core analysis combining mt (tipper) and dielectric...

www.aipg.org Oct.Nov.Dec.2016•TPGE-article1

CORE ANALYSIS COMBINING MT (TIPPER) AND DIELECTRIC SENSORS (SANS EC) IN EARTH AND SPACE

MichaelC. Mound CEO,TDDInternational

Hahnrainweg9,Baden,5400 Switzerland [email protected]

Kenneth L. Dudley

NASA LangleyResearchCenterHampton,[email protected]

ABSTRACT

On terrestrial planets andmoons of our solar systemcores reveal details about a geological structure'sformation, content, and history. The strategy for thesearch for life is focused first on finding water whichservesasauniversalsolvent,andidentifyingtherockswhichsuchsolventactupontoreleasetheconstituentsalts, minerals, ferrites, and organic compounds andchemicals necessary for life. Dielectric spectroscopymeasures the dielectric properties of a medium as afunctionof frequency. Reflectionmeasurements in thefrequency range from 300 kHz to 300 MHz werecarriedoutusingRFandmicrowavenetworkanalyzersinterrogating SansEC Sensors placed on cleangeological core samples. These were conducted toprove the concept feasibility of a new geologyinstrument useful in the field and laboratory. Theresults show that unique complex frequency spectracan be acquired for a variety of rock core samples.Using a combination of dielectric spectroscopy andcomputer simulation techniques the magnitude andphase information of the frequency spectra can beconverted to dielectric spectra. These low-frequencydielectric properties of natural rock are unique, easilydetermined,andusefulincharacterizinggeology.

TIPPER is an Electro-Magnetic Passive-Source Geophysical Method for Detecting and MappingGeothermal Reservoirs and Mineral Resources Thisgeophysical method uses distant lightning and solarwindactivityasitsenergysource.Themostinterestingdeflections are caused by the funneling of electronsintomoreelectricallyconductiveareaslikemineralizedfaults, water or geothermal reservoirs. We proposeTIPPER to be used with SansEC for determining terrain/ocean chemistry, oceandepth, geomorphologyof fracturestructures,andothersubsurfacetopographycharacteristics below the ice crust of Jovian moons.NASA envisions lander concepts for exploration of

these extraterrestrial icy surfaces and the oceansbeneath. One such concept would use a nuclearpowered heated tip formelting through the icesheathof Europa and inserting a down hole SansEC withTIPPER interface. NASA's Juno space probe alreadyon the way to Jupiter as part of theExploration New FrontiersProgram and the plannedEuropamissionwillconduct detailed reconnaissance of Jupiter's moonEuropa and investigate whether the icy moon couldharbor conditionssuitable for life. It hasalreadybeenobserved that Jovian moons have auroras that mayserveasnaturallyoccurring active energysources foraTIPPERinstrument.

Keywords:Dielectric Spectroscopy, SansECSensors,TIPPER,GeophysicalMapping

ACRONYMSANDSYMBOLS

A : AbsorptionR : ReflectionT : Transmissionɛ0 : freeSpacePermittivityɛr : relativePermittivityμ0 : freeSpacePermeabilityμr : relativePermeabilityC : equivalentCapacitancef : FrequencyI0 : CurrentAmplitudeJ(r): currentdensity k : absorptioncoefficientl : tracelengthL : equivalentInductanceρ(r): chargedensityω : angularfrequencyx : distance

2TPGE-article•Oct.Nov.Dec.2016 www.aipg.org

INTRODUCTION

The objective of this effort is to research and develop radio frequency instrumentation and data processing techniques for planetary surface and subsurface spectroscopy. Building on current innovative research we anticipate near future and long-term development of a series of unique experimental ground-based, airborne, and space qualified light-weight sounding instruments. These hardware systems and techniques will establish a baseline option of RF spectroscopic instruments for integration into future planetary science missions for Earth, Moon, and Mars in the near term as well as Jovian and Saturnian moons in the far term.

Fig. 1. Europa moon of Jupiter.

NASA will benefit from this initial activity by combining the skills and strengths of experts in Geology, Electromagnetic Sensors, Space Science, and Instrumentation. We will gain and advance the ability to integrate a series of ground based electromagnetic sensors with airborne electromagnetic sensors, and orbiting electromagnetic sensor platforms for the purpose of high resolution, broad area, multi-spectral scientific observations of surface and subsurface material composition of planetary bodies. This is to include science data on surface roughness, surface and subsurface chemistry (including organics), material states (solids [including ice], liquid, gaseous), dielectric characteristics of surface and subsurface geology, radar reflectivity, transmissivity, and emissivity for determining planetary albedo, atmospheric, climate, and other planetary properties. Such a wide range of science data from versatile electromagnetic sensors will enable and advance the Agency toward the longer term goal of exploration and understanding of planetary bodies within the solar system.

