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01-11 January 2011

https://ntrs.nasa.gov/search.jsp?R=20110002982 2020-07-05T06:03:50+00:00Z

Availability of NASA Tech Briefs and TSPsRequests for individual Tech Briefs or for Technical Support Packages (TSPs) announced herein shouldbe addressed to

National Technology Transfer CenterTelephone No. (800) 678-6882 or via World Wide Web at www.nttc.edu

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 also available at the same facility oron the World Wide Web at http://www.nasa.gov/offices/ipp/network/index.html

Innovative Partnerships Offices are located at NASA field centers to provide technology-transfer access toindustrial users. Inquiries can be made by contacting NASA field centers listed below.

Ames Research CenterLisa L. Lockyer(650) [email protected]

Dryden Flight Research CenterYvonne D. Gibbs(661) [email protected]

Glenn Research CenterKathy Needham(216) [email protected]

Goddard Space Flight CenterNona Cheeks(301) [email protected]

Jet Propulsion LaboratoryAndrew Gray(818) [email protected]

Johnson Space Centerinformation(281) [email protected]

Kennedy Space CenterDavid R. Makufka(321) [email protected]

Langley Research CenterElizabeth B. Plentovich(757) [email protected]

Marshall Space Flight CenterJim Dowdy(256) [email protected]

Stennis Space CenterRamona Travis(228) 688-3832 [email protected]

Carl Ray, Program ExecutiveSmall Business Innovation Research (SBIR) & Small Business Technology Transfer (STTR) Programs(202) [email protected]

Doug Comstock, DirectorInnovative Partnerships Program Office(202) [email protected]

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.

NASA Tech Briefs, December 2010 1

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

01-11 January 2011

5 Technology Focus: Sensors5 Distributed Aerodynamic Sensing and

Processing Toolbox

5 Collaborative Supervised Learning for Sensor Networks

5 Hazard Detection Software for Lunar Landing

6 Onboard Nonlinear Engine Sensor and Compo-nent Fault Diagnosis and Isolation Scheme

6 Network-Capable Application Process and Wire-less Intelligent Sensors for ISHM

9 Semiconductors & ICs9 Interface Supports Multiple Broadcast

Transceivers for Flight Applications

9 FPGA Sequencer for Radar Altimeter Applications

9 Miniature Sapphire Acoustic Resonator — MSAR

10 Process-Hardened, Multi-Analyte Sensor forCharacterizing Rocket Plume Constituents

10 SAD5 Stereo Correlation Line-Striping in an FPGA

13 Manufacturing & Prototyping13 Hybrid Composite Cryogenic Tank Structure

13 Nanoscale Deformable Optics

14 Reliability-Based Design Optimization of a Composite Airframe Component

14 Zinc Oxide Nanowire Interphase for EnhancedLightweight Polymer Fiber Composites

17 Mechanics/Machinery17 Plasma Igniter for Reliable Ignition of

Combustion in Rocket Engines

17 Wire Test Grip Fixture

18 A Sub-Hertz, Low-Frequency VibrationIsolation Platform

19 Materials & Coatings19 Carbon Nanofibers Synthesized on Selective

Substrates for Nonvolatile Memory and 3D Electronics

20 Nanoparticle/Polymer Nanocomposite Bond Coator Coating

21 Green Design21 High-Resolution Wind Measurements for

Offshore Wind Energy Development

21 Spring Tire

23 Software23 Marsviewer 2008

23 Mission Services Evolution Center Message Bus

23 Major Constituents Analysis for the Vehicle Cabin Atmosphere Monitor

24 Astronaut Health Participant Summary Application

24 Adaption of the AMDIS Method to Flight Statuson the VCAM Instrument

24 Natural Language Interface for Safety Certification of Safety-Critical Software

27 Physical Sciences27 Cryogenic Caging for Science Instrumentation

27 Wide-Range Neutron Detector for Space Nuclear Applications

27 In Situ Guided Wave Structural Health Monitoring System

28 Multiplexed Energy Coupler for Rotating Equipment

28 Attitude Estimation in Fractionated SpacecraftCluster Systems

28 Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

29 Active Flow Effectors for Noise and Separation Control

29 Method and System for Temporal Filtering inVideo Compression Systems

30 Apparatus for Measuring Total Emissivity ofSmall, Low-Emissivity Samples

30 Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

31 Simplified Architecture for Precise Aiming of aDeep-Space Communication Laser Transceiver

32 Two-Photon-Absorption Scheme for OpticalBeam Tracking

32 High-Sensitivity, Broad-Range Vacuum GaugeUsing Nanotubes for Micromachined Cavities

2 NASA Tech Briefs, January 2011

NASA Tech Briefs, January 2011 3

33 Wide-Field Optic for Autonomous Acquisition ofLaser Link

34 Extracting Zero-Gravity Surface Figure of a Mirror

35 Information Sciences35 Modeling Electromagnetic Scattering From Com-

plex Inhomogeneous Objects

35 Visual Object Recognition and Tracking of Tools

36 Method for Implementing Optical Phase Adjustment

36 Visual SLAM Using Variance Grid Maps

37 Rapid Calculation of Spacecraft Trajectories UsingEfficient Taylor Series Integration

37 Efficient Kriging Algorithms WeavEncke Method

37 Predicting Spacecraft Trajectories by the WeavEncke Method

38 An Augmentation of G-Guidance Algorithms

38 Comparison of Aircraft Icing Growth Assessment Software

41 Books & Reports41 Silicon-Germanium Voltage-Controlled Oscillator

at 105 GHz

41 Estimation of Coriolis Force and Torque Acting on Ares-1

41 Null Lens Assembly for X-Ray Mirror Segments

41 High-Precision Pulse Generator

Technology Focus: Sensors

A Distributed Aerodynamic Sensingand Processing (DASP) toolbox was de-signed and fabricated for flight test ap-plications with an Aerostructures TestWing (ATW) mounted under the fuse-lage of an F-15B on the Flight Test Fix-ture (FTF). DASP monitors andprocesses the aerodynamics with thestructural dynamics using nonintrusive,surface-mounted, hot-film sensing. Thisaerodynamic measurement tool bene-fits programs devoted to static/dynamicload alleviation, body freedom fluttersuppression, buffet control, improve-

ment of aerodynamic efficiencythrough cruise control, supersonicwave drag reduction through shockcontrol, etc.

This DASP toolbox measures localand global unsteady aerodynamic loaddistribution with distributed sensing. Itdetermines correlation between aerody-namic “observables” (aero forces) andstructural dynamics, and allows controlauthority increase through aeroelasticshaping and active flow control.

It offers improvements in flutter sup-pression and, in particular, body free-

dom flutter suppression, as well as aero-dynamic performance of wings for in-creased range/endurance of manned/unmanned flight vehicles. Other im-provements include inlet performancewith closed-loop active flow control, anddevelopment and validation of advancedanalytical and computational tools forunsteady aerodynamics.

This work was done by Martin Brennerand Christine Jutte of Dryden Flight ResearchCenter and Arun Mangalam of Tao Systems,Inc. Further information is contained in aTSP (see page 1). DRC-009-031

Distributed Aerodynamic Sensing and Processing ToolboxDryden Flight Research Center, Edwards, California

Collaboration methods for distrib-uted machine-learning algorithms in-volve the specification of communica-tion protocols for the learners, whichcan query other learners and/or broad-cast their findings preemptively. Eachlearner incorporates information fromits neighbors into its own training set,and they are thereby able to “bootstrap”each other to higher performance.

Each learner resides at a differentnode in the sensor network and makesobservations (collects data) independ-ently of the other learners. After being“seeded” with an initial labeled trainingset, each learner proceeds to learn in aniterative fashion. New data is collectedand classified. The learner can then ei-

ther broadcast its most confident classifi-cations for use by other learners, or canquery neighbors for their classificationsof its least confident items. As such, col-laborative learning combines elementsof both passive (broadcast) and active(query) learning. It also uses ideas fromensemble learning to combine the multi-ple responses to a given query into a sin-gle useful label.

This approach has been evaluatedagainst current non-collaborative alter-natives, including training a single classi-fier and deploying it at all nodes with nofurther learning possible, and permit-ting learners to learn from their ownmost confident judgments, absent inter-action with their neighbors. On several

data sets, it has been consistently foundthat active collaboration is the best strat-egy for a distributed learner network.The main advantages include the abilityfor learning to take place autonomouslyby collaboration rather than by requir-ing intervention from an oracle (usuallyhuman), and also the ability to learn ina distributed environment, permittingdecisions to be made in situ and to yieldfaster response time.

This work was done by Kiri L. Wagstaff ofCaltech, Umaa Rebbapragada of Tufts Uni-versity, and Terran Lane of the University ofNew Mexico for NASA’s Jet Propulsion Labo-ratory. For more information, contact [email protected]. NPO-46914

Collaborative Supervised Learning for Sensor Networks This technique could be applied to sensor networks for intruder detection, target tracking, anddata mining in cell-phone networks. NASA’s Jet Propulsion Laboratory, Pasadena, California

The Autonomous Landing and Haz-ard Avoidance Tech nology (ALHAT)Project is developing a system for safeand precise manned lunar landing thatinvolves novel sensors, but also specific

algorithms. ALHAT has selected imag-ing LIDAR (light detection and rang-ing) as the sensing modality for onboardhazard detection because imaging LI-DARs can rapidly generate direct meas-

urements of the lunar surface elevationfrom high altitude. Then, starting withthe LIDAR-based Hazard Detection andAvoidance (HDA) algorithm developedfor Mars Landing, JPL has developed a


Hazard Detection Software for Lunar LandingNASA’s Jet Propulsion Laboratory, Pasadena, California

mature set of HDA software for themanned lunar landing problem.

Landing hazards exist everywhere onthe Moon, and many of the more desir-able landing sites are near the most haz-ardous terrain, so HDA is needed to au-tonomously and safely land payloadsover much of the lunar surface. TheHDA requirements used in the ALHATproject are to detect hazards that are 0.3m tall or higher and slopes that are 5° orgreater. Steep slopes, rocks, cliffs, andgullies are all hazards for landing and,by computing the local slope and rough-ness in an elevation map, all of thesehazards can be detected. The algorithmin this innovation is used to measureslope and roughness hazards. In addi-

tion to detecting these hazards, the HDAcapability also is able to find a safe land-ing site free of these hazards for a lunarlander with diameter ≈15 m over most ofthe lunar surface.

This software includes an implemen-tation of the HDA algorithm, softwarefor generating simulated lunar terrainmaps for testing, hazard detection per-formance analysis tools, and associateddocumentation. The HDA software hasbeen deployed to Langley Research Cen-ter and integrated into the POST IIMonte Carlo simulation environment.The high-fidelity Monte Carlo simula-tions determine the required groundspacing between LIDAR samples(ground sample distances) and the

noise on the LIDAR range measure-ment. This simulation has also beenused to determine the effect of viewingon hazard detection performance. Thesoftware has also been deployed to John-son Space Center and integrated intothe ALHAT real-time Hardware-in-the-Loop testbed.

This work was done by Andres Huertas,Andrew E. Johnson, Robert A. Werner, andJames F. Montgomery of Caltech for NASA’sJet Propulsion Laboratory. For more informa-tion, contact [email protected].

This software is available for commer-cial licensing. Please contact Daniel Brod-erick of the California Institute of Technol-ogy at [email protected]. Refer toNPO-47178.

Intelligent sensor technology and sys-tems are increasingly becoming attractivemeans to serve as frameworks for intelli-gent rocket test facilities with embeddedintelligent sensor elements, distributeddata acquisition elements, and onboarddata acquisition elements. Networked in-telligent processors enable users and sys-tems integrators to automatically config-ure their measurement automation

systems for analog sensors. NASA andleading sensor vendors are working to-gether to apply the IEEE 1451 standardfor adding plug-and-play capabilities forwireless analog transducers through theuse of a Transducer Electronic DataSheet (TEDS) in order to simplify sensorsetup, use, and maintenance, to automat-ically obtain calibration data, and to elim-inate manual data entry and error.

A TEDS contains the critical informa-tion needed by an instrument or meas-urement system to identify, characterize,interface, and properly use the signalfrom an analog sensor. A TEDS is de-ployed for a sensor in one of two ways.First, the TEDS can reside in embedded,nonvolatile memory (typically flashmemory) within the intelligent proces-sor. Second, a virtual TEDS can exist as a

Network-Capable Application Process and Wireless IntelligentSensors for ISHMThis technology can be used for wireless sensor monitoring in vehicles, home security, systemautomation, and radio-frequency identification (RFID) for smart tags.Stennis Space Center, Mississippi

Onboard Nonlinear Engine Sensor and Component Fault Diag-nosis and Isolation SchemeJohn H. Glenn Research Center, Cleveland, Ohio

A method detects and isolates in-flightsensor, actuator, and component faultsfor advanced propulsion systems. Insharp contrast to many conventionalmethods, which deal with either sensorfault or component fault, but not both,this method considers sensor fault, actu-ator fault, and component fault underone systemic and unified framework.

The proposed solution consists of twomain components: a bank of real-time,nonlinear adaptive fault diagnostic esti-mators for residual generation, and aresidual evaluation module that in-cludes adaptive thresholds and a Trans-

ferable Belief Model (TBM)-based resid-ual evaluation scheme. By employing anonlinear adaptive learning architec-ture, the developed approach is capableof directly dealing with nonlinear en-gine models and nonlinear faults with-out the need of linearization. Softwaremodules have been developed and eval-uated with the NASA C-MAPSS enginemodel. Several typical engine-faultmodes, including a subset of sensor/ac-tuator/components faults, were testedwith a mild transient operation scenario.The simulation results demonstratedthat the algorithm was able to success-

fully detect and isolate all simulatedfaults as long as the fault magnitudeswere larger than the minimum de-tectable/isolable sizes, and no misdiag-nosis occurred.

This work was done by Liang Tang andJonathan A. DeCastro of Impact Technolo-gies, LLC and Xiaodong Zhang of WrightState University for Glenn Research Center.

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steve Fedor, MailStop 4–8, 21000 Brookpark Road, Cleveland,Ohio 44135. Refer to LEW-18518-1/9-1.


separate file, downloadable from the In-ternet. This concept of virtual TEDS ex-tends the benefits of the standardizedTEDS to legacy sensors and applicationswhere the embedded memory is notavailable. An HTML-based user inter-face provides a visual tool to interfacewith those distributed sensors that aTEDS is associated with, to automate thesensor management process.

