flight results from the merlin space weather monitor on giove-a 3 rd european space weather week...
TRANSCRIPT
![Page 1: Flight results from the Merlin space weather monitor on Giove-A 3 rd European Space Weather Week 13-17 November 2006, Brussels K A Ryden, P A Morris, D](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649ccd5503460f94996e8f/html5/thumbnails/1.jpg)
Flight results from the Merlin space weather monitor on Giove-A
3rd European Space Weather Week 13-17 November 2006, Brussels
K A Ryden, P A Morris, D J Rodgers, C S Dyer - QinetiQC I Underwood, B. Taylor, S Jason - SSTL/ University of SurreyH D Evans, E J Daly, G Mandorlo, G Gatti - ESA/ESTEC
![Page 2: Flight results from the Merlin space weather monitor on Giove-A 3 rd European Space Weather Week 13-17 November 2006, Brussels K A Ryden, P A Morris, D](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649ccd5503460f94996e8f/html5/thumbnails/2.jpg)
Giove-A
• Test-bed for European Galileo GNSS
– obtain frequency filing protection
– characterise the MEO environment
– validate certain critical payloads
– provide representative signal-in-space transmission
• Built and operated by SSTL
• Successfully launched in December 2005
• Orbit 23,260 km and 56 degrees inclination, 27 month lifetime
– electron dominated: charging and total dose hazards
– exposed to solar particle eventsSSTL image
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Galileo orbit
• Severe trapped electron environment– Charging effects
– Total ionising dose
• Galactic cosmic rays
• Solar protons and ions GALILEO altitudeGALILEO altitude
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Total ionising dose
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 2 4 6 8 10 12 14 16 18 20Thickness of Al sphere [mm]
GPS Total
GEO Total
GTO Total
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Internal charging
• ESD transients can cause anomalies and outages
• Cables, connectors, pcbs etc
High energy electrons from space environment
Dielectric
Shielding
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Merlin space weather hazard monitor
• Electrons and charging
• Total ionising dose
• Protons
• Ions (LET)
• 1kg, 2.5W (standard)
Developed from the earlier CREDO and SURF science detectors
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QinetiQ space radiation monitors
CREAM Cosmic Ray Effects and Activation Monitor (1986 onward)
• Charge deposition events in Si
• Flights: Shuttle(10 flights) /BA Concorde/Qantas/
CREDO Cosmic Ray Effects and Dosimetry Experiment (1991 onward)
• Ion LET spectra and proton flux
• Flights: UoSAT, STRV1a, Skynet, APEX, MIR, MPTB
SURF (2000 onward)
• Surface charging and internal charging (electron flux)
• Flights: STRV1d
Merlin (2005 onward)
• Charging/LET spectra/proton flux/TiD
• Flights: Giove-A, LWS/SET
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Merlin space weather hazard monitor
Electrons & electrostatic charging (3 shielding depths)
Ions (linear energy transfer)
Protons (>40 MeV flux)
Total dose RADFET (x2)
Integral rad-hard computer, data storage, power conditioning and communications
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Ion telescope Protontelescope
Total dosemonitor
Internalcharging(electron)monitor
Energydiscriminator
Analogueprocessingand ADC
Microcomputer and memory
Powerconditioningand filtering
RS422 businterface
RS422 bus Power bus
Lower board
Upper board
Merlin block diagram
Sensor suite (CREDO + SURF + Radfet)
Data handling
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Merlin-Giove-A
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Electrons & charging: SURF experiment
• Novel approach– internal charging current vs depth
measurement
– each plate has unique energy response curve so spectrum can be obtained
• Virtually immune to proton contamination
• Built and flown on STRV1d
• 300g, 0.3W
Space radiationparticles
Satellitetelemetry system
Lid 0.6mm Al
0.5mm Al plate1.0mm Al plate
Satellite exteriorwall
Satellite groundreference
fA fA
.
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SURF experiment: internal charging mode
0.00E+00
5.00E-10
1.00E-09
1.50E-09
2.00E-09
2.50E-09
3.00E-09
0 1 2 3 4 5 6
Electron energy (MeV)
Top plate
Bottom plate
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SURF results
• GTO orbit
• 500 x 36,000 km
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Merlin-Giove-A
• Located externally (under thermal blanket)
• Extra box shielding incorporated (5mm thick walls) due to severity of orbit
• SURF and Radfet set-up for Giove-A:
SURF plates
Housing (lid)
RADFETS
0.4 mm Al
2 mm Al
5 mm Al
0.5 mm Al
1 mm Al
Thermal blanket - 0.1 mm Al eq.
