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Course Outline1. Introduction. Spacecraft Subsystem Design, Orbital

Mechanics, The Solar-Planetary Relationship, SpaceWeather.

2. The Vacuum Environment. Basic Description –Pressure vs. Altitude, Solar UV Radiation.

3. Vacuum Environment Effects. Solar UVDegradation, Molecular Contamination, ParticulateContamination.

4. The Neutral Environment. Basic AtmosphericPhysics, Elementary Kinetic Theory, HydrostaticEquilibrium, Neutral Atmospheric Models.

5. Neutral Environment Effects. Aerodynamic Drag,Sputtering, Atomic Oxygen Attack, Spacecraft Glow.

6. The Plasma Environment. Basic Plasma Physics -Single Particle Motion, Debye Shielding, PlasmaOscillations.

7. Plasma Environment Effects. SpacecraftCharging, Arc Discharging.

8. The Radiation Environment. Basic RadiationPhysics, Stopping Charged Particles, Stopping EnergeticPhotons, Stopping Neutrons.

9. Radiation in Space. Trapped Radiation Belts, SolarProton Events, Galactic Cosmic Rays, HostileEnvironments.

10. Radiation Environment Effects. Total DoseEffects - Solar Cell Degradation, Electronics Degradation;Single Event Effects - Upset, Latchup, Burnout; Dose RateEffects.

11. The Micrometeoroid and Orbital DebrisEnvironment. Hypervelocity Impact Physics,Micrometeoroids, Orbital Debris.

12. Additional Topics. Design Examples - The LongDuration Exposure Facility; Effects on Humans; Modelsand Tools; Available Internet Resources.

InstructorDr. Alan C. Tribble has provided space environments effectsanalysis to more than one dozen NASA, DoD, and commercial

programs, including the International SpaceStation, the Global Positioning System (GPS)satellites, and several surveillance spacecraft.He holds a Ph.D. in Physics from theUniversity of Iowa and has been twice aPrincipal Investigator for the NASA SpaceEnvironments and Effects Program. He is theauthor of four books, including the course text:

The Space Environment - Implications for Space Design, andover 20 additional technical publications. He is an AssociateFellow of the AIAA, a Senior Member of the IEEE, and waspreviously an Associate Editor of the Journal of Spacecraftand Rockets. Dr. Tribble recently won the 2008 AIAA James A.Van Allen Space Environments Award. He has taught a varietyof classes at the University of Southern California, CaliforniaState University Long Beach, the University of Iowa, and hasbeen teaching courses on space environments and effectssince 1992.

Who Should Attend:Engineers who need to know how to design systems with

adequate performance margins, program managers whooversee spacecraft survivability tasks, and scientists whoneed to understand how environmental interactions can affectinstrument performance.

Review of the Course Text:“There is, to my knowledge, no other book that provides its

intended readership with an comprehensive and authoritative,yet compact and accessible, coverage of the subject ofspacecraft environmental engineering.” – James A. Van Allen,Regent Distinguished Professor, University of Iowa.

February 2-3, 2009Beltsville, Maryland

$1095 (8:30am - 4:00pm)

"Register 3 or More & Receive $10000 eachOff The Course Tuition."

SummaryAdverse interactions between the space environment

and an orbiting spacecraft may lead to a degradation ofspacecraft subsystem performance and possibly even lossof the spacecraft itself. This course presents anintroduction to the space environment and its effect onspacecraft. Emphasis is placed on problem solvingtechniques and design guidelines that will provide thestudent with an understanding of how space environmenteffects may be minimized through proactive spacecraftdesign.

Each student will receive a copy of the course text, acomplete set of course notes, including copies of allviewgraphs used in the presentation, and acomprehensive bibliography.

“I got exactly what I wanted from thiscourse – an overview of the spacecraftenvironment. The charts outlining theinteractions and synergism were excellent.The list of references is extensive andwill be consulted often.”

“Broad experience over many designteams allowed for excellent examples ofapplications of this information.”