Implementing and deploying theIEEE 1451.1-based Network-Capable Ap-plication Process (NCAP) can achievesupport for intelligent process in Inte-grated Systems Health Management(ISHM) for the purpose of monitoring,detection of anomalies, diagnosis ofcauses of anomalies, prediction of futureanomalies, mitigation to maintain oper-ability, and integrated awareness of sys-tem health by the operator. It can alsosupport local data collection and stor-age. This invention enables wide-areasensing and employs numerous globally

distributed sensing devices that observethe physical world through the existingsensor network. This innovation enablesdistributed storage, distributed process-ing, distributed intelligence, and theavailability of DiaK (Data, Information,and Knowledge) to any element asneeded. It also enables the simultaneousexecution of multiple processes, andrepresents models that contribute to thedetermination of the condition andhealth of each element in the system.

The NCAP (intelligent process) canconfigure data-collection and filteringprocesses in reaction to sensed data, al-lowing it to decide when and how toadapt collection and processing with re-gard to sophisticated analysis of data de-rived from multiple sensors. The userwill be able to view the sensing devicenetwork as a single unit that supports ahigh-level query language. Each querywould be able to operate over data col-lected from across the global sensor net-

work just as a search query encompassesmillions of Web pages.

The sensor web can preserve ubiqui-tous information access between thequerier and the queried data. Pervasivemonitoring of the physical world raisessignificant data and privacy concerns.This innovation enables different au-thorities to control portions of the sens-ing infrastructure, and sensor service au-thors may wish to compose servicesacross authority boundaries.

This work was done by Fernando Figueroa,Jon Morris, and Mark Turowski of StennisSpace Center and Ray Wang of MobitrumCorp. Inquiries concerning rights for the com-mercial use of this invention should be ad-dressed to:

Ray WangMobitrum Corporation8070 Georgia Avenue; Suite 209Silver Spring, MD 20910(301) 585-4040Refer to SSC-00313/5.


Semiconductors & ICs

A wireless avionics interface providesa mechanism for managing multiplebroadcast transceivers. This interfaceisolates the control logic required tosupport multiple transceivers so that theflight application does not have to man-age wireless transceivers. All of the logicto select transceivers, detect transmitterand receiver faults, and take auton -omous recovery action is contained inthe interface, which is not restricted tousing wireless transceivers. Wired, wire-less, and mixed transceiver technologiesare supported.

This design’s use of broadcast datatechnology provides inherent cross-

strapping of data links. This greatly sim-plifies the design of redundant flightsubsystems. The interface fully exploitsthe broadcast data link to determine thehealth of other transceivers used to de-tect and isolate faults for fault recovery.The interface uses simplified controllogic, which can be implemented as anintellectual-property (IP) core in a field-programmable gate array (FPGA).

The interface arbitrates the receptionof inbound data traffic appearing onmultiple receivers. It arbitrates the trans-mission of outbound traffic. This systemalso monitors broadcast data traffic todetermine the health of transmitters in

the network, and then uses this healthinformation to make autonomous deci-sions for routing traffic through trans-ceivers. Multiple selection strategies aresupported, like having an active trans-ceiver with the secondary transceiverpowered off except to send periodichealth status reports. Transceivers canoperate in round-robin for load-sharingand graceful degradation.

This work was done by Gary L. Block,William D. Whitaker, James W. Dillon, JamesP. Lux, and Mohammad Ahmad of Caltech forNASA’s Jet Propulsion Laboratory. For more in-formation, contact [email protected]

Interface Supports Multiple Broadcast Transceivers for Flight Applications NASA’s Jet Propulsion Laboratory, Pasadena, California

A sequencer for a radar altimeter pro-vides accurate attitude information for areliable soft landing of the Mars ScienceLaboratory (MSL). This is a field-pro-grammable-gate-array (FPGA)-only im -ple mentation. A table loaded externallyinto the FPGA controls timing, process-ing, and decision structures. Radar ismemory-less and does not use previousacquisitions to assist in the current ac-quisition. All cycles complete in exactly50 milliseconds, regardless of range orwhether a target was found.

A RAM (random access memory)within the FPGA holds instructions forup to 15 sets. For each set, timing is run,echoes are processed, and a comparisonis made. If a target is seen, more detailedprocessing is run on that set. If no targetis seen, the next set is tried.

When all sets have been run, theFPGA terminates and waits for the next50-millisecond event. This setup simpli-fies testing and improves reliability. Asingle vertex chip does the work of anentire assembly. Output products re-

quire minor processing to becomerange and velocity.

This technology is the heart of theTerminal Descent Sensor, which is an in-tegral part of the Entry Decent andLanding system for MSL. In addition, itis a strong candidate for manned land-ings on Mars or the Moon.

This work was done by Andrew C. Berkun,Brian D. Pollard, and Curtis W. Chen of Cal-tech for NASA’s Jet Propulsion Laboratory. Formore information, contact [email protected]

FPGA Sequencer for Radar Altimeter ApplicationsNASA’s Jet Propulsion Laboratory, Pasadena, California

A room temperature sapphireacoustics resonator incorporated intoan oscillator represents a possible op-portunity to improve on quartz ultra-stable oscillator (USO) performance,which has been a staple for NASA mis-sions since the inception of spaceflight.

Where quartz technology is very ma-ture and shows a performance im-provement of perhaps 1 dB/decade,these sapphire acoustic resonatorswhen integrated with matured quartzelectronics could achieve a frequencystability improvement of 10 dB or

more. As quartz oscillators are an es-sential element of nearly all types offrequency standards and reference sys-tems, the success of MSAR would ad-vance the development of frequencystandards and systems for both ground-based and flight-based projects.

Miniature Sapphire Acoustic Resonator — MSARQ values as high as 108 may be achieved at room temperature.NASA’s Jet Propulsion Laboratory, Pasadena, California


Current quartz oscillator technologyis limited by quartz mechanical Q. Witha possible improvement of more than×10 Q with sapphire acoustic modes, thestability limit of current quartz oscilla-tors may be improved tenfold, to 10–14 at1 second. The electromagnetic modes ofsapphire that were previously developedat JPL require cryogenic temperaturesto achieve the high Q levels needed toachieve this stability level. However sap-phire’s acoustic modes, which have notbeen used before in a high-stability oscil-lator, indicate the required Q values (ashigh as Q = 108) may be achieved atroom temperature in the kHz range.Even though sapphire is not piezoelec-tric, such a high Q should allow electro-static excitation of the acoustic modeswith a combination of DC and AC volt-ages across a small sapphire disk (≈ l mmthick). The first evaluations under thistask will test predictions of an estimatedinput impedance of 10 kilohms at Q =108, and explore the Q values that canbe realized in a smaller resonator, which

has not been previously tested foracoustic modes.

This initial Q measurement and excita-tion demonstration can be viewed similarto a transducer converting electrical en-ergy to mechanical energy and back.Such an electrostatic tweeter type excita-tion of a mechanical resonator will betested at 5 MHz. Finite element calcula-tion will be applied to resonator designfor the desired resonator frequency andoptimum configuration. The experimentconsists of the sapphire resonator sand-wiched between parallel electrodes. ADC+AC voltage can be applied to gener-ate a force to act on a sapphire resonator.With the frequency of the AC voltagetuned to the sapphire resonator fre-quency, a resonant condition occurs andthe sapphire Q can be measured with ahigh-frequency impedance analyzer.

To achieve high Q values, many exper-imental factors such as vacuum seal, gasdamping effects, charge buildup on thesapphire surface, heat dissipation, sap-phire anchoring, and the sapphire

mounting configuration will need atten-tion. The effects of these parameters willbe calculated and folded into the res-onator design. It is envisioned that theinitial test configuration would allow formovable electrodes to check gap spacingdependency and verify the input imped-ance prediction.

Quartz oscillators are key componentsin nearly all ground- and space-basedcommunication, tracking, and radio sci-ence applications. They play a key roleas local oscillators for atomic frequencystandards and serve as flywheel oscilla-tors or to improve phase noise in high-performance frequency and timing dis-tribution systems. With ultra-stable per-formance from one to three seconds, anEarth-orbit or moon-based MSAR canenhance available performance optionsfor spacecraft due to elimination of at-mospheric path degradation.

This work was done by Rabi T. Wang andRobert L. Tjoelker of Caltech for NASA’s JetPropulsion Laboratory For more information,contact [email protected]. NPO-47343

A multi-analyte sensor was developedthat enables simultaneous detection ofrocket engine combustion-product mole-cules in a launch-vehicle ground teststand. The sensor was developed using apin-printing method by incorporatingmultiple sensor elements on a singlechip. It demonstrated accurate and sensi-tive detection of analytes such as carbondioxide, carbon monoxide, kerosene,

isopropanol, and ethylene from a singlemeasurement.

The use of pin-printing technologyenables high-volume fabrication of thesensor chip, which will ultimately elimi-nate the need for individual sensor cali-bration since many identical sensors aremade in one batch. Tests were per-formed using a single-sensor chip at-tached to a fiber-optic bundle. The use

of a fiber bundle allows placement ofthe opto-electronic readout device at aplace remote from the test stand. Thesensors are rugged for operation inharsh environments.

This work was done by Kisholoy Goswamifor Stennis Space Center. For more informa-tion, contact: Kisholoy Goswami, In-noSense, LLC; (310) 530-2011. SSC-00348

Process-Hardened, Multi-Analyte Sensor for CharacterizingRocket Plume Constituents Stennis Space Center, Mississippi

High precision SAD5 stereo computa-tions can be performed in an FPGA(field-programmable gate array) atmuch higher speeds than possible in aconventional CPU (central processingunit), but this uses large amounts ofFPGA resources that scale with imagesize. Of the two key resources in anFPGA, Slices and BRAM (block RAM),Slices scale linearly in the new algorithmwith image size, and BRAM scales qua-dratically with image size. An approach

was developed to trade latency forBRAM by sub-windowing the image ver-tically into overlapping strips and stitch-ing the outputs together to create a sin-gle continuous disparity output.

In stereo, the general rule of thumb isthat the disparity search range must be1/10 the image size. In the new algo-rithm, BRAM usage scales linearly withdisparity search range and scales againlinearly with line width. So a doublingof image size, say from 640 to 1,280,

would in the previous design be an effec-tive 4× of BRAM usage: 2× for line width,2× again for disparity search range.

The minimum strip size is twice thesearch range, and will produce an out-put strip width equal to the disparitysearch range. So assuming a disparitysearch range of 1/10 image width, 10 se-quential runs of the minimum strip sizewould produce a full output image.

This approach allowed the innovatorsto fit 1280×960 wide SAD5 stereo disparity

SAD5 Stereo Correlation Line-Striping in an FPGA NASA’s Jet Propulsion Laboratory, Pasadena, California


in less than 80 BRAM, 52k Slices on a Vir-tex 5LX330T, 25% and 24% of resources,respectively. Using a 100-MHz clock, thisbuild would perform stereo at 39 Hz.

Of particular interest to JPL is thatthere is a flight qualified version of theVirtex 5: this could produce stereo re-sults even for very large image sizes at 3orders of magnitude faster than could

be computed on the PowerPC 750 flightcomputer. The work covered in the re-port allows the stereo algorithm to runon much larger images than before, andusing much less BRAM. This opens upchoices for a smaller flight FPGA (whichsaves power and space), or for other al-gorithms in addition to SAD5 to be runon the same FPGA.

This work was done by Carlos Y. Villal-pando and Arin C. Morfopoulos of Caltech forNASA’s Jet Propulsion Laboratory. Further in-formation is contained in a TSP (see page 1).

The software used in this innovation isavailable for commercial licensing. Please con-tact Daniel Broderick of the California Insti-tute of Technology at [email protected] to NPO-47245.


Manufacturing & Prototyping

A hybrid lightweight composite tankhas been created using specially de-signed materials and manufacturingprocesses. The tank is produced by usinga hybrid structure consisting of at leasttwo reinforced composite material sys-tems. The inner composite layer com-prises a distinct fiber and resin matrixsuitable for cryogenic use that is abraided-sleeve (and/or a filament-wound layer) aramid fiber preform thatis placed on a removable mandrel (out-fitted with metallic end fittings) and isinfused (vacuum-assisted resin transfermolded) with a polyurethane resin ma-trix with a high ductility at low tempera-tures. This inner layer is allowed to cureand is encapsulated with a filament-wound outer composite layer of a dis-tinct fiber resin system. Both inner andouter layer are in intimate contact, andcan also be cured at the same time. The

outer layer is a material that performswell for low temperature pressure ves-sels, and it can rely on the inner layer toact as a liner to contain the fluids.

The outer layer can be a variety of ma-terials, but the best embodiment may bethe use of a continuous tow of carbonfiber (T-1000 carbon, or others), orother high-strength fibers combinedwith a high ductility epoxy resin matrix,or a polyurethane matrix, which per-forms well at low temperatures. Aftercuring, the mandrel can be removedfrom the outer layer.

While the hybrid structure is not lim-ited to two particular materials, a pre-ferred version of the tank has beendemonstrated on an actual test tank arti-cle cycled at high pressures with liquid ni-trogen and liquid hydrogen, and the bestversion is an inner layer of PBO (poly-p-phenylenebenzobisoxazole) fibers with a

polyurethane matrix and an outer layerof T-1000 carbon with a high elongationepoxy matrix suitable for cryogenic tem-peratures. A polyurethane matrix has alsobeen used for the outer layer. The con-struction method is ideal because thefiber and resin of the inner layer has ahigh strain to failure at cryogenic temper-atures, and will not crack or produceleaks. The outer layer serves as more of ahigh-performance structural unit for theinner layer, and can handle external envi-ronments.

This work was done by Thomas DeLay ofMarshall Space Flight Center.

This invention is owned by NASA, and apatent application has been filed. For furtherinformation, contact Sammy Nabors, MSFCCommercialization Assistance Lead, [email protected]. Refer to MFS-32390-1.

Hybrid Composite Cryogenic Tank StructureA number of materials can be used to produce external and internal layers of the structure.Marshall Space Flight Center, Alabama

Several missions and instruments inthe conceptual design phase rely on thetechnique of interferometry to createdetectable fringe patterns. The intimateemplacement of reflective materialupon electron device cells based uponchalcogenide material technology per-mits high-speed, predictable deforma-tion of the reflective surface to a sub-nanometer or finer resolution with avery high degree of accuracy.

In this innovation, a layer of reflectivematerial is deposited upon a wafer con-taining (perhaps in the millions)chalcogenic memory cells with the re-flective material becoming the front sur-face of a mirror and the chalcogenicmaterial becoming a means of selec-tively deforming the mirror by the appli-cation of heat to the chalcogenic mate-rial. By doing so, the mirror surface can

deform anywhere from nil to nanome-ters in spots the size of a modern daymemory cell, thereby permitting real-time tuning of mirror focus and reflec-tivity to mitigate aberrations causedelsewhere in the optical system.

Modern foundry methods permit thedesign and manufacture of individualmemory cells having an area of or equalto the Feature (F) size of the design (as-sume 65 nm). Fabrication rules and re-straints generally require the instantia-tion of one memory cell to another nocloser than 1.5 F, or, for this innovation,90 nm from its neighbor in any direc-tion.

