effects on spacecraft charging of effects on spacecraft charging of
TRANSCRIPT
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Effects on Spacecraft Charging ofEffects on Spacecraft Charging of Modification of Materials by Space
Environment InteractionsEnvironment InteractionsJ.R. Dennison and Ryan Hoffmann
Materials Physics GroupPhysics Department, Utah State University
Introduction Section 0 Lecture 1 Slide 1Introduction Section 0 Lecture 1 Slide 1
Albuquerque New MexicoSeptember 20 25 2010
Materials Modifications Slide 1
September 20-25, 2010
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
AbstractAbstractWhile the effects on spacecraft charging from varying environmental conditions and from theselection of different construction materials have been studied extensively modification of materialsselection of different construction materials have been studied extensively, modification of materialsproperties by the space plasma environment can also have profound effects on spacecraft charging.This presentation focuses on measurement methods and modeling employed to assess the effectsof environment-induced material modifications on physical properties relevant to spacecraftcharging simulations. It also reviews several specific studies in which environment-inducedmaterial modifications have significant impact on predicted spacecraft charging.
We present an overview of testing and modeling conducted by the Utah State University (USU)Materials Physics Group and other investigators to quantify the changes in charging, dischargingand emission as materials properties are modified by variations in temperature charge
Introduction Section 0 Lecture 1 Slide 2
and emission as materials properties are modified by variations in temperature, chargeaccumulation and electrostatic fields, radiation dose and damage, surface modifications includingroughening and contamination, and the duration, rate and history of imposed environmental testconditions. Such changes have been shown to affect measurements of the following materialproperties: electron-, ion- and photon-induced electron emission yields, spectra, and yield decay
d k t d di ti i d d d ti it l t t ti di h d h dIntroduction Section 0 Lecture 1 Slide 2curves; dark current and radiation induced conductivity; electrostatic discharge and charge decaycurves; electron-induced surface charging, discharge and luminescence; and UV/VIS/NIR reflectivity,transmissivity, absorptivity, and emissivity. We also highlight a unified set of parameters andequations developed to relate these experimental methods to basic theories of electron transport.
Materials Modifications Slide 22
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
AbstractAbstractRecent USU studies related to several specific missions have highlighted the operational effects ofsuch environment-induced changes on material properties and ultimately on spacecraft charging.For example, studies of surface coatings for the 2005 concept of the Solar Probe Mission found thatabsolute and differential surface charging depended strongly on increased conductivity from highertemperatures and on radiation flux through enhanced charge accumulation and radiation inducedconductivity; interplay between these effects led to the prediction of a maximum in charging atintermediate distances over the Probe’s orbital range spanning from Jovian distances to within 4intermediate distances over the Probe s orbital range spanning from Jovian distances to within 4solar radii of the Sun. Extreme demands dictated by the science objectives of the James WebbSpace Telescope have placed particularly stringent requirements on materials and have potentiallyincreased risks from spacecraft charging: low temperatures lead to low charge transport anddissipation rates; long mission duration, prolonged eclipse conditions, and inaccessibility for
i t l d t t l l h l ti ti l ll d f
Introduction Section 0 Lecture 1 Slide 3
maintenance lead to extremely long charge accumulation times; large, unusually exposed surfaceareas lead to larger charge accumulation and increased probability of discharge; and very sensitiveelectronics and optics lead to low tolerance for charging, electrostatic discharge, and electron andphoton emission. Extreme radiation dose rates and fluences for potential polar and Jovian missionshave been found to substantially modify electron transport and to affect other properties such as
Introduction Section 0 Lecture 1 Slide 3y y p p p
reflectivity, emissivity and electrostatic discharge.
Given the increasingly demanding nature of space missions, there is clearly a need to extend ourunderstanding of the dynamic nature of material properties that affect spacecraft charging and toexpand our knowledgebase of materials’ responses to specific environmental conditions so that we
Materials Modifications Slide 33
expand our knowledgebase of materials responses to specific environmental conditions so that wecan more reliably predict the long term response of spacecraft to their environment.
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Introduction Section 0 Lecture 1 Slide 4Introduction Section 0 Lecture 1 Slide 4
Let us assume a spherical satellite….
