Fannin Street, Suite 720Houston, TX 77030Refer to MSC-24690-1, volume and num-

ber of this NASA Tech Briefs issue, and thepage number.


Integrated PEMFC Flow Field Design for Gravity-Independent Passive Water RemovalThe design solves safety as well as reliability issues.Lyndon B. Johnson Space Center, Houston, Texas

A gravity-independent PEM (protonexchange membrane) fuel cell stack hasbeen developed that will operate athigh-pressure H2 and O2 conditionswith the requirement for relatively mod-est H2 and O2 gas circulation. Untilnow, in order to get higher efficiency,excess reactant gas flow was required toprevent water slug formation in gaschannels, thus reducing fuel cell per-formance. In addition, this excess gasflow is typically supported by mechani-cal pumps and/or a high-pressure ejec-tor system. All of these in a closed spaceenvironment contributed to potentialsafety as well as reliability issues due tothe potential failure of mechanicalpumps and ejectors. ElectroChem’s Integrated Flow Field

(IFF) design for a PEM fuel cell solvesall these issues. It is based on a multilay-ered integrated flow-field structure thatforms a porous structure with distinctwetting properties. It results in in-creased exposure of the catalyst to thereactant gas, resulting in higher cellvoltage. This results in higher efficiencythan the conventional plate designs. Inaddition, the entire flow field makes fullcontact between the porous structureand the electrodes, thus avoiding dam-age to membrane electrode assemblies(MEAs) at elevated operating pressure

conditions. The same design also pro-vides transport of product water back tothe entire flow field for humidificationand greater performance. In the IFF cell there is no need for ex-

cess reactant gas, since the design isbased on a non-flow-through operation.

The IFF fuel cell allows the operation at100% reactant gas utilization. The de-sign also enables passive removal ofwater at various cell orientations.The figure demonstrates a complete

passive water removal at non-flow-throughoperation condition and a response to

Demonstration of a Non-Flow-Through Fuel Cell Operation following NASA load profile testing. TheIFF fuel cell performed passive water removal without gas circulation.

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reported and patented by JPL. This ar-chitecture consists of arrays of CNT bun-dles of 1 to 2 micrometers in diameter,spaced 5 micrometers apart. These bun-dles can be grown on any substrate thatis conducive for lithographic patterningand catalyst deposition for CNT growth(Fe, Ni, etc.). A diffusion barrier layer,typically an oxide layer, is deposited un-derneath the metal catalyst. Growth of CNTs on titanium sub-

strate with a diffusion barrier at 575 to600 °C has been demonstrated. Follow-ing the growth process, the CNT bun-dle arrays are welded into Ti by heatingthe Ti substrates to 1,050 °C such thatthe surface of Ti softens and the CNTsget rooted inside. This welding processprovides CNT field emission samplesthat are robust and are tightly bound to

the substrate. They have been shown towithstand high electric fields withoutgetting dislodged. The novelty here is the single process

step that allows the growth and in situwelding to produce vertically aligned,patterned CNTs on a metallic substrate.Even though the process was developedfor titanium substrate, it is possible to im-plement the same with other metallicsubstrates and catalyst combinations. It ispossible to deposit any of the metal layerson any other metal substrates to create amulti-metal substrate on which CNT bun-dle arrays or simply CNTs are grown. Themain advantage is that it allows creationof array patterns of CNTs, and weldsthem into place as opposed to previouslyreported processes that required deposit-ing loose CNTs on metallic films followed

by a welding process. It is not possible toachieve vertically oriented and patternedCNTs with such a welding process.

This work was done by Harish Manohara,Valerie Kristof, and Risaku Toda of Caltech forNASA’s Jet Propulsion Laboratory. Further in-formation is contained in a TSP (see page 1).

In accordance with Public Law 96-517,the contractor has elected to retain title to thisinvention. Inquiries concerning rights for itscommercial use should be addressed to:

Innovative Technology Assets ManagementJPLMail Stop 321-1234800 Oak Grove DrivePasadena, CA 91109-8099E-mail: [email protected] to NPO-48953, volume and number

of this NASA Tech Briefs issue, and thepage number.


Samples of lunar regolith have in-cluded small glass spheres. Most literaturehas suggested the small spheres wereformed by meteorite impacts. The result-ing transformation of kinetic energy tothermal energy caused the lunar surfaceto melt. The process yielded glass spheres.Recreating a meteorite impact that yieldsglass spheres is very challenging. Further-more, the melting temperature of certainminerals on the Moon precludes the useof standard thermal techniques. Glass spheres are created by using a

thermal and pneumatic process. Theprocess allows extremely high-melting-temperature material to be transformedinto sub-750-micron spheres. The ther-mal and mechanical process developedtransforms the molten material to thelowest energy morphology, a sphere,while locking in the glass chemistry. To produce a high volume of sub-

750-micron glass spheres, the feedstock

material was melted with a plasma sys-tem. The system uses high-power, re-motely coupled electric plasma. Themolten material is then routed througha molybdenum orifice and allowed tofall vertically by gravity. Approximatelyone meter from the discharge, a high-velocity pneumatic jet is positioned per-pendicular to the glass stream. At theimpingement zone, the molten glassmaterial is pneumatically removedfrom the primary stream path and rap-idly cooled to glass morphology whiletraveling to the collection area. At thecollection area, the spheres are me-chanically collected. The integrated plasma system and

mechanical forming process allow avery wide variety of material to beprocessed into spheres. Also, the rapidpneumatic quench locks ensure glassmorphology and precludes any signifi-cant devitrification.

Glass spheres are currently used in awide variety of consumer and commer-cial applications. The ability to thermallyreact feedstock materials at plasma tem-peratures extends the range of possibleglass chemistries available. The demon-strated ability to produce spheres directlyfrom a molten glass stream increases theupper diameter limit realized in tradi-tional solid to sphere processes. Exam-ples of current research work using theplasma process include production ofhigh-strength glass spheres for drillingproppants, and the integration of cata-lyst materials in bio-degradable glass forground water remediation applications.

This work was done by Mike Weinstein ofZybek Advanced Productions, Inc. for Mar-shall Space Flight Center. For more informa-tion, contact Sammy Nabors, MSFC Commer-cialization Assistance Lead, at [email protected]. Refer to MFS-32938-1.

Thermal Mechanical Preparation of Glass Spheres The forming process allows a very wide variety of material to be processed into spheres.Marshall Space Flight Center, Alabama

3–1 power ratio demand. It is an IFF fuelcell stack with 4 cells of 200 cm2 electrodesurface area.The results of IFF fuel cell configura-

tion have demonstrated 100% reactantgas utilization, reduced cost and weightpenalties, and system simplification withhigher reliability.This IFF design was developed for use

in a PEM fuel cell power plant for spaceapplication, but it could also be used forhigh-altitude balloon flight and air-inde-

pendent applications (e.g., manned andunmanned underwater vehicles). Whenthe IFF design is used in a PEM elec-trolyzer, it functions as an internal phaseseparator, which enhances overall systemefficiency.

This work was done by Michael Pien ofElectroChem, Inc. for Johnson Space Center.Further information is contained in a TSP(see page 1).

In accordance with Public Law 96-517,the contractor has elected to retain title to this

invention. Inquiries concerning rights for itscommercial use should be addressed to:

Michael S. Pien, Ph.D.Vice-President of Research and DevelopmentElectroChem, Inc.400 W Cummings Park # 5600 Woburn, MA 01801 Phone No.: (781) 938-5300 E-mail: [email protected] to MSC-24587-1, volume and num-

ber of this NASA Tech Briefs issue, and thepage number.