Chalcogenide is a semiconductingglass compound consisting of a combi-nation of chalcogen ions, the ratios ofwhich vary according to properties de-sired. It has been shown that the applica-

tion of heat to cells of chalcogenic mate-rial cause a large alteration in resistanceto the range of 4 orders of magnitude. Itis this effect upon which chalcogenide-based commercial memories rely. Uponremoval of the heat source, the chalco-genide rapidly cools and remains frozenin the excited state. It has also beenshown that the chalcogenide expands involume because of the applied heat,meaning that the coefficient of expan-sion of chalcogenic materials is largerthan 1.

In this innovation, chalcogenide-based cells are addressed (as thoughthey are a memory), and heated andcooled according to well-established cri-teria. In doing so, the exact size ofchalcogenide cell deformation is knownand predictable; therefore, the deforma-tion of the reflective surface is, likewise,

Nanoscale Deformable Optics This technology has potential applications in medical imaging, robotics, precision machining,and threat detection. NASA’s Jet Propulsion Laboratory, Pasadena, California


known and predictable. Control elec-tronics can also be implemented so thata closed-loop feedback can be main-tained. Changing the contents of thechalcogenide memory cells can compen-

sate for any change in environmental ef-fects that might cause a change in opti-cal path. This real-time control providessignificant control and stability in useconditions.

This work was done by Karl F. Strauss andDouglas J. Sheldon of Caltech for NASA’s JetPropulsion Laboratory. For more informa-tion, contact [email protected]. NPO-46891

The objective of this work was to in-crease the interfacial strength betweenaramid fiber and epoxy matrix. This wasachieved by functionalizing the aramidfiber followed by growth of a layer ofZnO nanowires on the fiber surface suchthat when embedded into the polymer,the load transfer and bonding areacould be substantially enhanced. Thefunctionalization procedure developedhere created functional carboxylic acidsurface groups that chemically interactwith the ZnO and thus greatly enhancethe strength of the interface betweenthe fiber and the ZnO.

The matrix-ZnO interface is en -hanced through increased surface area(>1,000 times), mechanical interlock-ing, and the creation of a functional gra-dient between the nanowires and ma-trix, which has been shown to improvethe interface strength of a carbon fibercomposite by well over 100 percent. Thecomposite compressive strength, shearstrength, shear modulus, interlaminarshear strength, and interfacial shearstrength should all be enhanced becausethe graded interface reduces the stressconcentration at the discrete fiber-to-matrix boundary.

The first milestone of the project wasto develop the functionalization proce-dure to enhance the attachment of theZnO nanowires to the aramid fiber.This was achieved with carboxylic acidgroups that split the peptide bond, cat-alyzed by a strong base, and created acarboxylate and a primary amine func-tional group. Carboxylic acid groupsare specifically chosen because theyoften discharge a proton leading tocharge coordination between the nega-tive oxygen atoms and the positive zincions. Furthermore, the bond angles ofcarboxylic acid functional groups are

Zinc Oxide Nanowire Interphase for Enhanced LightweightPolymer Fiber Composites This technique can be used in applications requiring reduced structural mass, such as in aircraft,missiles, rockets, and balloons. NASA’s Jet Propulsion Laboratory, Pasadena, California

A stochastic optimization methodol-ogy (SDO) has been developed to de-sign airframe structural componentsmade of metallic and composite materi-als. The design method accommodatesuncertainties in load, strength, and ma-terial properties that are defined by dis-tribution functions with mean valuesand standard deviations. A response pa-rameter, like a failure mode, has becomea function of reliability. The primitivevariables like thermomechanical loads,material properties, and failure theories,as well as variables like depth of beam orthickness of a membrane, are consid-ered random parameters with specifieddistribution functions defined by meanvalues and standard deviations.

The cumulative distribution conceptis used to estimate the value of the re-sponse parameter like stress, displace-

ment, and frequency for a specified reli-ability. This solution for stochastic opti-mization also yields the design andweight of a structure as a function of re-liability. Weight versus reliability istraced out in an inverted S-shapedgraph. The center of the graph corre-sponds to 50-percent probability of suc-cess, or one failure in two samples.

A heavy design with weight approach-ing infinity could be produced for a near-zero rate of failure. Likewise, weight canbe reduced to a small value for the mostfailure-prone design. Reliability can bechanged for different components of anairframe structure. For example, thelanding gear of an airliner can be de-signed for very high reliability, whereas itcan be reduced for a raked wingtip.

The design capability is obtained bycombining three codes: MSC/Nastran

code (the deterministic analysis tool), thefast probabilistic integration or the FPImodule of the NESSUS software (the prob-abilistic calculator), and NASA Glenn’s op-timization testbed CometBoards (the opti-mizer). For the raked wingtip structure ofthe Boeing 767-400ER airliner, the stochas-tic optimization process redistributed thestrain field and reduced weight by 17 per-cent over the traditional design.

This work was done by Shantaram S. Paiand Rula Coroneos of Glenn Research Centerand Surya N. Patnaik of Ohio Aerospace In-stitute. Further information is contained in aTSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressed toNASA Glenn Research Center, Innovative Part-nerships Office, Attn: Steve Fedor, Mail Stop4–8, 21000 Brookpark Road, Cleveland, Ohio44135. Refer to LEW-18497-1.

Reliability-Based Design Optimization of a Composite Airframe ComponentThis methodology accommodates uncertainties in load, strength, and material properties.John H. Glenn Research Center, Cleveland, Ohio


highly compatible with the zinc ion,making it the ideal functional group forbonding with zinc. Fourier TransformInfrared Spectroscopy (FTIR) was usedfor analyzing the absorbance frequen-cies and comparing to previously re-ported values, reactions, and bondstructures for validation.

Single-fiber mechanical testing help -ed to determine the fiber tensilestrength of the ZnO nanowire arrays.The results of the testing showed that

there was no degradation of the fiberstrength in spite of breaking enough sur-face bonds to create functional groupsonto which to anchor the nanowires. Itis critical that fiber strength is main-tained during functionalization andgrowth, because the composite proper-ties depend heavily on that fiberstrength. Composite lamina mechanicaltesting was also employed. Because ZnOnanowire arrays have been shown to in-crease interfacial shear strength at the

single fiber scale, improvements are ex-pected in several properties at the com-posite scale. Interlaminar shearstrength, laminar shear strength, andlaminar shear modulus are expected toincrease as a direct result of the func-tional gradient.

This work was done by Henry A. Sodanoof Arizona State University and Robert BrettWilliams of Raytheon for NASA’s Jet Propul-sion Laboratory. For more information, con-tact [email protected]. NPO-47214


Mechanics/Machinery

A plasma igniter has been developedfor initiating combustion in liquid-pro-pellant rocket engines. The device pro-pels a hot, dense plasma jet, consistingof elemental fluorine and fluorine com-pounds, into the combustion chamberto ignite the cold propellant mixture.The igniter consists of two coaxial,cylindrical electrodes with a cylindricalbar of solid Teflon plastic in the regionbetween them. The outer electrode is ametal (stainless steel) tube; the innerelectrode is a metal pin (mild steel,stainless steel, tungsten, or thoriated-tungsten). The Teflon bar fits snuglybetween the two electrodes and pro-vides electrical insulation betweenthem. The Teflon bar may have either a

flat surface, or a concave, conical sur-face at the open, down-stream end ofthe igniter (the igniter face). The ig-niter would be mounted on the com-bustion chamber of the rocket engine,either on the injector-plate at the up-stream side of the engine, or on thesidewalls of the chamber. It also mightsit behind a valve that would be openedjust prior to ignition, and closed justafter, in order to prevent the Teflonfrom melting due to heating from thecombustion chamber.

The plasma jet deposits the energy re-quired to initiate combustion, whilehighly reactive fluorine and fluorinecompounds create free-radicals in theflow-field to further promote rapid igni-

tion. The plasma jet is created and accel-erated electrically, and the feedstock forthe plasma is maintained in a solid, inertform, leading to a rugged, reliable andcompact design. The device should pro-mote rapid and reliable ignition inLOX/LCH4 engines in particular, andin liquid propellant engines in general.It could also be used in gas-turbine en-gines where prompt and reliable restartis critically important; for example, inhelicopter and jet aircraft engines.

This work was done by Adam Martin andRichard Eskridge of Marshall Space Flight Cen-ter. For further information, contact SammyNabors, MSFC Commercialization AssistanceLead, at [email protected]. Refer toMFS-32557-1.

Plasma Igniter for Reliable Ignition of Combustion in Rocket Engines Marshall Space Flight Center, Alabama

Wire Test Grip FixtureThis fixture can be used in any thin-gauge wire testing.John H. Glenn Research Center, Cleveland, Ohio

Wire-testing issues, such as the grip-ping strains imposed on the wire, play acritical role in obtaining clean data. In astandard test frame fitted with flat wedgegrips, the gripping action alone createsstresses on the wire specimen that causethe wire to fail at the grip location. Whenconventional wire grip fixtures are in-stalled, the test span as well as the amountof wire used increase dramatically due tothe large nature of the wire testing fix-ture. A new test frame, which is outfittedwith a vacuum chamber, negated the useof any conventional commercially avail-able wire test fixtures, as only 7 in. (17.8cm) existed between the grip faces.

An innovative grip fixture was de-signed to test thin gauge wire for a vari-ety of applications in an existing Instrontest frame outfitted with a vacuum cham-ber. This unit was designed to adapt to apredetermined test span constrained bythe vacuum chamber. The test frame wasfitted with flat grips so that no grippingstrain was induced into the brittle wirespecimen.

In order to accomplish the task of test-ing small-diameter brittle wire, a very sim-ple test fixture was designed. The firsttask was to create a technique to relievethe strains induced into the wire upongripping. This was accomplished with two1.5 in. (38 mm) wire spools. These spoolswere designed to relieve the grippingstrains by wrapping the wire around thespools to grip the fixtures circumferen-tially. On each spool, a small bolt was in-stalled to attach the wire to the spool.These bolts were placed 270° around thediameter of the spool so the wire con-tacted around the wheel. The conceptemployed ensured that the strains in thewire due to gripping would be reduced bythe smooth transition around the wheel.A small groove was machined into thespools to center the wire.

In an effort to save test wire, as well assimplify the installation of the test wireto the spools, a locating rail was devised.This rail established the span of the grip-ping spools by pinning the spools to athin, flat plate. When assembled, the

wire is easily wrapped around and se-cured to the spools. The wire is pre-loaded slightly on the fixture to stay inplace. This unit is then installed into thetest frame. The leading edge of the railwas designed to match up to the grips in-stalled in the test frame.

The machine was placed in the test-ready position. The loaded test rail wasinstalled up against the sides of the flattest wedge grips, which, by design, estab-lished the test wire centered in the testframe. Pre-existing marks on the testspools allow the operator to center thefixture, top to bottom, prior to gripping.The test spools were machined to awidth of 0.025 in. (0.64 mm), matchingthat of a standard, flat test specimen.When the flat wedge grips were closed,the wedges griped the spools and estab-lished the test span. After the grips seat,the test rail can be removed, and thewire is ready to test. If for some reasonthe specimen needs to be removed fromthe test frame, the installation rail canbe reinstalled on the pinned spools and


the sample ungripped. This design usesabout 8-in. (20-cm) of wire per tests.Multiple tests were conducted at bothroom and elevated temperature with nofailures in the grip region.

The novelty of this wire test fixturelies in its simplicity. Its compact featuresallow the user to install the fixture in atest frame with little or no modifica-

tions. The self-alignment feature de-signed into set-up places the wire speci-men in perfect alignment with the testframe. The loading spools, whengripped, are in direct contact with thetest frame water-cooled wedge grips.This helps to draw temperature awayfrom the fixture for ease of high-tem-perature testing.

This work was done by Christopher S. Burkeof Glenn Research Center. Further informa-tion is 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-18579-1.

One of the major technicalproblems deep-space opticalcommunication (DSOC) sys-tems need to solve is the isola-tion of the optical terminal fromvibrations produced by thespacecraft navigational controlsystem and by the moving partsof onboard instruments. Evenunder these vibration perturba-tions, the DSOC transceivers(telescopes) need to be pointedl000’s of times more accuratelythan an RF communication sys-tem (parabolic antennas).

Mechanical resonators havebeen extensively used to providevibration isolation for ground-based, airborne, and space-borne payloads. The effective-ness of these isolation systems isdetermined mainly by the abilityof designing a mechanical oscil-lator with the lowest possibleresonant frequency. The Low-Frequency Vibration IsolationPlatform (LFVIP), developedduring this effort, aims to re-duce the resonant frequency ofthe mechanical oscillators intothe sub-Hertz region in order tomaximize the passive isolation affordedby the 40 dB/decade roll-off response ofthe resonator. The LFVIP also providestip/tilt functionality for acquisition andtracking of a beacon signal. An activecontrol system is used for platform posi-tioning and for dampening of the me-chanical oscillator.

The basic idea in the design of the iso-lation platform is to use a passive isola-tion strut with a ≈100-mHz resonancefrequency. This will extend the isolation

range to lower frequencies. The har-monic oscillator is a second-order low-pass filter for mechanical disturbances.The resonance quality depends on thedissipation mechanisms, which aremainly hysteretic because of the low res-onant frequency and the absence of anyviscous medium.

The LFVIP system is configured usingthe well-established Stewart Platform,which consists of a top platform con-nected to a base with six extensible struts

(see figure). The struts are at-tached to the base and to theplatform via universal joints,which permit the extension andcontraction of the struts. Thestruts’ ends are connected inpairs to the base and to the plat-form, forming an octahedron.The six struts provide the vibra-tion isolation due to the proper-ties of mechanical oscillatorsthat behave as second-order low-pass filters for frequencies abovethe resonance. At high fre-quency, the ideal second-orderlow-pass filter response isspoiled by the distributed massand the internal modes of mem-brane and of the platform withits payload.

The mechanical oscillator isimplemented using a particulargeometry of a stainless steelmembrane. This geometry pro-vides a very soft mechanicalcompliance along the axis or-thogonal to the membrane andabout axes coplanar to themembrane. It also allows the de-sign of a membrane with suffi-ciently stiff compliances on the

other remaining directions.The proposed LFVIP has the potential

to yield a low-power, low-mass isolationsystem for payloads requiring stable plat-forms, such as imaging and free-spaceoptical communications.

This work was done by Gerardo G. Ortiz,William H. Farr, and Virginio Sannibale of Cal-tech for NASA’s Jet Propulsion Laboratory. Formore information, contact [email protected]

A Sub-Hertz, Low-Frequency Vibration Isolation Platform This system can be used for vibration isolation in semiconductor manufacturing, for space-based imaging systems, or fine pointing of free-space optical communication transceivers.NASA’s Jet Propulsion Laboratory, Pasadena, California

A CAD rendering of the Low-Frequency Vibration Isolation Platformwith payload. Shown is the configuration of the six LFVIP struts (fourshown). One of the lower left struts clearly shows the steel membranewith its topology designed to have a reasonably high stiffness alongthe membrane plane.