The Space Environment –Implications for Spacecraft Design

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COURSE OUTLINE• Introduction

– Why Study SEE?– The Earth’s Environment– The Solar Environment

• Vacuum– Environment– Effects

• Solar UV Degradation• Molecular Contamination• Particulate Contamination• Contamination Control

• Neutral – Environment– Effects

• Aerodynamic Drag• Sputtering• Atomic Oxygen Erosion• Spacecraft Glow

• Plasma– Environment– Effects

• Spacecraft Charging• Arc Discharging

• Radiation– Environment– Effects

• Total Dose• Dose Rate• Single Event

• Micrometeoroid/Orbital Debris– Environment– Effects

• Hypervelocity Impact Damage• Effects on Humans• Conclusions

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ABOUT THE INSTRUCTOR

• Dr. Alan Tribble– Over Twenty Years Experience in Space Environments and

Effects• Author of First Text on Space Environments & Effects• Principal Investigator for the NASA Space Environments & Effects

Program• Associate Editor for the AIAA Journal of Spacecraft and Rockets• Instructor for Space Environments & Effects Courses Since 1992

– Winner of the 2008 AIAA James A. Van Allen Award • Presented to recognize outstanding contributions to space and

planetary environment knowledge and interactions as applied to the advancement of aeronautics and astronautics.

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MOLECULAR CONTAMINATION

• Molecular Films On the Order of 1 m Thick May Be Deposited During On Orbit Operations

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MOLECULAR REQUIREMENTS

Affected Operational If Single If 5 OpticalElement Parameter Criteria Surface Surfaces

UV Sensora Signal Strength < 10% Absorption ~ 0.05 m ~ 0.004 m(0.2 - 0.3 m) (Level B) (~ Level A/20)

Solar Arraysb Power Production < 2% Power Loss ~ 0.015 ma N/A(Level A)

Thermal Control Surfaces s/ Ratio s < 2.0 initial s ~ 0.2 m N/A(Initial OSR s = 0.06) (Level H)

Visible Sensor Signal Strength < 10% Absorption ~ 0.2 m ~ 0.04 m(0.35 - 0.90 m) (Level H) (Level D)

IR Sensorc Signal Strength < 10% Absorption ~ 1.5 m ~ 0.3 m(1.0 - 2.0 m) (>> Level J) (~ Level J)

aassumes nominal contaminant absorptance profile - highly absorptive in the UVbassumes darker, photochemically deposited contaminant absorptance profile

crequires cryogenic surfaces that retain contaminants

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PARTICULATE CONTAMINATION

• Particulates on the Order of 1 m in Size May Be Deposited During Manufacturing, Assembly, Test, or Launch

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PARTICULATE REQUIREMENTS

Element Operational RequiredAffected Parameter Criteria CleanlinessIR Sensor Signal to Noise Ratio SNR > 8.0 200

Thermal Control Absorption s ~ 0.05 350Surfaces Emittance ~ 0.05 450

~ 1.0 650

Solar Arrays Power Production < 1% Power Loss 520

These Values Should Be Used For Comparison Only

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• An Object of Dry Mass M, Moving With Velocity v, Can Change Its Velocity by Ejecting a Mass of Fuel m at velocity v'.

• From Conservation of Momentum

v

M+m

v + v

m

M

v'

INITIAL FINAL

')()( vvmvvMvmM

THE ROCKET EQUATION - 1

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• Due to the Large Impact Speed of the Neutrals Some Surface Molecules May Be Dislodged Upon Impact

• The Reaction is Highly Dependent Upon Impact Energy and Surface Material Properties

SPUTTEREDMOLECULE

IMPACTINGNEUTRAL

REFLECTEDNEUTRAL

PHYSICAL SPUTTERING

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AO MASS LOSS

• Mass Loss is Quantified by the Relation

• The Erosion Rate is Given by

• Where RE is the Experimentally Determined Reaction Efficiency

dAdtREnvdm ot

oREnvdtdx

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SHUTTLE GLOW AND AURORA

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THE LEO PLASMA ENVIRONMENT

Parameter ValuePlasma Density 1 x 1011 m-3

Plasma Temperature 1000 K (0.13 eV)

Debye Length 1 cmElectron Gyroradius 1 cm

Ion Gyroradius 3 m

Electron Thermal Speed 200 km/sOrbital Velocity 8 km/s

Ion Thermal Speed 1 km/s

Electron Plasma Frequency 2.8 MHzIon Plasma Frequency 16.6 kHz

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NEGATIVEGROUND

POSITIVEGROUND

FLOATINGGROUND

PLASMAPOTENTIAL

ELECTRONCOLLECTION

IONCOLLECTION

STRUCTURES~ 90% OF ARRAY

VOLTAGENEGATIVE

STRUCTURESA FEW VOLTS

POSITIVE

STRUCTURESA FEW VOLTS

NEGATIVE

LEO GROUNDING RESULTS

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NOMINAL GEO CONDITIONS

Parameter ValuePlasma Density 1 x 106 m-3

Plasma Temperature 1,000,000 K (130 eV)