A methodology has been developedand the software written to predict theprobability of failure of transverselyisotropic (a type of anisotropy) materialsunder generalized thermomechanicalloading. This methodology is mechanis-tic in that it is based on the physicalcharacteristics of brittle fracture, andmorphological in that it considers thesize, shape, and orientation distributionof strength controlling defects or flaws.On that basis, it can also account for amaterial’s failure modes and direction ofdamage initiation from loading. It is ca-pable of predicting an anisotropic mate-rial’s probability of failure under tran-sient and cyclic loading. This innovationcan be applied to materials such asgraphite, coatings, or the individual brit-tle constituents of composite materials. The strength of an isotropic brittle ma-

terial is independent of the direction ofthe applied load. However, for many brit-tle materials, the strength of the materialchanges with the direction of the appliedload. These are termed anisotropic mate-rials. The most common type of materialstrength anisotropy is transverse isotropy,where material strength is isotropicwithin a plane but orthogonal to that

plane, the strength is greater than or lessthan the in-plane strength.The unit sphere methodology is an at-

tempt to provide an improved mecha-nistic basis to the problem of predictingstrength response of an anisotropic andcomposite material under multiaxialloading as compared to polynomial in-teraction equation formulations. It hasmultiple unique features including flaworientation and fracture toughnessanisotropy. These physically basedanisotropy functions are general andcan model tightly defined or more dif-fuse material anisotropy textures de-scribing flaw populations. Innovativeequations were developed in order toachieve this capability. The methodol-ogy also includes consideration ofstrength scatter to predict materialprobability of failure, shear sensitivity offlaws, and accounting for multiple fail-ure modes regarding overall failure re-sponse. One novel feature of thismethodology is the ability to predict theorientation of critical flaws under multi-axial loading.With this capability, the model can be

tuned to the physical attributes of thematerial by, for example, mapping the

toughness response of the material withrespect to orientation for indentationtesting, or mapping the observed orien-tation anisotropy of the pre-existingflaws in the material. In principle, by thismethodology, the physical attributes ofthe anisotropic material can also be usedto predict the multiaxial strength re-sponse of the material.It is intended for aerospace applica-

tions where trade-offs must be per-formed regarding safety, durability, andweight. It is anticipated that this softwarewill be used with finite element or mi-cromechanics-based codes describingthe behavior of composite materials.This incorporation would allow the fullexercise of the new methodology, in-cluding incremental time/load steps,and fatigue of composite laminates andwoven composite structures.

This work was done by Noel N. Nemeth ofGlenn Research Center. Further information iscontained in a TSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steven Fedor, MailStop 4–8, 21000 Brookpark Road, Cleveland,Ohio 44135. Refer to LEW-19018-1.

Mechanistic-Based Multiaxial-Stochastic-Strength Model forTransversely-Isotropic Brittle MaterialsThe methodology is applicable to a wide variety of graphite, coatings, and composite materials.John H. Glenn Research Center, Cleveland, Ohio

Materials & Coatings


Electronics/Computers

The Integrated Modular Avionics(IMA) architecture being developed forspace applications requires that sensordata be autonomously sampled andtransmitted to the system network. Thistransmission needs to occur on a prede-termined, fixed schedule to avoid con-flicts on the network. It needs to be ca-pable of building packets of sensor datafor individual application partitions(i.e., environmental control, propul-sion, and vehicle management). It mustbe easily configured for flexibility in sys-tem scheduling.Once a minor frame interrupt (MFI)

is received from the network, the timingwithin a frame begins. The poll list tablecontrols the timing. It starts theinput/output module (IOM) sample listexecution within each IOM. Afterenough time has elapsed for the IOMsto step through their respective samplelists, the poll list initiates the commandto start assembling the packets. Thesemay include, for example, a packet thatcontains only data for the environmen-tal control system, another packet couldinclude data for the propulsion system,

and yet another packet may contain RIU(remote interface unit) status informa-tion. These packets are transferred tothe network interface card (NIC). Thetables in the NIC schedule the transmis-sion onto the network for each packet.The tables may be unique by minorframe. This allows different packets ofdata to be sent on different minorframes of the system schedule. Self-checking lockstep processor ar-

chitectures, by their nature, are in-tended to detect differences between re-dundant elements and to prevent theirfurther propagation. Traditional meth-ods of dealing with detected differencesbetween the halves of a lockstep proces-sor pair are to cease lockstep operationand to initiate recovery. In an integratedprocessor application, ceasing lockstepoperation impacts all software applica-tions on the platform, as they are unableto perform their function until the re-covery has been completed and lockstepoperation is resumed. The methodbeing described here eliminates the lossof lockstep operation under certain con-ditions such that the recovery can be

done “seamlessly” to all applicationsother than the one directly accessing theresource that caused the detected differ-ence between lockstep halves.The Orion VMC (vehicle manage-

ment computer) processor design isbased upon the re-use of a processor de-sign from a commercial avionics prod-uct. That design includes the use of sev-eral commercial off-the-shelf (COTS)components for which there are noequivalent space-rated components.One of those COTS components isNOR flash that is used to store programand database information for theprocessor. A design solution that maxi-mizes the advantages of re-use, while sat-isfying the radiation requirements ofthe product when using these COTSNOR flash devices in the program flasharray, was needed.

This work was done by Mike Bartels, DeanSunderland, Terry Ahrendt, Tim Moore,David Yeager, Kevin Stover, James Tyrrell,and Bob Poucher of Honeywell for JohnsonSpace Center. Further information is con-tained in a TSP (see page 1).MSC-24769-1/81-1/5-1.

Methods for Mitigating Space Radiation Effects, Fault Detectionand Correction, and Processing Sensor Data A combination of three innovations enables increased efficiency, stability, and flexibility of datamanagement and systems functionality.Lyndon B. Johnson Space Center, Houston, Texas

NASA has an interest in utilizing theKa-band frequency allocation. One ofthe main reasons for migrating to Ka-band is the need for higher frequencybandwidth to enable higher data rates. Adual circular polarized wideband an-tenna for Ka-band communications ap-plications was designed leveraging anovel Ka-band polarizer design used inLunar Reconnaissance Orbiter/SolarDynamics Observatory (LRO/SDO).

The proposed design merges two com-ponents (polarizer and antenna) intoone unit, reducing its overall size. Itssimulated bandwidth extends beyondthe allocated bandwidth for NASA at Ka-band. This novel design could be used aswell for the feed component in high-gain antennas (HGAs).Satellite communications at the Ka-

band frequencies has been a topic ofinterest for the last decade. NASA has

had a Ka-band frequency allocation un-derused for many years due to variousreasons. When the transmitter’s outputdata rate after encoding is 450 Msps,the spectrum needs to be severely fil-tered to avoid interference withNASA’s DSN frequency allocation,which promotes large amounts of inter-symbol interference at the receiver.Transitioning to Ka-band will mitigatethis problem since the allocated band-

Compact Ka-Band Antenna Feed with Double CircularlyPolarized Capability This design could be used for the feed component in high-gain antennas.Goddard Space Flight Center, Greenbelt, Maryland


width is larger, allowing much higherdata rates to be sustained without suchsignal distortions.The Earth-shaped reflector antenna

at Ka-band consists of a single reflectorconfiguration where the feed is locatedat the focal point of the system usingsupporting struts, and the reflector isshaped to produce an Earth-shaped ra-diation pattern. The waveguide used tocarry energy to the antenna feed canbe located along one of, or be part of,the struts supporting the feed abovethe reflector.The antenna design consists of merg-

ing a corrugated feed antenna with a po-larizer to produce a satisfactory solution

of blockage reduction (size reduction)of the reflector aperture. What is usuallya two-component system has been re-duced to a single part, reducing mass,size, and cost. This antenna could beused in Ka-band HGA or Earth-shapedantenna reflector combinations. The po-larizer/antenna combination also allowsit to be used in dual circular polarizationapplications. The overall return loss isbetter than 20 dB for the simulated fre-quency range of 23.5 to 28.5 GHz, show-ing an excellent impedance match overNASA’s frequency allocation. The portisolation between the ports has not beenoptimized, but can be optimized for theapplication at hand.

For the current design, the isolationfor the standalone feed antenna and po-larizer combination varies between –15to –18 dB over the frequency band. For astandalone application (no reflector),this could be improved by improving theinternal wave impedance match betweenthe polarizer and feed antenna. For a re-flector application, it can be optimizedto partially cancel the reflection from thereflector back into the feed, which is typ-ically of the same order of magnitude.