A plasma-enhanced chemical vapor dep-osition (PECVD) growth technique hasbeen developed where the choice of start-ing substrate was found to influence theelectrical characteristics of the resultingcarbon nanofiber (CNF) tubes. It has beendetermined that, if the tubes are grown onrefractory metallic nitride substrates, thenthe resulting tubes formed with dc PECVDare also electrically conducting.

Individual CNFs were formed by firstpatterning Ni catalyst islands using e-beam evaporation and liftoff. The CNFswere then synthesized using dc PECVDwith C2H2:NH3 = [1:4] at 5 Torr and 700°C, and ≈200-W plasma power. Tubeswere grown directly on degeneratelydoped silicon <100> substrates with resis-tivity ρ≈1–5 mΩ-cm, as well as NbTiN.The ≈200-nm thick refractory NbTiN de-posited using magnetron sputtering had

ρ≈113 µΩ-cm and was also chemicallycompatible with CNF synthesis. Thesample was then mounted on a 45°beveled Al holder, and placed inside aSEM (scanning electron microscope). Ananomanipulator probe stage wasplaced inside the SEM equipped with anelectrical feed-through, where tungstenprobes were used to make two-terminalelectrical measurements with an HP4156C parameter analyzer.

The positive terminal nanoprobe wasmechanically manipulated to physicallycontact an individual CNF grown di-rectly on NbTiN as shown by the SEMimage in the inset of figure (a), whilethe negative terminal was grounded tothe substrate. This revealed the tubewas electrically conductive, althoughmeasureable currents could not be de-tected until ≈6 V, after which point cur-rent increased sharply until compliance(≈50 nA) was reached at ≈9.5 V. A na-tive oxide on the tungsten probe tipsmay contribute to a tunnel barrier,which could be the reason for the sup-pressed transport at low biases. Cur-rents up to ≈100 nA could be cycled,which are likely to propagate via the

Materials & Coatings

Carbon Nanofibers Synthesized on Selective Substrates forNonvolatile Memory and 3D Electronics This method can impact the application of carbon nanofiber tubes in 3D electronics applications. NASA’s Jet Propulsion Laboratory, Pasadena, California

Figure (a) Electrical Transport Measurements for a single CNF grown on an NbTiN buffer layer on Si.A nanoprobe was in contact with a CNF, as the SEM image in the inset indicates. The top inset showsthe I-V characteristic when compliance was increased to 100 nA. (b) Curve (1) corresponds to the casewhere both probes were shorted to the substrate and indicates high conductivity; curve (2) shows theCNF grown on NbTiN was electrically conductive; curve (3) corresponds to the case where no electri-cal conduction was detected for a CNF grown directly on Si, and suggests such CNFs are unsuitable fordc NEMS applications.

100

60

20

-20

-60

-100-40 -30 -20 -10 0 10 20 30 40

Voltage (V)

(b)

Cu

rren

t (n

A)

CNF

V+

V- -

Si substrate

Si substrate

Si substrateNbTiN

CNF

V+

V- -

CNF

V+

(1) (2)

(3)

V- -

(a)

Voltage (V)

Cu

rren

t (n

A)

60

40

20

0

-20

-40

-60-20 -15 -10 -5 0 5 10 15 20

Voltage (V)0 5 10 15 20C

urr

ent

(nA

)

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50

100

1µm


tube surface, or sidewalls, rather thanthe body, which is shown by the I-V infigure (a).

Electrical conduction via the side-walls is a necessity for dc NEMS (nano-electromechanical system) applica-tions, more so than for the fieldemission applications of such tubes.During the tests, high conductivity wasexpected, because both probes wereshorted to the substrate, as shown bycurve 1 in the I-V characteristic in fig-ure (b). When a tube grown on NbTiNwas probed, the response was similar tothe ≈100 nA and is represented by

curve 2 in figure (b), which could be cy-cled and propagated via the tube sur-face or the sidewalls. However, no mea-sureable currents for the tube growndirectly on Si were observed as shownby curve 3 in figure (b), even after test-ing over a range of samples. This couldarise from a dielectric coating on thesidewalls for tubes on Si. As a result ofthe directional nature of ion bombard-ment during dc PECVD, Si from thesubstrate is likely re-sputtered and pos-sibly coats the sidewalls.

This work was done by Anupama B. Kauland Abdur R. Khan of Caltech for NASA’s Jet

Propulsion Laboratory. For more information,contact [email protected].

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 202-2334800 Oak Grove DrivePasadena, CA 91109-8099E-mail: [email protected] to NPO-47157, volume and number

of this NASA Tech Briefs issue, and thepage number.

This innovation addresses the prob-lem of coatings (meant to reduce gaspermeation) applied to polymer matrixcomposites spalling off in service due toincompatibility with the polymer matrix.A bond coat/coating has been createdthat uses chemically functionalizednanoparticles (either clay or graphene)to create a barrier film that bonds well tothe matrix resin, and provides an out-standing barrier to gas permeation.

There is interest in applying claynanoparticles as a coating/bond coat toa polymer matrix composite. Often, nan-oclays are chemically functionalized with

an organic compound intended to facil-itate dispersion of the clay in a matrix.That organic modifier generally de-grades at the processing temperature ofmany high-temperature polymers, ren-dering the clay useless as a nano-additiveto high-temperature polymers. However,this innovation includes the use of or-ganic compounds compatible with high-temperature polymer matrix, and is suit-able for nanoclay functionalization, thepreparation of that clay into acoating/bondcoat for high-temperaturepolymers, the use of the clay as a coatingfor composites that do not have a high-

temperature requirement, and a compa-rable approach to the preparation ofgraphene coatings/bond coats for poly-mer matrix composites.

This work was done by Sandi G. Miller ofGlenn Research Center. Further informationis contained in a TSP (see page 1).

Inquiries concerning rights for the com-mercial use of this invention should be ad-dressed to NASA Glenn Research Center, In-novative Partnerships Office, Attn: StevenFedor, Mail Stop 4–8, 21000 BrookparkRoad, Cleveland, Ohio 44135. Refer toLEW-18607-1.

Nanoparticle/Polymer Nanocomposite Bond Coat or CoatingJohn H. Glenn Research Center, Cleveland, Ohio


Green Design

The spring tire is made from helicalsprings, requires no air or rubber, andconsumes nearly zero energy. The tiredesign provides greater traction in sandyand/or rocky soil, can operate in micro-gravity and under harsh conditions(vastly varying temperatures), and isnon-pneumatic.

Like any tire, the spring tire is approx-imately a toroidal-shaped object in-tended to be mounted on a transporta-tion wheel. Its basic function is alsosimilar to a traditional tire, in that thespring tire contours to the surface onwhich it is driven to facilitate traction,and to reduce the transmission of vibra-tion to the vehicle. The essential differ-ence between other tires and the springtire is the use of helical springs to sup-port and/or distribute load. They arecoiled wires that deform elasticallyunder load with little energy loss.

This design is an advancement of thewire-mesh tire technology definedunder U.S. Patent 3,568,748, entitled“Resilient Wheel.” The difference be-tween the two tire technologies is the

fundamental element used to createthe wire mesh that forms the tire. Theresilient wheel uses crimped wire meshto form the tire, but the spring tire usesa coiled wire mesh. Under the weight ofthe vehicle, the tire is driven or towed,as well as steered. The springs withinthe tire passively contour to the terrainby flexing and moving with respect toeach other.

There are three steps required to man-ufacture the spring tire. First, the springsare twisted together to form a rectangu-lar sheet with length of the tire circum-ference. Second, the ends of the rectan-gular sheet of springs are interlaced toform a mesh cylinder. Third, one end ofthe mesh cylinder is collapsed and at-tached to the wheel, and the other end isflipped inside out, attaching it to the op-posite end of the wheel.

The load-support springs are config-ured radially. This mitigates the pan-tographing of springs (rotation at theirin tersections). As a result, a relativelyhigh mesh density may be used withoutexcessive interference and stress be-

Spring TireThis tire design can be used where low vehicle energy consumption is required and for vehiclestraveling over rough terrain.John H. Glenn Research Center, Cleveland, Ohio

A mathematical transform, called theRosette Transform, together with a newmethod, called the Dense SamplingMethod, have been developed. TheRosette Transform is invented to apply toboth the mean part and the fluctuatingpart of a targeted radar signature usingthe Dense Sampling Method to constructthe data in a high-resolution grid at 1-kmposting for wind measurements overwater surfaces such as oceans or lakes.

This new technique enables the use ofNASA satellite scatterometer data, such asQuikSCAT data, which have been col-lected globally over a decade for measur-

ing high-resolution wind field at 1-kmposting on water surfaces. Valid in near-shore waters (10–15 km from shore), thehigh-resolution wind data are unique andcritical to calculate accurate wind powerdensity and its variability for the develop-ment of future offshore wind farms. Thenew technique was originally developedto monitor urban and suburban environ-ments, and it has been applied to obtainhigh-resolution radar signatures overocean and lake environments for high-resolution wind measurements.

This work was done by Son V. Nghiem andGregory Neumann of Caltech for NASA’s Jet

Propulsion Laboratory. For more information,contact [email protected].




High-Resolution Wind Measurements for Offshore Wind En-ergy DevelopmentNASA’s Jet Propulsion Laboratory, Pasadena, California

The Spring Tire, co-invented by NASA GlennResearch Center and the Goodyear Tire & Rub-ber Company. This airless, rubberless tire is ca-pable of contouring to the rocky surface of theMoon, yet consumes far less energy than anEarth tire. Photo Credit — Aaron Vandersom-mers/Goodyear


tween neighboring springs. Elimina-tion of pantographing also reducesfriction forces.

The load support springs are also in-terwoven. This minimizes or eliminatesthe need for load distribution springsto hold the load support springs to-gether. With fewer load distributionsprings, the load support springs con-

tour more freely and the overall tireweight is reduced. Cross-sections of thetire are approximately round, whichdistributes applied loads relatively uni-formly. This reduces tires stresses andimproves flotation and traction devel-opment in soft soil.

This work was done by Vivake M. Asnani ofGlenn Research Center and Jim Benzing and

Jim C. Kish of Goodyear Tire & Rubber Com-pany. Further information is contained in aTSP (see page 1).

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steve Fedor, MailStop 4–8, 21000 Brookpark Road, Cleve-land, Ohio 44135. Refer to LEW-18466-1.


Software

Marsviewer 2008 Marsviewer 2008 is designed for qual-

ity control, browsing, and operationaland science analysis of images and de-rived image products returned by space-craft. This program allows all derivedproducts (reduced data records, orRDRs) associated with each originalimage (experiment data record, orEDR) to be viewed in various ways, in-cluding in stereo, depending on the typeof image.

The program features a pluggable in-terface called a “file finder.” This en -capsulates knowledge of a specific mis-sion’s filename and directoryconventions, hiding the complexity be-hind each mission from the user, and al-lowing new missions to be added easily.Within a mission, different directoryconventions can also be supported. Thisfile-finder interface presents a similar in-terface to the user for all these missionsand directory structures. All EDRs foundfor a given Sol are displayed in a list (op-tionally with thumbnail images) for theuser to pick from.

Once an image is picked, a primary(vertical) tab pane allows the user to se-lect the left or right image, left or rightthumbnail, or stereo views. A secondary(horizontal) tab pane allows the EDR, orany of its RDRs, to be viewed. Most RDRsmay be viewed independently, or as col-ored overlays on a background image.Each of the 41 RDR types has a displaymethod appropriate for that type, andmost have display parameters that canbe adjusted.

The program understands two differ-ent image geometries (raw and lin-earized), and can show the actual pixelvalues under the cursor for every EDRand RDR matching the geometry type atonce. Various display manipulations,such as zoom, data range, contrast en-hancement, interval selection, and con-tour controls are available. Metadata(image labels) may be displayed andsearched as well. The stereo displayshows both left and right images simulta-neously. It works either in anaglyphmode (red/blue glasses), or by usingdedicated display hardware.

This innovation also covers the appli-cations “jadeviewer” and “jade_over-layer,” which are closely related deriva-tives from Marsviewer. The “jadeviewer”

application reuses the image display andvisualization portions of Marsviewerwithout the file finder. The user directlyspecifies filenames and RDR type, andcan then view the product as withMarsviewer.

This work was done by Nicholas T. Tooleand Robert G. Deen of Caltech for NASA’s JetPropulsion Laboratory. For more information,contact [email protected].


Mission Services EvolutionCenter Message Bus

The Goddard Mission Services Evolu-tion Center (GMSEC) Message Bus is arobust, lightweight, fault-tolerant mid-dleware implementation that supportsall messaging capabilities of the GMSECAPI, including publish/subscribe andrequest/reply. The Message Bus enablesNASA to provide an open-source mid-dleware solution, for no additional cost,that is self-configuring, easy to install,and can be used for the development ofGMSEC-compliant components. Someprofessional capabilities provided by thissoftware include failover and fault toler-ance, good performance, compression,debugging, and wide platform support.

This architecture is a distributedsoftware system that routes messagesbased on message subject names andknowledge of the locations in the net-work of the interested software compo-nents. Functional software componentsregister with the message bus, so that alocation directory can be maintained.The functional applications then sendmessages onto the bus with an indica-tion of the message type/subject/etc.Other applications that want to receivedata register with the message bus andindicate what message types/subjectsthey want to receive. The message busmaintains a routing table where routespublish messages to the applicationsthat have requested them. One mes-sage may be delivered to many differ-ent applications. Use of the messagebus eliminates the need for each appli-cation to create separate communica-tions paths with each application towhich it interfaces.

The nature of the GMSEC Message Busenables any project or user to quicklytake the initial steps for creating or con-necting GMSEC-compliant components,and for developing small systems withouthigh license fees and learning curves.This software uses middleware to facili-tate cross application or component com-munication on a software bus.

This work was done by Arturo Mayorga andJohn O. Bristow of Goddard Space Flight Cen-ter and Mike Butschky of Interface and ControlSystems. Further information is contained ina TSP (see page 1). GSC-15575-1

Major Constituents Analysisfor the Vehicle Cabin At-mosphere Monitor

Vehicle Cabin Atmosphere Monitor(VCAM) can provide a means for mon-itoring the air within enclosed environ-ments such as the International SpaceStation, the Crew Exploration Vehicle(CEV), a Lunar habitat, or another ve-hicle traveling to Mars. Its miniaturepre-concentrator, gas chromatograph(GC), and mass spectrometer can pro-vide unbiased detection of a large num-ber of organic species. VCAM’s softwarecan identify whether the chemicals areon a targeted list of hazardous com-pounds and their concentration. Itsperformance and reliability on orbit,along with the ground team’s assess-ment of its raw data and analysis results,will validate its technology for futureuse and development.

