Rainer'B.'Meinke'

Magne-c'Radia-on'Shielding'for'Space'Explora-on

EUCAS';2015''

Rainer'Meinke'

Rainer'B.'Meinke'

Human Space Exploration

2'

NASA$Core$Mission:$“Inves'ng)in)innova'ons)and)new)technologies)to)pursue)bold)missions)that)will)include!sending!humans!to!deep!space!to!compelling!des1na1ons!such!as!near3Earth!asteroids!and!Mars.”!

Rainer'B.'Meinke'

Heavy Lift Space Launch System (SLS)

3'

Explora3on$Beyond$Earth’s$Orbit:'•  Expand'reach'into'the'solar'system'aboard'Orion'spacecraG'•  SLS'NASA’s'first'explora-on;class'rocket'since'Saturn;V'•  Explore!deep3space!des1na1ons!including!near3Earth!

asteroids,!Lagrange!points,!moon!and!ul1mately!Mars.!!

Orion$Mul3=Purpose$Crew$Vehicle$(Orion$MPCV):$•  Carry'crew'of'up'to'four'astronauts'to'des-na-ons'at'or'

beyond'low'Earth'orbit'•  Europe’s'Automated'Transfer'Vehicle'(ATV)'will'provide'

propulsion,'power,'thermal'control,'as'well'as'supplying'water'and'gas'to'the'habitable'module.'

Rainer'B.'Meinke'

Space Radiation Hazard

4'

11=year$Solar$Ac3vity$Cycle:$Periodic'varia-on'in'number'of'solar'flares;'Billion;ton'clouds'of'electrified'gas'hurled'into'space'during'erup-ons.'Induced'changes'in'solar'system'plasma'density'affects'GCR'flux.''An13correla1on!between!GCR!flux!and!solar!ac1vity!for'energies'lower'than'10'GeV.'

Galac3c$Cosmic$Rays$(GCR):$ 'Mainly'protons'and'fully'ionized'atomic'nuclei'' ' ' ' ' 'HZE'(high'Z,'high'energy)'most'dangerous'component,'e.g.'Fe+26'

'Solar$Energy$Par3cles$(SEP):$'Protons,'electrons'and'HZE'ions'with'energies'ranging'from'a'few'

' ' ' ' ' 'ten'keV'to'about'1'GeV,'Solar!Wind!'

Ra-o'of'the'energy;integrated'cosmic'ray'fluxes'between'solar'minimum'and'maximum;''

Rainer'B.'Meinke'

Solar Eruptions

5'

NASA's$Goddard$Space$Flight$Center:$Genna$Duberstein'(USRA):'Lead'Producer'Tom$Bridgman'(GST):'Lead'Data'Visualizer'Karen$Fox'(ASI):'Writer'

Earth'

Rainer'B.'Meinke'

Radiation Dose Definitions

6'

Absorbed$Dose:$ $Amount'of'energy'deposited'by'ionizing'radia-on:''1Gy!=!1!Joule/kg!' ' ' 'Any'type'of'radia-on,'does'not'include'biological'effects'

Equivalent$Dose:$ $Absorbed'dose'weighted'with'biological'impact'of'radia-on'type'

HT!=!WR!DT,R!!!![Sievert];!!!!(stochas1c!health!risk)!WR:''Weigh-ng'factor'for'radia-on'type'R'(W'for'gamma'ray'='1)'DT,R:'Absorbed'dose'delivered'by'radia-on'type'R'over'-ssue/organ'T'

Effec3ve$Dose:$ $Summa-on'of'-ssue'equivalent'doses'weighted'with'appropriate'' ' ' ' '-ssue'weigh-ng'factors'

E!=!∑!WT!HT!!!![Sievert]!WR:''Weigh-ng'factor'for'radia-on'type'R'DT,R:'Absorbed'dose'delivered'by'radia-on'type'R'over'-ssue/organ'T'

1!Sv:!!!!!!!!!!!!!!!!!5.5%'chance'of'developing'cancer'50!mSv/year:!Occupa-onal'exposure'limit;'maximum'of'100'mSv'in'consecu-ve'5'years'1!Sv:!!!!!!!!!!!!!!!!!Maximum'allowed'radia-on'exposure'for'NASA'astronauts'over'their'career'

Rainer'B.'Meinke'

NASA Space Radiation Risk Assessment

7'

•  NASA'limits'astronaut'exposures'to'a'3%'risk'of'exposure;induced'death'(95%'confidence'intervals'in'the'projec-on'model).'