This work was done by Cornelis du Toitof QSS and Kenneth Hersey of MEI Tech-nologies for Goddard Space Flight Center.Further information is contained in a TSP(see page 1). GSC-16773-1

Dual-Leadframe Transient Liquid Phase Bonded PowerSemiconductor Module Assembly and Bonding ProcessThis module package and bonding process enable device operation at temperatures exceeding 400 °C.John H. Glenn Research Center, Cleveland, Ohio

A high-temperature-capable wide-bandgap semiconductor power modulepackage, coupled with a new high-tem-perature-capable bonding process (withan optimized assembly and manufactur-ing process), has been developed that,together, can allow device operation attemperatures exceeding 400 °C, with thepotential for higher-temperature opera-tion depending on the semiconductordevice characteristics.The semiconductor module is an

ultra-compact, hybrid power modulethat uses double leadframes and directleadframe-to-chip transient liquid phase(TLP) bonding. The unique advantagesinclude very high current-carrying capa-bility, low package parasitic impedance,low thermomechanical stress at hightemperatures, double-side cooling, andmodularity for easy system-level integra-tion. The new power module will have avery small form factor with 3 to 5× reduc-tion in size and weight from the priorart, no failure-prone bond wires, and willbe capable of operating from 450 to –125 °C.Traditional power semiconductor

modules use solder to attach the die tothe substrate, which requires that the de-vice be heated to a temperature higherthan the normal operating temperature.For very-high-temperature-operation de -vices, it isn’t feasible to use a solderingprocess. However, in this innovation, the

Top Baseplate

Top Substrate

Ceramic Adhesive

SiC MOSFET Die

Bottom Substrate

Bottom Baseplate

Gate High

Switch Node

Bus +

Bus -

Gate Low

An exploded view of the Semiconductor Module stackup.


Transient Liquid Phase (TLP) bonds at atemperature between the operationstemperature range of the device. It isalso a low-cost manufacturing process.A high-temperature module design

may have a profound impact on powerelectronics and energy conversion tech-nologies. For commercial applications,the new packaging and bonding processtechnology can be used in its current

form, or can be scaled down to mediumor conventional temperature rangeswith a significantly reduced cost, makingit a viable and economical option forlarge commercial markets such as hybridelectric vehicles, renewable energy con-version, and power supplies.

This work was done by John C. Elmes of Ad-vanced Power Electronics Corporation, andBrian Grummel, Zehng John Shen, and Wen-

dell Brokaw of the University of Central Floridafor Glenn Research Center. Further informationis contained in a TSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steven Fedor, MailStop 4–8, 21000 Brookpark Road, Cleveland,Ohio 44135. Refer to LEW-19091-1/2-1.

A 4-channel digitizer was designed,built, and tested. The very large, com-plex board enables SweepSAR. The pro-posed Deformation, Eco-Systems, andDynamics of Ice Radar (DESDynl-R) L-band SAR instrument employs multipledigital channels to optimize resolutionwhile keeping a large swath on a singlepass. High-speed digitization with veryfine synchronization and digital beamforming are necessary in order to facili-tate this new technique.The Quad First Stage Processor (qFSP)

was developed to achieve both the pro-

cessing performance as well as the digitiz-ing fidelity in order to accomplish thissweeping SAR technique. The qFSP uti-lizes high-precision and high-speed ana-log-to-digital converters (ADCs), eachwith a finely adjustable clock distributionnetwork to digitize the channels at the fi-delity necessary to allow for digital beamforming. The Xilinx-produced FX130TVirtex 5 part handles the processing todigitally calibrate each channel as well asfilter and beam-form the receive signals.Demonstrating the digital processing

required for digital beam forming and

digital calibration is instrumental to theviability of the proposed DESDynl instru-ment. The qFSP development bringsthis implementation to TechnologyReadiness Level (TRL) 6.

This work was done by Chung-LunChuang, Scott J. Shaffer, Robert F. Smythe,Eric N. Liao, Samuel S. Li, Arin C. Mor-fopoulos, Louise A. Veilleux, Chester N. Lim,and Noppasin Niamsuwan of Caltech forNASA’s Jet Propulsion Laboratory. Furtherinformation is contained in a TSP (see page1). NPO-48936

Quad First Stage Processor: A Four-Channel Digitizer andDigital Beam-Forming ProcessorNASA’s Jet Propulsion Laboratory, Pasadena, California


Mechanics/Machinery

A metallic sleeve provides protectionand guidance for the actuating lanyardpull of a parachute system reefing line cut-ter. This device ensures that the reefingline cutter is not damaged during packingor deployment. In addition, the device en-sures that the actuating lanyard that initi-ates the cutter is pulled within the device’sspecification cone angle. Combined, thesefeatures increase the durability of the reef-ing line cutter used in parachute reefingsystems, and significantly increases the re-liability of the underlying reefing cutter.Protecting such a critical element of thecontrolled deployment of parachutes sig-nificantly improves the operation of theparachute reefing system. The sleeve is designed as an “add on”

component to provide lanyard pullguidance and cutter bending resistance.The end user can procure off-the-shelfhardware with no changes, and thenchoose to add the cutter sleeve at a latertime based on usage and environment.This metallic sleeve is reusable and al-lows for a decrease in unit cost of thereefing line cutter.

The cutter sleeve provides contain-ment of gases or shrapnel in the eventof an unexpected cutter failure/rup-ture. It also provides a more positive re-tention location, in the form of agroove around its diameter, for attach-ment to a parachute through stitch-ing/sewing. Testing of reefing line cut-ters without the protective sleeve

resulted in failures that included bro-ken pull loops and bent cutters. Testingwith the protective sleeve resulted in allcutters functioning correctly.

This work was done by James H.McMichael, Hai D. Nguyen, Mark Landeck,and Richard Hagen of Johnson Space Center.Further information is contained in a TSP(see page 1). MSC-25523-1

Protective Sleeve for a Pyrotechnic Reefing Line CutterThe sleeve provides improved operation of a parachute reefing system.Lyndon B. Johnson Space Center, Houston, Texas

The Cutter Sleeve features a round end to protect the pull lanyard, a hole for the reefing line cuttersafety pin, and a groove that allows the sleeve to be sewn into the parachute.

Rounded end to protect pull lanyard

Hole for reefingline cutter safety pin

Groove to allow the sleeve to be sewn into parachute

Two fundamental problems facing thedevelopment of a portable system to sus-tain life on extraterrestrial surfaces are(1) heat rejection and (2) rejection ofmetabolically produced CO2 to an envi-ronment with a ppCO2 of 0.4 to 0.9 kPaas is present on Mars. Portable life sup-port systems typically use water for heatrejection via sublimation. Consequently,the water is removed from the life sup-port system and into the surroundingenvironment after use. This wastes avaluable resource required for humanlife that is expensive to transport fromEarth. Furthermore, rejecting the watervapor to the surrounding environment

contaminates it, severely interfering withany search for life on extraterrestrial sur-faces. A portable life support systemshould be able to use a variety of fluidsfor heat rejection, especially liquid CO2,as it can be easily acquired and cheaplystored on the surface of Mars. The use ofliquid CO2 as a coolant has the advan-tage that it will not interfere with scien-tific investigations by contaminating thearea as it is sublimated from the life sup-port system for heat rejection.A subsystem has been developed for a

portable life support system (PLSS) calledMetabolic heat regenerated TemperatureSwing Adsorption (MTSA). MTSA simul-

taneously addresses heat rejection andCO2 rejection to an environment rangingfrom vacuum to a ppCO2 of 0.9 kPa orgreater. The invention utilizes an adsor-bent-based subsystem that is cooled withliquid CO2, and is used to cleanse the ventloop of metabolically produced CO2.Once the adsorbent is fully loaded withmetabolically produced CO2, metabolicwaste heat from the expired breath isused to warm and regenerate the adsor-bent bed. Exhausted adsorbent coolingfluid is used to aid in additional heat re-jection and further cool the user.The basic principle is removal of CO2

by an adsorbent with regeneration

Metabolic Heat Regenerated Temperature Swing Adsorption Liquid CO2 as a coolant will not contaminate the area as it is sublimated from the life supportsystem for heat rejection.Lyndon B. Johnson Space Center, Houston, Texas


through temperature swing adsorption(TSA) over the temperature rangebound by the sublimation temperatureof CO2 (less than 195 K) and the meta-bolic vent loop (310 K). There are twobeds to facilitate continuous removal of

metabolically produced CO2 from thevent loop: one for loading the adsor-bent via a vent loop exiting the hel-met/undergarment of an astronaut’sportable life support system, and an-other for regenerating the adsorbent.