Debye Length 2 mElectron Gyroradius 7.5 km

Ion Gyroradius 3 m

Electron Thermal Speed 6,000 km/sIon Thermal Speed 30 km/s

Orbital Velocity 3 km/s

Electron Plasma Frequency 900 HzIon Plasma Frequency 50 Hz

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MagnetopauseCompressed to < 10 RE

SolarWind

Earth’sMagnetic

FieldLines

Compressed

Sun’sMagnetic

FieldDominant

Earth’sMagneticFieldDominant

HOT PLASMAPUSHED EARTHWARD

ENERGETICPROTONS

ENERGETICELECTRONS

vB x

VIEWFROMTOP

SEVERE SPACECRAFT CHARGINGMIDNIGHT - 6 AM

GEOMAGNETIC STORMS

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Solar Arrays That Are Placed in Plasma Chambers Are Observed to Arc.

ESD ON SOLAR ARRAYS

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DIELECTRIC BREAKDOWN DAMAGE

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• As an Energetic Particle Passes Through Matter it Will Create Atomic Displacements and/or Ionize Atoms in the Material

• As a Result the Material Properties Will be Altered

• Radiation Can be Thought of as Anything That Deposits Energy in a Material– Charged Particles (Electrons, Protons)– Uncharged Particles (Neutrons)– Photons (Gamma Rays, X-Rays)

WHAT IS RADIATION?

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FUNDAMENTAL FORCES

• Four Forces– Strong Nuclear

• Important Near the Nucleus

– Weak Nuclear• Important Near the

Nucleus– Electrical

• Very Significant for Particles That are Charged

– Gravitational• Only Important for Very

Large Masses Nuclear Forces OnlyDominates Near theNucleus

Electrical Force AlwaysDominates Outsidethe Nucleus

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STOPPING POWER

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Photon Energy (MeV)

Abs

orpt

ion

Coe

ffic

ient

(cm

^2/g

)

0

0 .0 2

0 .0 4

0 .0 6

0 .0 8

0 .1

0 .1 2

0 .1 4

0 .1 6

0 .1 8

0 .2

0 .1 1 1 0 1 0 0

Compton

Pair Production

Photoelectric

Total

10-1 100 101 102

CrossSection(cm2/g)

PHOTON CROSS SECTION

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ATMOSPHERIC NEUTRONS

• The Neutron Flux is a Function of Altitude and Latitude

• The Worst Location is a Polar Route at About 55,000 Feet

Neutron Flux vs Altitude

00.20.40.60.8

11.21.4

0 20 40 60 80 100

Altitude (Thousand Feet)

Flux

(n /

cm^2

s)

Neutron Flux vs Latitude

00.20.40.60.8

11.21.41.6

0 20 40 60 80 100

Latitude (Deg.)

Flux

(n /

cm^2

s)

Normand, E., and Baker, T. J., “Altitude and Latitude Variations in Avionics SEU and Atmospheric Neutron Flux,” IEEE Tns. Nuc. Sci., Vol. 40, No. 6, pp. 1484 - 1490, December 1993.

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• Trapped Radiation Belts (Van Allen Belts)– Energetic Electrons and Protons That Are Trapped by the

Earth’s Magnetic Field

• Solar Particle Events (SPE’s)– Energetic Particles, Mostly Protons, Emitted During Solar

Flares

• Galactic Cosmic Rays (GCR’s)– Energetic Nuclei Originating Outside the Solar System

• Hostile Radiation Environments– Nuclear Weapons in Space

• Nuclear Power Systems– Radioisotope Thermoelectric Generators (RTG’s)

RADIATION IN SPACE

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VAN ALLEN BELTS

Displaying a Model of the Explorer 1 Spacecraft are (l-r): Dr. James Pickering (JPL), Dr. James Van Allen (Univ. of Iowa), and Dr. Wehrner Von Braun (MSFC).

Van Allen Published the First Data on the Trapped Radiation Belts, Which are Sometimes Called the Van Allen Belts.