'

•  Experimental'studies'have'shown'that'HZE'nuclei'produce'both'qualita-ve'and'quan-ta-ve'differences'in'biological'effects'compared'to'terrestrial'radia-on.'

•  Large'uncertain-es'in'predic-ng'exposure'outcomes'to'humans.''

Data:$Radia3on$Assessment$Detector$$Mars$Science$Laboratory$–$Curiosity$Rover$

•  Silicon'detectors'and'a'cesium'iodide'detector'measure'high;energy'charged'par-cles.''

•  Signal'processor'analyzes'the'pulses'to'iden-fy'high;energy'par-cles'and'determines'their'energies.''

•  Iden-fy'neutrons,'gamma'rays,'protons,'alpha'par-cles'and'heavy'ions'up'to'iron.'

Unprotected!astronauts!would!receive!radia1on!dose!of!0.7!Sv!132!mSv/day!in!space!

Rainer'B.'Meinke'

Dosimetry Comparison

8'

Chiara'La'Tessa'

Rainer'B.'Meinke'

Micro-Meteorite Protection

Micro-Meteorite Fluence Models for Solar System:

•  The damage capability of micro-meteoroid depends on their mass, velocity (7-10 km/sec), density, and angle of impact.

•  The physical response of an impacted structure depends on the material, thickness, temperature, stress level, and the number and spacing of the plates (including shielding) composing the shielding.

•  Based on models of the micro-meteoroid fluence and calculations of the number of impacts that can lead to failure, the degree of damage can be estimated and appropriate design or operational measures need to be implemented.

Protection: •  Multi-layered Systems of Kevlar (similar to MLI) •  Layer spacing important parameter (spread debris before next impact)

9'

Rainer'B.'Meinke'

Passive versus Active Shielding Needed

10'

Shielding'Thickness'[g/cm2]'

Required'

===$Passive$Shielding$Performance$===$

Rainer'B.'Meinke'

Active Magnetic Shielding Proposed

11'

Doughnut;shaped'manned'spaceship,'pictured'near'Mars,'wards'off'lethal'solar'protons'(curved'white'trails)'with'huge'built;in'magne-c'coil'(5'Tesla).'

By:''Dr.'Wernher'von'Braun'Director'of'NASA’s'George'C.'Marshall'Space'Flight'Center,'Huntsville,'Ala.'

Popular'Science'–'Jan'1969'Page'98'

Rainer'B.'Meinke'

ARSSEM Project

12'

12$Double=helix$Dipole$coils$surrounding$spaceship$habitat$(∫BdL$=$4$Tm,$AML$Coil$Design)$

Ac3ve$Radia3on$Shielding$for$Space$Explora3on$Missions$$

R.'Bapston'et'al,'INFN'Perugia.'Final'Report'ESTEC'Contract'N°4200023087/10/NL/AF'

Rainer'B.'Meinke'13'

Field'Enhancement'between'coils' Strong'Arrac-ve'Forces'between'Neighboring'Coils'

Fy$=$=28$MN$per$Coil$

High$Pressure$Ac3ng$on$Habitat$

ARSSEM

Rainer'B.'Meinke'

Space Radiation Superconducting Shield

14'

Union'European'Seventh'Framework'Program'

Rainer'B.'Meinke'

Toroidal Magnetic Shield

15'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

Toroidal Magnetic Field Shielding

16'

Bending$Radius:$R)[m])=)P)[GeV/c]/(0.3)q)B)[T])

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

Continuous Toroid Configuration

17'

Rainer'B.'Meinke'

120-Segments Toroidal Coil

18'

Origins'of'secondary'par-cles'Large'contribu-on'to'GCR'doses'

Increased'number'of'coils'for'more'uniform'force'distribu-on'on'habitat'120'Coils'providing'integrated'flux'(∫'BdL)'of'8'Tesla'meter''

Rainer'B.'Meinke'

Main Toroidal Coil Parameters

19'

Columbus'Superconductor'

Rainer'B.'Meinke'

Quench Protection

20'

1320!Subdivisions!