DIELECTRIC SPECTROSCOPY

Dielectric reflectance spectroscopy is a maturing science that can be used to derive significant information about mineralogy with little or no sample preparation.[1] It may be used in applications when other methods would be too complicated, time consuming, or require destruction of precious samples. In this paper we propose a dielectric measurement system concept capable of being embedded in drilling tools and drill heads for use in down-hole operations on Earth and other terrestrial bodies in the solar system. The system can also be adopted for core sample analysis.

As an electromagnetic wave enters a mineral, a portion of the energy is reflected from grain surfaces, while some of the energy is absorbed, and the remainder of the energy passes through the grain structure. This follows the law of energy conservation as the total energy reflected, transmitted, and absorbed through a material must equal to one hundred percent of the incident electromagnetic wave.

R+T+A=1 The electromagnetic energy that is reflected from grain surfaces or refracted through a particle are said to be scattered. Scattered energy may encounter another grain or be scattered away from the surface so that it may be detected and measured. For certain classes of minerals spectroscopy is an excellent tool. Among these classes are clay mineralogy, OH-bearing minerals, iron oxides and hydroxides, carbonates, sulfates, olivines and pyroxenes.[2]

All materials have a complex index of refraction:

ɛ=ɛ’–iɛ” electric permittivityμ=μ’–iμ” magnetic permeability

where ɛ is the complex index of refraction, and ɛ’ is the real part of the index or the energy storage term, i = (-1)1/2, and ɛ” is the imaginary part of the index of refraction or the energy loss factor.


Fig.2.Dielectricmechanisms.

Theenergy inanelectromagneticwave interactswithmaterials through either a relaxation or resonanceprocess. The index of refraction is determined bychemical, thermal, mechanical, and electronicmechanisms in the core material as a function offrequency. At lower frequencies, electromagneticexcitationcausesphysicalmovementandrelaxationofthe ionic or polar molecules within a core samplematerial. At higher frequencies, electromagneticexcitationcausesresonancesoftheatomicnucleusorthe electron cloud surrounding the nucleus.Depending on the natureofthematerial,thedielectricmechanism,andtheexcitationfrequency (f), energyiseitherstoredorlost.[3] [4]

When energy enters an absorbing medium, it isabsorbedaccordingtoBeersLaw:

I = Io e-kx

Where, I is the observed intensity, Io is the originalintensity, k is an absorption coefficient and x is thedistancetraveledthroughthemedium.

The absorption coefficient is related to the complexindexofrefractionbytheequation:

k = 4 p f ɛ”

Electromagnetic energy can be absorbed inmineralsby the processes described above. The variety ofabsorption processes and their wavelengthdependence allows for the derivation of informationabout the chemistry of a mineral from reflected oremittedelectromagneticenergy. Thismayberecordedasanenergyspectrauniquetotheconstituentsofthecorematerialsample.[5]

THEORY OF SANSEC

Fig.3. AGenericOpen-CircuitSansECSensor.

An open circuit resonant sensor has been developed for the purpose of dielectricspectroscopy of geological materials. TheSansECsensorisaplanarresonantspiralorhelixstructure configured as an open circuit withoutdirect (Sans) electrical connection (EC) to thematerial it is sensing or to the recording instrumentation. The sensor is composed ofconductivematerialandformedinamannersuchthat the natural response of the geometry is toself-resonatewhenimpingeduponbyanexternalelectro-magneticfield.

Electromagnetic resonance theory is wellestablished for classical electromagneticresonators such as resonant cavities, dielectricresonators, and LCR (inductive-capacitive-resistive) resonantcircuits orstructures. [6][7][8] Theopen-circuit resonator used as a sensor is atechnology having unique features andapplications. Itis interrogatedbya magnetic near field, self resonates at a specific fundamentalfrequency with useful harmonics, has a highpower exchange efficiency, and responds toperturbations within its self-resonant field bydetectable shifts in frequency, amplitude, phase,and resonance bandwidth. [9] This is thefoundation for using open-circuit resonators forsensingpurposes.


Fig. 4. Illustration of the Dominant Mode CurrentDistributiononanOpen-CircuitResonantSpiral (blue:lowestcurrentsto red:highestcurrents)

The electro dynamic process of the open-circuit resonator is governed by Maxwell’s equations withzero current boundary conditions at both ends of theresonant spiral. The free electrons carried by theconductor are uniformly distributed along the conductive trace when no external source is applied,butwhendrivenbyanoscillatingelectromagneticfieldthe induced electromotive force (EMF) pushes theelectrons carried by the conductor into the resonantstatewhere the electronsmovebackand forthalongthe conductive trace. The time-dependent current profile alongtheconductivetracehastheform:

(1) 𝐼𝐼 = 𝐼𝐼0𝑐𝑐𝑐𝑐𝑐𝑐(𝜋𝜋𝜋𝜋𝑙𝑙

)𝑒𝑒−𝑖𝑖𝑖𝑖𝑖𝑖

Where,x ϵ [-l/2, l/2]istheparameterizationcoordinatealongthe lengthoftheconductivetrace; l isthetracelength;I0 isthemaximumcurrentamplitude; and ω isthe angular frequency with t as time. The inducedcurrent along the conductive trace has a cosinedistributionwith thepeakmagnitudeatthemiddlepartofthetraceand zerovalues atbothendsofthetrace.During each oscillation cycle, the total current willreach the peak magnitude twice (in oppositedirections)andatthesemomentstheenergystoredintheresonatorisintheformofthemagneticfield.

From the continuity equation, the charge densityprofilehasthefollowingform:

(2) 𝑞𝑞 = 𝑞𝑞0𝑐𝑐𝑠𝑠𝑠𝑠(𝜋𝜋𝜋𝜋𝑙𝑙

)𝑒𝑒−𝑖𝑖(𝑖𝑖𝑖𝑖+𝜋𝜋2)

Where, q0 is themaximumchargedensityvalue.Thecharge is a sine distribution along the trace andcreates the potential difference and consequentlyinduces the electric field between the differentlocalized segments of the trace. During eachoscillation cycle, the electric field reaches its peak

magnitude twiceandat thesemoments theenergy isstoredintheelectricfield.

When resonating, the open-circuit sensor producesboth electric and magnetic fields which occupy thespace between the conductive traces and alsopenetrates into thespacenear theresonator.For theplanar spiral sensor, the magnetic field and electricfield will penetrate into the space beyond the planarsurfaceof thesensor.This isan important featureforsensing purposes because it allows the sensor tomeasurethepropertiesofthematerialsplacedincloseproximity.

Any physical quantity that affects the material’spermittivity,permeability,orconductivitywillaffect thesensor’s resonant parameters and therefore can bemeasured. Electric theory describes the LCRresonator by its lumped parameters of inductance L,capacitance C,andresistance R.Fortheself-resonantcoil, the equivalent lumped parameters can becalculated based on the distributed parameters, asshown inequation(3)andequation(4),where μ0 isthefreespacepermeability,μr istherelativepermeability,ɛ0 is the free space permittivity, ɛr is the relativepermittivity, and J(r) and ρ(r) are the current andchargedensityfunctionsalongtheconductivetrace. [9]

(3) 𝐿𝐿 = µ0µr4π|I0|2∬𝐉𝐉(𝐫𝐫)∙𝐉𝐉(𝐫𝐫′)�𝐫𝐫−𝐫𝐫′�

d𝐫𝐫d𝐫𝐫′

(4) 𝐶𝐶−1 = 14πε0εr|q0|2∬𝛒𝛒(𝐫𝐫)∙𝛒𝛒(𝐫𝐫′)�𝐫𝐫−𝐫𝐫′�

d𝐫𝐫d𝐫𝐫′

However,thecurrentandchargedensityfunctionsarenotmeasurable in actual experiments. Therefore, theequivalent inductance and capacitance values of aself-resonant coil are the calculated values and areusedonlyforprincipleanalysis.Fromequation(3)andequation(4),itcanbeclearlyseenthedependencyofinductance and capacitance upon the material’srelative permeability μr and relative permittivity ɛr.Ifthematerial in theelectricandmagnetic fieldchanges itspermeability and/or permittivity, the resonatorequivalent LC value will change correspondingly, sowilltheresonance parameters.

It isnotablethatequation(3)andequation (4)areforthe cases where the resonant sensor trace is totallyembedded in thematerial having isotropicproperties.Formostactualapplications,forexample,thematerialis put on one side of the resonant sensor, thedependency function between the sensor parametersand thematerial properties isnot obviousandneedsto be characterized and calibrated by experiments orcomputationalmethods. [10]


IN THE LABORATORY

The laboratory is equipped with measurementinstrumentation, tools, hardware, material resources,and various means of fabrication. The primaryinstruments used in experimental SansEC sensorresearchare radio frequencyandmicrowavenetworkanalyzers.The laboratoryhasthreenetworkanalyzersthat together cover frequency ranges from10 kHz to50 GHz. Figure 5 illustrates an Agilent E8364CPerformance Network Analyzer (PNA) systeminterrogating aSansEC sensor. ThePNA is a vectornetwork analyzer capable of generating andmeasuringthefrequency,magnitude,andphaseofanelectromagneticwave.Itisshownhereconnectedtoanear-fieldsquareloopantenna. [11] Theloopantennaisusedto illuminateor“ping”theSansECsensorwithabroadband frequency sweep from the networkanalyzer and then “listen” or receive the returnresponsefromtheSansEC.