This work was done by Taber MacCal-lum of Paragon Space Development Corp.for Johnson Space Center. Further informa-tion is contained in a TSP (see page 1).MSC-24859-1

CubeSat Deployable Log Periodic Dipole ArrayAny small satellite with a need for a VHF antenna might benefit from this design, in addition tocommunications and military applications.NASA’s Jet Propulsion Laboratory, Pasadena, California

The antenna is composed of two maindeployable structural components thathelp it achieve the large packing factornecessary to fit within the small volumeof the CubeSat. The primary componentof the antenna array is a tension stiff-ened truss, which is preloaded using alarge tape spring. The truss bays areformed from solid discs connected bythin Kevlar thread. The Kevlar threadsare set up in a hexapod configuration,and are fully tensioned and preloadedfrom the force of the tape spring, whichruns through the center of the truss.The truss gets its overall stiffness fromthe properties and configuration ofthese Kevlar wires.There are 21 elements on the an-

tenna corresponding to the full desiredfrequency range of 30 to 300 MHz. Theassembly, including cable spooler andmotor, fits within a 2-U CubeSat. This isachieved by keeping the dipole discsthin, and by stacking them back-to-back. Additionally, the tape springboom rolls up on itself to provide excel-lent stowed volume.When stowed, the dipoles are sand-

wiched inside the fixed tube of theCubeSat, and cannot deploy until theyare forced outward by the tape spring.To ensure the hexapod thread does notget tangled or frayed during antenna

stowing and deployment, a scheme wasdevised where each individual wire iswrapped in a figure-eight configurationaround two posts. The wire is laid on topof itself in subsequent wraps around theposts, with little chance of forming a tan-gle or knot. When the discs are pulledapart, there is minimal force required todislodge the wire from the posts. Thisthread management scheme is effective;however, it does have drawbacks in that

it is very tedious and requires several setsof hands working simultaneously. Theposts also serve a dual purpose and pro-vide a torsional locking feature betweenadjacent discs.

This work was done by Mark W. Thomson,Vine M. Bach, Phillip E. Walkemeyer, DanielL. Kahn, Andrew Romero-Wolf, and SamuelC. Bradford of Caltech for NASA’s Jet Propul-sion Laboratory. Further information is con-tained in a TSP (see page 1). NPO-49107

The Antenna Array assembly, including cable spooler and motor, fits within a 2-U CubeSat. At left is aCAD model of the VHF array stowed in a 3U CubeSat structure; at right is the initial stowed prototypeof the LPDA.

ConfiningTube

Tape Spring Boom

Tape Spool

Dipole Discs

3U CubeSat Structure

Cable Spooler

A vehicle entering the atmosphere of aplanet will do so at hypersonic speedsand will need to decelerate and maneu-ver through that atmosphere while pro-tecting its payload from excessive heat-ing. As a consequence, the vehicle shape

must be designed to provide optimalaerodynamic lift and drag properties,while minimizing convective and radia-tive heating to the vehicle outer surfaces. These needs are met by this inven-

tion, which provides a convex structure

with a continuous slope that can be de-scribed by four linear segments and sixcurvilinear segments joined together toprovide a convex shape defined by nineparameters. Viewed parallel to the y-axis in a Cartesian coordinate system,

Re-entry Vehicle Shape for Enhanced Performance A convex structure is used with a continuous slope. Ames Research Center, Moffett Field, California


the projected cross-sectional shape in-cludes first and second linear segments,spaced apart from each other and lo-cated on opposite sides of an x-axis,with each of the first and second seg-ments being oriented substantially at aselected non-zero angle �qc relative tothe x-axis, each segment having a firstsegment end of closest approach to thex-axis with each closest approach seg-ment end being located at substantiallythe same distance R from the x-axis.The projected shape includes a thirdlinear segment that is oriented substan-tially perpendicular to the x-axis adja-cent to the end of closest approach tothe x-axis for each of the first and sec-ond linear segments.

The present invention provides an im-provement over prior blunt body shapesin that the shape is actually of a class ofgeometric shapes that is describable by arelatively small number of geometry-shape parameters, and that provides abroad range of geometric shapes with fa-vorable aerodynamic and aerothermalproperties. These properties can thenbe analyzed by optimization methods fordesired performance. Optimization of the vehicle geometry-

shape parameters can, for example, min-imize heating levels subject to con-straints that reduce aerodynamicperformance, such as lift/drag, or canminimize weight of a thermal protectionsystem, allowing a greater payload.

Other properties can be optimized or es-tablished as constraints on a geometricparameter search, such as a requirementthat a minimum lift/drag be met or ex-ceeded, while minimizing center of grav-ity offset from vehicle centerline, to easepacking of a working vehicle while inspace operations.

This work was done by James L. Brown,Joseph A. Garcia, and Dinesh K. Prabhu ofAmes Research Center. Further information iscontained in a TSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto the Ames Technology Partnerships Divisionat 1-855-NASA-BIZ (1-855-6272-249) [email protected]. Refer to ARC-15606-1.


Physical Sciences

A new concept of aircraft aerody-namic control surfaces has been devel-oped in connection with another newconcept of active wing shaping controlfor reducing aircraft drag that will resultin less fuel burn. The first concept is re-ferred to as a variable camber continu-ous trailing edge flap or, alternatively, avariable camber continuous leadingedge slat. The variable camber trailingedge flap (or leading edge slat) com-prises multiple chord-wise segments(three or more) to form a cambered flapsurface, and multiple span-wise seg-ments to form a continuous trailingedge (or leading edge) curve with nogaps that could be prescribed by a math-

ematical function or the equivalent withboundary conditions enforced at theend points to minimize tip vorticities.Aerodynamic simulations have shownthat this type of flap can reduce aerody-namic drag substantially as compared toa conventional flap. A new active wing-shaping control concept is proposed inconnection with the presently disclosedvariable camber continuous trailingedge flap (or leading edge slat). The ac-tive wing-shaping control is designed tochange a wing shape in-flight in order toachieve a desired optimal wing shape foroptimal drag reduction. Currently, as fuel is burned, wing load-

ing is reduced and causes the wing

shape to change in bending and twist.This wing shape change causes the wingsto be less aerodynamically efficient. Thisproblem can be further exacerbated bymodern high aspect flexible wing de-sign. Aircraft designers typically addressthe fuel efficiency goal by usually reduc-ing aircraft weights, improving propul-sion efficiency, and/or improving theaerodynamics of aircraft wings passively.In so doing, the potential drag penaltydue to changes in the wing shapes wouldstill exist at off-design conditions. The unique or novel features of the

new concepts are: 1. Variable camber flap provides thesame lift capability for lower drag as

Variable Camber Aerodynamic Control Surfaces and ActiveWing Shaping Control Concepts are examined to reduce aerodynamic drag and decrease fuel consumption. Ames Research Center, Moffett Field, California

In order to study atmospheric orevolved gases, it is highly advantageousfor an instrument (e.g. mass spectrome-ter (MS), thermal conductivity detector(TCD)) to simplify the gas stream with afront-end gas chromatograph (GC).When used for planetary missions, high-performance GCs have to satisfy the ad-ditional challenging requirements ofsurviving high inertial loads with lowmass, power, and volume in order to beincluded in Ventures-, Discovery- andNew Frontiers-class missions in today’sbudget-constrained reality.The development and adoption of ad-

vanced MEMS-GCs at JPL would provide akey enabling technology for near-term mis-sions to Mars or Venus. A MEMS (Micro-Electro-Mechanical Systems)-based GC sys-tem would be significantly smaller, about 1kg (including electronics), with a powerconsumption of less than 1 W (for isother-mal operation). It would also not have themany complicated fittings and joints of aconventional GC, significantly enhancinginertness and robustness.

