GLAST LAT Project
ISOC CDR, 4 August 2004
GLAST Large Area Telescope:
Gamma-ray Large
Area Space
Telescope
Instrument Science Operations Center
CDR
Section 4.2
Operations Scenarios
Lori Bator
ONE-SLAC
lbator@slac.stanford.edu
650-926-5352
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Topics
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LAT Operation Phases
Description of LAT Operations
Monitoring Requirements
L&EO Support
Anomaly Resolution Process
Status
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
LAT Operations Phases
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LAT I&T
– Pre-FSW (EM)
– Post-FSW (Flight unit level)
Observatory I&T
– NRL
– Spectrum
Launch and Early Orbit (L&EO) – Phase 0
– LAT power-on and configuration
– Initial checkout
First year – Phase 1
– Survey mode
Second and subsequent years – Phase 2
– Pointed observation
– Survey mode
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Pre-launch Testing
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LAT I&T Phase Tests
– Goal: Verify and validate development of ISOC tools and
functions on testbed and through software simulation
Data Challenges
– Goal: “End to end” test of science analysis software
Ground Readiness Tests (GRTs)
– Goal: Verify and validate system interfaces and data flows
Observatory I&T Phase Tests
– Goal: Verify and validate ISOC capabilities
End-to-End (ETE) tests
– Goal: Verify and validate interface between ground system
and observatory
Mission Simulations
– Goal: Verify operation team readiness prior to launch
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Initial Turn-On and Checkout (Phase 0)
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Turn-on (power-up) procedure will not be executed
automatically
– Humans required to check environmental conditions prior
to significant steps
– Must establish correct LAT configuration to ensure
communications
Functional checkout of ACD, CAL and TKR
Perform initial calibrations
Special requirements
– ACD will have control of triggering; therefore no science
data taking available for ~ 3 days
– Phototube high voltages need to be turned on one at a time
and monitored
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Science Operations (Phases 1 and 2)
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Data taking
– Daily
– On the order of a few commands to initiate
Calibration
– Weekly, biweekly and monthly
– On the order of a few commands to initiate
Load changes to tables and FSW
– Infrequent
– On the order of a few commands and/or file uploads which may be large
Load new tables and files
– Infrequent
– On the order of a few commands and/or file uploads which may be large
Diagnostics
– Infrequent
– On the order of a few commands and/or file uploads which may be large
SAA management
– FSW turns down high voltage automatically based on SAA message from
S/C
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Monitoring Requirements
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LAT FSW monitors parameters onboard and will take action (poweroff or stop activity) in response to limit violations
 S/C monitors some temperatures and will power off LAT if needed
 MOC monitors HK data for limit violations
– No critical monitoring or actions required
– ISOC will define limits in LAT T&C database
– ISOC will provide and direct use of any contingency procedures
 ISOC monitors HK and Science data for limit violations and trends
– Respond to degradation, noise, changes in performance, and
failure by uploading commands or files to change configuration
– No critical monitoring except during power-up
– Monitor ACD temperatures when switching between pointed and
survey modes
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Limits
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Yellow
– Monitored point is outside the designed or acceptance
tested range but still within the qualification tested range
– Operator monitors data and notifies responsible engineer in
a timely manner
Red
– Monitored point is operating outside the qualification tested
range
– FSW or S/C initiates immediate action
– Operator initiates contingency procedure (if called for) and
immediately notifies responsible engineer
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
T&C Database Delivery Process
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LAT T&C database is initially provided to Spectrum
– CDRL delivery prior to LAT ship to Spectrum
– ITOS format
Updates
– Provided by ISOC to Spectrum until L+60 days
– After L+60 days, updates are provided by ISOC to MOC
– Format and method of notification and delivery are defined
in Operations Data Products ICD (492-MOC-009)
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GLAST LAT Project
ISOC CDR, 4 August 2004
Anomaly Response Process
START
*Contingency procedure will identify who
to notify and will convene contingency
meetings when appropriate
MOC notifies ISOC of limit
violation or Instrument Alert
or
ISOC detects out of limit
condition
Red limit or
Instrument
Alert?
YES
CHS initiates
contingency
procedure*
Convene contingency
meeting and identify
contingency lead
NO
NO
ISOC notifies POC for the
subsystem or type of anomaly
POC identifies
diagnostic operations
CHS performs
diagnostic operations
POC analyzes and recommends
response or action
Document: LAT-PR-04500
Anomaly
resolved or
acceptable workaround?
YES
Generate tests or
resolution** and
perform under direction
of contingency lead
**Tests and resolutions will
be validated on the testbed
Generate and
distribute
anomaly report
Update
documentation,
s/w and operations
where applicable
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
L&EO Support
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Estimate 9 Persons for L&EO Support
– 1 CAL seat
– 1 TKR seat
– 1 ACD seat
– 1 I&T seat
– 1 OPS seat
– 1 FSW/DAQ seat
– 1 SYS/Thermal/Mech seat
– 1 Mgmt/Science/contingency lead
– 1 optional seat
Support area and infrastructure on same scale as Spectrum
has requested
Document: LAT-PR-04500
Section 4.2
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GLAST LAT Project
ISOC CDR, 4 August 2004
Status
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ISOC operations concept documented in LAT-SS-01378 ISOC
Operations Plan
Detail on operations will evolve from FSW development and
I&T tests
– Detail will be captured in Operations Handbook (ECD Oct
2005) and Operations Procedures (ECD L-6 months)
• Command sequences
• Constraints
• Contingency actions
Document: LAT-PR-04500
Section 4.2
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