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Omnidirectional Equatorial Flux

Earth Radii

Flux

(per

sq c

m p

er s)

1.00E+ 00

1.00E+ 01

1.00E+ 02

1.00E+ 03

1.00E+ 04

1.00E+ 05

1.00E+ 06

1.00E+ 07

1.00E+ 08

1.00E+ 09

-10 -8 -6 -4 -2 0 2 4 6 8 10

0.1 MeV

1 MeV

10 MeV

0.1 MeV

1 MeV

3 MeV

ELECTRONS PROTONS

3 MeV

0.1 MeV

1 MeV

0.1 MeV

1 MeV10 MeV

OMNIDIRECTIONAL EQUATORIAL FLUX

Earth Radii

10 28 6 4 2 10864

109

108

107

106

105

104

103

102

101

100

Flux(cm-2 s-1)

INTENSITY OF THE BELTS

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SPE COMPOSITION

Large Solar Proton Event Spectra at 1 AU

1.00E+07

1.00E+08

1.00E+09

1.00E+10

1.00E+11

1 10 100 1000

Kinetic Energy (MeV)

Inte

gral

Flu

ence

, (pr

oton

s /

cm^2

)

Feb 1956Nov 1960Aug 1972Aug 1989Sep 1989Oct 1989

Wilson, J. W., Cucinotta, F. A., Simonsen, L. C., Shinn, J. L., Thibeault, S. A., and Kim, M. Y., "Galactic and Cosmic Ray Shielding in Deep Space", NASA TP 3682, December 1997

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GCR COMPOSITION

Galactic Cosmic Ray Fluence, Solar Max (1981)

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

1.00E-01 1.00E+00 1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06

Kinetic Energy (A MeV)

Annu

al F

luen

ce, (

part

icle

s / c

m^2

- A

MeV

)

Z = 1Z = 2Z: 3 - 10Z: 11 - 20Z: 21 - 28

Wilson, J. W., Cucinotta, F. A., Simonsen, L. C., Shinn, J. L., Thibeault, S. A., and Kim, M. Y., "Galactic and Cosmic Ray Shielding in Deep Space", NASA TP 3682, December 1997

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• In Many Materials, the Total Dose of Radiation is the Critical Issue in Determining Useful Lifetime

Material Damage Threshold (RAD)Biological Matter 101 - 102

Electronics 102 - 104

Lubricants, Hydraulic Fluid 105 - 107

Ceramics, Glasses 106 - 108

Polymeric Materials 107 - 109

Structural Metals 109 - 1011

RADIATION DAMAGE THRESHOLDS

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GPS Trapped Radiation: 20,000 km - 55 Deg

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+04 1.00E+05 1.00E+06 1.00E+07 1.00E+08 1.00E+09 1.00E+10 1.00E+11 1.00E+12 1.00E+13

Fluence (# cm ^-2 day^-1)

Ener

gy (M

eV)

Protons

Electrons - Solar Min

Electrons - Solar Max

20,000 km @ 55 degrees

104 105 106 107 108 109 1010 1011 1012 1013

Fluence (cm-2 day -1)

101

Energy(MeV)

100

10-1

10-2

Protons

Electrons - Solar Min.

Electrons - Solar Max.

GPS RADIATION ENVIRONMENT

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Altitude = 20,000 kmInclination = 55 deg.

Shielding = Full-Sphere

Shie ld ing Thic kne ss (m ils - Al)

Dos

e (r

ad/d

ay)

0.10

1.00

10.00

100.00

1000.00

10000.00

10 100 1000

To ta l

Pro to n

Ele c tro n

Bre m s.

GPS RADIATION DOSE

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DESIGN EXAMPLE: SOLAR ARRAY SIZING

• Solar Array Size is Driven by the Amount of Energy That Must be Produced– A = Solar Array Area (m2)– P = Power Required (W)– = Efficiency

• Efficiency is Degraded by Radiation– BOL Value is Greater Than the EOL Value

• Efficiency Loss is Minimized by Adding a Transparent Shield– Coverslide

– S = Sun’s Power Output (1367 W/m2 at Earth Orbit)

SPA

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VIN

VOUT

p-type substrate

n+ n+

n-well

p+ p+p+ n+

VSSVDD

Source

Gate

Drain Source

SEE ILLUSTRATION

Radiation(proton, ion, neutron, …)