JPL partnered with Cbana Labs tocouple their MEMS-GC to a miniatur-ized adaptation of a JPL ion trap massspectrometer, a version of which is cur-rently operating in the Vehicle Cabin At-mosphere Monitor (VCAM) on the In-ternational Space Station (ISS).However, since a MEMS-GC has neverflown in space before, JPL is looking atways to reduce risk and to test theMEMS-GC cheaply and rapidly using theNanoRacks service to the ISS.The MEMS-GC system includes the

MEMS-GC chip (with MEMS-preconcen-trator, MEMS-valves, MEMS-column inthe middle of a Vespel block), a MEMS-TCD (in a separate Vespel block), aminiature diaphragm sample pump, andelectronics. Cabin air would be used asthe carrier gas.

This work was done by Richard D. Kidd,Murray R. Darrach, Vachik Garkanian, andStojan Madzunkov of Caltech; and Byung-hoon Bae of Cbana Labs for NASA’s Jet Propul-sion Laboratory. Further information is con-tained in a TSP (see page 1). NPO-48859

NanoRacks-Scale MEMS Gas Chromatograph SystemThis is a compact, simple, cost-effective system.NASA’s Jet Propulsion Laboratory, Pasadena, California

MEMS-GC System Model includes the MEMS-GCchip (with MEMS-preconcentrator (PC), MEMS-valves, MEMS-column in the middle of a Vespelblock), a MEMS-thermal conductivity detector(TCD, in a separate Vespel block), a miniature di-aphragm sample pump, and electronics. Mass: 1kg, power: 1 W (peak 5 W), size: 4¥4¥4 in.(ª10¥10¥10 cm) (A 1U NanoLabs module).


compared to a conventional flap. 2. Continuous trailing edge flap (orleading edge slat) provides a contin-uously curved trailing edge (or lead-ing edge) with no gaps to minimizevorticities that can lead to an in-crease in drag.

3. The active wing-shaping control methodutilizes the novel flap (or slat) conceptdescribed herein to change a wing shape

to improve aerodynamic efficiency byoptimizing span-wise aerodynamics.

4. An aeroelastic method for analyzingwing deflection shape under aerody-namic loading is used in a wing-con-trol algorithm to compute a desiredcommand for the flap-actuation sys-tem to drive the present flap (or slat)system to the correct position forwing shaping.

This work was done by Nhan Nguyen ofAmes Research Center. Further information iscontained in a TSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto the Ames Technology Partnerships Divisionat 1-855-NASA-BIZ (1-855-6272-249) [email protected]. Refer to ARC-16644-1.

Spacecraft Line-of-Sight Stabilization Using LWIR Earth SignatureApplications could include remote science and planetary science missions, Earth surveillanceand reconnaissance, and deep space optical communication.NASA’s Jet Propulsion Laboratory, Pasadena, California

Until the time of this reporting, whena space vehicle required a reference sig-nal for inertial pointing, the choiceswere a signal beacon from an Earth lo-cation, the Earth radiance in the visiblespectrum, or a star tracker. However,limitations can arise from using thesetechniques. For example, the signalbeacon suffers from limited signalpower (either in RF or optical) and willconstrain the application to limitedranges, errors due to stray-light andcentroiding limit the accuracy of a startracker, and the spatial/temporal vari-ability of the Earth’s albedo and its illu-mination by the Sun introduces limita-tions when used in the visible or nearinfrared light.To bypass these limitations, the

bright and near-uniform image of theEarth in the LWIR (long wavelength in-frared) (8 to 13 micron) may be usedto obtain a reference signal for inertialstabilization and pointing of a space-craft platform.The potential of using the bright and

near-uniform Earth thermal infrared (orLWIR) signature as a stable referencefor accurate (microrad or less) inertialpointing and tracking of an optical com-munication beacon onboard a space ve-hicle was investigated, including the de-termination of the fundamental limits ofapplicability of the proposed method forspace missions in deep space. In thethermal infrared, Earth’s emission ap-pears relatively uniform and is inde-pendent of the Sun’s illumination.Therefore, it can be used as a stablepointing reference.Objective of the stabilization is to

align the Earth’s image along the de-

The brightness and near-uniformity of the Earth LWIR Signature as a function of range indicates itsgreat potential as a stable reference for inertial pointing of planetary spacecraft, when the Earth isnot fully illuminated by the Sun. This figure shows the multistage stabilization block diagram, and theresulting time history of the detector line-of-sight azimuth and elevation angles with respect to a ref-erence datum onboard the spacecraft, and demonstrates that submicroradian stabilization accuracy isachievable with a multistage line-of-sight stabilization approach.

t [s]

Payload Dynamics(tip/tilt)

LOSStabilizationController

EarthSensor

AttitudeController

SpacecraftDynamics

AttitudeSensor

Star Tracker + GyroSensor Noise

Reaction WheelNoise

SPACECRAFT LEVEL OUTER LOOP

StabilizedAttitude θ

DETECTOR LEVEL INNER LOOP

ReferenceCentroid

azmelm

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

az,e

l [m

icro

rad

]


sired line of sight (LOS) in the face ofexisting system disturbances. Because ofthe submicroradian precision levels re-quired by high-precision pointing, alarge dynamic range is involved in thedynamic response of the pointing sys-tem. Hence, the pointing and trackingalgorithms are based on a multistage ap-proach that includes: (a) a coarse stage(outer loop) based on sequential loopclosure of a vehicle attitude stabilizationfeedback control loop at a low controlbandwidth (10–3 to l0–1 Hz) to compen-sate for typical attitude control distur-bances; followed by (b) a fine stage(inner loop) based on an image bore-sight stabilization feedback loop athigher frequencies that makes use of anarticulated (tip/tilt) fast steering mirror

to track the Earth’s LWIR reference sig-nal in the image plane.A simulation package has been devel-

oped that generates spacecraft and gim-baled camera dynamic model, inputs re-alistic spacecraft disturbances, stabilizesthe spacecraft attitude dynamics via aproportional-integral-derivative (PID)control loop at 0.01 Hz, propagates theazimuth and elevation states of the dy-namics of the detector plane, adds thesensor noise model to the computed de-tector azimuth and elevation based on adetector model and centroiding algo-rithm, and stabilizes the detector line-of-sight via PID control at 100 Hz. A blockdiagram is shown in the figure.A comparison of the performance of a

quantum-well infrared photodetector

sensor array using data from actualspace-qualified components has beencarried out. Preliminary results involv-ing the effect of the sensor performanceon the LOS system stabilization havebeen studied. Using realistic noise spec-tra from the Mars Reconnaissance Or-biter mission, simulations demonstratedthat submicroradian stabilization accu-racy, shown in the figure as time historyof the detector line-of-sight azimuth andelevation angles with respect to a refer-ence datum on-board-the spacecraft, isfeasible using this approach.

This work was done by Marco B. Quadrelliand Sabino Piazzolla of Caltech for NASA’sJet Propulsion Laboratory. For more informa-tion, contact [email protected]. NPO-48934

Technique for Finding Retro-Reflectors in Flash LIDAR ImageryLyndon B. Johnson Space Center, Houston, Texas

Orbital rendezvous and docking oftwo spacecraft is a topic of continued in-terest to NASA. For crewed missions, it isfrequently the case that the target is co-operative (i.e., is equipped with some sortof navigation aid). If one of the relativenavigation instruments is a Flash LIDAR,then this aid may be a suite of retro-re-flectors. One of the most difficult as-pects of this problem (especially at closerange) is finding the retro-reflectors in aFlash LIDAR image amongst a substan-tial amount of clutter. A new technique has been developed

for autonomously finding the three-di-mensional location of candidate retro-reflectors in a Flash LIDAR image. With

no a-priori state information, this newapproach is capable of finding an ana-lyst-defined number of reflectors. It iseffective at rejecting most bright non-re-flector objects. This technique, whichcontinues to be developed and tested,has substantially better performance(finds more reflectors, with fewer falsepositives) than simpler approaches withonly a modest increase in computa-tional resources.The Orion/Multi-Purpose Crew Vehi-

cle is a new crewed vehicle being de-signed by NASA and Lockheed Martinfor piloted exploration missions capableof destinations beyond low Earth orbit(LEO). The vehicle will also maintain

the capability to perform rendezvous,proximity operations, and docking(RPOD) with other orbital assets and el-ements in the exploration architecture.The vision navigation sensor (VNS) is aFlash LIDAR, and will be the primarynavigation instrument used by the Orionduring the RPOD flight phase. Thus,maturing techniques for finding reflec-tors in Flash LIDAR imagery of coopera-tive vehicles is critical to the currentOrion relative navigation architecture.