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Merlin pre-flight calibration
SURF plates
Housing (lid)
RADFETS
0.4 mm Al
2 mm Al
5 mm Al
0.5 mm Al
1 mm Al
Thermal blanket <0.2 mm Al eq.
REEF Sr-90 source
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Realistic Electron Environment Facility
• 90Sr source: 3.7 G Bq• Vacuum chamber• -10 to +40°C temperature
control of thermal plate• Electron current
controlled by variation of source-to -sample distance
• ESD detection system• Surface potential
measurements (‘TREK’ probes)
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Electron spectrum comparisons• REEF
capability brackets the average (AE8) and worst-case (FLUMIC) electron environments predicted for GEO
0.01
0.1
1
10
0.1000 1.0000 10.0000Energy (MeV)
Cur
rent
(pA
/cm
2 )
REEF (30mm) REEF (187.5mm)
Average GEO (AE-8min) NASA worst case GEOWorst case GEO (FLUMIC)
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Merlin-Giove-A: pre-flight calibration (REEF)
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100 150 200
time / s
char
ging
cur
rent
pA
/cm
2
0,5 mm shield, 0.5 mm collector
1.0 mm shield, 0.5 mm collector
1.5 mm shield, 1.0 mm collector
Source position: 0
Source position: 135,000
Merlin pre-flight calibration in REEF
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• Two particle telescopes (CREDO)– ion LET spectrum
– protons (400 keV energy deposition threshold)
Pul
se h
eigh
t dis
crim
inat
orCOINCIDENCE GATE
SIGNAL
Si diode, area 3cm2, 300um thick
NON-COINCIDENCE COUNTERS
COINCIDENCE COUNTERS
Merlin-Giove-A
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Radiation monitors installed on Giove-A
Picture: SSTL
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Launch 28th December 2005
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MERLIN-GIOVE A: CHARGING CURRENTS DUE TO TRAPPED ELECTRONS
0.00
0.05
0.10
0.15
0.20
29/12/2005 15:36:00 29/12/2005 20:24:00 30/12/2005 01:12:00 30/12/2005 06:00:00 30/12/2005 10:48:00 30/12/2005 15:36:00
Date
Cu
rren
t (p
A/c
m2)
0
5
10
15
20
25
30
L (
Re)
:
B (
kGau
ss)
Shield 0.5mm, collector 0.5mmShield 1.0mm, collector 0.5mmShield 1.5mm, collector 1.0mmB (model)L (model)
1st day of data: electrons/charging
GALILEO altitudeGALILEO altitude
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Jan & Feb 2006: electrons/charging
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Jan & Feb 2006: electrons & dose
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21 Feb 2006 electron eventMERLIN-GIOVE A: CHARGING CURRENTS DUE TO TRAPPED ELECTRONS
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
21/02/200600:00
21/02/200602:24
21/02/200604:48
21/02/200607:12
21/02/200609:36
21/02/200612:00
21/02/200614:24
21/02/200616:48
21/02/200619:12
21/02/200621:36
22/02/200600:00
Date
Cu
rren
t (p
A/c
m2)
0
5
10
15
20
25
30
L (
Re)
:
B (
kGau
ss)
Shield 0.5mm, collector 0.5mmShield 1.0mm, collector 0.5mmShield 1.5mm, collector 1.0mmB (model)L (model)
![Page 26: Flight results from the Merlin space weather monitor on Giove-A 3 rd European Space Weather Week 13-17 November 2006, Brussels K A Ryden, P A Morris, D](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649ccd5503460f94996e8f/html5/thumbnails/26.jpg)
6 days laterMERLIN-GIOVE A: CHARGING CURRENTS DUE TO TRAPPED ELECTRONS
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
27/02/200600:00
27/02/200602:24
27/02/200604:48
27/02/200607:12
27/02/200609:36
27/02/200612:00
27/02/200614:24
27/02/200616:48
27/02/200619:12
27/02/200621:36
28/02/200600:00
Date
Cu
rren
t (p
A/c
m2)
0
5
10
15
20
25
30
L (
Re)
:
B (
kGau
ss)
Shield 0.5mm, collector 0.5mmShield 1.0mm, collector 0.5mmShield 1.5mm, collector 1.0mmB (model)L (model)
![Page 27: Flight results from the Merlin space weather monitor on Giove-A 3 rd European Space Weather Week 13-17 November 2006, Brussels K A Ryden, P A Morris, D](https://reader036.vdocuments.site/reader036/viewer/2022062421/56649ccd5503460f94996e8f/html5/thumbnails/27.jpg)
Jan-May 2006: electrons & dose
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April 06 electron event
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April 06 electron event
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Single belt transit – 17th April 2006
Merlin-Giove-A: Single transit though belt 17 April 2006
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
17/04/2006 09:21 17/04/2006 10:33 17/04/2006 11:45 17/04/2006 12:57 17/04/2006 14:09
day/month/year/time
de
po
sit
ed
cu
rre
nt
/ p
A c
m-2
3.40
3.45
3.50
3.55
3.60
3.65
3.70
3.75
3.80
pro
vis
ion
al
do
se
/ k
rad
(SiO
2)
charging current (0.5mmshield, 0.5 mm collector)
charging current (1.0mmshield, 0.5mm collector)
charging current (1.5mmshield, 1.0mm collector)
dose (3mm Al eq. in +zdirection)
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Jan-Aug 2006: electrons and dose
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Jan-Aug 2006: electrons and dose
AE8/sectored shielding model of the expected dose.