Fig. 5. RF Network Analyzer connected to LoopAntennailluminatingaSansECSensor.

Thetransmittedenergyfromthe loopantennaexcitesresonantmodesinthesensor.Theresonantresponsefrequency is usually comprised of a fundamental andassociatedharmonicsrelatedtothesensorgeometry.Thesensoriscoupledtotheloopantennathroughthemagnetic near field and the induced current (totalcurrent) in the sensor will have the maximummagnitude near its resonant frequency. At resonantstate, the energy radiation of the sensor reaches itsmaximumvalueandsodoestheenergytransferredtoheat by the intrinsic resistance of the sensor trace.The resonant frequency of thesensor is indicatedbytheminimumamplitude of the reflection coefficient atthe terminals of the loop antenna. The response ismeasured by the network analyzer as a return lossscatteringparameter.ThereturnlossS-parameter S11is the reflection coefficient and is displayed on thenetwork analyzer as a distinct amplitude resonancesignatureasafunctionoffrequency.

SANSEC SPECTROMETER

The SansEC reflectance spectrometer is anarrangementofanarrayofmultipleopencircuitplanarresonant spiral sensors each operating at a uniquefundamentalfrequency.

Fig.6. SansECSensorsofuniquefrequencies.

Thearrayisintendedtoeitherbebroughtintocontactwith an extracted geologic core sample or to bebrought into contact with the material surface of thewall of a down-hole bore hole. Theway inwhich thesensor array is brought into contact with the testsample relies on getting electromagnetic waves to travelfromtheSansECSensorsintotherocksample.As the incident electromagnetic energy couples intothematerialmediumchangesoccur inamplitudeandphase that are directly related to the electricpermittivity, magnetic permeability,andconductivity ofthe coresampleormineralformation. Becausethereisa large contrast between the permittivity of rock andthe baseline permittivity of Free Space, thespectrometer tooleasilymakesadirectmeasurementofthereflectionpropertiesoftherock.

Fig.7. Proof-of-ConceptSensorongeologiccoresample.


Depending on the nature of the rock, thepermittivity,permeability, and conductivity differ for differentfrequenciesoftheincidentelectromagneticwaves.Forthe proof-of-concept tests, sensor 1, sensor 2, andsensor 3 were placed in the exact same position ontheflatsmoothsurfaceofthesemi-cylindricalgeologiccore sample simulating a linear array of sensorsscanningacrossthesample.Thisallowedformultipleinterrogation frequencies to couple into the rocksample. The scattering of multi-frequencyelectromagnetic energy from grain surfaces orrefracted through mineral particulates and layerscausesdielectricdispersion.Dispersionallows for thetaking inaccountof themolecularmaterialpropertiesthat constitute a mineral formation. With multiplefrequencymeasurementsthephenomenaofdielectricdispersion may be observed as scattering parameterspectrarepresentativeof theuniquecharacteristicsofthe test sample and relevant to the geologicalidentificationof thecorematerialsandformationsfromwhichthesamplewasextracted.

Response Characteristics of Geologic Cores

Sixuniquecoresamplessimilar insizeandshape tofigure7weremeasuredusing the threesensormulti-frequency SansEC spectrometer technique. All sixexperiments produced repeatable and promisingresults. Two reflection spectra for two different coresamplesareshowninfigures8and9.

Fig. 8. S-Parameter plot depicting ReflectionResonancesforGeologicCoreSample157491.

The initial laboratory experiments proved that aSansEC sensor placed on a geological materialsurface is capable of determining physicalcharacteristics and qualities about the materialuponwhichitisplaced. [7][8][9][10][11]

Fig. 9. S-Parameter plot depicting ReflectionResonancesforGeologicCoreSample154192.

The detection of the differences in frequency andamplitude of the induced currents within a materialsubstrate offers a means of identifying geologicalspecimens.

EXTENDED SANSEC SPECTROMETER

An array of SansEC sensors of unique frequenciesmayalsobearrangedonthesurfaceofaboretool.Ifarrangedinalinearfashionalongthelongitudinalaxisofacylindricalpenetrator,thesensorscouldsensethedielectric reflectance profile of the wall surface as afunctionofdepthas the toolsliddown theborehole.The illustration in figure 7 depicts such a devicewithsevenunique frequencySansECsensorsattached to formthemulti-frequencyspectrometerarray.

Fig. 10. Illustration cylindrical bore-holepenetrator.


PlanetaryThermalPenetratorsare methodsofdrillingusing ahotdrilltiptomeltice,ratherthancutthroughit. These deviceshavebeen testedinAntarctica.

Fig.11. Cylindricalthermalmeltprobe penetrator.