Upset occurs if channel current turned on

Latchup occurs if parasitic current loop initiated

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MITIGATION TECHNIQUES

• Shielding– Prevent the Radiation Environment From Reaching the Crew

or Sensitive Electronics• Not Effective on Very Energetic (GeV) Charged Particles

• Parts Selection– Choose Parts or Materials That Can Withstand the Total

Dose Environment Anticipated– Choose Parts That are Immune or Resistant to SEE

• Fault Tolerance– Hardware

• Redundancy, Majority Voting, …– Software

• Error Detection and Correction (EDAC), Hamming Codes, …

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MEDIUM IMPACT CRATER

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COLUMBIA ACCIDENT INVESTIGATION

• Executive Summary– The Physical Cause of the Loss of Columbia and its Crew

Was a Breach in the Thermal Protection System on the Leading Edge of the Left Wing, Caused by a Piece of Insulating Foam Which Separated From the Left Bipod Ramp Section of the External Tank at 81.7 Seconds After Launch, and Struck the Wing in the Vicinity of the Lower Half of Reinforced Carbon-Carbon Panel Number 8. During Re-Entry This Breach in the Thermal Protection System Allowed Superheated Air to Penetrate Through the Leading Edge Insulation and Progressively Melt the Aluminum Structure of the Left Wing, Resulting in a Weakening of the Structure Until Increasing Aerodynamic Forces Caused Loss of Control, Failure of the Wing, and Breakup of the Orbiter. This Breakup Occurred in a Flight Regime in Which, Given the Current Design of the Orbiter, There was no Possibility for the Crew to Survive.

• Columbia Accident Investigation Board, August 2003

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• Most MM’s Originate From Comets or Asteroids

• Meteor 'Showers' Are Those Few Days of the Year When Ground Observers May See a >10 Fold Increase in MM Flux for a Period of a Few Days.

• With the Exception of Very Short Term Missions, i.e., The Shuttle Orbiter, These Short Term Variations Will Not be Significant.

• The Data That Follows is Based on a Yearly Average for the Micrometeorite Flux.

• Meteor Showers– Quantrantids

• January 1 - 6– Lyrids

• April 19 - 24– Eta Aquarids

• May 2 - 7– Delta Aquarids

• July 15 - August 15– Perseids

• July 27 - August 17– Orionids

• October 12 - 16– Taurids

• October 26 - November 25– Leonids

• November 15 - 19– Geminids

• December 7 - 15

METEOR SHOWERS

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CUMULATIVE EFFECTS

• 5 Years Exposure in LEO Resulted in Noticeable Surface Damage to Many Panels on the Long Duration Exposure Facility (LDEF)

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ED WHITE’S 1965 SPACE WALK

Ed White’s Space Walk in 1965 Generated Some Orbital Debris When a Glove Floated Out of the Open Hatch of the Capsule

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SHIELDING

• Whipple Shield– Outer Layers Fragment Impacting Particle– Inner Layers Catch Fragments

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NASA INTERNET SITES

• Glenn Research Center– Space Environments and

Experiments Branch• http://www.grc.nasa.gov/WWW

/epbranch/

• Goddard Space Flight Center– Radiation Effects and Analysis

• http://radhome.gsfc.nasa.gov– National Space Science Data

Center (NSSDC)• http://nssdc.gsfc.nasa.gov

– Community Coordinated Modeling Center (CCMC)

• http://ccmc.gsfc.nasa.gov/modelweb/

• Jet Propulsion Laboratory– Radiation Effects Group

• http://parts.jpl.nasa.gov

• Johnson Space Center– Orbital Debris Program Office

• http://orbitaldebris.jsc.nasa.gov

• Langley Research Center– Space Environments and

Technology Archive System (SETAS)

• http://setas-www.larc.nasa.gov/

• Marshall Space Flight Center– Space Environments and Effects

Program• http://see.msfc.nasa.gov

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OTHER INTERNET SITES

• NOAA – Space Weather Prediction

Center• http://www.swpc.noaa.gov

• Space Weather– Science News and Information

• http://www.spaceweather.com– Space Science Institute

• http://www.spaceweathercenter.org/

• Space Environment Information System (SPENVIS)

– interface to models of the space environment and its effects, including the natural radiation belts, solar energetic particles, cosmic rays, plasmas, gases, and "micro-particles".