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Sept & Oct 2006: electrons and dose
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Giove-A/Merlin charging currents and dose
0
0.05
0.1
0.15
0.2
0.25
28/12/2005 27/01/2006 26/02/2006 28/03/2006 27/04/2006 27/05/2006 26/06/2006 26/07/2006 25/08/2006 24/09/2006 24/10/2006
Date
Cu
rre
nt
pA
/cm
2
0
2
4
6
8
10
12
Do
se
kR
ad
s(S
iO2
)
Shield 0.5mm collector 0.5mmShield 1.0mm collector 0.5mmShield 1.5mm collector 1.0mmRadFET shield 6mmRadFET shield 3mm
Jan-Oct 2006: electrons and dose(D
aily
ave
rag
e)
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Jan-Aug 2006: electrons and FLUMIC seasonal modulation function
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Giove-A/Merlin: 1-Day Mean Charging Current
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
30/12/2005 18/02/2006 09/04/2006 29/05/2006 18/07/2006 06/09/2006 26/10/2006
Date
Ch
arg
ing
cu
rre
nt
pA
/cm
2
FLUMIC
shield 0.5mm, collector 0.5mm
Jan-Oct 2006: top SURF plate compared to DICTAT worst case
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Giove-A/Merlin: 1-Day Mean Charging Current
0.00
0.05
0.10
0.15
0.20
0.25
30/12/2005 18/02/2006 09/04/2006 29/05/2006 18/07/2006 06/09/2006 26/10/2006
Date
Ch
arg
ing
cu
rre
nt
pA
/cm
2
FLUMIC
shield 1.0mm, collector 0.5mm
Jan-Oct 2006: middle SURF plate compared to DICTAT worst case
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Giove-A/Merlin: 1-Day Mean Charging Current
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
30/12/2005 18/02/2006 09/04/2006 29/05/2006 18/07/2006 06/09/2006 26/10/2006
Date
Ch
arg
ing
cu
rre
nt
pA
/cm
2
FLUMIC
shield 1.5mm, collector 1.0mm
Jan-Oct 2006: bottom SURF plate compared to DICTAT worst case
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Jan-Aug 2006: electron spectrum ‘hardness’
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6th July 2006 – minor SPEGiove-A/Merlin
6th July 2006 event
0.001
0.01
0.1
1
10
100
05 July 12:00 06 July 00:00 06 July 12:00 07 July 00:00 07 July 12:00 08 July 00:00 08 July 12:00 09 July 00:00
Date
Flu
x (
cm
-2.s
-1)
0.0001
0.001
0.01
0.1
1
10
100
Cu
rren
t (p
A/c
m2 )
Coincident ProtonsIon channel 1Charging current
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Merlin Giove-A Integral LET Spectra 1st Aug - 31st Oct 2006
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
10 100 1000 10000 100000
LET (MeV/(g.cm -2))
Inte
gra
l F
lux (
m -2
.s -1
.sr
-1)
IonsCREME96
Background LET spectrum
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Conclusions• Good data from all Merlin sensors
– Electrons/charging rates measured at three shielding depths
– Total dose at two shielding depths
– > 40 MeV protons (500 keV deposition threshold to be sure of protons)
– LET spectrum (background)
• Numerous electron enhancement events have been observed via the charging (electron deposition) and total dose effects
• Clear 27 day interval in electron enhancements (persistent coronal holes)
• April ‘event’ was the most severe so far – ‘worst case’ events are of engineering significance and their magnitude needs to be captured
– April event still produced less than DICTAT ‘worst case’ predicted charging currents for the plates
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…..conclusions
• Ionising dose is delivered in surges during the electron events
• From Jan to August 2006, approximately half of the dose was delivered by just one electron event
• Dose at 6mm shield depth (Merlin +z direction) observed is greater than the predicted value (using AE8/sectored shielding models) at this stage: however may not be typical of whole solar cycle
• Post-script
– 2nd Merlin for NASA ‘Living with a Star’ now built & qualified