Ref. ID BX-EPS-SP4-120-01
Class CDRL
Phase SP4 – Preliminary Design
Pages 23
BX – SAT
PROJECT :
Failure Mode Effects Analysis
TITLE:
for Electrical Power Subsystem
Confirmed by
Written by
PABLO CALLA
Reviewed by
KATTIA FLORES
Form Checked by
LUIS SILVA
Approved by
ANTONIO MENDOZA
09
—
17
—
2013
CAST Shenzhou Institute
ABSTRACT
This document details the FMEA (Failure Mode Effect Analysis) for Electrical
Power Subsystem of BX-SAT Virtual Satellite Project, containing definitions for the
mission and the stages, severity and probability criteria, the Single Point Failures found
and the complete FMEA sheet.
KEY WORDS
CHANGE INFO
Serial No.
Date
Changed by
Methods
LIST OF ACRONYMS
ACRONYMS
DEFINITION
FMEA
Failure Mode Effects Analysis
CAST Shenzhou Institute
Page:
4 / 23
Content
1
Scope ............................................................................................................................. 6
2
Applicable Documents .................................................................................................. 6
3
Definition of FMEA ...................................................................................................... 6
3.1
3.2
3.3
3.4
3.5
4
Definition of Stages .......................................................................................................... 6
Definition of Mission Success .......................................................................................... 8
Definition of Severity Classification Categories .............................................................. 8
Definition of Probability of Occurrence ........................................................................... 9
Definition of SPF (Single Point Failure) .......................................................................... 9
FMEA ............................................................................................................................ 9
4.1
Assumption of the Analysis .............................................................................................. 9
4.2
FMEA Analysis ............................................................................................................... 10
4.2.1 Single Point Failures................................................................................................... 10
4.2.2 FMEA Sheet ................................................................................................................11
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
5 / 23
List of Tables
Table 1 – Working Modes...................................................................................................... 7
Table 2 – Severity Classification Category ........................................................................... 8
Table 3 – Probability of Occurrence ...................................................................................... 9
Table 4 – Single Point Failure table..................................................................................... 10
Table 5 – PCU FMEA table ................................................................................................. 11
Table 6 – Solar Array FMEA table ...................................................................................... 15
Table 7 – Battery – BCRB - FMEA table ............................................................................ 18
Table 8 – PIU FMEA Stage I-table ...................................................................................... 20
Table 9 – PDU - APS FMEA table ...................................................................................... 22
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
6 / 23
Failure Mode Effect Analysis
Electrical Power Subsystem
1 Scope
This document presents the principles and requirements regarding the Failure Mode Effect
Analysis implementation for the Electrical Power Subsystem of BX-SAT.
2 Applicable Documents
BXTP-SZI-01
BX-SAT Request for Proposal
BXTP-RD-02
BX-SAT Statement of Work
ECSS-Q-ST-30-02C
Failure Mode Effects Analysis Standard
BX-SYS-SP3-219-01
Preliminary Technical Requirements for System
3 Definition of FMEA
3.1 Definition of Stages
There are two (2) stages defined for the BX-SAT Project FMEA Analysis, in this stages
there are different working modes (see Table 1 for Working Modes).
The Stage I (Launch/Transfer/IOT phase) period corresponds from the lift-off up to the end
of the IOT (In Orbit Test) and it is approximately 960 hours. For the Launch and Transfer
phase is considered about 240 hours (considering an adjustment factor for failure rates) and
for the IOT (In-Orbit Acceptance Test period) is considered about 1 month (around 720h).
In Stage II (Operational Phase) period corresponds from the end of the IOT up to the end
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
7 / 23
of life (EOL) and it is approximately 131400 hours (15 years).
