GLAST LAT Project
Gamma-ray Large
Area Space
Telescope
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
GLAST Large Area Telescope:
Mechanical Systems Peer Review
March 27, 2003
2.3 – Risk List
Marc Campell
SLAC
Mechanical Systems Mgr.
marcc@slac.stanford.edu
Document: LAT-PR-0XXXX
Section 2.3 Risk List
1
GLAST LAT Project
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
Topics
Agenda
• Risk list
Document: LAT-PR-0XXXX
Section 2.3 Risk List
2
GLAST LAT Project
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
Risk Summary
ID #
Risk Rank
Risk Description
Risk Mitigation
•X-LAT plate to Electronics box thermal joint does
not perform as designed
•1) Clarity interface responsibilities and
requirements -complete
•2) Detail interface options -complete
•3) Complete interface analysis – prelim.
Complete (Wang)
Mech 0001
Mech 306
•4) Prototype interface techniques (Lam )
High
•5) Complete detail box thermal analysis
(Haller)
•6) Select Design approach (Campell)
•7) Complete integrated analysis (Wang)
•8) Complete EM Test (Lam)
• Radiator VCHP to Downspout and X-LAT heat pipes
thermal joint fails during thermal vac test
Mech 0002
Mech 307
Very Low
Document: LAT-PR-0XXXX
•1) Prototype verification test (ECD-July 03)
•2) Develop process control requirements
(ECD-Aug 03)
Section 2.3 Risk List
3
GLAST LAT Project
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
Risk Summary
ID #
Mech 0003
Mech 308
Risk Rank
Low
Risk Description
Risk Mitigation
•CAL to Grid friction joint does not perform as
designed. The critical joint properties (coefficient of
friction and bolt clamping force) can not be directly
verified before or after environmental test
•EM testing of joint and FE model verification.
•Maintain large design margins for joint load
capability
• 1) EM Test completed
• 2) FE Model Verification
• 3) Independent analysis complete
• Maturing spacecraft design may result in late
changes in Instrument/SC interfaces; resulting in
LAT design changes past I-CDR and associated cost;
schedule impact
Mech 0004
Mech 321
Low
Document: LAT-PR-0XXXX
• Identify priority of detailed I/T design tasks
with Spectrum via ongoing working groups
•(1) Identify key I/F's driving detailed design
by Peer Review 26 March.
•(2) Complete final Interface drawings by 28
March to support final S/C-LAT ICD release.
•(3) Finalize CG and document of internal
agreements 28 March.
•(4) Develop and agree upon closure plan with
Spectrum for all issue identified in (1), LAT
CDR (28 April
Section 2.3 Risk List
4
GLAST LAT Project
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
Risk Summary
ID #
Risk Rank
Risk Description
Risk Mitigation
•Availability of Grid and ACD-BEA for match drilling
at mutually acceptable timeframes
Mech 0005
Mech 323
•Establish multiple windows of opportunity to
do the operation and or additional tooling
• 1) Develop schedule window work-arounds
(ECD – June 03)
Low
•2) Evaluate creating drill template to remove
schedule dependency (ECD-June 03)
• Repeatable X-LAT Thermal Joint performance
Mech 0006
Mech 541
•X-LAT plates are removed to service electronics
boxes
Moderate
•X-LAT plates could be removed after LAT or
Observatory thermal testing
•Repeatable Radiator Thermal Joint Performance
Mech 0007
Mech 542
•Same as Mech 0001
Moderate
•1) Same as Mech 0002
•“Wet” joint is disassembled & re-assemble after LAT
thermal balance test
•6 joints per radiator must be made within pot life of
thermal adhesive
Document: LAT-PR-0XXXX
Section 2.3 Risk List
5
GLAST LAT Project
DOE/NASA Mechanical Systems Peer Review, March 27, 2003
End of
Section 2.3
Document: LAT-PR-0XXXX
Section 2.3 Risk List
6