•  Toroidal'magnet'subdivided'in'n'sub;coils'(number'tbd)'•  Normal'opera-on:'Switches'between'coils'are'superconduc-ng'•  ' ' I)=)700)A)•  Dump'sequence:'Switches'are'warmed'up'to'normal'conduc-ng'state'•  Required'energy'to'ac-vate'switch'500'J/dble'pancake'

F;P.'Juster'and'C.'Berriaud'

Rainer'B.'Meinke'

Shielding Efficiency Simulation

21'

SR2S$Simula3ons:$INFN'–'Perugia:' 'F.'Ambrogini,'W.'J.'Burger'TAS;1: ' ' 'M.'Giraudo,'M.'Vuolo'

NIAC$Simula3ons$(see$later):$INFN'–'Perugia:' 'W.'J.'Burger'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

Particle Interactions with Shield

22'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

Multi-Toroid 3-Coil Configuration

23'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

“Pumpkin” Field Configuration

24'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

Thermal Environment

25'

Permanent$Heat$Loads:$

Rainer'B.'Meinke'

Thermal Radiation Shield

26'

Cryogenic$Design/Protec3on$

Rainer'B.'Meinke'

Estimated Shielding Efficiency

27'

~20%'

~23%'

M.'Voulo'M.'Giraudo'

Rainer'B.'Meinke'

MAARSS

28'

•  Shayne Westover, PI – NASA JSC •  Rainer Meinke - Advanced Magnet Lab, Inc. •  Shashi Manikonda - Advanced Magnet Lab, Inc. •  Shaun Nerolich – Capstone •  Scott Washburn – University of Colorado, Boulder •  Roberto Battiston – INFN, University of Perugia, Italy •  W.J. Burger, Dipartimento di Fisica Perugia, Italy

NASA Innovative Advanced Concepts

Magnet)Architectures)and)Ac've)Radia'on)Shielding)Study'

Technology$Roadmap$Development$==$SC$Magnets$for$Future$Space$Applica3ons$==$

Rainer'B.'Meinke'

Ultra-Lightweight, Expandable Magnets

29'

==$Paradigm$Shi\$in$Magnet$Technology$Needed$=='

Conven3onal$normal$and$superconduc3ng$magnets$are$too$heavy$for$space$applica3ons!$

Deep$Space$facilitates$applica3on$of$superconduc3vity$•  Low'ambient'temperature'(~2.8'K)'•  Ultra;high'vacuum'(~'10;17'Torr)'

Expandable$coils$enable$launch$of$very$large$magnets$into$space:$•  Achieve'required'∫B'dl'with'very'large!coils,'but'modest!field!strength!(1'T'to'1.5'T)'•  Modest'field'strength'limits'forces'on'conductors'and'requirements'for'coil'support'

structure'•  Build;up'of'magne-c'pressure'during'coil'excita-on'causes'automa1c!coil!expansion!'''

Rainer'B.'Meinke'

General Design Goals/Requirements

30'

•  High$Temperature$Superconductors$!$Enable$Passive$Cooling:$•  Thermal'shielding'required'(sun,'planet,'spaceship'habitat'(300'K)'•  High'thermal'conduc-vity'of'conductor'support'blankets'•  Avoid'hot'spots''

•  Very$High$Opera3onal$Current$(40=50$kA):$$•  Limit'coil'inductance'and'facilitate'quench'safety''

•  Persistent$Mode$Opera3on:$•  “Superconduc-ng”'splice'joints'needed''•  Superconduc-ng'flux'pump'for'charging'of'coils'•  Slow'charging'of'coils'needed'to'avoid'quenching'of'superconductor'•  Power'generated'by'solar'panels''

•  Coils$Consis3ng$of$Thin$Tape$Conductor$(50=100$mm$wide):$•  Conductor$remains'opera-onal'when'punctured'by'micro'meteorites'•  Sandwiched'between'high'strength'fiber'blankets'''

•  Ultra$Lightweight$Coils$!$Reduce$Par3cle$Showers$of$Incoming$GCR$Radia3on$

Rainer'B.'Meinke'

Conductor Choice

31'

Low Temperature Superconductors (LTS): " Required cooling too complex " Expandability excluded (low minimum quench energy)

MgB2: # Lightweight conductor

" Operational temperature of 10-15 K (complex cooling system) " Expandability excluded (very brittle conductor)

ReBCO (2G Conductor): # Operation near 40 K possible for needed current and field # Relatively large minimum quench energy # Expandability of coils experimentally proven

Rainer'B.'Meinke'

Expandable Superconducting Coil

32'

•  YBCO'tape'conductor's-tched'to'silk'fabric''•  Rota-on'of'central'shaG'folds'coil'similar'to'umbrella'•  Coil'equipped'with'voltage'taps'and'quench'detec-on'system''

Prepara-on'of'Cryogenic'Test'

Background'Field'Coil'

Rainer'B.'Meinke'

Cryogenic Test of Foldable Coil

33'

Test$Coil$$Voltage$Taps$

Opening$Coil$

Background$Field$Voltage$Taps$

Closing$Coil$

No$Quench$Ini3ated!$

Opening/closing$3me$~$1$sec$

Rainer'B.'Meinke'