Manyareas of our solar systemare ideal candidatesfor thermal drill exploration. A thermal melting probecould penetrate ice in remote Earth locations, Mars,Europa or other equally remote exploration targets.Shownbelowinfigure12isaconceptualrenderingofa NASA thermalmelt probeabout tobegina journeydeep through the ice of Jupiter’s moon Europa on aquest topenetrate through to thehidden liquidoceanbeneath.

Fig.12. Conceptual thermalmeltprobe lander

A SansEC spectrometer would be implemented andintegrated into the exploration probe in a fashionsimilar to that illustrated in figure10asan instrumentfor acquiring the dielectric geological profile of theformations between the surface and the sub-surfaceocean.

COMPUTATIONAL EXPERIMENTS

Computational Electromagnetic Modeling (CEM) andsimulation isaveryuseful researchanddevelopmenttool.Byusingiterationandfeedbacktomodelphysical

hardware and then validate the CEM against thatphysical hardware by means of experimentalmeasurements, a better and more economicalhardware product can be realized. Simultaneously amorerobustdesigntoolisdevelopedthatwillenhancethenextstageofdesigncomplexity.Asunderstanding and confidence in the computational model and theexperimental measurement increases, the ability tointegrate sub-elements into larger systems occurs. Inthis manner we undertake steps in designing,integrating, and understanding SansEC resonantsensors both as computational models and physicalhardware components. We use FEKO,"FEldberechnungfürKörpermitbeliebigerOberfläche"or "Field Calculations for Bodies with ArbitrarySurface",acommercialcomputationalelectromagneticsoftware package tomodel our open-circuit resonantsensors. [11] [12]

Themodelingeffortenablesanintuitiveunderstandingof the electromagnetic field penetration interactionswith simulated geological formations and coresamples. The insights gained are used to inform theexperimental design and testing on actual geologicalcoresamples.

THE ROLE OF TIPPER

The concept of the mathematical relationship of thevertical tohorizontal field, subsequently being named‘Tipper’ by Keeva Vozoff, has been around andconceptually well understood since the early 60’s.However,mostoftheacademicworkwasnotblessedwith largenumbersofexperimentaldatasitestoworkwith; and the focus was not really directed towardinterpretation experience. Dr. Vozoff was one of theearlyEMgeophysics academics andwas involved inearly3Dnumericalmodelingworkappliedto MagnetoTelluric (MT). There were others at MIT that wereinterested in MT, and was involved in somecommercialattemptsandcollaborations,paststudentsof Dr. Ted Madden, including Dr. Charlie Swift. Asacademics, the group lacked the vital ingredient ofdeployment and the special techniques required bysound field practice and data acquisition ofMTdata.They were familiar with the Tensor mathematicsrelatedtoMTresponseandEMmodelingtechniques,but those early days were prior to the availability ofcomputer capability andservedasaprincipal limitingissue.

ItwaswellaftertheHztohorizontal Hrelationshipwasrecognized that Keeva came up the name “tipper”. Itneeded a name, and, as this seemed somewhatdescriptive, itstuck. Thatistosay,Keevawasnottheone who actually discovered the Tipper


concept. CharlieSwift,atMITwas the first topublish(in his doctoral thesis) the full Tensor mathematicsdescribingtheMTresponse,includingHztohorizontalH. Thereare,tobefound,severalratherdifficultandpossibly, more cumbersome mathematical means toexpress the field responses, but the Tensorexpression, together with relations for coordinaterotation,proved tobeasubstantialcontribution to thestudyandtreatmentoftheMTresponse. Thisdidnotrevealanynewbasicknowledgeoftherelatedphysicsand EM field theory, as being now studied by Dr. Francis Bostick, and his team. This, however, did provide some new and useful means to view andassesstheMTdata.

Subsequently,workbyDr.DarrellWord,drewupon the CharlieSwiftTensortreatment,toexaminesomeoftheTensor response properties, including coordinaterotation behavior and added someuseful implicationsabout the natureof the target structure. Inparticular,the elliptical properties of the loci of the Tipper andImpedance complex components. This permitsinteresting and useful general properties of the targetstructure (especially strike and dip, among other items). There are special theoretical structuralanomalies and symmetries that yield useful insightsinto revealing the cause of a measured response,especially the nature of the dimensionality. Such behavior as the ellipticity and elliptical orientation forTIPPER, certainly provide for innovative intuitiveresults of the interpretation by the current iteration ofTIPPERbytoday’sTDDInternational team,headedbyByronArnason.

Fig. 13. Byron Arnason and the revolutionary tripod-mounted ROVERthatenables theHzhighproductiondetectionforlongdistanceTIPPERsurveys.

