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TMT'OPT'PRE'07'056'REL01

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Lifting Talon design. Volume-7: Summary and Future Plans. Prototype Testing. Test Plans ... 1g dead weight not additional. 0-10000m. 10g, any axis. TBC. 0 to ... – PowerPoint PPT presentation

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Title: TMT'OPT'PRE'07'056'REL01


1
TMT M1 Segment Support Assembly (SSA) Preliminary
Design Review (PDR)Volume-1 OVERVIEW
  • Pasadena, California
  • October 24-25, 2007
  • Contributors to the development effort
  • from IMTEC
  • RJ Ponchione, Eric Ponslet, Shahriar Setoodeh,
    Vince Stephens, Alan Tubb, Eric Williams
  • from the TMT Project
  • George Angeli, Curt Baffes, Doug MacMynowski,
    Terry Mast, Jerry Nelson, Ben Platt, Lennon
    Rodgers, Mark Sirota, Gary Sanders, Larry Stepp,
    Kei Szeto
  • TMT Confidential
  • The Information herein contains Cost Estimates
    and Business Strategies Proprietary to the TMT
    Project and may be used by the recipient only for
    the purpose of performing a confidential internal
    review of the TMT Construction Proposal.
    Disclosure outside of the TMT Project and its
    External Advisory Panel is subject to the prior
    written approval of the TMT Project Manager.
  • Note HYTEC, Inc. merged with IMTEC Inc. in
    March 2007.

2
Outline
  • Volume-1 Overview
  • Thirty Meter Telescope Overview
  • SSA Project Overview
  • Key Design Requirements
  • Design Concept
  • SSA Preliminary Design
  • Key Subsystems
  • Axial Support
  • Lateral Support
  • Tower, Guide Flexure, Locks, Registration
  • Warping Harness
  • Subcell
  • Volume-2 System Level Calculations
  • M1 Segmentation
  • Segmentation Correction (for Variable Segment
    Geometry)
  • Budgets
  • Installation Alignment
  • Edge Gap
  • Actuator Stroke

3
Outline
  • Volume-3 System-Level Finite Element Analysis
  • Model Description
  • Optical Performance
  • Stiffness and Modes
  • Buckling
  • Sensitivity Analyses
  • Stress Analysis
  • Backup Slides
  • Volume-4 Warping Harness Design and Analysis
  • Fundamental Approach Architecture
  • Warping Harness Requirements
  • Opto-mechanical
  • Mechanical
  • Design Concept
  • Performance Analysis
  • Actuator arrangement
  • Surface correction
  • Derived Requirements for Components
  • Mechanical Electrical Design

4
Outline
  • Volume-5 Flexure Design and Analysis
  • Design Load Combinations
  • Central Diaphragm
  • Rod-Type Flexures
  • Lateral Guide Flexure
  • Volume-6 Subcell Integration Segment Handling
  • Subcell Integration Alignment
  • Fixed Frame Installation
  • Dummy Mass
  • Subcell Alignment
  • Segment Lifting Jack Lifting Talon
  • Jack design
  • Lifting Talon design
  • Volume-7 Summary and Future Plans
  • Prototype Testing
  • Test Plans
  • Component testing
  • Full Prototype testing
  • Schedule

5
Thirty Meter Telescope
BRIEF TELESCOPE OVERVIEW
6
M1 Array
  • 30m Diameter
  • 60m ROC
  • 492 Segments
  • 1.44m x 45mm1

PSA On Mirror Cell
Note 1) 45mm for Glass-Ceramic, 50mm for Fused
Silica
7
Segment Size
  • Nominal Segment size is 1.44 m across vertices
  • Limited by blank size to maintain several
    competitive suppliers
  • Thickness
  • 45 mm if glass ceramic
  • 50 mm if fused silica (ULE)
  • Aperture limits
  • Outermost corners 15.0 m radius
  • Innermost corners 1.45 m radius

1.44
30m diameter
15.0
1.45
8
M1 Parameters
  • Fundamental M1 Parameters
  • Constant-gap segmentation
  • 82 different segment shapes
  • Six identical sectors
  • Nominal segment
  • 1.44m regular hexagonal meniscus
  • Glass-Ceramic, 45mm thick
  • 60m paraxial radius of curvature
  • Neglect asphericity in support design activities
  • Average segment ROC 62.5m
  • Assume worst case CTE -0.05 ppm/C in analyses
  • Alternate segment
  • Fused Silica, 50mm thick meniscus
  • SSA can be re-tuned to accommodate

9
M1 Parameters
  • Segmentation Pattern

Sector Boundary - Note Fixed Frame Clocking
60?
View from Sky
10
Thirty Meter Telescope
SSA PROJECT OVERVIEW
11
SSA Project Scope
  • IMTEC Design/Development Responsibilities
    Include
  • Segment Support Assembly (SSA)
  • Segment Lifting Jack
  • Segment Lifting Talon
  • Attaches Mounted Segment Assembly (MSA) to
    Segment Handling Crane
  • Subcell Integration Hardware
  • Mass Simulator
  • Surveying Target Holders
  • Subcell Alignment Tooling
  • Release Prototype Drawings
  • Build, Test and Deliver Prototypes
  • Refine design for production
  • Propagate design to 82 versions (segmentation
    effects)