Table 1 – Working Modes
(Corresponding to the BX-SYS-SP3-219-01.doc)
WORKING MODES
DESCRIPTION
Pre launching mode
Some equipment must be power on in the
fairing for pre launch testing
Launch Mode (with Launch Vehicle)
Some equipment should powered on, to
maintain good condition of satellite
Injection orbit GTO
STAGE I
Intermediate orbit 1
LEOP (Launch and
Earlier Orbit
Operation –
Transfer Phase)
Intermediate orbit 2
Intermediate orbit 3
Intermediate orbit 4
Drift orbit
Earth acquisition
Gyro calibration
Establish firing attitude
Apogee maneuver
Turn back to sun acquisition
Earth acquisition
Gyro calibration
Establish firing attitude
Apogee maneuver
Turn back to earth pointing
Gyro calibration
Establish firing attitude
Apogee maneuver
Turn back to earth pointing mode
Gyro calibration
Establish firing attitude
Perigee maneuver
Turn back to earth pointing mode
Antenna reflectors deployment
Wheel spin-up to establish the normal attitude
Position acquisition
Test the satellite before deliver to customer
IOT (In Orbit Test)
STAGE II
Earth acquisition
Gyro calibration
Establish firing attitude
Apogee maneuver
Turn back to sun acquisition
Solstice Season
(Summer, Winter)
Equinox Season
(Sunlight, Eclipse )
GEO (Operational
Phase)
De-Orbit
At the End of Life put satellite 300 km above
GEO
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
8 / 23
3.2 Definition of Mission Success
The mission success depends on the spacecraft design that shall have a probability of
success that exceeds the one required in the Request for Proposal.
For the Pre-Operational Phase (Stage I), assuming that there was no problem in the Launch
Phase or in the Separation Phase, the mission success is considered when the satellite is
positioned in GEO, the solar panel, the east and west antennas are fully deployed.
In the Operation Phase (Stage II), assuming that all the transponders, the payload in
general and all the component of the different subsystems meet their respective
performance; the mission success is considered when the satellite fully completes the
131400 working hours.
3.3 Definition of Severity Classification Categories
Table 2 – Severity Classification Category
Severity Category
Severity Description of Consequences (failure effects)
Level
Failure Effect
Catastrophic
1
Failure propagation
Critical
2
Loss of mission
Major
3
Major mission degradation
Minor or Negligible
4
Minor mission degradation or any other effect
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
9 / 23
3.4 Definition of Probability of Occurrence
Table 3 – Probability of Occurrence
Possibility
Definition
A
Very Likely – Frequent
B
Medium Likely – Probably
C
Likely – Occasionally
D
Unlikely – Seldom
E
Extremely Unlikely – Improbable
3.5 Definition of SPF (Single Point Failure)
A SPF or Single Point Failure is a failure of a single unit or component which causes a loss
of the satellite mission or failure propagation (That means Severity Level 1 and 2) and has
no compensating measures.
4 FMEA
4.1 Assumption of the Analysis
The assumptions for the Failure Mode Analysis in the BX-SAT Project are the followings:

The FMEA Analysis will be done considering the experience of the trainees and the
experience and guidance of the tutors.

The failures are considered one at a time and will be analyze independently and
separated from other failures.

Failures caused by wear-out are not considered because the lifetime of the satellite
equipments exceeds the mission duration (15 years).

Any failure caused by human factor is not considered.
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
Page:
10 / 23
4.2 FMEA Analysis
4.2.1 Single Point Failures
Table 4 – Single Point Failure table
Subsystem : EPS – Electrical Power Subsystem
Failure Mode
End Effect or
Effect on System
Control Measures
Recommendations
1
Solar Array
EED
Pyro cutter
malfunctions.
Deployment failure
of one wing, major
degradation on
power supply.
Pyro cutter test, EED
test. Inspection
procedures.
3
PCU
Capacitor Short
circuit on a module.
BCR, BDR, TMTC
Loss of the mission
Self healing
capacitors.
Circuit protections.
BDR Transformer
Loss of a battery.
Major degradation
on power supply.
Double lip lacquer
techniques are used.
Redundancy is also
considered
MEA error
Main bus
overvoltage or
voltage drop. Lose
of inside
equipment, Loss of
mission
Redundancy rings
considered.
Manufacture
inspection
No Item
4
5
PCU
PCU
6
PCU
Main Bus
Disconnection
Loss of the mission
The shunt bar
material is alloy to
ensure the
connections
7
PIU
Function failure, Pyro
cutters failure
Loss of mission
Ground tests and
inspection
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this
document is reserved by CSI and shall not be released to third party without a written authorization of CSI.
CAST Shenzhou Institute
4.2.2
Page:
11 / 23
FMEA Sheet
Table 5 – PCU FMEA table
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PCU
Checked by :
EP Subsystem
Date :
08/20/2013
Failure Effects
No.