The work provided by Dr. Darrell Word, however,produced several survey sites employing full 5

component measurements, including Tipper andrelatedparameters.Therewereofcourseattemptstoassociate the Tipper behavior with the geology, withfairly interesting and satisfying results. Then throughthethousandsofcommercialMTsitesmeasuredbyanearly user of TIPPER, similar techniques wereemployed,alwayscomputingandmakingsomeuseofTIPPER in these interpretations. In all cases, thisexperience covered essentially the entire frequencyband (except that the high end was usually nomorethan10Hz).

TherewasmuchuseandexperiencewithTIPPER tofollow,andan essential point here, is that inmostallcases,thesitedensitydidnottendtobeashighasforthe higher frequency banduse, asneeded forminingexploration, etc.; and, the availability of good, useful3D modeling capability did not exist; and, of course,themain focus for theMTwork was to interpret andmap the conductivity obtained from the impedancefunction. TIPPER was then mostly used (in a morecrude hand-wavingmanner)tohelpponderthegeneralshape of the conductivity structure.Although TIPPERwasrecognizedandtreatedasanessentialcomponentoftheobservableMTresponseateach measuringsite,itwasnotusedbyitselfasanindependentsurveytool.What is important here is that the current iteration ofTIPPER,providedandpioneeredbyourgroup,notablyby our Byron Arnason (one of the original patent co-authors) brought to us an impressive innovation androvingHzcoilmethodology,with thecleverpendulummountandrapiddeploymentanddataacquisition;andeventually, an enormous quantity of experience andexperimentaldata.Therearenowbetter3Dmodelingresources, but the biggest improvement in TIPPERsurveyinghasarisenfromournewrefinedsystemandthe rather enormous experience in recording andobserving and interpretingTIPPERdata ina geologicenvironment.

NewworkhasprovenTIPPERtonowprovideawealthof useful information about the strike and diporientationoftheanomalyandthenatureandaspectsof its dimensionality. Some useful illustrations canconveythis.Theinherentskineffectintheconductivemedium provides useful insight about relative depthand spatial orientations, although values of relatedconductivity (measurementsorestimated)areneededformorerefineddepthdetermination.

Althoughthe'newwork'isimportantandsubstantial,itdidnotamount to recognitionofhow to identify strikeand dip information and the nature ofdimensionality. The properties of the skin effectrelationship to depth is not a new idea in regard to TIPPER.One newandhighlyimportant point,howeveristhatourByronArnasonhastogained andeffectively


used experimental insights and intuitions towardapplying the said information in the real worldexplorationproblems ashavebeenexperienced. Thishas been accomplished via the combination of fieldpractice,EMknowledgealongwithfamiliaritywithlocaland regional geology and exploration techniques.

Estimationofstrikeanddip(and depth)thereto,aswellas the qualitative degree of three-dimensionality areproperties that indeed were almost always employedbyothers;however,itwasobviousthatmorescientificand practical applications were required, especiallywith respect to depiction for 3D cases. This requiredgreater focus, experience and better resources. Ingeneral, as to 3D geometry, precise and confident interpretations require some means of quantitativelymodeling the problem. Better resolution and resultsarebecomingreality.

Finally, it is important to recognize the benefit of anindependent Reference H station to observe thesurface horizontal H field (primary field) in anindependent noise environment. This is not afundamentalessential to theTIPPERmethod,but it isusually of substantial benefit in reduction ofmeasurement noise. This technique, first developedand used commercially byGeotronics Corporation, isdoneinthedataprocessingviacrosspowerspectrumstacking between the survey data and the Referencesite data, depending on the notion that the desiredHsignals are precisely correlated and the respectivenoisesareindependent.

TDD’s current methodology uses this approacheffectively.

FUTURE DEVELOPMENT

NASA has long been interested in geology forplanetaryscience.EarlyLunarAstronautsweretrainedin geology techniques and one of the last LunarAstronauts, Harrison Schmitt, was a professionalgeologists. AllApolloastronautswentthroughgeologyfield training to prepare them for collecting rocksamplesonthemoon.

The lunar samplesand data returned toEarth in the1960sand70’srevealedthatthemoonhas acomplexgeology.Still,asubstantialportionofthelunarsurfacehas not been explored, and a number of geologicalquestionsremainunanswered.Today,datafromlunarsatellite probe missions continue to add to ourunderstanding of the moon’s mineralogy,geomorphology, chemicalcomposition,andhistory.Eachmodern missionusesitsownuniquesuiteofinstruments to explore the moon. From thesecombinedexplorationslunarscientistsarefinding

Fig.14. AstronautCharlieDukeduringApollo16usingaboreholetoolforverticalprofilesamplesofthelunarregolith.

water,oxygen,andawealthofinterestingcompoundsembedded in the lunar surface and waiting to beexplored by future sampling missions. TIPPER andSansEC based instruments could play a role in thefutureexplorationsofEarth’smoon.

