Transcript Section 1.0 - Overview

GLAST LAT Project
Mechanical Design Integration Peer Review, March 2003
Mechanical Design Integration Peer Review, March 2003
1. Introduction and Overview
Martin Nordby
[email protected]
24 March 2003 rev 1
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Mechanical Design Integration Peer Review, March 2003
1. Introduction & Overview
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Introduction
Mechanical Design Engineering Organization
Mechanical Design Overview
– LAT layout and interface definitions
– System block diagram
– Design details
– Design changes since Delta PDR
– CCB’s: approved since Delta PDR and pending
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Review Material
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All presentation material and documentation is available on the web at:
http://www-glast.slac.stanford.edu/MechanicalSystems/Meetings&Talks/2003-03-DesignIntCDR/DesignIntCDR.htm
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Hard copies of all presentation material are reproduced in the binders available to reviewers
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Hard copies of all documentation, back-up material, drawings, and reports are available for
review
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Mechanical Design Engineering Organization
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LAT Organization
– Since Delta PDR, LAT engineering organization and responsibilities have changed
– Instrument Design Engineering group added
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LAT Chief Engineer: Lowell Klaisner
Responsible for design integration, systems analysis, and fabrication planning for the LAT
Works with Systems Engineering to manage LAT interfaces and resolve interface and internal
subsystem design issues
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4.1.8 Mechanical Systems subsystem re-scoped to focus on flight hardware
development, fabrication, and testing
Work Breakdown
– Mechanical Design Integration
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4.1.8 Mechanical Systems
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Part of Chief Engineer’s Design Engineering group
Interface design and development within and external to the LAT
Managing of LAT mechanical metrics: mass, dimensions, dissipated power
LAT structural and thermal analysis
Performing LAT-level design and trade studies
Flow-down of environmental and test parameters to LAT subsystems
LAT environmental test planning and technical management
Design and development of Grid Box, Radiators, and heat pipes from subsystem requirements
flowed down from LAT
Fabrication and verification testing of subsystem hardware and delivery to I&T group
Peer Reviews will follow this work breakdown
– Mechanical Design Integration Peer Review: 26 Mar 2003
– Mechanical Systems Peer Review: 27 Mar 2003
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Mechanical Design Overview
LAT Structural Design Parameters
Design
Spec
Mass
2679.4 kg
<3000 kg
Center of Gravity 149.3 mm
<185 mm
Width
1806 mm <1820 mm
Height
1081.5 mm 1100 mm
Tracker (TKR)
Mass
Size
Interfaces
Calorimeter (CAL)
Anticoincidence Detector (ACD)
Mass
Size
Interfaces
504.9 kg (Mar 2003 est)
372 mm sq x 640 h
Grid Ti flexure mount and
Cu strap
Mass
Size
Interfaces
270.1 kg (Mar 2003 est)
1806 mm w x 1081.5 mm h
Grid bolted joint, shear pins
1375.8 kg (Mar 2003 est)
364 mm sq x 224 mm h
Grid bolted friction joint
Grid/X-LAT Plate/Radiators
Mass
Size
Interfaces
LAT Mass Budget and Current
Estimates (kg)
Estimate
Budget
TKR
504.9
510.0
CAL
1375.8
1440.0
ACD
270.1
280.0
Mech
329.3
345.0
Elec
199.3
220.0
LAT Total
2679.4
3000
329.3 kg (Mar 2003 est)
1580 mm sq x 236 mm h
Four-point mount to SC
flexures
Electronics
Mass
Size
Interfaces
199.3 kg (Mar 2003 est)
1417 mm sq x 222 mm h
Stand-off to CAL; thermal joint
to X-LAT Plate
Source: LAT-TD-00564-6 “LAT Mass Status
Report Mass Estimates for Mar 2003”
LAT Overview
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System Block Diagram
MLI
Surrounding ACD
ACD
Base Elec Ass’y
alum frame
CAL Modules
alum bottom plate
TKR Module
CFC tray, side
walls
Grid
monolithic alum
structure
Spacecraft
LAT mounting
structure
Spacecraft
SC bus structure
Solar Arrays
S.A. mount
Elec. Boxes
alum electronics
box
EMI Skirt
Shields E-Boxes,
supports X-LAT Pl
X-LAT Plate
monolithic alum
structure
Radiator Mnt Bkt
Support Radiators
at corners of Grid
Htr Switch Boxes
Operate Radiator
heaters
LAT Radiators
on +/- Y sides of
LAT Grid
MLI Insulation
MLI surrounding
underside of LAT
LAT Block Diagram
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LAT Design Details
Radiator Mount at Grid corners.
Note mid-side Grid Wing
Grid corner detail showing heat pipes,
purge grooves; corner chamfer and
bottom flange for ACD
Copper thermal straps
Reverse-angle view of VCHP
S-bends and DSHP connection
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TKR mid-side and corner flexures
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LAT Interface Details
Grid Wing with SC mount bracket
EMI Skirt cut-outs
around SC stay-clear
SC proposed interface stay-clear
on top of octagonal SC volume
PAF, per Boeing PPG
LAT inside LV fairing
static stay-clear
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LAT Underside Design Details
Empty boxes
GASU box
SIU boxes
Upside-down view of a Grid Y midside, showing DSHP’s, Grid Wing,
and EMI Skirt
PDU box
TPS (16x)
EPU boxes
TEM (16x)
LAT Underside View of
Electronics Boxes
Detail of TEM, TPS,
and EPU box stack
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Design Changes Since Delta-PDR
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Subsystem changes affecting system performance
– TKR bottom tray re-work: strengthens CC tray in high-stress corner regions
– TKR flexure re-design: accommodates updated bottom tray design and provides for
stiffer cantilever mode for TKR
– ACD mass growth: accommodates larger tile overlaps and increase in structural
stiffness and strength
Interface changes
– Wing bracket: re-designed to include vertical SC mount bracket hanging under Grid
– TKR thermal straps: copper straps provide compliant joint to Grid
– E-box mounting to CAL plate: E-boxes hard-mounted to CAL back plates now
– X-LAT plate thermal connection: V-Therm cloth
– CAL-Grid friction joint questioned by GSFC: currently investigating discussion
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Design Changes Since Delta PDR (cont)
VCHP
S-bends
SC-LAT mount
region still in work
Panels cut-out
locations fixed
LAT Delta PDR Design
July 2002
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Radiator panels widened and
shortened, reducing thermal efficiency
LAT CDR Design
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Change Control Board Changes Since Delta-PDR
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ACD mass growth
– Added structural mass to increase design margins
– Added mass in scintillating tiles to increase size of tiles and overlap between tiles
Mechanical Systems mass growth
– Added mass for Grid box additions: Grid Wing, bottom flange, EMI Skirt stiffening, X-LAT
thermal straps
– Added mass for slightly increased Radiator area
Calorimeter mass de-allocation
– Decreased mass allocation to reflect reduction in size of CsI logs
– Log size was reduced to accommodate tolerance stack-up within CFC box structure
Power allocation update (pending)
– Updated power allocations based on current measured values
– Already using updated allocations in thermal analysis
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