The software processes a sum totalspectra (counts vs. mass channel) withthe intention of computing abundanceratios for N2, O2, CO2, Ar2, and H2O. Abrute-force powerset expansion com-pares a library of expected mass lineswith those found within the data. Leastsquares error is combined with a penaltyterm for using small peaks. This permitscalibration even in the presence of un-expected/unknown system contamina-tion or unknown/novel ratios of atmos-pheric constituents.

Automated, reliable mass calibra-tion is a substantial improvement be-yond other comparable systems. Amethod of compensation for variableresponse component spectra has beenutilized via a weighted sum based onthe central peak for each expectedcomponent.


It is fully autonomous, non-GUI-based,self-calibrating, and compliant with theVXWORKS flight software system.

This work was done by Lukas Mandrake,Benjamin J. Bornstein, Stojan Madzunkov,and John A. Macaskill of Caltech for NASA’sJet Propulsion Laboratory. For more informa-tion, contact [email protected].


Astronaut Health Partici-pant Summary Application

The Longitudinal Study of AstronautHealth (LSAH) Participant Summarysoftware captures data based on a cus-tom information model designed togather all relevant, discrete medicalevents for its study participants. Thissoftware provides a summarized view ofthe study participant’s entire medicalrecord. The manual collapsing of all thedata in a participant’s medical recordinto a summarized form eliminates re-dundancy, and allows for the capture ofentire medical events. The coding toolcould be incorporated into commercialelectronic medical record software foruse in areas like public health surveil-lance, hospital systems, clinics, and med-ical research programs.

The software also enables structuredcoding that enforces a custom set ofrules, as well as captures the context ofthe coded term. The terminology used isSNOMED CT, which is a massive termi-nology consisting of over 366,000 con-cepts with unique meanings and formal,logic-based definitions that are organ-ized into 18 hierarchies. In addition, itcontains more than 993,000 descriptionsor synonyms for flexibility in expressingclinical concepts. SNOMED CT is also acompositional terminology, so multipleconcepts can be grouped together tocreate an expression that has a totallydifferent logical definition. By usingsome custom composition rules alongwith the context within the ParticipantSummary, a user can greatly reduce thenumber of candidate concepts, whichnot only improves productivity, it en-sures that only legal SNOMED expres-sions can be created.

LSAH defines the line between theterminology and the informationmodel. It takes a middle road betweenputting all the structure in a complexcoded term and putting all the structurein numerous database fields.

This work was done by Kathy Johnson-Throop of Johnson Space Center; Ralph Krogof National Space Biomedical Research Insti-tute; Deborah Eudy and Diane Parisian ofEASI; Seth Rodriguez and John Rogers ofBarrios Technology; and Mary Wear, RobertVolpe, and Gina Trevino of Wyle Laborato-ries. Further information is contained in aTSP (see page 1). MSC-24172-1

Adaption of the AMDISMethod to Flight Status onthe VCAM Instrument

Software has been developed to func-tion onboard the International SpaceStation (ISS) to help safeguard humanhealth by detecting compounds of con-cern in the cabin atmosphere, both inidentity and concentration. This soft-ware calibrates and processes a stan-dard 2D dataset (mass spectrum versustime) output from a gas chro-matogram/mass spectrometer by iden-tifying temporal events, including thepossibility for near simultaneous eventoverlap, reducing the mass spectra foreach event and comparing to an arbi-trary library of known compounds. Thelevel of autonomy, adjustment of pa-rameters for the VCAM devices’ specificdata characteristics, and adaptive massresolution to ease requirement of preci-sion mass calibration are three uniquefeatures of this design. The estimationof concentration is also a significant ad-dition to the standard AMDIS (NIST)implementation. Solution filtrationbased on elution time, and an arbitra-tion algorithm for similar matches, pro-vide the user with a more succinct, sin-gle-valued estimate in comparison toalgorithms designed to merely augmentexpert hand analysis.

This work was done by Lukas Mandrake,Benjamin J. Bornstein, Seungwon Lee, andBrian D. Bue of Caltech for NASA’s JetPropulsion Laboratory. For more information,contact [email protected].


Natural Language Interfacefor Safety Certification ofSafety-Critical Software

Model-based design and automatedcode generation are being used increas-ingly at NASA. The trend is to move be-yond simulation and prototyping toactual flight code, particularly in the

guidance, navigation, and control do-main. However, there are substantial ob-stacles to more widespread adoption ofcode generators in such safety-criticaldomains. Since code generators are typ-ically not qualified, there is no guaran-tee that their output is correct, and con-sequently the generated code still needsto be fully tested and certified.

The AutoCert generator plug-in sup-ports the certification of automaticallygenerated code by formally verifyingthat the generated code is free of differ-ent safety violations, by constructing anindependently verifiable certificate, andby explaining its analysis in a textualform suitable for code reviews. This en-ables missions to obtain assurance aboutthe safety and reliability of the codewithout excessive manual effort. The keytechnical idea is to exploit the idiomaticnature of auto-generated code in orderto automatically infer logical annota-tions that describe properties of thecode. These allow the automatic formalverification of the safety properties with-out requiring access to the internals ofthe code generator. The approach istherefore independent of the particulargenerator used. The use of a combinedgeneration/analysis tool can allow sys-tem engineers to concentrate on themodeling and design, rather than worry-ing about low-level software details. Byproviding tracing between code and ver-ification artifacts, and customizablesafety reports, the tool supports bothcertification and debugging. Althoughintegrated with the code generator, Au-toCert is functionally independent inthe sense that it does not rely on the cor-rectness of any generator components.The tool has two main benefits: (1) ithelps catch bugs in autocoders, and (2)it helps with the certification process forthe autogenerated code, thus mitigatingthe risk of using COTS autocoders thatlack a trusted heritage.

The AutoCert technology also has anumber of advantages over other ap-proaches to formal verification. It canhandle code with arbitrary loops, andcan handle code generated from bothcontinuous and discrete models. More-over, the certification system based onannotation inference is more flexibleand extensible than decentralized ar-chitectures where certification infor-mation is distributed throughout thecode generator. Identifying the pat-terns that are used to infer the annota-tions is an iterative process, but by al-lowing tracing between VCs(verification conditions) and state-


ments of the auto-generated code, thetool lets missing annotations and, thus,missing patterns, to be pinpointedmore easily. By raising the level of ab-straction at which verification knowl-edge is expressed, one can concisely

capture many variations of the underly-ing code idioms. In particular, one caneasily deal with optimizations that ob-scure low-level code structure.

This program was written by Ewen Denneyand Bernd Fischer of USRA/RIACS for Ames

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

Inquiries concerning rights for the commer-cial use of this invention should be addressed tothe Ames Technology Partnerships Division at(650) 604-5761. Refer to ARC-15990-1.


Physical Sciences

Aircraft engine rotating equipmentoperates at high temperatures andstresses. Noninvasive inspection of mi-crocracks in those components poses achallenge for nondestructive evalua-tion. A low-cost, low-profile, high-tem-perature ultrasonic guided wave sensorwas developed that detects cracks insitu. The transducer design providesnondestructive evaluation of structuresand materials.

A key feature of the sensor is that itwithstands high temperatures and ex-cites strong surface wave energy to in-

spect surface and subsurface cracks.The sol-gel bismuth titanate-based sur-face acoustic wave (SAW) sensor cangenerate efficient SAWs for crack in-spection. The sensor is very thin (sub-millimeter) and can generate surfacewaves up to 540 °C. Finite elementanalysis of the SAW transducer designwas performed to predict the sensor be-havior, and experimental studies con-firmed the results.

The sensor can be implemented onstructures of various shapes. With aspray-coating process, the sensor can be

applied to the surface of large curva-tures. It has minimal effect on airflow orrotating equipment imbalance, and pro-vides good sensitivity.

This work was done by George Zhao of In-telligent Automation, Inc. and Bernhard R.Tittmann of The Pennsylvania State Univer-sity for Glenn Research Center.


In Situ Guided Wave Structural Health Monitoring SystemJohn H. Glenn Research Center, Cleveland, Ohio

A method has been developed forcaging science instrumentation to pro-tect from pyro-shock and EDL (entry,descent, and landing) acceleration dam-age. Caging can be achieved by immers-ing the instrument (or its critical parts)in a liquid and solidifying the liquid bycooling. After the launch shock and/orafter the payload has landed, the solid isheated up and evaporated.

In the example of a sensitive x–y seis-mometer, the volume is filled with CO2(at an elevated pressure), or other com-patible liquid. Then the liquid is frozenand maintained at a temperature below–80 °C for the duration of the flight. Thesolid is then allowed to sublime througha valved port. Other uses include cagingof drag-free elements of LISA (laser in-terferometer space antenna) spacecraft

and their progeny, caging instrumenta-tion and avionics for penetrator mis-sions, and caging of electronics to sur-vive launch shock.

This work was done by Konstantin Pena-nen and Talso C. Chui of Caltech for NASA’sJet Propulsion Laboratory. Further informa-tion is contained in a TSP (see page 1). NPO-46930

Cryogenic Caging for Science Instrumentation NASA’s Jet Propulsion Laboratory, Pasadena, California

A digital, wide-range, neutron detec-tion (WRND) system in a compact, VMEform factor monitors neutron activitywithin the core of a nuclear reactoracross the reactor’s entire operatingrange, from 1.0 n/cm2/s up to 1010

n/cm2/s. This allows for a reduction inthe complexity of space-based nuclearinstrumentation systems, as a single in-strument can be used instead of requir-ing different instrumentation for eachof the operation ranges of the reactor(start-up, ramp-up, and nominal power).

This instrument consists of one ormore fission chamber detectors, an inte-grated electronics module, and inter-

connected cabling, all of which areadapted for the space environment fromproven, terrestrial-based technology.WRND delivers logarithmic output sig-nals to a host system, proportional toneutron flux and rate across the entireoperating range of the reactor. The elec-tronics module hardware and firmwareare the basis of the innovation.

WRND is broadly compatible withmany potential future applications (nu-clear power, nuclear propulsion, etc.).Nothing in the initial design assumes aparticular type of reactor, or whether itwill be vehicle- or land-based. This inno-vation’s ability to function over a wide

range of neutron fluxes ensures its de-velopment is not necessarily linked withany particular reactor type, and in noway limits future nuclear power imple-mentation options, while still providingNASA with the needed functionality.

This work was done by John F. Merk of Au-rora Flight Sciences and Alberto Busto ofBlack River Technology for Glenn ResearchCenter.

Inquiries concerning rights for the commer-cial use of this invention should be addressedto NASA Glenn Research Center, InnovativePartnerships Office, Attn: Steve Fedor, MailStop 4–8, 21000 Brookpark Road, Cleve-land, Ohio 44135. LEW-18469-1

Wide-Range Neutron Detector for Space Nuclear Applications John H. Glenn Research Center, Cleveland, Ohio


A multiplexing antenna assembly canefficiently couple AC signal/energy into,or out of, rotating equipment. The unitonly passes AC energy while blockingDC energy. Concentric tubes that aresliced into multiple pieces are assembledtogether so that, when a piece from anouter tube aligns well with an inner tubepiece, efficient energy coupling isachieved through a capacitive scheme.

With N outer pieces and M innerpieces, an effective N×M combinationcan be achieved in a multiplexed man-ner. The energy coupler is non-contact,which is useful if isolation from rotatingand stationary parts is required. Addi-tionally, the innovation can operate inhigh temperatures. Applications includerotating structure sensing, non-contactenergy transmission, etc.

This work was done by Xiaoliang Zhao ofIntelligent Automation, Inc. for Glenn Re-search Center.

Inquiries concerning rights for the com-mercial use of this invention should be ad-dressed to NASA Glenn Research Center, In-novative Partnerships Office, Attn: SteveFedor, Mail Stop 4–8, 21000 BrookparkRoad, Cleveland, Ohio 44135. Refer toLEW-18467-1

Multiplexed Energy Coupler for Rotating EquipmentJohn H. Glenn Research Center, Cleveland, Ohio

An attitude estimation was examinedin fractioned free-flying spacecraft. In-stead of a single, monolithic spacecraft,a fractionated free-flying spacecraftuses multiple spacecraft modules.These modules are connected onlythrough wireless communication linksand, potentially, wireless power links.The key advantage of this concept isthe ability to respond to uncertainty.For example, if a single spacecraftmodule in the cluster fails, a new onecan be launched at a lower cost andrisk than would be incurred with on-orbit servicing or replacement of themonolithic spacecraft.

In order to create such a system, how-ever, it is essential to know what the nav-igation capabilities of the fractionatedsystem are as a function of the capabili-ties of the individual modules, and tohave an algorithm that can perform esti-mation of the attitudes and relative posi-tions of the modules with fractionatedsensing capabilities.

Looking specifically at fractionated at-titude estimation with startrackers andoptical relative attitude sensors, a set ofmathematical tools has been developedthat specify the set of sensors necessaryto ensure that the attitude of the entirecluster (“cluster attitude”) can be ob-

served. Also developed was a navigationfilter that can estimate the cluster atti-tude if these conditions are satisfied.

Each module in the cluster may haveeither a startracker, a relative attitudesensor, or both. An extended Kalman fil-ter can be used to estimate the attitudeof all modules. A range of estimationperformances can be achieved depend-ing on the sensors used and the topol-ogy of the sensing network.

This work was done by Fred Y. Hadaeghand Lars James C. Blackmore of Caltech forNASA’s Jet Propulsion Laboratory. For moreinformation, contact [email protected]

Attitude Estimation in Fractionated Spacecraft Cluster Systems NASA’s Jet Propulsion Laboratory, Pasadena, California

Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems Applications range from dynamic control and underwater detection to health monitoring anduse in acoustic structures.Langley Research Center, Hampton, Virginia

The Stacked HYBATS (Hybrid Act ua -tion/Transduction system) dem on -strates significantly enhanced electro-mechanical performance by using thecooperative contributions of the electro-mechanical responses of multilayer,stacked negative strain components andpositive strain components. Both experi-mental and theoretical studies indicatethat, for Stacked HYBATS, the displace-ment is over three times that of a same-sized conventional flextensional actua-tor/transducer. The coupled resonancemode between positive strain and nega-tive strain components of Stacked HY-

BATS is much stronger than the reso-nance of a single element actuation onlywhen the effective lengths of the twokinds of elements match each other.Compared with the previously inventedhybrid actuation system (HYBAS), themultilayer Stacked HYBATS can be de-signed to provide high mechanical loadcapability, low voltage driving, and ahighly effective piezoelectric constant.