Potential Shielding Coil Configurations

34'

Extensive'set'of'poten-al'coil'configura-ons'analyzed'and'compared'Straight$solenoids$selected$as$best$solu3on$

Rainer'B.'Meinke'

6+1 Shield Coil System

35'

NIAC$Phase=1$Baseline$Design:$

Rainer'B.'Meinke'

Artist View of Spacecraft with Shielding

36'

Rainer'B.'Meinke'

2G Conductor Performance

37'

Very high critical currents in 2.2 µm thick 20% Zr-added tapes over a broad temperature range

“$4X$Ic$–$wire”$developed$in$ARPA=E$REACT$program'

Current$State=of=Art:$50=mm$wide$Tape:$5000$A$*$50/12$~$20$kA$$

!$Addi3onal$Factor$of$2=4$$$$$$$$$$$$$$$$in$conductor$performance$required$

Other$Poten3al$Solu3ons:$•  ReBCO$layer$on$both$sides$of$tape$$•  Roebel$Cable$$

Rainer'B.'Meinke'

Superconducting Splice Required

38'

Soldering'joint'resistance:''>'2×10;8'Ω !'Heat'load'per'joint:'>'30'War

Conven3onal$Solder$Joint:$Impossible'to'establish'a'superconduc-ng'closed'loop'for'persistent'current'mode'opera-on'in'YBCO'magnet'and'flux'pump'opera-on.''Goal/Requirement:$Joint'resistance'≤'1×10;12'Ω !'Heat'load'per'joint:'<'2×10;3'War''

Rainer'B.'Meinke'

Procedures for Fabricating SC Joint

39'

Rainer'B.'Meinke'

Quench Detection/Protection

40'

Conven3onal'Wisdom:$$Quench'protec-on'of'large'magnets'consis-ng'of'ReBCO'conductor'difficult'or'impossible''Quench$Detec3on:$•  Voltage'tap'response'too'slow''•  Fiber'op-c'sensors**)'co;wound'with'conductor'detect'temperature'changes'anywhere'in'

coil'winding'solve'this'problem'$Quench$Protec3on:$•  Switch'large'frac-on'of'coil'winding'to'normal'conduc-ng'state'in'shortest'possible'-me'•  CLIQ'system'successfully'test'at'CERN'for'large'quadrupole'magnets+)'

•  Ini-ate'AC'current'ringing'in'coil'in'case'of'quench'•  Resul-ng'AC'losses'in'superconductor'heat'complete'coil'

•  Eliminate'coil'insula-on'!'Conductor'copper'cladding'forms'con-nuous'passage'for'current'discharge++)'

+) 'IEEE'TRANSACTIONS'ON'APPLIED'SUPERCONDUCTIVITY,'VOL.'24,'NO.'3,'JUNE'2014,''New,'Coupling'Loss'Induced,'Quench'Protec-on'System'for'Superconduc-ng'Accelerator'Magnets,'E.'Ravaioli,'et'al.'

++) 'IEEE'TRANSACTIONS'ON'APPLIED'SUPERCONDUCTIVITY,'VOL.'21,'NO.'3,'JUNE'2011,''HTS'Pancake'Coils'Without'Turn;to;Turn'Insula-on,'Seungyong'Hahn,'et'al.'

**) 'NCSU'Development,'J.'Schwartz''

Rainer'B.'Meinke'

Habitat Field Compensation Coil

41'

Compensa3on$Coils:$$

•  Solenoidal'coil'concentric'to'habitat,'coil'does'not'need'to'expand'•  Compensate'return'flux'of'main'coils'through'habitat'•  Cryogenic'system'housed'in'habitat'(small'magne-c'field)'•  Thermal'shielding'between'habitat'(~290'K)'and'shielding'coils'•  Conven-onal'cryostat'like'MRI'coil''

-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 50000

5

10

15

Position [mm]

Fiel

d [G

auss

]

Field along Habitat Axis at R = 0.0 [mm]

Diameter'of'Compensa-on'Coil'''''''''''' '7.20'[m]''Length'of'Compensa-on'Coil:''''''''''''' '15.8'[m]''Current'in'Compensa-on'Coil:''''''''' '10220'[A]''Mean$Field$in$Habitat:$$$$$$$$$$$$$$$$$ $ $10.3$[Gauss]$$

Pitch'length'decreases'towards'coil'ends'Similar'to'MRI'Gradient'Coils'Further$op3miza3on$possible$

Rainer'B.'Meinke'