This work was done by John A. Christian ofJohnson Space Center. Further information iscontained in a TSP (see page 1). MSC-25237-1

Novel Hemispherical Dynamic Camera for EVAsJohn H. Glenn Research Center, Cleveland, OhioA novel optical design for imaging sys-

tems is able to achieve an ultra-wide fieldof view (UW-FOV) of up to 208°. The de-sign uses an integrated optical design(IOD). The UW-FOV optics design re-duces the wasted pixels by 49% whencompared against the baseline fisheye

lens. The IOD approach results in a de-sign with superior optical performanceand minimal distortion.

This work was done by Jason Geng ofXigen LLC for Glenn Research Center. Fur-ther information is contained in a TSP (seepage 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steven Fedor, MailStop 4–8, 21000 Brookpark Road, Cleve-land, Ohio 44135. Refer to LEW-18984-1.


Software

360° Visual Detection andObject Tracking on an Au-tonomous Surface Vehicle

This software addresses the problemof an autonomous vehicle patrolling aregion for objects of interest using mul-tiple cameras. The system must identifyand track the objects over time and lo-calize their positions in the world. It im-plements an autonomous perceptionand situation awareness system, whichreceives images from an omnidirec-tional camera head, identifies objects ofinterest in these images, and probabilis-tically tracks the objects’ presences overtime, even as they may exist outside ofsensor range.The software consists of three func-

tional parts. The Image Server recordsthe images from all cameras on the cam-era head simultaneously. It also recordsthe data from the inertial navigation sys-tem (INS) that provides the vehicle poseat the image frame. Next, the ImageServer stabilizes the images to produceimages with horizontal, image-centeredhorizons. Finally, in addition to passingon the images and pose to the next sys-tem for further processing, the ImageServer efficiently logs this large amountof data for offline use.The Contact Server detects objects of

interest in the stabilized images and cal-culates the absolute bearing of eachcontact. Two object-detection algo-rithms are employed, loosely trained ontemplates of the 3D objects of interest.Additionally, the Contact Server adjuststhe images for better detection results;for example, adjusting for variable light-ing conditions.The Object-level Tracking and

Change Detection (OTCD) Server inte-grates the information from the ContactSever over time and over all cameras toprobabilistically track the objects of in-terest and to detect changes of interest.OTCD maintains a database of hypothe-sized true objects, along with a probabil-ity of existence that measures the confi-dence that the object exists at itshypothesized location at a given time. Fi-nally, OTCD can send downstream alertswhen a new object appears or a knownobject disappears.The software detects objects of inter-

est from arbitrary perspectives andwidely varied lighting conditions, and lo-

calizes and tracks these objects overtime. It tracks the existence of these ob-jects in their estimated positions, evenwhen they are out of sensor range, en-abling a patrol vehicle to leave and comeback and hypothesize whether the sameobjects of interest are in the same posi-tion viewed earlier (change detection).The software integrates information formultiple source cameras to provide a360° view of the environment, and tracksobjects seamlessly as they transition be-tween cameras. It includes several help-ful analysis utilities, such as a real-timeremote viewer of the scene and identi-fied objects, efficient multi-leveled datalogging, and the capability to processdata logs offline for replays.

This work was done by Michael Wolf,Yoshiaki Kuwata, Christopher Assad, RobertD. Steele, Terrance L. Huntsberger, David Q.Zhu, Andrew Howard, and Lucas Scharen-broich of Caltech for NASA’s Jet PropulsionLaboratory. For more information, [email protected].

This software is available for commerciallicensing. Please contact Dan Broderick [email protected]. Refer toNPO-47850.

Simulation of Charge Carrier Mobility in Conducting Polymers

Electric conduction in polymers is oneof the key elements in avoiding cata-strophic internal electrostatic dischargein dielectrics during space missions. Thissoftware package enables the simulationof carrier mobility for any given site con-centration, which is a material design pa-rameter that can be varied in experimen-tal studies. The software computes thecharge mobility for a disordered networkof carrier sites. The mobility is obtainedby computing the average drift velocityfor an applied electric field. The mobilityis given by the ratio of the drift velocity tothe electric field.The software uses an efficient Monte

Carlo technique to sample the transittime of carriers injected on one end ofthe simulation domain. The mobilitycan be obtained as a function of temper-ature and site concentration, which areparameters of interest for experimentsand materials design.This software is implemented in C++

and is highly modular. New models and

variations in the simulation process caneasily be added. Parallelization for exe-cution on a distributed computing plat-form was implemented.This program enables the calculation

of charge mobility in polymers withvarying dopant concentration, as afunction of electric field and tempera-ture. The objective is to use this pro-gram to explore the parameter spaceand identify the material parametersthat best meet the design requirements.The program will be used to optimize anew material system and will help solvethe problem of catastrophic internalelectrostatic discharges in dielectrics,which is one of the largest sources ofanomaly or failure in space missions.Deep space missions to the outer plan-ets and their moons, where the radia-tion environment is particularly harsh,will benefit most from the new model-ing capability.

This work was done by Paul A. Von All-men and Seungwon Lee of Caltech for NASA’sJet Propulsion Laboratory. For more informa-tion, contact [email protected].


Observational Data Formatter Using CMOR for CMIP5

The current software has been devel-oped to work on NASA instrumentdatasets, an upgrade over similar softwarethat only worked on datasets from climatemodel output. NASA is attempting to re-format satellite data to fit the specific andhighly detailed data format and metadatarequirements for CMIP5 (Coupled ModelIntercomparison Project Phase 5). Thissoftware has relieved science data teamsfrom multiple instruments from the taskof understanding and conforming to theCMIP5 data requirements.The software reads in netcdf files,

combined with select metadata inputfrom the user, and intelligently callsfunctions from the CMOR (ClimateModel Output Rewriter) library to writeout new netcdf files in the proper formatfor inclusion in CMIP5. Currently, thesoftware is capable of ingesting data fromAIRS (Atmospheric Infrared Sounder),MLS (Microwave Limb Sounder), TES


(Tropospheric Emission Spectrometer),MODIS (Moderate Resolution ImagingSpectroradiometer), AVISO (Frenchspace agency data provider), andQuikSCAT (Quick Scatterometer).The unique feature is integration of

the CMOR function library, written in

C, with code able to understand the out-put of science data teams. Many conven-tions used in the climate modeling com-munity differ radically from those usedin the observational data community,and this software serves as a bridge be-tween the two.

This work was done by Steven J. Lewis of Cal-tech for NASA’s Jet Propulsion Laboratory. Formore information, contact [email protected].