The negative strain component willcontract, and the positive strain compo-nent will expand in the length directionswhen an electric field is applied on thedevice. The interaction between the two

elements makes an enhanced motionalong the Z direction for Stacked-HY-BATS. In order to dominate the dynamiclength of Stacked-HYBATS by the nega-tive strain component, the area of thecross-section for the negative strain com-ponent will be much larger than the totalcross-section areas of the two positivestrain components. The transverse strainis negative and longitudinal strain posi-tive in inorganic materials, such as ceram-ics/single crystals. Different piezoelectricmultilayer stack configurations can makea piezoelectric ceramic/single-crystalmultilayer stack exhibit negative strain or


Three related innovations combineimproved non-linear motion estima-tion, video coding, and video compres-sion. The first system comprises amethod in which side information isgenerated using an adaptive, non-linearmotion model. This method enables ex-trapolating and interpolating a visualsignal, including determining the firstmotion vector between the first pixelposition in a first image to a secondpixel position in a second image; deter-mining a second motion vector betweenthe second pixel position in the secondimage and a third pixel position in athird image; determining a third mo-

tion vector between the first pixel posi-tion in the first image and the secondpixel position in the second image, thesecond pixel position in the secondimage, and the third pixel position inthe third image using a non-linearmodel; and determining a position ofthe fourth pixel in a fourth image basedupon the third motion vector.

For the video compression element,the video encoder has low computa-tional complexity and high compres-sion efficiency. The disclosed systemcomprises a video encoder and a de-coder. The encoder converts the sourceframe into a space-frequency represen-

tation, estimates the conditional statis-tics of at least one vector of space-fre-quency coefficients with similar fre-quencies, and is conditioned onpreviously encoded data. It estimates anencoding rate based on the conditionalstatistics and applies a Slepian-Wolfcode with the computed encoding rate.The method for decoding includes gen-erating a side-information vector of fre-quency coefficients based on previouslydecoded source data and encoder sta-tistics and previous reconstructions ofthe source frequency vector. It also per-forms Slepian-Wolf decoding of asource frequency vector based on the

Method and System for Temporal Filtering in Video Compression SystemsThis filtering improvement increases efficiency for visual signal components for low-power applications.Stennis Space Center, Mississippi

New flow effector technology for separa-tion control and enhanced mixing is basedupon shape memory alloy hybrid compos-ite (SMAHC) technology. The technologyallows for variable shape control of aircraftstructures through actively deformable sur-faces. The flow effectors are made by em-bedding shape memory alloy actuator ma-terial in a composite structure. Whenthermally actuated, the flow effectordef1ects into or out of the flow in a pre-scribed manner to enhance mixing or in-duce separation for a variety of applica-tions, including aeroacoustic noisereduction, drag reduction, and f1ight con-trol. The active flow effectors were devel-oped for noise reduction as an alternativeto fixed-configuration effectors, such as

static chevrons, that cannot be optimizedfor airframe installation effects or variableoperating conditions and cannot be re-tracted for off-design or fail-safe conditions.

Benefits include:• Increased vehicle control, overall effi-

ciency, and reduced noise throughoutall f1ight regimes,

• Reduced flow noise,• Reduced drag,• Simplicity of design and fabrication,• Simplicity of control through direct cur-

rent stimulation, autonomous re sponseto environmental heating, fast re sponse,and a high degree of geometric stability.The concept involves embedding pre-

strained SMA actuators on one side ofthe chevron neutral axis in order to gen-

erate a thermal moment and def1ect thestructure out of plane when heated. Theforce developed in the host structureduring def1ection and the aerodynamicload is used for returning the structureto the retracted position. The chevrondesign is highly scalable and versatile,and easily affords active and/or auton -omous (environmental) control.

The technology offers wide-rangingmarket applications, including aero-space, automotive, and any applicationthat requires flow separation or noisecontrol.

This work was done by Travis L. Turner ofLangley Research Center. For further informa-tion, contact the Langley Innovative Partner-ships Office at (757) 864-8881. LAR-17332-1

positive strain at a certain direction with-out increasing the applied voltage. Thedifference of this innovation from theHYBAS is that all the elements can bemade from one-of-a-kind materials.

Stacked HYBATS can provide an ex-tremely effective piezoelectric constantat both resonance and off resonance fre-quencies. The effective piezoelectric

constant can be alternated by varyingthe size of each component, the degreeof the pre-curvature of the positive straincomponents, the thickness of each layerin the multilayer stacks, and the piezo-electric constant of the material used.Because all of the elements are piezo-electric components, Stacked HYBATScan serve as projector and receiver for

underwater detection. The performanceof this innovation can be enhanced byimproving the piezoelectric properties.

This work was done by Ji Su of Langley Re-search Center, Xiaoning Jiang of TSR Tech-nologies, and Tian-Bing Zu of the NationalInstitute of Aerospace. Further information iscontained in a TSP (see page 1). LAR-17671-1


Active Flow Effectors for Noise and Separation ControlThese variable effectors provide enhanced vehicle and aeroelastic control.Langley Research Center, Hampton, Virginia


generated side-information and theSlepian-Wolf code bits.

The video coding element includes re-ceiving a first reference frame having afirst pixel value at a first pixel position, asecond reference frame having a secondpixel value at a second pixel position, anda third reference frame having a thirdpixel value at a third pixel position. It de-termines a first motion vector betweenthe first pixel position and the secondpixel position, a second motion vector be-

tween the second pixel position and thethird pixel position, and a fourth pixelvalue for a fourth frame based upon a lin-ear or nonlinear combination of the firstpixel value, the second pixel value, andthe third pixel value. A stationary filter-ing process determines the estimatedpixel values. The parameters of the filtermay be predetermined constants.

This work was done by Ligang Lu, DrakeHe, Ashish Jagmohan, and Vadim Sheinin ofIBM for Stennis Space Center.

Inquiries concerning rights for the commer-cial use of this invention should be addressedto:

IBM 1101 Kitchawan RoadYorktown Heights, NY 10598Telephone No. (914) 945-3114E-mail: [email protected] to SSC-00291/309/310, volume

and number of this NASA Tech Briefs issue,and the page number.

Apparatus for Measuring Total Emissivity of Small, Low-Emissivity SamplesGoddard Space Flight Center, Greenbelt, Maryland

An apparatus was developed for meas-uring total emissivity of small, light-weight, low-emissivity samples at lowtemperatures. The entire apparatus fitsinside a small laboratory cryostat. Sam-ple installation and removal are rela-tively quick, allowing for faster testing.

The small chamber surrounding thesample is lined with black-painted alu-minum honeycomb, which simplifies dataanalysis. This results in the sample viewinga very high-emissivity surface on all sides,an effect which would normally require amuch larger chamber volume. The sam-ple and chamber temperatures are indi-

vidually controlled using off-the-shelf PID(proportional–integral–der iv ative) con-trollers, allowing flexibility in the test con-ditions. The chamber can be controlled ata higher temperature than the sample, al-lowing a direct absorptivity measurement.

The lightweight sample is suspendedby its heater and thermometer leads froman isothermal bar external to the cham-ber. The wires run out of the chamberthrough small holes in its corners, andthe wires do not contact the chamber it-self. During a steady-state measurement,the thermometer and bar are individuallycontrolled at the same temperature, so

there is zero heat flow through the wires.Thus, all of sample-temperature-controlheater power is radiated to the chamber.

Double-aluminized Kapton (DAK)emissivity was studied down to 10 K,which was about 25 K colder than anypreviously reported measurements. Thisverified a minimum in the emissivity atabout 35 K and a rise as the temperaturedropped to lower values.

This work was done by James Tuttle andMichael J. DiPirro of Goddard Space FlightCenter. For further information, contact theGoddard Innovative Partnerships Office at(301) 286-5810. GSC-15697-1

A diffractive optic element (DOE) canbe used as a beam splitter to generatemultiple laser beams from a single inputlaser beam. This technology has been re-cently used in LRO’s Lunar OrbiterLaser Altimeter (LOLA) instrument togenerate five laser beams that measurethe lunar topography from a 50-kmnominal mapping orbit (see figure). Anextension of this approach is to use amultiple-zone DOE to allow a laser al-timeter instrument to operate over awider range of distances. In particular, amultiple-zone DOE could be used forapplications that require both mappingand landing on a planetary body. In this

case, the laser altimeter operating rangewould need to extend from several hun-dred kilometers down to a few meters.

The innovator was recently involved inan investigation how to modify theLOLA instrument for the OSIRIS aster-oid mapping and sample return mission.One approach is to replace the DOE inthe LOLA laser beam expander assemblywith a multiple-zone DOE that wouldallow for the simultaneous illuminationof the asteroid with mapping and land-ing laser beams. The proposed OSIRISmultiple-zone DOE would generate thesame LOLA five-beam output pattern forhigh-altitude topographic mapping, but

would simultaneously generate a wide di-vergence angle beam using a small por-tion of the total laser energy for the ap-proach and landing portion of themission. Only a few percent of the totallaser energy is required for approachand landing operations as the return sig-nal increases as the inverse square of theranging height. A wide divergence beamcould be implemented by making thecenter of the DOE a diffractive or refrac-tive negative lens. The beam energy andbeam divergence characteristics of a mul-tiple-zone DOE could be easily tailoredto meet the requirements of other mis-sions that require laser ranging data.

Multiple-Zone Diffractive Optic Element for Laser Ranging ApplicationsThis technology can be used on unmanned aerial vehicles, or in collision-avoidance and roboticcontrol applications in cars, trains, and ships. Goddard Space Flight Center, Greenbelt, Maryland

Current single-zone DOE lithographicmanufacturing techniques could also beused to fabricate a multiple-zone DOE bymasking the different DOE zones duringthe manufacturing process, and thesame space-compatible DOE substrates(fused silica, sapphire) that are used onstandard DOE’s could be used for multi-ple-zone DOE’s.

DOEs are an elegant and cost-effec-tive optical design option for space-

based laser altimeters that require mul-tiple output laser beams. The use ofmultiple-zone DOEs would allow forthe design and optimization of a laseraltimeter instrument required to oper-ate over a large range of target dis-tances, such as those designed to bothmap and land on a planetary body. Inaddition to space-based laser altimeters,this technology could find applicationsin military or commercial unmanned

aerial vehicles (UAVs) that fly at an alti-tude of several kilometers and need toland. It is also conceivable that varia-tions of this approach could be used inland-based applications such as colli-sion avoidance and robotic control ofcars, trains, and ships.

This work was done by Luis A. Ramos-Izquierdo of Goddard Space Flight Center.Further information is contained in a TSP(see page 1). GSC-15620-1


(a) (b) (c)

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The simplified architecture is a mini-mal system for a deep-space optical com-munications transceiver. For a deep-space optical communications link thesimplest form of the transceiver requires(1) an efficient modulated opticalsource, (2) a point-ahead mechanism(PAM) to compensate for two-way lighttravel, (3) an aperture to reduce the di-vergence of the transmit laser communi-cation signal and also to collect the up-link communication signal, and (4) areceive detector to sense the uplinkcommunication signal. Additional com-ponents are introduced to mitigate forspacecraft microvibrations and to im-prove the pointing accuracy.

The Canonical Transceiver imple-ments this simplified architecture (seefigure). A single photon-counting “smartfocal plane” sensor combines acquisi-tion, tracking, and forward link data de-tection functionality. This improves opti-cal efficiency by eliminating channelsplits. A transmit laser blind sensor (e.g.silicon with 1,550-nm beam) providestransmit beam-pointing feedback via the

two-photon absorption (TPA) process.This vastly improves the transmit/receiveisolation because only the focused trans-mit beam is detected. A piezoelectric tip-tilt actuator implements the required

point-ahead angle. This point-aheadmechanism has been demonstrated tohave near zero quiescent power and isflight qualified. This architecture alsouses an innovative 100-mHz resonant fre-

Simplified Architecture for Precise Aiming of a Deep-SpaceCommunication Laser TransceiverNew optical transceiver is a combination of innovative technologies. NASA’s Jet Propulsion Laboratory, Pasadena, California

Aft-Electronics(Sensor Read-Out,

PAM actuation)

TransceiverElectronics

(Acq/Trk/SOH,Uplink Receiver,

Laser)

SPACECRAFT

Sub-Hz Strut Hexpod Isolation Platformwith Tip/Tilt Control

Point AheadMechanism

Si or InGaAsPArray

1550 nmTransmitter

DichroicBeamsplitter1550 nm HT1064 nm HR

+retro

1064 nm Beacon1550 nm Transmit

The Canonical Transceiver Architecture simplifies the design of the deep-space optical transceiver. In-novative technologies enabling its implementation include a single photon-counting detector array,two-photon absorption downlink tracking, a low-power point-ahead mechanism, and a sub-Hertz vi-bration isolation platform.

A new optical beam tracking ap-proach for free-space optical communi-cation links using two-photon absorp-tion (TPA) in a high-bandgap detectormaterial was demonstrated. This track-ing scheme is part of the canonical ar-chitecture described in the precedingarticle. TPA is used to track a long-wave-length transmit laser while direct ab-sorption on the same sensor simultane-ously tracks a shorter-wavelengthbeacon. The TPA responsivity was meas-ured for silicon using a PIN photodiodeat a laser beacon wavelength of 1,550nm. As expected, the responsivity showsa linear dependence with incidentpower level. The responsivity slope is 4.5× 10–7 A/W2. Also, optical beam spotsfrom the 1,550-nm laser beacon werecharacterized on commercial charge-coupled device (CCD) and complemen-tary metal-oxide semiconductor(CMOS) imagers with as little as 13.7µW of optical power (see figure). Thisnew tracker technology offers an inno-vative solution to reduce system com-plexity, improve transmit/receive isola-tion, improve optical efficiency,improve signal-to-noise ratio (SNR),and reduce cost for free-space opticalcommunications transceivers.

This work was done by Gerardo G. Ortizand William H. Farr of Caltech for NASA’sJet Propulsion Laboratory. Further informa-

tion is contained in a TSP (see page 1). NPO-46063

Two-Photon-Absorption Scheme for Optical Beam TrackingThis approach reduces cost for free-space optical communication receivers.NASA’s Jet Propulsion Laboratory, Pasadena, California

Two-Photon Absorption generated signal levels caused by a 1,550 nm laser focused spot on a siliconCMOS focal plane array detector at various power levels. Note that the spot is distinguishable evenwith incident power levels in the 10’s of microwatts.

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quency passive isolation platform to filterspacecraft vibrations with voice coil actu-ators for active tip-tilt correction belowthe resonant frequency.

The canonical deep-space opticalcommunications transceiver makes syn-ergistic use of innovative technologies to

reduce size, weight, power, and cost.This optical transceiver can be used toretire risks associated with deep-spaceoptical communications on a planetarypathfinder mission and is complemen-tary to ongoing lunar and access link de-velopments.