Item
Failure Mode
Possible
Failure Cause
Local Effects
End Effects
1
S3R
1 Section Failure
Switch
malfunction
Loss in the total
power
2
BCR
Charge current
setting failure
BCR register
failure,
connection lost
Battery
overcharge or
not charging
BCR
1 BCR failure
Connection lost,
short circuit
Battery
overcharge or
not charging
4
BCR
Cannot set the
charge mode
BCR connection
lost, BCR
malfunction
Battery
overcharge or
not charging
5
BCR
Loss of
telemetry
Short circuit
Component
Measure loss
6
BCR
Loss of the
telecommand
Short circuit
No Ground
Control over
the module
3
Criticality
Less power
supply
capability
Battery
degradation,
total
discharge
Loss of
mission
Battery
degradation,
total
discharge
Parameter
Monitoring
Loss
Battery
degradation
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
Seve
rity
Single
Point
Failure
4
N
E
Not measurable
3
N
E
No change in the
charge current
E
Battery charge
current, bus current
and temperature
monitoring
Module
Redundancy to
be considered
Keep a redundancy
active
Physical and
software
redundancy
considered.
PCU testing
1
N
Internal circuitry
redundancy
considered
Physical and
software
redundacy
considered.
Keep a margin for the
number of switches
PCU testing
3
N
E
No charge sequence
measured
3
N
E
No parameter data
Robust Software
algorithm
PCU testing
4
N
E
Parameters cannot
be modified
Robust Software
algorithm
PCU testing
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
12 / 23
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PCU
Checked by :
EP Subsystem
Date :
08/20/2013
Failure Effects
No.
Item
Failure Mode
Possible
Failure Cause
7
BDR
1 BDR failure
Connection lost,
short circuit
8
BDR
Loss of
telemetry
Short circuit
9
BDR
Loss of the
telecommand
Short circuit
10
BDR
Transformer
failure
Short circuit
Criticality
Seve
rity
Single
Point
Failure
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
Redundancy is
considered
Keep a redundancy
active
Local Effects
End Effects
No battery
discharge, or
total battery
discharge
Satellite
power loss
1
N
E
No discharge in
eclipse mode, or
continue discharge
in solstice
Component
Measure loss
Parameter
Monitoring
Loss
3
N
E
No parameter data
Robust Software
algorithm
PCU testing
Battery
degradation
4
N
E
Parameters cannot
be modified
Robust Software
algorithm
PCU testing
Loss of a
battery
1
Y
E
BDR status changed
Redundancy
rings.
Use of Double lip
lacquer techniques.
1
Y
E
Main bus voltage
drop or overvoltage
measurements
Redundancy
rings considered
Inside circuitry
redundancy
No Ground
Control over
the module
The battery
affected cannot
supply power
11
MEA
MEA error
Short circuit,
unit failure,
control error
Main bus
control loss
Main bus
overvoltage or
voltage drop.
Lose of inside
equipment,
Loss of
mission
12
Filter
Capaci
tor
Failure
Short circuit or
open circuit
Main bus
voltage
changes
Main bus
ripple
3
N
E
Main bus variable
voltage
measurement
13
Regula
tor
Capaci
tor
Failure
Short circuit
Loss of the
regulator
Loss of the
mission
1
Y
E
Regulator Status
changed
Components in
parallel or series
considered
Manufacture and
model
inspection.
Redundancy
rings
Special component
manufacture
Use of self healing
capacitors
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
13 / 23
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PCU
Checked by :
EP Subsystem
Date :
08/20/2013
Failure Effects
No.
Item
Failure Mode
Possible
Failure Cause
Criticality
Local Effects
End Effects
Seve
rity
Single
Point
Failure
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
12
TM/T
C
ML failure
Short circuit
Component
Measurement
loss
Parameter
Monitoring
Loss
3
N
E
No parameter data
Robust Software
algorithm
PCU testing
13
TM/T
C
DS failure
Short circuit
Component
Measurement
loss
Parameter
Monitoring
Loss
3
N
E
No parameter data
Robust Software
algorithm
PCU testing
Loss of control,
in case of
overvoltage.
Main bus
overvoltage.
Possible loss
of equipment
due to
overvoltage.
2
N
E
Overvoltage
measurements
Redundancy
component is
considered
Redundancy inside the
component
Loss of control,
in case of
overvoltage.
Main bus
overvoltage.
Possible loss
of equipment
due to
overvoltage.