Information Technology

Available guidance approaches forlarge numbers (i.e., swarms) of artificialagents are currently very limited.Swarms in nature (e.g., bees, birds, ants)typically contain hundreds to thousandsof agents. The problem is how to mimicnature, and develop guidance laws forartificial (man-made) swarms containinghundreds to thousands of artificialagents.A new guidance solution lets go of

conventional deterministic approachesand instead looks at statistical ap-proaches. Because swarms contain astatistically meaningful number of

agents, a probabilistic approach ismore relevant to the problem. In par-ticular, a probabilistic guidance ap-proach (PGA) has been developed thatcontrols the statistical ensemble (i.e.,the desired probability density across aswarm of agents), rather than any sin-gle individual agent’s trajectory. Be-cause the PGA works with a statisticallylarge ensemble of agents, the “law oflarge numbers” kicks in, and the PGAapproach actually becomes more accu-rate and simpler to implement as thenumber of agents becomes large. Thisis in sharp contrast to deterministic ap-

proaches to swarm guidance that be-come more complex and unwieldy asthe number of agents becomes large.The main idea is to have each agent

follow an independent realization of aMarkov chain. The desired distributionemerges as the ensemble of agents inthe swarm maneuvers about, asymptoti-cally achieving a desired statisticalsteady-state condition, and eliciting aclear emergent behavior from theswarm. The implementation of the prob-abilistic guidance law is completely de-centralized, and leads to an importantswarm behavior that exhibits au-

Probabilistic Guidance for Swarms of Autonomous AgentsA probabilistic approach is simpler to implement as the number of agents becomes large. NASA’s Jet Propulsion Laboratory, Pasadena, California

Propellant Loading Physics Model for Fault Detection Isolationand Recovery Microsoft Excel spreadsheet is used to simulate the operation. John F. Kennedy Space Center, Florida

A Fault Detection, Isolation and Re-covery (FDIR) system needs some in-ternal concept of how the monitoredsystem operates. This “operating con-cept” needs mathematical logic torepresent the cause and effect rela-tionship between constituent compo-nents of the system, health and statusof those components, and the result-ing health and status of the overallsystem. Models constructed with com-mercial simulation systems such asMATLAB and Simulink may ignore in-dividual component contribution tosystem operation. Instead, the mod-eler may naturally focus on overall sys-tem parameters with lumped valuesrepresenting the individual compo-nent characteristics. The resultingsimulations faithfully calculate overallsystem operation, but may miss anom-alies that occur because of plugged,stuck, or otherwise inoperable indi-vidual components. This innovation is a spreadsheet writ-

ten for Microsoft Excel with equationsthat simulate cryogenic propellant load-

ing system operating characteristics.The spreadsheet takes commands froman operator to open and close valves,change pump speeds, and change pres-sure set-points. The spreadsheet contin-uously calculates the operating state ofthe propellant loading system includingmeasurements such as pressures, flowrates, pump speeds, and tank levels. Thesimulation is component-oriented, con-taining comprehensive mathematicaldescriptions of valves of different typesand sizes, pneumatic supply systempumps, filters, and tanks. An “antago-nist” operator may introduce faults incertain of the components. The spread-sheet simulates the effects of the intro-duced faults. The software simulates operation of

the Simulated Rapid Propellant Load-ing (SRPL) System hardware at theKSC Cryogenics Laboratory. The Excelspreadsheet uses Active Control but-tons and sliders drawn in Excel thatallow valves to be opened and closedand pumps to be controlled at variousspeeds. Other Active Control sliders

allow the antagonist operator to intro-duce faults in all the components thatmake up the physics model of theSRPL. The Excel spreadsheet has a unique up-

date feature that calculates the pressures,temperatures, and flows in the physicsmodel of the SRPL. The update featurecalculates all these values, then waits onesecond and recalculates based on updatedtank levels, ullage quantities, and bulk liq-uid temperatures. Thus, the spreadsheet iscapable of continuously updating the liq-uid levels integrating flow rates and heatflux in the system in real time. Equations can be translated into C

code and used in the embedded proces-sor. The results calculated by the Ccode can be validated easily by compar-ing calculated values to the output ofthe spreadsheet.

This work was done by Charles Goodrich,Rebecca Oostdyk, Mark Lewis, and Christo-pher Forney of Kennedy Space Center. Furtherinformation is contained in a TSP (see page1). KSC-13631


tonomous self-repair and maintenancecapabilities.The development area relies heavily

on the theory of Markov processes,Monte-Carlo-Markov-Chain samplingmethods, graph theory, and Lyapunovstability analysis. The development isaided by recent research in designingfast mixing Markov chains that con-verge to desired distributions and in-corporate constraints on transitionprobabilities, and many classical re-

sults on convergence of Markovchains.The main novel feature is that the

PGA guidance law is probabilistic in na-ture, and specifies the desired spatialprobability density distribution for theswarm rather than the exact desiredpaths of the individual agents. Conse-quently, PGA is a more natural and use-ful guidance statement when dealingwith swarms comprised of a statisticallylarge number of agents, compared to de-

terministic methods that become un-wieldy as the number of agents becomeslarge.

This work was done by David S. Bayardand Behcet Acikmese of Caltech for NASA’s JetPropulsion Laboratory. For more informa-tion, contact [email protected].

The software used in this innovation isavailable for commercial licensing. Pleasecontact Dan Broderick at [email protected]. Refer to NPO-47851.

Visual odometry (VO) refers to the es-timation of vehicle motion using on-board cameras. A common mode of oper-ation utilizes stereovision to tri angulate aset of image features, track these overtime, and infer vehicle motion by com-puting the apparent point cloud motionwith respect to the cameras. It has beenobserved that stereo VO is subject todrift over time. It is well known that stereo triangula-

tion suffers from bias induced from cor-relation error (i.e., subpixel errors inmatching between features in the left andright images of a stereo pair). The natureof this bias is a complicated function ofthe error statistics of the correlation anddepends on scene structure, camera con-figuration, and imaging geometry. Thegoal of this work was to better character-ize the stereo bias than has been done todate, and explore the effect of compen-sating for this bias on VO drift. The problem was approached in

terms of a stochastic propagation oferror from the image plane to triangu-lation. The end result is a better repre-sentation of stereo bias than has beenaccomplished thus far. In early tests,

this stereo bias correction has had adramatic effect in reducing VO drift. Ina simulated run of 100 m, the drift wasreduced from an uncorrected 47 cm tojust 7 cm. The preliminary conclusionis that VO drift is due primarily tostereo bias rather than to inherent biasin the non-linear estimator used to re-cover motion. Given a model of noise in correlation

matching between the left and right im-ages of a stereo pair, the projection ofany point in the world into the stereopair can be indexed by its pixel locationin the left image and the horizontalshift of that location in the right image,referred to as disparity. Thus, everypoint in the world that is simultaneouslyvisible in both cameras can by describedas (x,y,d). Considering only integer val-ues, a lookup table was constructed andindexed by (x,y,d), where (x,y) spans thewhole of the left image, and d spans val-ues corresponding to reasonable rangesin the scene. At each (x,y,d), the as-sumed noise profile is taken from corre-lation and a Monte Carlo simulation isperformed to propagate that noise pro-file into the triangulated point in space.

The results are stored in a table indexedby image column, row, and disparity. Given any point correspondence, the

corresponding (x,y,d) is looked up, inter-polated from integer to real values as re-quired, and the triangulation statistics areextracted. The lookup table generation isa one-time process for any calibrated imag-ing system, and the subsequent lookup hasminimal com p utational overhead. Fromthe triangulation statistics, the likely bias istaken and added directly to the triangu-lated point. In ensemble, this produces apoint cloud with higher fidelity than theuncorrected cloud and, consequently, abetter incremental VO estimate. VO bias compensation has focused pri-

marily on correcting the motion estimaterather than on correcting the stereo. Thismethod can be implemented in real-timeon a deployed system and shows verypromising preliminary results.

This work was done by Adnan I. Ansar ofCaltech for NASA’s Jet Propulsion Laboratory.For more information, [email protected].