This work was done by Gerard G. Ortiz,William H. Farr, and Jeffrey R. Charles ofCaltech for NASA’s Jet Propulsion Laboratory.Further information is contained in a TSP(see page 1). NPO-46073

A broad-range vacuum gauge hasbeen created by suspending a single-walled carbon nanotube (SWNT)(metallic or semiconducting) in a Schot-tky diode format or in a bridge conduc-tor format, between two electricallycharged mesas. SWNTs are highly sensi-tive to molecular collisions because of

their extremely small diameters in therange of 1 to 3 nanometers. The meas-urement parameter will be the changein conductivity of SWNT due to decreas-ing rate of molecular collisions as thepressure inside a chamber decreases.

The rate of heat removal approachesa saturation limit as the mean free path

(m.f.p.) lengths of molecules increasedue to decreasing pressure. Only thosesensing elements that have a long relax-ation time can produce a measureableresponse when m.f.p. of molecules in-creases (or time between two consecu-tive collisions increases). A suspendedSWNT offers such a capability because

High-Sensitivity, Broad-Range Vacuum Gauge Using Nanotubesfor Micromachined Cavities NASA’s Jet Propulsion Laboratory, Pasadena, California


of its one-dimensional nature and ultra-small diameter. In the initial approach,similar architecture was used as that of aSWNT-Schottky diode that has been de-veloped at JPL, and has its changingconductivity measured as the test cham-ber is pumped down from atmosphericpressure to high vacuum (10–7 Torr).Continuous response of decreasing con-ductivity has been measured as a func-tion of decreasing pressure (SWNT is a

negative thermal coefficient material)from atmosphere to <10–6 Torr. A mea-sureable current change in the hun-dreds of nA range has been recorded inthe 10–6 Torr regime.

This work was done by Harish Manoharaand Anupama B. Kaul of Caltech for NASA’sJet Propulsion Laboratory. For more informa-tion, contact [email protected].

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:



Wide-Field Optic for Autonomous Acquisition of Laser Link This system has application in conventional wide-angle imaging such as low-light cockpit imag-ing, and in long-range motion detection. NASA’s Jet Propulsion Laboratory, Pasadena, California

An innovation reported in “Two-Camera Acquisition and Tracking of aFlying Target,” NASA Tech Briefs, Vol. 32,No. 8 (August 2008), p. 20, used a com-mercial fish-eye lens and an electronicimaging camera for initially locatingobjects with subsequent handover to anactuated narrow-field camera. But thisoperated against a dark-sky back-ground. An improved solution involvesan optical design based on custom opti-cal components for the wide-field opti-cal system that directly addresses thekey limitations in acquiring a laser sig-nal from a moving source such as an air-craft or a spacecraft.

The first challenge was to increase thelight collection entrance aperture diam-eter, which was approximately 1 mm inthe first prototype. The new design pre-sented here increases this entrance aper-ture diameter to 4.2 mm, which is equiv-alent to a more than 16 times largercollection area. One of the trades madein realizing this improvement was to re-strict the field-of-view to +80° elevationand 360° azimuth. This trade stems frompractical considerations where laserbeam propagation over the excessivelyhigh air mass, which is in the line ofsight (LOS) at low elevation angles, re-sults in vulnerability to severe atmos-pheric turbulence and attenuation. Anadditional benefit of the new design isthat the large entrance aperture is main-tained even at large off-axis angles whenthe optic is pointed at zenith.

The second critical limitation for im-plementing spectral filtering in the designwas tackled by collimating the light priorto focusing it onto the focal plane. This al-lows the placement of the narrow spectralfilter in the collimated portion of the

beam. For the narrow band spectral filterto function properly, it is necessary to ad-equately control the range of incident an-gles at which received light intercepts thefilter. When this angle is restricted via col-limation, narrower spectral filtering can

be implemented. The collimated beam(and the filter) must be relatively large toreduce the incident angle down to only afew degrees. In the presented embodi-ment, the filter diameter is more than tentimes larger than the entrance aperture.

(a) (b)

FPA

MountingFlange is Near Centerof Gravityof Lens withCamera.

Removable RearLens Cell Doublesas Camera DustSeal During I&T.

Filter

92mm

241 mm

Filter

Focal Plane

(a) The custom optical design and ray-trace of the Wide-Field Optical Assembly; and (b) a Conceptual Op-tomechanical Design for holding the optical components and providing interface to the focal plane array(FPA). The collected light is substantially collimated prior to being passed through the spectral filter.



Specifically, the filter has a clear apertureof about 51 mm.

The optical design is refractive, and iscomprised of nine custom refractive ele-ments and an interference filter. The re-stricted maximum angle through thenarrow-band filter ensures the efficient

use of a 2-nm noise equivalent band-width spectral width optical filter at lowelevation angles (where the range islongest), at the expense of less efficiencyfor high elevations, which can be toler-ated because the range at high elevationangles is shorter. The image circle is 12

mm in diameter, mapped to 80×360° ofsky, centered on the zenith.

This work was done by Norman A. Page,Jeffrey R. Charles, and Abhijit Biswas of Cal-tech for NASA’s Jet Propulsion Laboratory.Further information is contained in a TSP(see page 1). NPO-46945

The technical innovation involves re-finement of the classic optical tech-nique of averaging surface measure-ments made in different orientationswith respect to gravity, so the effects ofgravity cancel in the averaged image.Particularly for large, thin mirrors sub-ject to substantial deformation, the fur-ther requirement is that mount forcesmust also cancel when averaged overmeasurement orientations. The zero-gravity surface figure of a mirror in ahexapod mount is obtained by analyz-ing the summation of mount forces in

the frame of the optic as surface metrol-ogy is averaged over multiple clockings.This is illustrated with measurementstaken from the Space InterferometryMission (SIM) PT-Ml mirror for bothtwofold and threefold clocking. Thepositive results of these measurementsand analyses indicate that, from thisperspective, a lighter mirror could beused; that is, one might place less re-liance on the damping effects of the el-liptic partial differential equations thatdescribe the propagation of forcesthrough glass.

The advantage over prior art is relax-ing the need for an otherwise substantialthickness of glass that might be needed toensure accurate metrology in the absenceof a detailed understanding and analysisof the mount forces. The general insightsdeveloped here are new, and provide thebasic design principles on which mirrormount geometry may be chosen.

This work was done by Eric E. Bloemhof,Jonathan C. Lam, V. Alfonso Feria, and Zen-sheu Chang of Caltech for NASA’s Jet Propul-sion Laboratory. For more information, con-tact [email protected]. NPO-47259

Extracting Zero-Gravity Surface Figure of a Mirror NASA’s Jet Propulsion Laboratory, Pasadena, California


Information Sciences

Modeling Electromagnetic Scattering From Complex Inhomo-geneous ObjectsComplex, inhomogeneous objects can be easily modeled using commercial CAD packages.NASA Langley Research Center, Hampton, Virginia

This software innovation is designedto develop a mathematical formulationto estimate the electromagnetic scatter-ing characteristics of complex, inhomo-geneous objects using the finite-ele-ment-method (FEM) andmethod-of-moments (MoM) concepts,as well as to develop a FORTRAN codecalled FEMOM3DS (Finite ElementMethod and Method of Moments for 3-Dimensional Scattering), which will im-plement the steps that are described inthe mathematical formulation. Verycomplex objects can be easily modeled,and the operator of the code is not re-quired to know the details of electro-magnetic theory to study electromag-netic scattering.

Consider a complex inhomogeneousobject geometry, the electromagneticscattering characteristics of which areto be estimated when illuminated by aplane electromagnetic wave. To facili-tate the mathematical formulationusing the hybrid FEM/MoM, the objectis assumed to be enclosed by a surfaceindicated as a fictitious outer bound-ary. Inside the boundary, the electro-magnetic fields are obtained using the

FEM, whereas the electromagneticfields outside the fictitious boundaryare obtained using the assumed equiva-lent electric and magnetic currentsflowing on the fictitious boundary.Continuity of the electromagneticfields across the fictitious boundary re-sults in partly sparse/dense matrix thatis solved for the unknown fields insidethe fictitious boundary including theboundary surface.

The steps laid out in the mathemati-cal formulation are carried out inFEMOM3DS. Along with the mainFEMOM3DS, the innovation uses acommercial computer-aided-design(CAD) package for geometrical model-ing, and a post-processing package suchas Techplot for displaying graphicallythe results obtained using FEMOM3DS.In the present FEMOM3DS code theCOSMOS/M commercial software isused as a CAD tool to model the geom-etry of a given problem. The COS-MOS/M is also used to discretize theFEM region using the tetrahedral ele-ments. Various inhomogeneous regionsare taken care of by having many partsin the FEM region. Using the COS-

MOS/M, common boundaries whereboundary conditions are to be imple-mented are also identified. The datafile created by the COSMOS/M fornode and element information is thengenerated and processed through thepreprocessor part of FEMOM3DS codeto create edge information and nodeinformation. The preprocessed data arethen run through the main part ofFEMOM3DS to obtain electromagneticscattering. The output files from theFEMOM3DS can be used for displayingthe results in a graphical format.

The FEMOM3DS is written in FOR-TRAN 77. The code was successfullycompiled on a CONVEX machine.However, the code can be compiled onany 32-bit machine like PCs or SUN,SGI UNIX Station. To get correct re-sults, dimensions must be given in cen-timeters, frequency of operation mustbe given in GHz and incident and ob-servation angles must be specified indegrees.

This work was done by Manohar Desh-pande and C. J. Reddy of Langley ResearchCenter. Further information is contained in aTSP (see page 1). LAR-17090-1

A method has been created to auto-matically build an algorithm off-line,using computer-aided design (CAD)models, and to apply this at runtime.The object type is discriminated, andthe position and orientation are identi-fied. This system can work with a singleimage and can provide improved per-formance using multiple images pro-vided from videos.

The spatial processing unit uses threestages: (1) segmentation; (2) initial type,pose, and geometry (ITPG) estimation;

and (3) refined type, pose, and geometry(RTPG) calculation. The image segmen-tation module files all the tools in animage and isolates them from the back-ground. For this, the system uses edge-de-tection and thresholding to find the pix-els that are part of a tool. After the pixelsare identified, nearby pixels are groupedinto blobs. These blobs represent the po-tential tools in the image and are theproduct of the segmentation algorithm.

The second module uses matched fil-tering (or template matching). This ap-

proach is used for condensing syntheticimages using an image subspace thatcaptures key information. Three degreesof orientation, three degrees of position,and any number of degrees of freedomin geometry change are included. To dothis, a template-matching framework isapplied. This framework uses an off-linesystem for calculating template images,measurement images, and the measure-ments of the template images. These re-sults are used online to match seg-mented tools against the templates.

Visual Object Recognition and Tracking of ToolsThis method can be used to track tools held and used by humans, such as surgical tools.

Lyndon B. Johnson Space Center, Houston, Texas

Visual SLAM Using Variance Grid MapsThis algorithm is suitable for real-time navigation on irregular terrain.NASA’s Jet Propulsion Laboratory, Pasadena, California

An algorithm denoted “Gamma-SLAM” performs further processing, inreal time, of preprocessed digitized im-ages acquired by a stereoscopic pair ofelectronic cameras aboard an off-roadrobotic ground vehicle to build accu-rate maps of the terrain and determinethe location of the vehicle with respectto the maps. Part of the name of the al-gorithm reflects the fact that theprocess of building the maps and de-termining the location with respect tothem is denoted “simultaneous local-ization and mapping” (SLAM). Mostprior real-time SLAM algorithms havebeen limited in applicability to (1) sys-tems equipped with scanning laserrange finders as the primary sensors in(2) indoor environments (or relativelysimply structured outdoor environ-ments). The few prior vision-based

SLAM algorithms have been feature-based and not suitable for real-time ap-plications and, hence, not suitable forautonomous navigation on irregularlystructured terrain.

The Gamma-SLAM algorithm incor-porates two key innovations:• Visual odometry (in contradistinction

to wheel odometry) is used to estimatethe motion of the vehicle.

• An elevation variance map (in contradis-tinction to an occupancy or an elevationmap) is used to represent the terrain.The Gamma-SLAM algorithm makes

use of a Rao-Blackwellized particle filter(RBPF) from Bayesian estimation the-ory for maintaining a distribution overposes and maps. The core idea of theRBPF approach is that the SLAM prob-lem can be factored into two parts: (1)finding the distribution over robot tra-

jectories, and (2) finding the map con-ditioned on any given trajectory. Thefactorization involves the use of a parti-cle filter in which each particle encodesboth a possible trajectory and a mapconditioned on that trajectory. The baseestimate of the trajectory is derivedfrom visual odometry, and the map con-ditioned on that trajectory is a Cartesiangrid of elevation variances. In compari-son with traditional occupancy or eleva-tion grid maps, the grid elevation vari-ance maps are much better forrepresenting the structure of vegetatedor rocky terrain.

This work was done by Andrew B.Howard of Caltech and Tim K. Marks of theUniversity of California San Diego forNASA’s Jet Propulsion Laboratory. For moreinformation, contact [email protected]

The final module is the RTPG proces-sor. Its role is to find the exact states ofthe tools given initial conditions providedby the ITPG module. The requirementthat the initial conditions exist allows thismodule to make use of a local search(whereas the ITPG module had globalscope). To perform the local search, 3Dmodel matching is used, where a syn-thetic image of the object is created andcompared to the sensed data. The avail-ability of low-cost PC graphics hardwareallows rapid creation of synthetic images.In this approach, a function of orienta-tion, distance, and articulation is defined

as a metric on the difference between thecaptured image and a synthetic imagewith an object in the given orientation,distance, and articulation. The syntheticimage is created using a model that islooked up in an object-model database.

A composable software architecture isused for implementation. Video is firstpreprocessed to remove sensor anom-alies (like dead pixels), and then isprocessed sequentially by a prioritizedlist of tracker-identifiers.

This work was done by James English,Chu-Yin Chang, and Neil Tardella of En-ergid Technologies for Johnson Space Center.

Further information is contained in a TSP(see page 1).


Energid Technologies124 Mount Auburn StreetSuite 200 NorthCambridge, MA 02138Phone No.: (617) 401-7090Toll Free No.: (888) 547-4100Refer to MSC-23947-1, volume and num-

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

A method has been developed to me-chanically implement the optical phaseshift by adjusting the polarization of thepump and probe beams in an NMOR(nonlinear magneto-optical rotation)magnetometer as the proper phase shiftis necessary to induce self-oscillation.This innovation consists of mountingthe pump beam on a ring that sur-rounds the atomic vapor sample. Thepropagation of the probe beam is per-

pendicular to that of the pump beam.The probe beam can be considered asdefining the axis of a cylinder, while thepump beam is directed radially. Themagnetic field to be measured defines athird vector, but it is also taken to liealong the cylinder axis. Both the pumpand probe beams are polarized suchthat their electric field vectors are sub-stantially perpendicular to the magnetfield. By rotation of the ring supporting

the pump beam, its direction can be var-ied relative to the plane defined by theprobe electric field and the magneticfield to be measured.