2
N
E
Overvoltage
measurements
Redundancy
component is
considered
Redundancy inside the
component
Main bus
voltage drop,
local overheat.
Less power
supply
capability,
low
equipment
performance.
E
Considerable
voltage drop
observed.
Physical and
software
redundancy on
BCR and S3R
considered
PCU testing
14
15
16
OVP
OVP
PCU –
Main
Bus
Function loss
Unnormal action
(switch connect
itself)
Main Bus
overload
Open circuit
(switch cannot
connect)
Unit Failure
Not enough
power from S3R
or BDR.
2
N
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
14 / 23
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PCU
Checked by :
EP Subsystem
Date :
08/20/2013
Failure Effects
No.
17
17
18
19
Item
Main
bus
Harnes
s
Primar
y
Groun
ding
Second
ary
Groun
ding
Failure Mode
Disconnection
Harness
isolation Loss
Grounding fault
Grounding fault
Possible
Failure Cause
Criticality
Seve
rity
Single
Point
Failure
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
Shunt bar adopts
alloy material
for the
connections
Inspection during
manufacture
Special component
manufacture
Local Effects
End Effects
Loss of any part
with the main
bus connection.
SA, batteries or
PDU
Complete loss
of the unit
affected
Failure of the
mission
1
Y
E
Observable by
Telemetry
Degradation,
short circuit
Power loss,
mayor
degradation in
current
transmission
Less power
supply
capability
3
N
E
Considerable
reduction on the
PCU output current.
Redundant
component is
considered.
S/c of
BDR/BCR to
ground
Transformer
primary and
secondary
winding short
circuit or
input/output
filter capacitor
short circuit
Insufficient
power during
eclipse;
TM/TC signal
distortion
None
Double dip
lacquer
techniques for
transformer
windings.
S/c of
PFDU/PLDU to
ground
Transformer
primary and
secondary
winding short
circuit or
input/output
filter capacitor
short circuit
Insufficient
power during
eclipse;
TM/TC signal
distortion
None
Double dip
lacquer
techniques for
transformer
windings.
2
2
N
N
E
E
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
15 / 23
Table 6 – Solar Array FMEA table
Subsystem :
EPS
Prepared by :
EP subsystem
Equipment :
Solar array
Checked by :
EP subsystem
Date :
08/20/2013
Failure Effects
No.
Item
1
Solar
array
2
Solar
array
3
Solar
array
Failure Mode
EED failure
Telemetry loss
1 string failure
Possible
Failure Cause
Local Effects
Criticality
End Effects
Pyro cutter
malfunction,
PIU failure
Not
deployment of
one wing.
Major
degradation on
power
generation.
Loss of
mission
Short circuit
Component
Measure loss
Parameter
Monitoring
Loss
Short circuit,
Degradation
Little loss in
power supply
generation
Less power
supply
capability
Seve
rity
1
3
4
Single
Point
Failure
Y
N
N
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
E
Not enough power
generation. No
current is measured
in the affected solar
array.
Pyro cutter
command
redundancy.
Ground
telecommand.
Keep redundancy active
E
No current or
temperature
measure on the solar
array
Lost measure
estimation
SA testing; PCU testing
Little drop in the SA
output current value.
Guarantee the
correct
functioning of
the subsystem
considering this
error as possible
SA testing; Keep a safe
power margin
D
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
16 / 23
Subsystem :
EPS
Prepared by :
EP subsystem
Equipment :
Solar array
Checked by :
EP subsystem
Date :
08/20/2013
Failure Effects
No.
Item
Failure Mode
Possible
Failure Cause
Local Effects
Criticality
End Effects
Seve
rity
Single
Point
Failure
Pro
bab
ility
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
SA testing; Keep a safe
power margin
4
Solar
array
1 section failure
Short circuit,
Degradation
Loss in power
supply
generation
Less power
supply
capability
3
N
E
Considerable drop
of the SA output
current value.
Guarantee the
correct
functioning of
the subsystem
considering this
error as possible
5
Solar
array
One connector
power loss
Lose connection
1/4 power
loss in
generation
Insufficient
EOL power
1
N
E
Considerable drop
of the SA output
current value.
Each connector
has a double
fixation point
2 power connector per
wing, total 4
Considerable drop
of the SA output
current value.
Guarantee
Mechanism
correct
functioning.