This software is available for commerciallicensing. Please contact Dan Broderick [email protected]. Refer to

Reducing Drift in Stereo Visual Odometry The drift was reduced from an uncorrected 47 cm to just 7 cm. NASA’s Jet Propulsion Laboratory, Pasadena, California

In the United States, as many as7,000 commercial and private aircraftmay be in the air simultaneously at anygiven time and date, and the total num-

ber of commercial flights in a given 24-hour period generally exceeds 50,000.To maintain the safety and efficiency ofair travel, this innovation receives pro-

posed flight plans and associated flightroute information and flight parame-ters for aircraft operating in a given re-gion (e.g., the continental United

Future Air-Traffic Management Concepts Evaluation Tool An aircraft monitoring system and an aircraft user system can interact and negotiate changeswith each other. Ames Research Center, Moffett Field, California


A previously created direct numeri-cal simulation (DNS) database of mix-ing of species under supercritical pres-sure has been examined and analyzedfor the purpose of understanding themodeling requirements in the contextof large eddy simulation (LES). Of par-ticular interest is reproducing in LESthe feature of uphill species diffusionthat is identified in DNS. The exami-nation of the database was performedby employing Minkowski functionalsthat provide the geometrical, topologi-cal, and morphological aspects of iso-surfaces that are extracted from a fieldthrough computing dimensionlessshapefinders: genus, planarity, and fil-amentarity.The analysis is restricted to simply

connected isosurfaces having a nullgenus. Isosurfaces of the second invari-ant of the deformation tensor and ofthe dissipation calculated as a result ofall transport processes were found to bequite different; those derived from thesecond invariant turned out to havemore randomness when compared tothose derived from the dissipation thathad better defined volumetric extent.

Upon filtering, at the same filter width,there were more structures of greaterextent and with well-defined morphol-ogy resulting more from the dissipationthan from the second invariant.Independent of the filter width, the

dissipation-related isosurfaces hadmore complex structure than those is-sued from the second invariant, as evi-denced by larger planarity and filamen-tarity. In general, the structuresoriginating from the second invariantwere filamentary, a feature that was re-tained when filtering, whereas thoseoriginating from the dissipation hadmore comparable planarity and fila-mentary values. Having thus examinedthe template LES solution, the activityof terms in the differential LES equa-tions was examined and, in addition tothe classical subgrid-scale (SGS) termsissued from the convective terms of theoriginal equations, other SGS termswere identified.When evaluated on the database,

some of these new terms were shownto have important contributions in theLES equations. The importance of thecontribution of each term increased

with increasing pressure. Several mod-els were proposed and tested for thesesignificant SGS terms with the goal ofpreserving, in future LES, the featuresobserved in the template LES solution.The model that best reduced the erroron all terms compared to the templatevalues was based on an ApproximateDeconvolution Model combined withexplicit filtering that succeeded in re-ducing the error by more than a factorof two on terms occurring in the mo-mentum, species, and energy equa-tions. Particularly crucial was the effectof the model for recovering the flux ofspecies experiencing uphill diffusion,a phenomenon identified for multi-species but not for binary-species mix-ing. Based on this study, caution is ad-vised on simply extrapolating resultsfrom supercritical-pressure binary-species mixing to multi-species mixing.

This work was done by Josette Bellan andGiulio Borghesi of Caltech for NASA’s JetPropulsion Laboratory. For more informa-tion, contact [email protected]. NPO-49179

Examination and A Priori Analysis of a Direct NumericalSimulation Database for High-Pressure Turbulent FlowsMinkowski functionals are employed that provide the geometrical, topological, andmorphological aspects of isosurfaces.NASA’s Jet Propulsion Laboratory, Pasadena, California

States), and provides actual flightroutes and schedules based on ex-pected air traffic. This innovationavoids or minimizes air traffic incidentsby changing one or more flight planparameters where appropriate, for oneor more of these aircraft. This innovation comprises methods

for evaluating and implementing airtraffic management tools, and ap-proaches for managing and avoidingan air traffic incident before an inci-dent can occur. A first system receivesparameters for flight plan configura-tions (e. g., initial fuel carried, flightroute, flight route segments followed,flight altitude for a given flight routesegment, aircraft velocity for eachflight route segment, flight route as-cent rate, flight route descent rate,flight departure site, flight departuretime, flight arrival time, flight destina-tion site and/or alternate flight desti-

nation site), flight plan schedules, ex-pected weather along each flight routesegment, aircraft specifics, airspace (al-titude) bounds for each flight routesegment, and what navigational aidsare available. The invention provides flight-plan

routing and direct routing, or wind op-timal routing, using great-circle naviga-tion and spherical Earth geometry. Italso provides for aircraft dynamic ef-fects, such as wind effects at each alti-tude, altitude changes, airspeedchanges, and aircraft turns to providepredictions of aircraft trajectory and,optionally, aircraft fuel use. A second system provides several avi-

ation applications using the first system.Several classes of potential incidentsare analyzed, and averted, by appropri-ate changes en route of one or more pa-rameters in the flight plan configura-tion, as provided by a conflict detection

and resolution module and/or trafficflow management modules. These ap-plications include conflict detectionand resolution, miles-in-trail or min-utes-in-trail aircraft separation, flightarrival management, flight re-routing,weather prediction and analysis, and in-terpolation of weather variables basedupon sparse meas urements.

This work was done by Banavar Sridhar,Kapil S. Sheth, Gano Broto Chatterji, KarlD. Bilimoria, Shon Grabbe, and John F.Schipper of Ames Research Center. Furtherinformation is contained in a TSP (see page1).

Inquiries concerning rights for the com-mercial use of this invention should be ad-dressed to the Ames Technology PartnershipsDivision at 1-855-NASA-BIZ (1-855-6272-249) or [email protected]. Refer toARC-14653-2.


Resource-Constrained Application of Support Vector Machines to ImageryFast computation of the SVM decision function over an image using minimal RAM.NASA’s Jet Propulsion Laboratory, Pasadena, California

Machine learning techniques haveshown considerable promise for au-tomating common visual inspectiontasks. For example, Support Vector Ma-chine (SVM) classifiers that have beenlearned from labeled training data de-liver strong detection performance bothfor finding human faces in photographsand locating geologic landforms such ascraters and volcanoes in planetary im-ages gathered by spacecraft. However,SVMs are computationally expensive toapply to an image using the traditionalspatial scanning method in which a rec-tangular window is slid across the imageone pixel at a time and the SVM is eval-uated on each patch of pixels under thewindow. The new software uses small fastFourier transforms (FFTs) and the over-lap-and-add technique from signal pro-cessing to quickly and efficiently com-pute the exact SVM decision functionover an entire image using minimal ran-dom access memory (RAM).SVMs classify a feature vector by com-

puting a weighted combination of ker-nel evaluations between the feature vec-tor and a set of “support vectors.” The

support vectors are positive and negativeexamples from the training set that wereidentified during the learning phase.Each kernel evaluation is essentially anonlinear measurement of the similaritybetween the feature vector and a givensupport vector. For many of the com-monly used kernels, the kernel evalua-tion can be expressed as a linear dotproduct between the feature vector andthe support vector followed by addi-tional nonlinear operations. The linearpart of the computation actually domi-nates the workload, which enables thesoftware to achieve a significant speedupby performing the linear calculationsover the entire image with FFTs. A fur-ther refinement uses the overlap-and-add technique to limit the amount ofRAM required. Overlap-and-add com-putes small, localized FFTs and thenpieces partial results together to estab-lish the final answer.The software provides an effective way

to apply SVMs to image data and is par-ticularly well suited for resource-con-strained environments such as onboarda spacecraft. The technique allows exact

computation of the SVM decision func-tion over an image using minimal RAM(typically less than 5% of the size of theimage). Also, the approach is comple-mentary to “reduced set” methods,which speed up SVM calculations by re-ducing the number of support vectorsrequired. Used together, the two meth-ods can yield a multiplicative gain in per-formance. The software implementationis not specific to any particular domain.Thus far, it has been demonstrated forthe crater detection problem; however,in principle, it can be used for a varietyof image inspection tasks. One could en-vision a variety of smartphone appsbased around the ability to take a pic-ture and detect/classify/count objectsin the picture.

This work was done by Michael C. Burl ofCaltech, and Philipp G. Wetzler of the Univer-sity of Colorado, Boulder for NASA’s JetPropulsion Laboratory. Further information iscontained in a TSP (see page 1).

The software used in this innovation isavailable for commercial licensing. Please con-tact Dan Broderick at [email protected]. Refer to NPO-48072.

National Aeronautics andSpace Administration

technology focus electronics/computers - nasa · 2014-03-11 · technology focus...

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