Transcript Section 2.D - Mechanical Design and Status Overview

GLAST LAT Project
March 24, 2003
GLAST Large Area Telescope:
Gamma-ray Large
Area Space
Telescope
Tracker Subsystem
WBS 4.1.4
2D: Mechanical Design and Status
Overview
Thomas Borden
Stanford Linear Accelerator Center
Tracker Subsystem Engineer
[email protected]
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
Agenda
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PDR Design
ART Status
Bottom Tray Redesign
CDR Design
Design Requirements
Documentation Status
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
PDR Design
• PDR structural design: documented in HTN-102070-0002, based on
GEVS appendix A, Delta II
– Vibration level drive design
19 Carbon-Fiber
Tray Panels
– Acoustic and shock are under vibration level envelope
– June 01 Peer Review and January 02 LAT PDR
• At PDR the design philosophy was to use limited analysis with
prototype testing to verify acceptability
• In February “new” vibration levels received from the Project Office
Carbon– General GEVS level
Fiber Wall
– Prior to first Prototype Vibration Test
– Difference is full spectrum at 50 Hz for general GEVS vs. 300 Hz
for Delta II
• Official launch vehicle change from Delta II to Delta Heavy spring
2002
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
ART Status
• Anomaly Review Team (ART) convened by IPO in June after second
prototype vibration test.
• ART committee report, LAT-LR-00870-01, summarizes findings and
lists recommendations:
– Implement the corrective action plan proposed by the Tracker Team
– Conduct evaluation of failed parts to ensure expected material strength
was achieved
– Strengthen the development of process controls during this phase of
development
– Tracker Team should develop and maintain a list of uncertainties and
mitigation strategies
– The LAT IPO should conduct an EM Production Readiness Review prior
to Engineering Model fabrication
– The formal Anomaly Review Committee should be released pending
closure of open action items
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
Bottom Tray Redesign
• Several design variations have been pursued:
– All metallic closeouts – Invar, rejected - Invar is magnetic
– Titanium corner joints in Carbon-Carbon closeouts, insufficient
strength margins in closeouts
– Titanium corner joints in Carbon-Carbon/M55J composite
closeouts
• Titanium corner joints with Carbon-Carbon/M55J composite
closeouts chosen
• Draft drawings complete
• All materials on hand, fabrication imminent
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
CDR Design
• Based on the following specifications:
– LAT-SS-00778, LAT Environmental Specification
– LAT-SS-00138, Tracker Mechanical/Thermal Interface
Specification
– LAT-SS-00176, Tracker Electrical Interface Specification
– LAT-SS-00134, Tracker Subsystem Level-IV Specification
• The Tracker is fully compliant with these specifications
2D
Tracker Peer Review, WBS 4.1.4
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GLAST LAT Project
March 24, 2003
Documentation
• All Drawings released or in release cycle
• All specifications released or in release cycle
• Released processes and procedures for items in fabrication and draft
versions for items not yet in fabrication.
• PRR held for ladder assembly, production began 12/1/03
• PRR scheduled for tray assembly
• Web site has copies of all drawings and documentation.
2D
Tracker Peer Review, WBS 4.1.4
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