Materials Modifications Slide 44
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
A simplified approach to spacecraft charging modeling…
MaterialsPropertiesp
I+e-
+
Introduction Section 0 Lecture 1 Slide 5
I
γ
+_
Introduction Section 0 Lecture 1 Slide 5
Satellite Moving through Space
Space Plasma Environment
Spacecraft Potential Models
Materials Modifications Slide 55
g p
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
What do you need to know about the materials properties?
Charge Accumulation• Electron yields
D i f thy
• Ion yields• Photoyields
Charge Transport
Dynamics of the space environment and satellite motion lead to dynamic spacecraft chargingCharge Transport
• Conductivity• RIC• Dielectric Constant I+
e-
+
charging
• Solar Flares• Rotational eclipse
Introduction Section 0 Lecture 1 Slide 6
• ESD
As functions of materials species flux and energy
I
γ
+_
Introduction Section 0 Lecture 1 Slide 6species, flux, and energy.
Complex dynamic interplay between space environment satellite motion and materials properties
Materials Modifications Slide 6
environment, satellite motion, and materials properties
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Dale Ferguson’s “New Frontiers in Spacecraft Charging”
#1 Non-static Spacecraft Materials Properties#2 Non-static Spacecraft Charging Models
These result from the complex dynamic interplay between space environment, satellite motion, and materials properties
Specific focus of this talk is the change in materials properties as a function of:
Introduction Section 0 Lecture 1 Slide 7
• Time (Aging), t• Temperature, T• Accumulated Energy (Dose), D• Dose Rate, ĎIntroduction Section 0 Lecture 1 Slide 7Dose Rate, Ď• Accumulated Charge, ΔQ or ΔV• Charge Profiles, Q(z)• Charge Rate (Current), Ŏ
C d ti it P fil ( )
Materials Modifications Slide 77
• Conductivity Profiles, σ(z)
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Complex dynamic interplay between space environment, t llit ti d t i l tisatellite motion, and materials properties
Test FacilitiesConference Sessions
S i 3
USU PostersUSU StudiesSession 3:Materials Characterization Session• Hoffmann—Effects of charge accumulation on electron yields
• Evans—Effects of surface modification on reflectivity and photoyields
Introduction Section 0 Lecture 1 Slide 8
Session 8: Aging, Radiation and Temperature Effects on Charging and Arcing Session
• C Sim—Effects of aging and temperature on ESD• Hodges—Effects of charge accumulation, t, D and Ď on surface voltage• Dennison and Prebola—Effects of contamination and surface modification on chargingIntroduction Section 0 Lecture 1 Slide 8and Arcing Session
ONERA-Sirene JAXA-Solar Arrays QinetiQ-REEFmodification on charging• Wilson—Effects of incident energy on charge and energy deposition• A Sim—Theoretical models of t, T, Q, D and Ď on transport propertiesEnvironment ↔ Materials ↔ Materials ↔ SpacecraftConditions Conditions Properties Charging
Materials Modifications Slide 88
g g
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
“New Frontiers” from a Materials Perspective
Consider 5 Cases of Dynamical Change in Materials:y g
• Contamination and Oxidation• Surface Modification
R di ti Eff t ( d t)• Radiation Effects (and t)• Temperature Effects (and t)• Radiation and Temperature Effects
Introduction Section 0 Lecture 1 Slide 9Introduction Section 0 Lecture 1 Slide 9
Materials Modifications Slide 9
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case I: Evolution of Contamination and Oxidation
104
)
“All spacecraft surfaces are eventually carbon…”
Approx. Contamination Thickness (nm)0 5 10
103
Veq
) (in
vol
ts--C. Purvis
This led to lab studies by Davies, Kite, and Chang
102
tent
ial (
10-V
and Chang
1.4 SE Yield Evolution Neg ChargingAu
Introduction Section 0 Lecture 1 Slide 10
101
Neg
ativ
e P
ot
1.2
1.0
0.8
0.6SE
Yie
ld
(0 - 300 angstroms Carbon Contamination)
10-angstrom Increments
Neg. ChargingAu
Introduction Section 0 Lecture 1 Slide 10
100N
706050403020100
Contamination (Exposure Time in hours)
0.4
0.2
300025002000150010005000Primary Energy (eV)
0 angstroms 300 angstroms Emax Evolution
Pos. ChargingC on Au
Materials Modifications Slide 10
( p )
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case I: Evolution of Contamination and Oxidation
-5 VDCGrounded Guard PlateWake Side
-15 V
+5 VBefore After
Kapton, HNBefore After
Ag
• 13 Grounded Samples• 12 Biased Samples: for 3 sets of 4 samples with low
t bi f hcurrent biases for charge-enhanced contamination studies.• 6 Concealed samples
Introduction Section 0 Lecture 1 Slide 11+5 VDC -15 VDC
• 6 Concealed samplesSample Holders
• Holder area 5 cm x 15Introduction Section 0 Lecture 1 Slide 11 SUSpECS on MISSE-6
See poster by Dennison, Evans and Prebola
Black KaptonBefore After Before After
Ag coated Mylar with micrometeoroid impact
• Holder area 5 cm x 15 cm• 9 mm diameter exposed sample area
Materials Modifications Slide 11
sample area
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case II: Surface Modification
Reflectivity changes with surface roughness
S t b ESee poster by Evans b.