On Mars, most of our current knowledge about thegeology of the surface and sub-surface comes fromimages taken by orbiting spacecraft. Interestinggeological features such as avalanches, caves, andsuspectedlavatubeshavebeenspottedfromorbitbyhigh resolution imaging cameras. Inverted relieffeaturesin theshapeofstreamsare evidenceofwaterhaving flowed on the Martian surface in the distantpast.Researcherspropose thatsomeofthelayersonMarsare causedbygroundwaterrisingtothesurfaceinmanyplaces.Moreexcitinglythereisevidencefromrecentorbitalobservationsthatwaterinthe liquidstateiscurrentlyflowinginsubsurfacechannels onMars.

Onthegroundroversarenotintheimmediatevicinityto validate observations hinting at sub-surface liquidwaterflow. However, the CuriosityRoverhasused itsdrill tool to bore holes and acquire rock core samplefrom inside rock structures for testingof thechemicalconstituentsthatmakeup particularrocks.

Fig.15.CoresampleonMars.


ItisnotdifficulttoimagineSansECsensorsintegratedinto the drillsof groundbasedexploresonmars.Wecan even imagine SansEC spectroscopy sensorsincorporated into the wheels of future ground basedroversconstantlyacquiringatrailofRFspectroscopicdata as the vehicle rolls along the varying surface oftheplanet.

Thelatestnewsfromourroboticexploresinthe outer solar system is confirming that several moons ofJupiter and Saturn have compelling geologicalfeaturesandformationsthatmakeconvincing casestoinstrument the next scout and flagshipmissions withelectromagnetic sensors capable of detecting,characterizing, and mapping, sub-surfacegeomorphologies. Magnetometer data fromtheGalileospace probe provides evidence of an induced dipolemagnetic fieldconsistent with thepresenceofasaltyocean onEuropa. Jupiter’smagneticfieldisinclinedtoits rotation axis, and the four Galilean satellitesCallisto, Europa, Io, and Ganymede experience atime-varying magnetic field. Europa responds to thisfield as a nearly perfectly conducting sphere,generating electrical currents that create a magnetic field that opposes and cancels the time-varyingcomponent in its interior.This data alongwith,gravitydata,andobservedsurface featuresstronglysuggestthatEuropahasanoceanat least several kilometersthickbeneathitsiceshellandthattheoceancontainsconductive electrolytessuchassulfatesoralkalisalts.A world that shows strong evidence for an ocean ofliquidwater beneathitsicycrust couldhostconditionsfavorableforlife. [13][14][15]

Fig.16.ConceptualizationofEuropa’ssubsurfaceocean and geomorphologicalfeatures.

CONCLUSIONS

TheSansECsensorandTIPPERrepresentourbeliefthat the combination of these innovations couldenhance science data returns of future explorationspacemissions. [16] These dedicated electromagneticsensors offerbaselinecomponentsthatcouldformthearchitecture of instrument systems to acquire betterdata and knowledgeofwhatlies beneaththesurfacesof terrestrial and extra-terrestrial terrains throughoutthesolarsystem.

ACKNOWLEDGMENTS

The authors gratefully acknowledge NASA’s AvSPAEST Project and the team members of NASALangley Research Center, George Szatkowski, LarryTicatch, Chuantong Wang, and Laura Smith. Weacknowledge special appreciation to the IndianaGeologicalSurvey and Personal Communications with ByronArnason,PresidentofJumboMiningCompany,and Vice-President of Technology, TDD InternationalB.V. t.b.e.EdwinKing, FormerPresident/CEO JumboMiningCorp,formerCEOofASOMAInstrumentsInc.,Dr. Darrell Word, former VP of Geotronics CorpMagneto Telluric manufacturer and surveyingcompany, Dave Hartshorn, Chief Geologist andManager, WUCC Copper Mines, Milford, Utah, and Blair Salisbury, Geophysicist with TexasGulf SulfurandCSM.

REFERENCES

[1] Clark, R. N., “Spectroscopy of Rocks andMinerals, and Principles of Spectroscopy”, inManual of Remote Sensing, Volume 3,RemoteSensingfortheEarthSciences,(A.N.Rencz,ed.)JohnWileyandSons,NY,p3- 58,1999.

[2] Clark, R.N., “Reflectance Spectra”, AGUHandbook of Physical Constants,178-188,1995

[3] Hippel A. R. Dielectrics and Waves. N. Y.:JohnWilley&Sons,1954.

[4] KremerF.,SchonhalsA.,LuckW.BroadbandDielectric Spectroscopy, Springer-Verlag,2002

[5] Volkov A. A., Prokhorov A. S., BroadbandDielectric Spectroscopy of Solids,RadiophysicsandQuantumElectronics,2003,vol.46,Issue8,p.657–665.


