This 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 All the space you need 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft and Countermeasures Selected Cases Wolfgang Keil EADS ASTRIUM GmbH Friedrichshafen

Page 1 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

Page 2 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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. )

Page 3 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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: (satellite news digest)

Page 4 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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)

Page 5 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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

Page 6 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Origin of Effect: SPE: 14/15 July 2000, the Proton flux has not significantly exceeded the 1989 design flare, for >10 MeV its pfu is less than pfu in maximum (1989 flare), Particle Flux Units (pfu)=1p + cm -2 sr -1 s -1

Page 7 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Manifested Effects: XMM-Newton (Solar Cells)

Page 8 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Manifested Effects: CLUSTER (Solar Cells), Degradation BOL (16 July 2000)-July 2005~14.8%, <5%/y; Differences in SA,

Page 9 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  SPE Nov 2001

Page 10 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft - Temporary Effects - CLUSTER, courtesy ESOC/J. Volpp, L.Jagger Proton storms SC 4: 2001 SC 4: proton flux SEUs

Page 11 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft 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.

Page 12 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft Temporary Effects - ROSETTA Position SREM Measurements at AU EARTH MARS ROSETTA 30° behind Earth

Page 13 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft Temporary Effects - ROSETTA SREM Measurements, courtesy P.Nieminen, ESTEC Rosetta SREM vs. GOES proton data, solar event of 8 September 2005 SREM on Rosetta GOES

Page 14 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft 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)

Page 15 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Radiation Damage on Semiconductor

Page 16 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Proton Interaction

Page 17 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Interaction with galactic cosmic rays and Si (ions)

Page 18 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Bit flip in Memory Cell (SEU)

Page 19 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Latch up

Page 20 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft 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

Page 21 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  Radiation Sensitivity of Parts CMOS (SOS/SOI) (insensitive) CMOS APS Standard bipolar (bad low dose rate performance, some degrade unbiased) Low power Schottky bipolar NMOS DRAMs (highest sensitivity) CCD (ideal particle counter, SOHO )

Page 22 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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)

Page 23 2nd European Space Weather Week - Presentation_Keil.ppt - 17 Oct 2005 Radiation Effects on Spacecraft  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)