MONTHLY PROGRAM STATUS REVIEW

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Section 5 Probabilistic Risk Assessment
. . . Ron Duphily TRW Space Technology Division
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Failure Severity Criticality Categories for FMEAs

• Severity criticality codes for these FMEAs are
  defined as follows
• 1) Effective loss of the Mission (non-recoverable
  complete loss of ALI data)
• 2) Loss of the Hyperion Mission (non-recoverable
  complete loss of Hyperion data)
• 3) Serious degradation, but still meets some of
  the Level I ALI and/or Hyperion requirements
• 4) Some degradation or operations impact, but
  still achieves the baseline mission
• 5) Little or no impact to mission success or
  mission operations
• Some examples are
• Category 1 Power System, ACS, WARP, or ALI
  instrument dying completely
• Category 2 Hyperion instrument failing by
  itself
• Category 3 A Hyperion ASP failure, or an X-Band
  Phased Array failure
• Category 4 Heaters
• Category 5 PPT, GPS, AC, etc.

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EO-1 Minimal MissionReliability Block Diagram
Attitude Control Subsystem (ACS)
Electrical Power Subsystem (EPS)
Communications Subsystem (CS)
Command Data Handling Subsystem (CDHS)
Reaction Control Subsystem (RCS)
0.9490
0.9679
0.9535
0.9638
Has Redundancy
0.9999
ALI
WARP
Reliability _at_ 1 year 0.7447 Failure Likelihood
0.2553
0.8960
0.9846
? Failure Rate in Failures per Billion Hours
Has Consequence Category 1 from FMEA
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Attitude Control Subsystem (ACS)Reliability
Block Diagram
FMEA ID 8.0
FMEA ID 6.2
FMEA ID 6.3
FMEA ID 6.4
FMEA ID 6.1
ACS LVPC
ACE RSN
ACE I/O
Prop I/O
RWA (x3)
Redundant Thruster Valves Cat Bed Heaters
?400
?650
?800
?1670
FMEA ID 11.0
FMEA ID 12.0
FMEA ID 13.0
FMEA ID 9.0
FMEA ID 10.0
Coarse Sun Sensors (3)
Magnetic Torquer Bars (MTB)x3
Three Axis Magnetometer TAM
Autonomous Star Tracker
IRU (3 Gyros)
?48
?1609
?390
?408
Update IRU Data with TAM Ground
Ops Interventions
? Failure Rate in Failures per Billion Hours
Reliability _at_ 1 year 0.9490 Failure Likelihood
0.0510
Has Consequence Category 1 from FMEA
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Electrical Power Subsystem (EPS)Reliability
Block Diagram
FMEA ID 1.7
FMEA ID 1.10
FMEA ID 1.9
FMEA ID 1.11
PSE RSN
PSE LVPC
Power Output Module 1
Power Output Module 2
?650
?900
?400
?900
FMEA ID 1.5
FMEA ID 2.2
FMEA ID 1.6
FMEA ID 1.4/1.8
Battery (21/22 cells-Short) (22/22 cells-open)
Battery Charge Module
Battery Enable Relay Box (BERB)
Yoke/SADA Hinge
?110
Redundant Batt Temp
Outside panel has power
Triple-redundant relays
R.9999726
R.9999678
FMEA ID 1.3
FMEA ID 2.1
FMEA ID 1.1
FMEA ID 3.0/1.2
SADA Motor Electronics
Solar Array
Solar Array Module
Solar Array Release (HOPs)
?636
Redundant Strings
Redundant HOPs
Redundant windings Electronics
R.9994829
R.9995
Reliability _at_ 1 year 0.9679 Failure
Likelihood 0.0321
R.9999878
? Failure Rate in Failures per Billion Hours
Has Consequence Category 1 from FMEA
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Command Data Handling (CDH) Reliability Block
Diagram
FMEA ID 5.2
FMEA ID 5.1
FMEA ID 5.3
FMEA ID 5.4
Redundant Fiber Optic Harness
Redundant Star Coupler
Redundant Data Bus Controller
R.9999907
R.9999878
R.9999726
Has Consequence Category 1 from FMEA
Reliability _at_ 1 year 0.9638 Failure
Likelihood 0.0362
? Failure Rate in Failures per Billion Hours
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Communications Subsystem (CS)Reliability Block
Diagram
FMEA ID 15.2
FMEA ID 15.1
FMEA ID 15.3
FMEA ID 15.4
S-Band Transponder and Diplexer
Omni Antennas (2)
3 db Hybrid