Coil Strong Back

42'

Coil'Fully'Expanded' Coil'Folds'around'Strong;back'

Coil'Folded'and'Stacked'for'Launch'

Lightweight'coil'support'structure'Counteract'axial'forces''

Rainer'B.'Meinke'

Forces Acting on Shielding Coils

43'

Coils$behave$like$6$perm.$magnets$$$$!$strong$repulsive$forces$

'Inter;coil'support'structure'needed''Forces'act'on'conductors'that'are'bonded'to'flexible'fabric'liner''Forces'not'uniform'over'length'of'solenoids''Possible'bending'on'strong'back''Distor-on'of'‘ideal’'cylinder'geometry'of'each'individual'coil'

Rainer'B.'Meinke'

Forces Acting in Shielding Arry

44'

Resul-ng'Radial'Force:''~'9'MN'on'each'individual'solenoid''

-1.5 -1 -0.5 0 0.5 1 1.5

x 104

-1.5

-1

-0.5

0

0.5

1

1.5x 104

Habitat

Forces Acting on Indicated Test CoilAxial: 0.00 [MN]

Horizontal: 8.93 [MN]Vertical: -0.00 [MN]

Inside'bulging'of'individual'coils'at'contact'point.'Remaining'circumference's-ll'outside'directed'forces.'

Coil$shapes$are$changing$in$array$configura3on.$Itera3on$needed$to$determine$Shapes$and$configura3on$

Rainer'B.'Meinke'

Forces versus Axial Position

45'

-2000 0 2000 4000 6000 8000 10000-1.5

-1-0.5

00.5

11.5

x 104

-1.5

-1

-0.5

0

0.5

1

1.5

x 104

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Development$of$strong$axial$forces$near$coil$ends.$Solenoids$have$tendency$to$contract$in$axial$direc3on.$Appropriate$support$structure$needed.$

Rainer'B.'Meinke'46'

Forces'in'Axial'Direc-on' Forces'in'Radial'Direc-on'

Coil'distor-ons'of'up'to'30'cm'near'coil'ends'

Rainer'B.'Meinke'

Fringe Magnetic Field

47'

50$m$ 50$m$

20$m$

•  Large'fringe'magne-c'field'outside'of'array'•  Effect'on'shielding'efficiency'•  Breaks'speed'of'approaching'capsule'(posi-ve)'

Distance'to'Habitat'Center:'20'm,'Radius'20'm''

Approaching'Orion'SpacecraG'

10'm'

800'G'

Rainer'B.'Meinke'

Shield Efficiency

48'

Rainer'B.'Meinke'

Improve Shielding Efficiency

49'

Rainer'B.'Meinke'

Optimized Tilted Windings

50'

Remaining$Issues$with$6=around=1$Shielding$Coil$Design:$•  Large'forces'ac-ng'between'coils'undesirable'•  Direct'contact'between'coils'imprac-cal'

!$Tilt$Coil$Windings$and$Introduce$Space$between$Coils$

Forces$between$coils$can$be$significantly$reduced$–$Shielding$field$present$in$gaps$

Rainer'B.'Meinke'

Summary

51'

•  Human'missions'to'near;Earth'asteroids'and'to'Mars'are'a'declared'goal'of'ESA,'NASA'•  Space'is'hos-le'environment'(SPE,'GCR,'HZE'nuclei,'micro'meteorites)'''•  Astronaut'exposure'needs'to'be'limited'(≤'3%'risk'of'exposure;induced'death)'

•  Combina-on'of'ac-ve'and'passive'radia-on'shielding'needed'•  Surround'spaceship'habitat'with'magne-c'fields'with'largest'possible'∫B'dL'•  Superconduc-vity'cons-tutes'enabling'technology'

•  Low'ambient'temperature'(few'Kelvin)'and'ultra;high'vacuum'facilitate'applica-on'of'superconduc-vity''

'•  Two'very'different'concepts'for'superconduc-ng'magnet'systems'developed'•  Both's-ll'require'substan-al'R&D,'but'seem'feasible'given'sufficient'funding'

•  Both'concepts'have'advantages'and'disadvantages'•  More'work'needed'to'select'the'“winning”'technology'•  Combina-on'of'both'technologies'might'be'best'

•  However,'human'explora-on'of'the'solar'system's-ll'be'risky''''

Rainer'B.'Meinke'

Rectifier Type Flux Pump

52'

Flux'Pump'Principle'

Rec-fier'Type'Flux'Pump'

Persistent'Mode'Opera-on'and'Superconduc-ng'Splices'Required'