GLAST LAT Project
Gamma-ray Large
Area Space
Telescope
Manager’s Face to Face - ISOC, 17 March 2005
GLAST Large Area Telescope
WBS 4.1.B
Instrument Science Operations Center
Manager’s Face to Face Meeting
17 March 2005
Rob Cameron
rac@slac.stanford.edu
650-926-2989
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GLAST LAT Project
Manager’s Face to Face - ISOC, 17 March 2005
ISOC Coordination Activities
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LAT Project
– Planning transition from LAT development and delivery
phase to operations phase
Operations Planning
– Definition of Operations Steering Committee
– Meetings of ISOC team leads
– Coordination of Calibration and Analysis Methods Science
Group with ISOC tasks
LAT Configuration Tracking and Control Database
– Working with Systems Engineering, sub-systems to define
and implement configuration DB
– Working group being established
– Plan: keep existing methods in place; provide glue where
necessary
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GLAST LAT Project
Manager’s Face to Face - ISOC, 17 March 2005
Ops Constraints On LAT Diagnostic TLM
Summary of results from meeting between ISOC, FSW, Erik Andrews on use of LAT Diagnostic TLM
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TCS
– Cannot keep TCS diagnostic on, as Alert-initiated TDRSS MA link would never close
EPU Boot
– Continuous EPU boot diagnostic data stream @3.2 kbps is a concern
– concern is overflow of S/C FIFO telemetry buffer, which is emptied at 1kbps on TDRSS MA
– move EPU boot tlm to HSK APID
MEM
– use only during RT comm for monitoring?
– not a concern for pool space diagnostic: small dataset
LFS
– File System Status: monitor at least daily, during RT contact (but only a small response)
– Directory or Root Listing: used infrequently, only during RT contact?
– File Dump: use only during RT contact, and/or use via science stream
MSG, LIM
– TBD impact
– ISOC should plan to dump and clear MSG log at least daily, during RT contact
ITC, command response
– Response should be on for all ATS commands
• low rate, limited response – acceptable impact
– Response can also be on for file uploads during RT contat
Dwell
– Constraint on ISOC usage, to be assessed case by case
– Duration should be limited as much as possible
TBD: Commanding of diagnostic tlm in ATS, to coincide with planned RT schedule vs. RT PROC request
– Potential impact on Alert capability if scheduled RT comm is missed
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GLAST LAT Project
Manager’s Face to Face - ISOC, 17 March 2005
Non-ITAR ITOS?
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Met with Greg Greer on possibility of non-ITAR ITOS. Two solutions proposed:
1. Create a package that would be limited to receiving and processing
telemetry, creating a “monitor only” system.
– Remove all commanding-related components from ITOS, and
potentially modify the STOL engine to eliminate commanding-related
directives. This option must be usable for operational real-time
monitoring of the LAT, and hence receiving real-time telemetry (LAT +
spacecraft) from the GLAST MOC. It would not be usable for
command-sequence generation and PROC testing with the LAT
Testbed.
2. Create a package capable of formulating and transmitting CCSDS
commands, but only at the CCSDS packet level.
• Remove all ITOS components and functions related to transfer-frame
encapsulation of command packets, as well as any other functionality
associated with the CCSDS COP-1 commanding protocol. Would be
suitable for command-sequence / PROC validation, provided that the
command packets produced by this restricted package are identical
to those generated by the complete ITOS system at the MOC. The
planned VSC interface between ITOS and the LAT or LAT simulation
operates with CCSDS packets, so this option must be and should be
suitable for LAT command-sequence and PROC development, test
and validation at SLAC.
 Next step: work with GLAST Project at NASA to see if either option can be
made non-ITAR restricted
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GLAST LAT Project
Manager’s Face to Face - ISOC, 17 March 2005
Interface Testing with GSSC
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ISOC will support first formal interface test with GSSC on 18 March.
Test of data transfers of sample mission planning products between
GSSC and ISOC using FastCopy. Specific steps involving ISOC are:
– ISOC sends GSSC a dummy memory load packaged per the
Operations Data Products ICD
– ISOC sends GSSC a dummy PROC request packaged per the ICD
– GSSC sends ISOC a preliminary timeline file packaged per the ICD
 GSSC and ISOC will examine delivered files to confirm that they are
what was expected. A conference call has been set up to allow
participants to coordinate during the test.
 A retest is scheduled for 5 April if any problems occur.
 The full description of test is available at
http://glast.gsfc.nasa.gov/ssc/dev/gssc_testing/plans/GST2-ST5plan.txt.
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GLAST LAT Project
Manager’s Face to Face - ISOC, 17 March 2005
Issues and Concerns
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Project milestones
– MOR is now very early relative to launch, Jan 2006, and
should be delayed
ISOC staffing
– ISOC software development under threat because of
delayed availability of developers
VSC availability for ISOC testing
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