20 db Directional Coupler
?5430
Test port
Not credible failure R 1.0
Failure not credible R1.0
FMEA ID 16.1.2/16.1.3/16.2/16.3/16.4
FMEA ID 14.9
FMEA ID 16.1.1
X-Band Modulator (RF Exciter)
X-Band Phased Array Antenna
X-Band RSN
Use S-Band as backup Redundant RT tranceiver Loss
of 1/2 of XPAA elements OK
Use S-Band as backup
Use S-Band as backup
Reliability _at_ 1 year 0.9535 Failure
Likelihood 0.0465
? Failure Rate in Failures per Billion Hours
Has Consequence Category 1 from FMEA
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Reaction Control Subsystem (RCS)Reliability
Block Diagram
FMEA ID 7.1
FMEA ID 7.4
FMEA ID 7.3
FMEA ID 7.2
Propellant Tank Press. Transducer
Hydrazine Thruster Valves
Thruster Cat Bed Heaters
Hydrazine Latch Valve
Failure to open is category 3
Redundant valves
Redundant Heaters
Tank Press. TLM not required
R.9999981
R.9999963
FMEA ID 6.3
Prop I/O (from ACS)
Reliability _at_ 1 year 0.999967 Failure
Likelihood 0.000033
R.9999726
Has Consequence Category 1 from FMEA
? Failure Rate in Failures per Billion Hours
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WARP Reliability Block Diagram
FMEA ID 14.5
FMEA ID 14.2 14.3
Duty Cycle 10
FMEA ID 14.1
FMEA ID 14.4
RS-422 Input
LVPC/RSN
Processor
Power Filter Box
?1120
?1940
?4541
?300
Memory 1
FMEA ID 14.9
Duty Cycle 12
FMEA ID 14.6
Memory Interface
RF Exciter
?7790
FMEA ID 14.7 14.8
Use S-Band backup mode
?4131
Memory 2
R.99565
Reliability _at_ 1 year 0.8960 Failure Likelihood
0.1040
Has Consequence Category 1 from FMEA
?Failure Rate in Failures per Billion Hours
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ALI Reliability Block Diagram
FMEA ID 17.1
FMEA ID 17.2
FMEA ID 17.3
FMEA ID 17.4
FMEA ID 17.5
FPA (4 SCAs)
Focal Plane Electronics (FPE)
Mechanisms
ALI Control Electronics (ALICE)
Calibration Lamps 5DC 1/2 Stdby
Redundant Launch Latch Backup cover opening
mechanism
?906
?840
Redundancy
Redundant
R.9997966
R.9999929
R.9999512
FMEA ID 17.7
FMEA ID 17.6
FMEA ID 17.8
FMEA ID 17.9
Radiator Heater Sensors
Focal Plane Heater Sensors
Outgas Heaters
Telescope Heaters
Use radiator, Bar heater sensor as backup
Use Bar heater Sensor as backup
Degradation of data
Degradation of data
R.9999969
R.9999969
? Failure Rate in Failures per Billion Hours
Reliability _at_ 1 year 0.9846 Failure
Likelihood 0.0154
Has Consequence Category 1 from FMEA
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Hyperion Reliability Block Diagram
SWIR
DC/DC Converter
Analog Board
Clock Bias Board
Digital Board
Focal Plane Electronics
Cryo Cooler Electronics
?300
?25
?47
?65
?400
?1430
VNIR
DC/DC Converter
Analog Board
Clock Bias Board
Digital Board
Focal Plane Electronics
?300
?25
?47
?65
?400
HEA
Cover Motor Bearings
Motor/ Heater Drive Board
Microprocessor
Data Formatter
DC/DC Converter
Telemetry Board
?183
?100
?950
?200
?300
?100
Hyperion single point failure
Reliability _at_ 1 year 0.9839 Failure Likelihood
0.0161
?Failure Rate in Failures per Billion Hours
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EO-1 FMEA Category 1 Failure Probabilities
13
Hyperion Unit Failure Probabilities
14
EO-1 FMEA Category 1R Failure Probabilities
15
_at_ 4 mos 0.90 for Minimal Mission
0.75
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PRA Summary

• Reliability at 1 year for FMEA Category 1
  0.7491
• Reliability at 1 year for FMEA Category 1R
  0.9941
• Redundant 1R items have small impact on
  reliability
• Reliability at 1 year for Category 1 1R
  0.7447
• If 1R items were not redundant then R 0.6917
• Category 1 single point failures are primary
  drivers of residual risk.
• Completing Minimal Mission in 4 months has
  acceptable failure probability of 10.