Recalibrate by
software or by
telecommand
SA testing; Mechanism
testing
6
Solar
array
Solar tracking
error
Solar tracker
error, SADA
decalibration
Loss in power
supply
generation
Less power
supply
capability
3
N
E
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
17 / 23
Subsystem :
EPS
Prepared by :
EP subsystem
Equipment :
Solar array
Checked by :
EP subsystem
Date :
08/20/2013
Failure Effects
No.
7
Item
Solar
array
Failure Mode
No solar
tracking
Possible
Failure Cause
Solar tracker
error, SADA
failure
Criticality
Local Effects
End Effects
Loss in power
supply
generation
Less power
supply
capability
Seve
rity
1
Single
Point
Failure
N
Pro
bab
ility
E
Detection method /
observable
symptoms
Compensating
provisions
Recommendations and
Remarks
Considerable drop
of the SA output
current value.
Reset the
software, ensure
mechanism
functioning.
SA testing; Mechanism
testing
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
18 / 23
Table 7 – Battery – BCRB - FMEA table
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
Battery - PIU
Checked by :
EP Subsystem and tutor
Date :
08/20/2013
Failure Effects
No.
1
Item
Battery
Failure Mode
1 cell failure
2
Battery
3
Battery
Overcharge
4
Battery
Over
temperature
Telemetry loss
Possible
Failure Cause
Internal cell
failure
Short circuit
Pressure sensor
malfunction;
BCR
malfunction
Temperature
sensor
malfunction;
BCR
malfunction;
Battery cell
malfunction
Criticality
Seve
rity
Single
Point
Failure
3
N
Proba
bility
Local Effects
End Effects
Loss of capacity
of one cell,
decrease of
battery voltage
Increase of
DOD; No other
effects as long
as no other
failure occurs
Component
Measure loss
Parameter
Monitoring
Loss
4
N
E
Degradation on
battery life.
Degradation on
power supply
capability
3
N
E
Degradation on
battery cell’s
life.
Degradation on
power supply
capability
3
N
E
E
Detection
method /
observable
symptoms
Compensatingpr
ovisions
Recommend
ations and
Remarks
TM cell voltage
Battery
oversizing
more cells on
each battery
Lost measure
estimation
Battery
testing; PCU
testing
Lost measure
estimation
Battery
testing; PCU
testing
Lost measure
estimation
Battery
testing; PCU
testing
No current,
voltage, pressure
or temperature
measure on the
Battery
Over pressure
detected; Over
voltage on the
battery
Over
temperature
detected;
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
Battery - PIU
Checked by :
EP Subsystem and tutor
Date :
08/20/2013
Failure Effects
No.
19 / 23
Item
Failure Mode
Possible
Failure Cause
Criticality
Local Effects
End Effects
Seve
rity
Single
Point
Failure
Proba
bility
Detection
method /
observable
symptoms
Compensatingpr
ovisions
2 TM per battery
5
Battery
Loss of one
strain gauge
resistor failure
Loss of one TM
cell pressure
No effects as
long as no other
effect occurs
3
N
D
TM cell pressure
6
Battery
Recondition
circuit loss
Loss of
reconditioning
controller circuit
Loss of
reconditioning
function
No effects as
long as no other
effect occurs
3
Y
E
TM
7
BCRB
Circuit
disconnection
(drop)
Power relay
disconnection
Reduction of
power margin.
4
N
C
TM
8
BCRB
Telemetry loss
Short circuit
Component
Measure loss
(TM)
No effects as
long as other
failures occurs
Parameter
Monitoring
Loss
4
N
E
9
BCRB
Telecommand
loss
Short circuit
Component
Control loss
(TC)
Parameter
Monitoring
Loss
4
N
E
No current or
voltage measure
on the BCRB
No current,
voltage, pressure
or temperature
measure on the
BCRB
Recommend
ations and
Remarks
Battery
testing; PCU
testing
The charge
and discharge
fulfills the
same
functions, the
function of
reconditionin
g act as the
secondary
means
Redundancy of
power relay
Resend TC to
reconnect
Lost measure
estimation
BCRB
testing; PCU
testing
Lost measure
estimation
BCRB
testing; PCU
testing
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
20 / 23
Table 8 – PIU FMEA Stage I-table
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PIU
Checked by :
EP Subsystem and tutor
Date :
08 – 20 - 2013
Failure Effects
No.