This work was done by David C. Hovde ofSouthwest Sciences and Eric Corsini of theUniversity of California, Berkeley, for God-dard Space Flight Center. For further informa-tion, contact the Goddard Innovative Part-nerships Office at (301) 286-5810.GSC-15608-1

Method for Implementing Optical Phase AdjustmentGoddard Space Flight Center, Greenbelt, Maryland


A variable-order, variable-step Taylorseries integration algorithm was imple-mented in NASA Glenn’s SNAP (Space-craft N-body Analysis Program) code.SNAP is a high-fidelity trajectory prop-agation program that can propagatethe trajectory of a spacecraft about vir-tually any body in the solar system. TheTaylor series algorithm’s very highorder accuracy and excellent stabilityproperties lead to large reductions incomputer time relative to the code’sexisting 8th order Runge-Kuttascheme. Head-to-head comparison onnear-Earth, lunar, Mars, and Europamissions showed that Taylor series inte-gration is 15.8 times faster than Runge-Kutta on average, and is more accurate.These speedups were obtained for cal-culations involving central body, otherbody, thrust, and drag forces. Similarspeedups have been obtained for calcu-lations that include J2 spherical har-monic for central body gravitation.The algorithm includes a step size se-lection method that directly calculates

the step size and never requires a re-peat step.

High-order Taylor series integration al-gorithms have been shown to providemajor reductions in computer time overconventional integration methods in nu-merous scientific applications. The objec-tive here was to directly implement Taylorseries integration in an existing trajectoryanalysis code and demonstrate that largereductions in computer time (order ofmagnitude) could be achieved while si-multaneously maintaining high accuracy.

This software greatly accelerates thecalculation of spacecraft trajectories. Ateach time level, the spacecraft position,velocity, and mass are expanded in ahigh-order Taylor series whose coeffi-cients are obtained through efficientdifferentiation arithmetic. This makesit possible to take very large time stepsat minimal cost, resulting in large sav-ings in computer time. The Taylor se-ries algorithm is implemented prima-rily through three subroutines: (1) adriver routine that automatically intro-

duces auxiliary variables and sets up ini-tial conditions and integrates; (2) a rou-tine that calculates system reduced de-rivatives using recurrence relations forquotients and products; and (3) a rou-tine that determines the step size andsums the series. The order of accuracyused in a trajectory calculation is arbi-trary and can be set by the user. The al-gorithm directly calculates the motionof other planetary bodies and does notrequire ephemeris files (except to startthe calculation). The code also runswith Taylor series and Runge-Kuttaused interchangeably for differentphases of a mission.

This work was done by James R. Scott andMichael C. Martini of Glenn Research Cen-ter. Further information is contained in aTSP (see page 1).


Rapid Calculation of Spacecraft Trajectories Using EfficientTaylor Series IntegrationSoftware greatly accelerates the calculation of spacecraft trajectories.John H. Glenn Research Center, Cleveland, Ohio

More efficient versions of an interpo-lation method, called kriging, have beenintroduced in order to reduce its tradi-tionally high computational cost. Writ-ten in C++, these approaches were testedon both synthetic and real data.

Kriging is a best unbiased linear esti-mator and suitable for interpolation ofscattered data points. Kriging has longbeen used in the geostatistic and mining

communities, but is now being re-searched for use in the image fusion ofremotely sensed data. This allows a com-bination of data from various locationsto be used to fill in any missing datafrom any single location.

To arrive at the faster algorithms,sparse SYMMLQ iterative solver, co-variance tapering, Fast MultipoleMethods (FMM), and nearest neigh-

bor searching techniques were used.These implementations were usedwhen the coefficient matrix in the lin-ear system is symmetric, but not neces-sarily positive-definite.

This work was done by NargessMemarsadeghi of Goddard Space Flight Cen-ter. For further information, contact the God-dard Innovative Partnerships Office at (301)286-5810. GSC-15555-1

Efficient Kriging AlgorithmsGoddard Space Flight Center, Greenbelt, Maryland

A combination of methods is proposedof predicting spacecraft trajectories thatpossibly include multiple maneuversand/or perturbing accelerations, withgreater speed, accuracy, and repeatabilitythan were heretofore achievable. The

combination is denoted the WeavEnckemethod because it is based on unpub-lished studies by Jonathan Weaver of theorbit-prediction formulation of the notedastronomer Johann Franz Encke. Weaverevaluated a number of alternatives that

arise within that formulation, arriving atan orbit-predicting algorithm optimizedfor complex trajectory operations.

In the WeavEncke method, Encke’smethod of prediction of perturbed or-bits is enhanced by application of mod-

Predicting Spacecraft Trajectories by the WeavEncke MethodLyndon B. Johnson Space Center, Houston, Texas


A research project is underway to pro-duce computer software that can accu-rately predict ice growth under any me-teorological conditions for any aircraftsurface. An extensive comparison of theresults in a quantifiable manner againstthe database of ice shapes that havebeen generated in the NASA GlennIcing Research Tunnel (IRT) has beenperformed, including additional datataken to extend the database in theSuper-cooled Large Drop (SLD) regime.The project shows the differences in iceshape between LEWICE 3.2.2, Glen-nICE, and experimental data.

The Icing Branch at NASA Glenn hasproduced several computer codes overthe last 20 years for performing icingsimulation. While some of these toolshave been collaborative projects, mosthave been developed primarily by oneperson, with some assistance by others.The state of computing has alsochanged dramatically in that time pe-riod. As these codes have grown in com-plexity and have been accepted by usersas production icing tools, there hasarisen a need for the developers to ad-here to standard software practices usedto develop commercial software.

The project addresses the validationof the software against a recent set of ice-shape data in the SLD regime. This vali-dation effort mirrors a similar effort un-dertaken for previous validations ofLEWICE. Those reports quantified theice accretion prediction capabilities ofthe LEWICE software. Several ice geom-etry features were proposed for compar-ing ice shapes in a quantitative manner.The resulting analysis showed thatLEWICE compared well to the availableexperimental data.

The effects of super-cooled largedroplets in icing have been researched

Comparison of Aircraft Icing Growth Assessment SoftwareThe goal is to provide software that can predict ice growth under any condition for any aircraft surface.John H. Glenn Research Center, Cleveland, Ohio

ern numerical methods. Among thesemethods are efficient Kepler’s-equationtime-of-flight solutions and self-startingnumerical integration with time as theindependent variable. Self-starting nu-merical integration satisfies the require-

ments for accuracy, reproducibility, andefficiency (and, hence, speed). Self-start-ing numerical integration also supportsfully analytic regulation of integrationstep sizes, thereby further increasingspeed while maintaining accuracy.

This work was done by Jonathan K.Weaver of Johnson Space Center and DanielR. Adamo of United Space Alliance. For fur-ther information, contact the JSC InnovationPartnerships Office at (281) 483-3809.MSC-23802-1

The original G-Guidance algorithmprovided an autonomous guidance andcontrol policy for small-body proximityoperations that took into account uncer-tainty and dynamics disturbances. How-ever, there was a lack of robustness in re-gards to object proximity while inautonomous mode. The modified G-Guidance algorithm was augmentedwith a second operational mode that al-lows switching into a safety hover mode.This will cause a spacecraft to hover inplace until a mission-planning algorithmcan compute a safe new trajectory. Nostate or control constraints are violated.When a new, feasible state trajectory iscalculated, the spacecraft will return tostandard mode and maneuver towardthe target. The main goal of this aug-mentation is to protect the spacecraft inthe event that a landing surface or obsta-cle is closer or further than anticipated.The algorithm can be used for the miti-

gation of any unexpected trajectory orstate changes that occur during standardmode operations.

In order to have the G-Guidance algo-rithm detect an unsafe condition, it re-quired some modification. This modifi-cation provides a policy to safelymaneuver the spacecraft between its cur-rent state and a desired target state whileensuring satisfaction of thruster and tra-jectory constraints, along with safety con-straints. In standard mode, this modifica-tion brings the spacecraft from itscurrent position closer to its target state.In safety mode, the algorithm maintainsthe spacecraft’s current state at zero ve-locity. Since the safety mode is designedto be temporary, the destination locationin this mode is also temporary, and oncea new destination location is provided,the spacecraft returns to standard mode.

The G-Guidance algorithm uses botha planned trajectory (feedforward) and

a control policy (feedback), along withsensors to monitor actual spacecraftstate. The feedback is designed to en-sure that the spacecraft stays within aspecified proximity to the feedforward.The feedforward is designed to achievethe goals of each mode: hover for safetymode and maneuver toward target forstandard mode. By giving the spacecraftthe ability to re-compute its trajectoryon-the-fly in response to local condi-tions, minimization of fuel usage is pro-vided. The original G-Guidance algo-rithm provides robustness to uncertaintyaffecting the dynamics. The safety aug-mentation provides a form of state-con-straint robustness, which further miti-gates risk.

This work was done by John M. CarsonIII and Behcet Acikmese of Caltech forNASA’s Jet Propulsion Laboratory. For moreinformation, contact [email protected]

An Augmentation of G-Guidance Algorithms This augmented algorithm can be used in small-body proximity operations utilizing modelpredictive control with a need for safety from surface-constraint uncertainty. NASA’s Jet Propulsion Laboratory, Pasadena, California


extensively since 1994. Since then, sev-eral experimental efforts have beenmade to document SLD ice shapes andto investigate the underlying physics.While this project provides comparisonsto standard icing conditions, the empha-

sis was placed on the newer data, whichis predominately SLD.

This work was done by William Wright,Mark G. Potapczuk, and Laurie H. Levinsonof Glenn Research Center. Further informationis contained in a TSP (see page 1).



Books & Reports

Silicon-Germanium Voltage-Controlled Oscillator at 105 GHz

A group at UCLA, in collaborationwith the Jet Propulsion Laboratory, hasdesigned a voltage-controlled oscillator(VCO) created specifically for a com-pact, integrated, electronically tunablefrequency generator useable for submil-limeter-wave science instruments operat-ing in extreme cold environments. TheVCO makes use of SiGe heterojunctionbipolar transistors (HBTs). The SiGeHBTs have a 0.13-micrometer emitterwidth. A differential design was usedwith two VCOs connected to form aquadrature signal. A 2.5-V supply is re-quired to power the circuit. A cross-cou-pled CMOS pair is used for emitter-de-generation of the SiGe HBTs, and thedesign uses coupled load and base in-ductors. The circuit oscillates at 105GHz. A linear superposition of VCOs hasbeen designed to achieve four times theoscillation frequency of the fundamen-tal oscillator.

This work was done by Alden Wong, TimLarocca, and M. Frank Chang of UCLA , andLorene A. Samoska of Caltech for NASA’s JetPropulsion Laboratory. Further information iscontained in a TSP (see page 1).NPO-47116

Estimation of Coriolis Forceand Torque Acting on Ares-1

A document describes work on the ori-gin of Coriolis force and estimating Cori-olis force and torque applied to the Ares-1 vehicle during its ascent, based on aninternal ballistics model for a multi-seg-mented solid rocket booster (SRB).

The work estimates Coriolis forceand torque applied to the vehicle dur-ing its ascent. Maveric flight simulationsoftware was used to produce the re-quired angular velocity data for theCoriolis force and torque computa-tions. For the simulation of gas move-ment in SRB, software was developedusing a dynamical model of internalballistics of the five-segmented SRB.Also included in the work are a studyand estimate of Coriolis force and

torque applied to the rocket due to SRBnozzle movement. For calculation of in-ternal ballistics, Coriolis force, andtorque computations, MATLAB soft-ware was used.

Coriolis force and torque were calcu-lated and applied to Ares-1 during its as-cent. Two cases were considered: Corio-lis force and torque applied to therocket originating from gas movementin SRB, and Coriolis force and torqueoriginating from exhaust gas movementin SRB nozzle. Coriolis force and torqueare the largest during the first 20 sec-onds after the launch when rocket angu-lar velocity is large. SRB Coriolis force isabout 5.4 times larger than nozzle Cori-olis force, and SRB Coriolis torque isabout 2.8 times larger than the nozzleCoriolis torque at the time t=10 seconds.The inclusion of flexible rocket modeldoes not provide a significant change tothe results of Coriolis force and torquecomputations in comparison with a rigidrocket model.

This work was done by Ryan M. Mackeyand Igor K. Kulikov of Caltech; VadimSmelyanskiy and Dmitry Luchinsky of AmesResearch Center; and Jeb Orr of BD SystemsInc. for NASA’s Jet Propulsion Laboratory.Further information is contained in a TSP(see page 1).


Null Lens Assembly for X-Ray Mirror Segments

A document discusses a null lens as-sembly that allows laser interferometryof 60° slumped glass mirror segmentsused in x-ray mirrors. The assemblyconsists of four lenses in precise align-ment to each other, with incorporatedpiezoelectric nanometer stepping actu-ators to position the lenses in six de-grees of freedom for positioning rela-tive to each other.

Each lens is first installed and epoxiedinto a 410 stainless steel “cell.” The outerhousing is designed to allow five degrees

of freedom of the lens. The cell is placedonto a 3/8-in. (≈ 9-mm) ball bearing inthe base of the housing, which providesa pivot point for the rotations, and al-lows slight x and y translations (microns)by allowing the cell to slide against it.Rotations are accomplished by 5 com-mercial picomotors that push on the cellin 30-nanometer increments. Springplungers on the opposite side of the cellfrom the picomotors secure the cell inthe housing.

The 410 stainless steel is used for thecell, baseplate, and rails because it has alow CTE (coefficient of thermal expan-sion) relative to most other metals. It isused exclusively in the “growth path” ofthe optical assembly so that when bulktemperature changes occur in the lab,the lenses will move a consistent amountapart from each other (which is a lesssensitive factor in alignment), but willnot tilt or rotate (alignment is very sensi-tive to rotations).

This work was done by David W. Robinsonof Goddard Space Flight Center. Further infor-mation is contained in a TSP (see page 1).GSC 15790-1

High-Precision Pulse Generator

A document discusses a pulse genera-tor with subnanosecond resolution im-plemented with a low-cost field-pro-grammable gate array (FPGA) at lowpower levels. The method used exploitsthe fast carry chains of certain FPGAs.Prototypes have been built and tested inboth Actel AX and Xilinx Virtex 4 tech-nologies. In-flight calibration or controlcan be performed by using a similar andrelated technique as a time intervalmeasurement circuit by measuring a pe-riod of the stable oscillator, as the delaysthrough the fast carry chains will vary asa result of manufacturing variances aswell as the result of environmental con-ditions (voltage, aging, temperature,and radiation).

This work was done by Richard Katz andIgor Kleyner of Goddard Space Flight Center.Further information is contained in a TSP(see page 1). GSC- 15831-1


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