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2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005This document is the property of EADS SPACE. It shall not be communicated to third parties without prior written agreement.Its content shall not be disclosed. © EADS SPACE - 2004

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Radiation Effects on Spacecraft and Countermeasures

Selected Cases

Wolfgang KeilEADS ASTRIUM GmbH

Friedrichshafen

2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005

Radiation Effects on Spacecraft

DOCUMENTED DATA ON OBSERVED EFFECTS

SPACE WEATHER OBSERVED SELECTED CASES Predicted Effects (e. g. XMM, CLUSTER) Manifested Effects Temporary Effects

COUNTERMEASURES

Origin (Environment, Source Term) Cause (Failure Mechanism) Effects on S/C Tools for Evaluation of Source Term and Effects (e.g. SPENVIS)

Radiation behavior differentiation on:– Payload (Experiments, Instruments, Sensors, etc.)– Platform (Power subsystem, Avionics, Propulsion, OBDH, TM&TC, Thermal subsystem)

Countermeasures by Design– Radiation Analysis (criticality analysis) on unit/system level– Selection of hardened electronic parts and materials– Implementation of EDAC, TMR, etc.

Countermeasures by Operational Measures



At industry limited data is collected and evaluated on S/C behavior in orbit.

Information on in orbit performance is mainly at space operation centres (e. g. ESOC) or at Institutes (PI).

Lessons learned is a product assurance task (alerts, warning notes issuing dept. )



Documented Data on Observed Effects due to Space Environment

– excellent overview but fairly old status from 1996:

NASA-RP-1390, “Spacecraft System Failures and Anomalies Attributed to the Natural Space Environment”

or:http://www.sat-index.com (satellite news digest)



SELECTED CASES

– Predicted Effects

– Manifested Effects:

· Solar cell degradation (e. g. CLUSTER, XMM)

– Temporary Effects

· Startracker behaviour (e.g. ROSETTA)

· Bit flips and EDAC behaviour (e.g. mass memory, CLUSTER SSR)

· Measured data on SREM (e.g. ROSETTA)



Predicted Effects: ECSS-E-10-04A, ECSS-E-10-12A draft, Source Term and Effects: Tools: e.g. SPENVIS, CREME96

Cosmic ray LET spectra for typical missions



Origin of Effect: SPE: 14/15 July 2000, the Proton flux has not significantly exceeded the 1989 design flare, for >10 MeV its 24000 pfu is less than 40000 pfu in maximum (1989 flare), Particle Flux Units (pfu)=1p+ cm-2 sr-1 s-1



Manifested Effects: XMM-Newton (Solar Cells)



Manifested Effects: CLUSTER (Solar Cells), Degradation BOL (16 July 2000)-July 2005~14.8%, <5%/y; Differences in SA,

220

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Year 2001 - 2005

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sc1 sc2 sc3 sc4



SPE Nov 2001


Radiation Effects on Spacecraft -Temporary Effects - CLUSTER, courtesy ESOC/J. Volpp, L.Jagger

Proton stormsSC4 SSR Total Bit Error and Proton Flux 2003

03-Nov (1570)

30-Oct (176)

30-Oct (502)

29-Oct (227)

29-Oct (29500)

26-Oct (466) 5-Nov (353)

1

10

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1000

10000

1-Jan-03 1-Feb-03 1-Mar-03 1-Apr-03 1-May-03 1-Jun-03 1-Jul-03 1-Aug-03 1-Sep-03 1-Oct-03 1-Nov-03 1-Dec-03

Average uncertainty in plotted time = 12.29 hrs

SS

R T

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Pro

to

n flu

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/c

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/s

/s

r)

bit error proton flux

SC4 2001 Bit Error and Proton Flux

06-Nov (401)

25-Sep (112)

15-Apr (166)

15-Aug (40)26-Dec (47)

25-Sep (12900)

16-Aug (493)15-Apr (951) 26-Dec (779)

3-Apr (1110)

6-Nov (31700)

24-Nov (18900)

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1000


SS

R T

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l B

it E

rro

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10000023-Jun-00 1-Oct-00 9-Jan-01 19-Apr-01 28-Jul-01 5-Nov-01 13-Feb-02

Pro

to

n flu

x (p

/c

m-2

/s

/s

ra

d)

bit error proton flux

SC 4: 2001

SC 4: 2003

1000

10010

10000protonflux

SEUs



Temporary Effects - ROSETTA The solar flare on 8/9 Sept. 05, hit the spacecraft at the

beginning of the weekly non-coverage period. When the signal was acquired for the weekly contact on 15 Sept. the spacecraft was found with the active Star Tracker crashed in INIT mode, and the second Star Tracker (not used for attitude control) in Standby mode.

AOCS had determined the attitude over a period of 6 days using gyroscopes only, and accumulated therefore a drift of about 0.7 degrees, of which 0.3 degrees offset in the High Gain Antenna pointing direction, small enough to allow the RF signal to be received on ground. The recovery activities took most of the ground station pass on 15 Sept. At the end both Star Trackers were back in tracking mode and the nominal attitude reacquired.


Radiation Effects on SpacecraftTemporary Effects - ROSETTA Position SREM Measurements at 1.23-1.6 AU

EARTH

MARS

ROSETTA

30° behind Earth


Radiation Effects on SpacecraftTemporary Effects - ROSETTA SREM Measurements, courtesy P.Nieminen, ESTEC

Rosetta SREM vs. GOES proton data, solar event of 8 September 2005

SREM on Rosetta

GOES



COUNTERMEASURES Detailed knowledge necessary on:

– Origin (Environment, Source Term)

– Cause (Failure Mechanism)

· Total Ionizing Dose

· Single Event Effects (SEU, SEL, SEGR, SEB)

· Displacement Effects

– Effects on S/C

· specified parameters and reliability

– Tools for Evaluation of Source Term, Effects (e.g. SPENVIS , CREME96, GEANT4)



Radiation Damage on Semiconductor



Proton Interaction



Interaction with galactic cosmic rays and Si (ions)



Bit flip in Memory Cell (SEU)



Latch up



Displacement Effects (e. g. solar cell, opt.): Nonionising energy loss (NIEL) manifesting

in lattice defects Lattice defects by ejection of atoms from

their equilibrium position due to incident particles with suitable kinetic energy

Knocked out atom position may be taken by the displacing ion

Affected electrical parameters: leakage current, conductivity, mobility of carriers



Radiation Sensitivity of Parts

CMOS (SOS/SOI) (insensitive)CMOSAPSStandard bipolar (bad low dose rate performance, some degrade unbiased)Low power Schottky bipolarNMOS DRAMs (highest sensitivity)CCD (ideal particle counter, SOHO)



Radiation response behavior differentiation on: – Payload (Experiments, Instruments (laser crystal), Sensors

(CCD, APS, HgCdTe), glas windows, etc.)

– Platform (Power subsystem, Avionics, Propulsion, OBDH,

TM&TC, Thermal subsystem -degradation)



Countermeasures by Design– Selection of hardened electronic parts and materials

– Irradiation Tests (total dose, SEU tests)

– Implementation of shielding (intelligent selection of absorbing

material)

– Implementation of EDAC, TMR etc.

– Redundancy of boards, units (not useful for weak devices)

Countermeasures by Operational Measures– Operational concept (e. g. XMM) (not suitable for SW events)

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