[6] Allen H. Meitzler, Ann Arbor, and George S. Saloka, Ford Motor Company, Dearborn, Mich, “Resonant Cavity Flexible Fuel Sensor and System,” U.S. Pat. No.5361035, Nov. 1, 1994.

[7] Ali Bitar, et al, Caterpillar Inc., Peoria, Ill,

“Linear Position Sensor Using A Coaxial Resonant Cavity,” U.S. Patent No.4737705, Apr. 12, 1988.

[8] Michael A. Fonseca, Mark G. Allen, Jason

Kroh, and Jason White, “Flexible Wireless Passive Pressure Sensors for Biomedical Applications,” Solid-State Sensors, Actuators, and Microsystems Workshop, Hilton Head Island, South Carolina, 2006, pp. 37-42.

[9] André Kurs, Aristeidis Karalis, Robert Moffatt,

J. D. Joannopoulos, Peter Fisher, and Marin Soljačić, “Wireless Power Transfer via Strongly Coupled Magnetic Resonances,” Science, Vol. 137, July 2007, pp. 83-86.

[10] Chuantong Wang, Kenneth L. Dudley, and

George N. Szatkowski EMSS, “Open Circuit Resonant (SansEC) Sensor for Composite Damage Detection and Diagnosis in Aircraft Lightning Environments”, AIAA Paper 2012-2792, in Proceedings of the 4th AIAA Atmospheric and Space Environments Conference, 25-28 June 2012, New Orleans, LA

[11] Laura J. Smith, Kenneth L. Dudley, George N.

Szatkowski, “Computational Electromagnetic Modeling of SansEC Sensors,” 27th International Review of Progress in Applied Computational Electromagnetics, Williamsburg VA, Mar. 27-31, 2011.

[12] EMSS, “FEKO Comprehensive

Electromagnetic Solutions User’s Manual”, EM Software & Systems-S.A. (Pty) Ltd. 32 Techno Avenue, Technopark, Stellenbosch, 7600, South Africa, 2011

[13] Hand, K. P., & Chyba, C.F. (2007) Empirical

constraints on the salinity of the europan ocean and implications for a thin ice shell. Icarus. 189:2, 424-438.

[14] Khurana, K.K., Kivelson, M.G., Hand, K.P.,

and Russell, C.T. (2009) Electromagnetic induction from Europa's ocean and the deep interior. In Europa. Eds. R. Pappalardo, W. McKinnon, & K. Khurana. Univ. of AZ Press

[15] Ronald Greeley, Christopher F. Chyba, James W. Head III, Thomas B. McCord, William B. McKinnon, Robert T. Pappalardo, Patricio Figueredo, “Geology of Europa” lasp.colorado.edu

[16] Stanley E. Woodard, "SansEC sensing

technology — A new tool for designing space systems and components," Aerospace Conference, 2011 IEEE, Big Sky,2011,pp.1-11.

TIPPER TECHNICAL REFERENCES (not cited herein): [a] V. F. Labson et.al.,"Geophysical Exploration

with Audio Frequency Natural Magnetic Fields," Geophysics Vol.50, No.4, Apr 1985,pp.656-664

[b] Vozoff, Keeva,,"Magnetotelluric Exploration," Geophysics Vol. 37 No. 1 Feb 1972, pp. 667

[c] Dr. Lynette Hart-Professor, UC Davis Dennis

Mills-President, Instrumentation and Measurement, Vol.59, No.12, Dec. 2010, pp.3206-3213.

Dr. Michael C. Mound, AIPG CPG-03195, is the CEO of TDD International Business Development. Dr. Mound is a Certified Petroleum Geologist (AAPG #1229), GSA Senior Fellow #1623930, Senior Member SME #4056760, and a member of several other professional organizations. Dr. Mound has been employed in the oil industry, the mining industry, analytical and plant automation, and has studied and worked for both US and European Geological surveys, and academic institutions. Michael Mound can be reached at [email protected].

Kenneth Dudley is a Senior Researcher at the NASA Langley Research Center with 30 years of federal service. He attended the USAF Academy, the NASA Engineering Apprentice Program, and the Peninsula Graduate Center. His expertise is in radio frequency spectrum and network analysis, and was on the Special Team investigating the crash of TWA Flight-800. His recent research involved novel wireless sensors and lightning strike protection for air vehicles. He has authored/coauthored many papers and holds multiple U.S. patents featuring applied aerospace electromagnetic technologies.


This abbreviated article summarizes the wedding of two distinctly unfamiliar technologies that have never been mated similarly. Michael and his colleagues welcome contact from readers who are sufficiently piqued to pursue the scholarly background that supports their findings, including some dozen separate patents and significant research. This introduction is intended to entice those who would like to know the derivations and connections used to test that which the authors are delighted to show - the science of how planetary geology and space missions can be mutually supporting.

core analysis combining mt (tipper) and dielectric...

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