1. GLAST Large Area Telescope:
Gamma-ray Large Area Space Telescope
GLAST Large Area Telescope:
Instrument Science Operations Center CDR
Section 4.2
Operations Scenarios
Lori Bator
ONE-SLAC

2. Topics LAT Operation Phases Description of LAT Operations
Monitoring Requirements
L&EO Support
Anomaly Resolution Process
Status

3. LAT Operations Phases 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

4. Pre-launch Testing 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

5. Initial Turn-On and Checkout (Phase 0)
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

6. Science Operations (Phases 1 and 2)
Data taking
Daily
On the order of a few commands to initiate
Calibration
Weekly, biweekly and monthly
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
Diagnostics
SAA management
FSW turns down high voltage automatically based on SAA message from S/C

7. Monitoring Requirements
LAT FSW monitors parameters onboard and will take action (power-off 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

8. Limits
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

9. T&C Database Delivery Process
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)

10. Anomaly Response Process

11. L&EO Support 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

12. Status
ISOC operations concept documented in LAT-SS 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