1
2
3
Item
PIU
PIU
PIU
Failure Mode
Possible Failure
Cause
Criticality
Single
Point
Failure
Pro
bab
ility
Detection
method /
observable
symptoms
Compensating
provisions
Recommendation
s and Remarks
Local Effects
End Effects
Seve
rity
Short circuit
Component
Control loss
and operation
failure
Parameter
Monitoring
Loss; Lost of
the mission
1
N
E
No signal of the
PIU
Redundancy rings
Doble fixation
point connectors
Telemetry loss
Short circuit
Component
measure loss
and possible
operation
failure
Parameter
Monitoring
Loss; Possible
lost of the
mission
1
N
E
No current or
voltage measure
on the PIU
Lost measure
estimation
Doble fixation
point connectors
Procedure
control circuit
loss
Failure of the
oscillation,
frequency division,
clock distribution
or pulse generating
circuit
Procedure
loss
Possible
mission
failure
3
N
E
No deployment
process signals
Independent circuits
for main or redundant
part
Inspection. tests
Telecommand
loss
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PIU
Checked by :
EP Subsystem and tutor
Date :
08 – 20 - 2013
Failure Effects
No.
4
5
21 / 23
Item
PIU
PIU
Failure Mode
Possible Failure
Cause
Local Effects
Criticality
End Effects
Seve
rity
Single
Point
Failure
Pro
bab
ility
Detection
method /
observable
symptoms
Compensating
provisions
Recommendation
s and Remarks
Inspection. tests
Doble fixation
point connectors
function failure
Failure of the
procedure control
termination unit,
pyro failure
Pyro cutter
failure
Mission loss
1
Y
E
TM signals
If the procedure fails,
ground control can
operate the component
trough TC.
Power supply
failure
Conection lost
Faliure of the
operation
Mission
failure
1
N
E
Power on
telemetry signal
Redundancy
connection rings
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
22 / 23
Table 9 – PDU - APS FMEA table
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PDU - APS
Checked by :
EP Subsystem and tutor
Detection
method /
observable
symptoms
Compensating provisions
Date :
08 – 20 - 2013
Failure Effects
No.
1
Item
PDU
Failure Mode
Possible
Failure Cause
Criticality
Local
Effects
End Effects
Prob
abilit
y
Seve
rity
Single
Point
Failure
1
N
E
TM
Overvoltage and over current
protection; redundant design
in function level
Converter
failure
Internal Failure
None
The equipments
or components
cannot operate;
Affect the
spacecraft power
supply safety
Without
power input,
the devices
cannot work
Failure of the
mission
1
N
E
TM
Each connector has a double
fixation point
2
PDU
switch failure
Loose
connection of
the connector
3
PDU
Loss of a heater
distribution
circuit
Conenction
loss
Loss of a in
the
spacecraft
Loss in the
thermal control
2
N
E
TM state
Each connector has a double
fixation point
PDU
Loss of many
heater
distribution
circuit
Conenction
loss
Loss of
many heaters
in the
spacecraft
Loss in the
thermal control
1
N
E
TM state
Each connector has a double
fixation point
4
Recommendations
and Remarks
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.
CAST Shenzhou Institute
Page:
23 / 23
Subsystem :
EPS
Prepared by :
EP Subsystem
Equipment :
PDU - APS
Checked by :
EP Subsystem and tutor
Detection
method /
observable
symptoms
Compensating provisions
Date :
08 – 20 - 2013
Failure Effects
No.
5
Item
PDU
Failure Mode
Loss of
telemetry
Possible
Failure Cause
Connection
loss
Criticality
Prob
abilit
y
Seve
rity
Single
Point
Failure
None
4
Y
E
Tm state
None
1
N
E
TM
Overvoltage and over current
protection; redundant design
in function level
1
N
E
TM
Each connector has a double
fixation point
Local
Effects
End Effects
Loss of the
signal
measure
3
APS
Converter
Failure
Internal failure,
s/c
None
The equipments
or components
cannot operate;
Affect the
spacecraft power
supply safety
18
APS
Switch failure
Loose
connection of
the connector
No
telecomman
ds reach the
unit
The equipments
or components
cannot operate;
Recommendations
and Remarks
This document is confidential and proprietary of CAST Shenzhou Institute (CSI). The copyright of this document is reserved by CSI and shall not be released to third party
without a written authorization of CSI.