• www.spenvis.oma.be

• Instructor’s Web Site– Links to Site’s of Interest

• http://www.atribble.com

Sampler2009

Slide #42

Applied TechnologyInstitute (ATI)www.aticourses.com

Copyright Dr. Alan Tribble. Do Not Reproduce Without Permission.

www.atribble.com

SPACE ENVIRONMENT EFFECTS

PLASMA MMOD

Solar UVOutgassing/

ContaminationAerodynamic

Drag SputteringAtomic Oxygen Attack

Spacecraft Glow Spacecraft Charging

Van Allen Belts

Galactic Cosmic Rays

Solar Proton Events Impacts

Avionics EMI From Arc DischargingEMI Due To

Impacts

Attitude Determination & Control

Degradation of Sensors Induced Torques

Noise Source for Sensors

Torques Due to Induced Potentials

Electrical Power Arcing on Solar ArraysDestruction/

Obscuration of Solar Cells

Environmental Control & Life Support

Toxic Fumes EMI From Arc DischargingPenetration of

Habitat

PropulsionDrag Makeup

Fuel Requirement

Rupture of Pressurized Tanks

StructuresDielectric Breakdown on

SurfacesPenetration

Telemetry, Tracking, and Communications

Degradation of Sensors

EMI From Arc Discharging EMI due to impacts

Thermal ControlChange in

Absorptance / Emittance

Total Dose Degradation; Single Event Effects

Total Dose Degradation; Single Event Effects

Change in Absorptance / Emittance

Change in Absorptance / Emittance

Cold Surfaces May Experience Heating

Spac

ecra

ft Su

bsys

tem

s

Space Environments and Effects

Total Dose Degradation; Single Event Effects

RADIATIONNEUTRALVACUUM

Degradation of Sensor Coatings

Reduction in Coverslide Transmittance

Reduction in Coverslide Transmittance Degradation of Solar Cell Output

Sampler2009

Slide #43

Applied TechnologyInstitute (ATI)www.aticourses.com

Copyright Dr. Alan Tribble. Do Not Reproduce Without Permission.

www.atribble.com

SYNERGISTIC EFFECTSVACUUM NEUTRAL PLASMA RADIATION MMOD

So la r UVO utg a ssing /

C o nta m ina tio nAe ro d yna m ic

Dra gSp utte ring

Ato m ic O xyg e n Atta c k

Sp a c e c ra ft G lo w

Sp a c e c ra ft C ha rg ing

Va n Alle n Be lts

G a la c tic C o sm ic

Ra ys

So la r Pro to n Eve nts

Im p a c ts

So la r UVPho to c he m ic a l

De p o sitio n o f C o nta m ina nts

Pho to e m issio n o f Ele c tro ns

So la r C yc le A lte rs O D

De nsity

O utg a ssing / C o nta m ina tio n

O utg a sse d Ma te ria l Ma y

Enha nc e G lo w

O utg a sse d Ma te ria l Ma y

Inc re a se Arc Ra te

Ae ro d yna m ic Dra g

Ma y Re fle c t C o nta m ina nts to

S/ C

Re m o ve s O D Fro m Lo we r

O rb its

Sp utte ring

Sp utte re d Ma te ria l Ma y b e

C o nta m ina nt So urc e

Ato m ic O xyg e n Atta c k

AO Ma y C le a n C o nta m ina te d

Surfa c e s

A O Re sista n t Ma te ria ls a re

Susc e p tib le to G lo w

AO Atta c k Ma y Alte r Surfa c e

C o nd uc tivitie s

Sp a c e c ra ft G lo w

PLA

SMA

Sp a c e c ra ft C ha rg ing

Charging May Enhance

Contaminantion Rate

C ha rg ing Ma y

Enha nc e Sp utte ring

Va n Alle n Be lts

G a la c tic C o sm ic Ra ys

So la r Pro to n Eve nts

SPE's Sup p re ss

G C R's

MM

OD

Im p a c tsIm p a c ts Ma y

G e ne ra te C o nta m ina nts

Im p a c ts Ma y Slig h tly

Inc re a se Dra g

Im p a c ts Ma y Exp o se

Und e rlying Surfa c e s to

Ero sio n

Im p a c t Va p o riza tio n Ma y Stim ula te Arc ing

Ra d ia tio n Ma y Inc re a se C ha rg ing

VA

CU

UM

NEU

TRA

LR

AD

IATI

ON

So la r C yc le A lte rs A tm o sp he ric De nsity

Ra d ia tio n Ma y Stim ula te

O utg a ssing