Introduction Section 0 Lecture 1 Slide 12
Successive stages of roughenied of Cu
Introduction Section 0 Lecture 1 Slide 12
c.
Materials Modifications Slide 12
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Cases I and II: Reflectivity as a Feedback MechanismReflectivity changes with surface roughness and contaminationReflect→Charging→Contaminationg g
Charging→ Reflectivity
Reflect→Emissivity→Temp→Contamination
Large C
Radiation → Reflect→Emissivity→Temp→Contamination
Introduction Section 0 Lecture 1 Slide 13
Solar Probe Mission: Charging vs. EmissivitySee Donegan, Sample, Dennison and Hoffmann
Breakdown
X:41.583
Y:58.444Radiation Damage (Color Change) of TedlarIntroduction Section 0 Lecture 1 Slide 13Ground Tests: Threshold Charging vs. Absorption
Y:58.444
Before AfterZoomed Images
Radiation Damage (Color Change) of Tedlar
B. Mihaljcic in Guild’s 11th SCTS TalkSee Lai & Tautz, 2006 & Dennison 2007
Materials Modifications Slide 13
JWST Structure: Charging vs. Ablation
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case III: Radiation Effects(a)
Large Dosage (>108 Rad)
Medium Dosage (>107 Rad)
Low Dose Rate (>100 Rad/s)
“…Earth is for Wimps…” H. Garrett (b)
Introduction Section 0 Lecture 1 Slide 14
“…auroral fields may cause significant surface charging…” H. Garrett
Examples: RBSP, MMS, JUNO, JGO/JEO
Mechanical Modification of Electron
Examples:
Radiation induced Conductivity (RIC) )()(),( T
RICRIC DTkDT Introduction Section 0 Lecture 1 Slide 14
Examples: RBSP, JUNO, JGO/JEO
Mechanical and Optical Materials Damage
Transport and Emission PropertiesCaused by bondbreaking and trap creation
(see Hoffmann & A Sim posters)
(RIC)Temperature depndant
(see A Sim posters)
)(),( RICRIC DTkDT
Materials Modifications Slide 14
p g(see Hoffmann & A Sim posters)
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case IV: Temperature Effects
Examples:Strong T Dependence for Insulators
IR and X-Ray ObservatoriesJWST, WISE, WMAP, Spitzer, Herscel, IRAS, MSX, ISO, COBE, Planck
Insulators
Charge Transport• Conductivity
RIC Planck
Outer Planetary MissionGalileo, Juno, JEO/JGO. Cassini,
• RIC• Dielectric Constant• ESD
Introduction Section 0 Lecture 1 Slide 15
Pioneer, Voyager,
Inner Planetary MissionSPM Ulysses Magellan MarinerIntroduction Section 0 Lecture 1 Slide 15SPM, Ulysses, Magellan, Mariner
(see A Sim and C Sim posters)
Materials Modifications Slide 15
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case IV: Temperature Effects
46
48
50p p y
vty
(Ohm
-cm
))
σVRH~exp(T-¼)σ ~exp(T-1)
Strong T Dependence for Insulators
Charge Transport
40
42
44
(Cal
cula
ted
Res
istiv σTAH~exp(T 1)• Conductivity
• RIC• Dielectric Constant• ESD
k(T)230 240 250 260 270 280 290 300
38
Temperature (K)
Ln ( T
t
ESD
Introduction Section 0 Lecture 1 Slide 16Uniform Trap Density Exponential Trap Density
Introduction Section 0 Lecture 1 Slide 16 1)( Tc
cTT
TT )(
RICokTk )(
cTTT
ee
heBeRIC mm
mmTkmkTk
43**23
21 22)(
Materials Modifications Slide 16
)()(),( TRICRIC DTkDT
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case IV: Temperature Effects—JWST
JWST
Very Low TemperatureVirtually all insulators go to infinite resistance—perfect charge
Large Open StructureLarge fluxesMinimal shieldinginfinite resistance perfect charge
integrators
Long Mission Lifetime (10-20 yr) N i
a s e d g
Variation in FluxLarge solar activity variationsIn and out of magnetotail
Introduction Section 0 Lecture 1 Slide 17
No repairsVery long integration times
Large Sunshield
In and out of magnetotail
Complex, Sensitive HardwareLarge sensitive optics
Introduction Section 0 Lecture 1 Slide 17g
Large areasConstant eclipse with no photoemission
g pComplex, cold electronics
Materials Modifications Slide 17
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
WideTemperature Range<100 K to >1800 K
Wide Dose Rate RangeFive orders of magnitude variation!
Introduction Section 0 Lecture 1 Slide 18
Wide Orbital RangeEarth to Jupiter FlybySolar Flyby to 4 Rs
Introduction Section 0 Lecture 1 Slide 18
Materials Modifications Slide 1818
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
“We anticipate significant thermal
d h iand charging issues.”
J S l
Introduction Section 0 Lecture 1 Slide 19
J. Sample
Introduction Section 0 Lecture 1 Slide 19Charging Study by Donegan, Sample, Dennison and Hoffmann(See Donegann Poster for update)
Materials Modifications Slide 1919
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
Introduction Section 0 Lecture 1 Slide 20Introduction Section 0 Lecture 1 Slide 20
Wide Dose Rate RangeFive orders of magnitude
Wide Orbital RangeEarth to Jupiter Flyby
WideTemperature Range<100 K to >1800 K
Materials Modifications Slide 2020
gvariation!Solar Flyby to 4 Rs
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
Dark Conductivity vs T RIC vs T
Introduction Section 0 Lecture 1 Slide 21 Tk
EDC B
o
eT
)( )298()( KTT Dark Conductivity Dielectric Constant
Introduction Section 0 Lecture 1 Slide 21oDCBeT )(
)(
RICRIC )(k (T)T
DT
)298()( KTT RTr
)298()( KTRTESDESD
ESDeETE RIC Electrostatic Breakdown
Materials Modifications Slide 2121
RICRIC )(( ) )( ESDESD
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
A peak in charging at ~0.3 to 2 AU
“…Curiouser and curiouser…
--Alice
Introduction Section 0 Lecture 1 Slide 22Introduction Section 0 Lecture 1 Slide 22
Materials Modifications Slide 2222
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Case V: Temperature and Dose Effects
General Trends
Dose rate decreases as ~r-2
T decreases as ~e-r
σDC decreases as ~ e-1/T
1/TσRIC decreases as ~ e-1/T
and decreases as ~r-2
Introduction Section 0 Lecture 1 Slide 23A fascinating trade-offIntroduction Section 0 Lecture 1 Slide 23A fascinating trade off• Charging increases from increased dose rate at closer orbits• Charge dissipation from T-dependant conductivity increases f t t l bit
Materials Modifications Slide 2323
faster at closer orbits
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Conclusions
• Satellites are not cows…Complex satellites require:Complex satellites require: • Complex materials configurations• More power• Smaller more sensitive devices• Smaller, more sensitive devices• More demanding environments
• There are numerous clear examples where accurate dynamic
Introduction Section 0 Lecture 1 Slide 24
• There are numerous clear examples where accurate dynamic charging models require accurate dynamic materials properties
• It is not sufficient to use static (BOL or EOL) materials Introduction Section 0 Lecture 1 Slide 24
( )properties
• Enivronment/Materials Modification feedback mechanisms can
Materials Modifications Slide 24
cause a whole herd of new problems
INTRODUCTION TO INTERFACEING AND CONTROL WITH LabVIEW
Alec M Sim
Materials Modifications
11th
SCTC
Acknowledgements
Support & Collaborations
NASA SEE ProgramJWST (GSFC/MSFC)SPM (JHU/APL)RBSP (JHU/APL)
Introduction Section 0 Lecture 1 Slide 25
RBSP (JHU/APL)Solar Sails (JPL)AFRL Boeing
Introduction Section 0 Lecture 1 Slide 25
USU Materials Physics Group
Materials Modifications Slide 25