12
SSA Overview
PRIMARY SEGMENT ASSEMBLY (PSA)
Actuator1
Subcell
Mounted Segment Assembly (MSA)
Produced at Optics Shop
IMTEC Responsibility
Optical Coating
Polished Mirror Assembly (PMA)
Fixed Frame Assembly (1 ea) Adjustable
Alignment Positioners (AAPs, 3 ea) Actuator
Flexure (3 ea)
IMTEC Responsibility
Edge Sensors1 (6-drive, 6-sense)
Polished Mirror Segment
Segment Support
Central Diaphragm (1 ea.) Moving Assembly (1
ea.)
Cables Connectors for Sensor1 WH
--Whiffletrees (3 ea) --Moving Frame Assembly (1
ea) --Warping Harness Actuators (21 ea) --Lateral
Guide Flexure (1 ea) --Tower Assembly (1
ea) --Lock Assemblies (3 ea) --Sheet Flexures (6
ea)
Electrical Bulkhead Panel Assembly
Comprises the SSA
Removed for Re-coating
1) In WBS, Actuator is part of the M1CS not
M1Optics
13
SSA Overview
PSA ATTACHED TO MIRROR CELL
Polished Mirror Segment
Primary Segment Assembly (PSA)
Add Segment Support
Polished Mirror Assembly (PMA)
Include Subcell Actuators
Add Optical Coating, Edge Sensors, Sensor WH
Cabling Connectors Mounted Segment Assembly
(MSA)
14
SSA Overview
SEGMENT SUPPORT ASSEMBLY (SSA)
15
KEY DESIGN REQUIREMENTS
Requirements
16
Key Requirements (1/4)
  • SSA-Induced Surface Errors
  • Goal Minimize gravity and thermal distortion
    while controlling cost
  • Optical performance of SSA evaluated by system
    level PSS analysis
  • Performed by Project and JPL using IMTEC unit
    case predictions as inputs
  • When complete, analysis to consider all SSA
    distortion effects
  • Gravity, Thermal Distortion, Thermal Clocking,
    Polishing, Mfg,
  • Assumptions
  • Observing segment-zenith angle -15 to 80 ?
    max ?? 80
  • 0 to 65 telescope Zenith 15 from M1
    curvature
  • Observing temperature 9C (TSITE) 4C
  • Based on Armazones site testing data (80 of
    observing time within /-4C)
  • Alignment Phasing System (APS) Warping
    Harness used regularly to null DC errors
  • - Seasonal mean temperature offset, Tmean
  • - Difference between optics shop
    figuring temp and Tref
  • Single Support-System design, customized for each
    segment type
  • Accommodate shape variations from M1 segmentation
    (up to 0.5)
  • No backlash or stick-slip
  • Flexure-based mechanisms

17
Key Requirements (2/4)
  • Accommodate 2.5mm actuator stroke
  • SSA hard stops nominally at 3.0mm
  • Survive full differential tip/tilt
  • Remote-controlled warping harness
  • Control 2nd and 3rd order Zernikes
  • Correction capability 200 to 2100 nm P-V (38 to
    410 nm RMS)
  • Improvement ratio (RMS before correction / RMS
    after correction)
  • gt 15 on 2nd order terms focus astigmatism
  • gt 5 on 3rd order terms coma trefoil
  • Periodic Adjustment
  • Capability to readjust up to 10 times per night
    (1/hour), if necessary
  • Power dissipation lt2 Watts/segment
  • Includes all segment heat sources (Actuators,
    sensors, electronics, etc.)
  • 50 years lifetime high reliability
  • Only significant wear items are warping harness
    moment actuators
  • 6-DOF adjustable Subcell repeatable
    registration system
  • Correct for Mirror Cell tolerances ( 5 mm
    adjustment range, set-and-forget)
  • Removal/replacement of SSA with 50 µm
    repeatability

18
Key Requirements (3/4)
  • SSA mass lt 90 kg (moving mass lt 45 kg)
  • Not including actuators, segment, edge sensors
    cables for edge sensors
  • Ref Segment mass 153 kg for glass ceramic
  • Static stiffness gt 12 N/µm, piston
  • Assuming rigid actuator mirror cell
  • Natural frequencies of PSA gt 35 Hz with 10N/mm
    actuator stiffness
  • Avoid rotating machinery disturbances at 25 and
    30 Hz
  • 50 or 60 Hz AC power grids possible
  • Permit higher actuator control bandwidth
  • EXCEPT
  • Torsional modes permitted to be lt35 Hz
  • Unlikely to be excited on telescope
  • fn gt8 Hz required for static stiffness
  • Environments
  • Operating conditions such as temperatures,
    g-levels, etc
  • summary slide to follow

19
Key Requirements (4/4)
  • MSA shall be compatible with Coating Chamber
    requirements TBC
  • Cleanliness, Outgassing and Coating process
    compatibility
  • SSA design shall be designed for manufacture
  • 492 units Spares allows for economies of scale
    if the design is sound
  • Maintainability and Servicing considerations
  • Segment exchanges are frequent and must be
    straightforward
  • Recoating every 2 years implies 5 segment
    exchanges per week on average
  • Cost control is fundamental to the design
  • Cost of manufacture and test
  • Cost of ownership
  • Reliability
  • Maintainability

20
Environments
  • 1. About any axis in local x-ySSA plane
  • 2. In local zSSA direction (piston)
  • 3. SSA on telescope
  • 4. Scaled up from 1.2m segment loads by a2
  • 5. Scaled up from 1.2m segment loads by a3
  • 6. All dynamic loads treated as quasi-static. 1g
    dead weight not additional

21
SSA Design
DESIGN CONCEPT
22
Key Functions of SSA
  • Support segment with minimum distortion
    (observation mode)
  • Relative to reference state (as figured) ?SEG
    0, TREF
  • Ability to position segment in 3 DOFs (piston,
    tip, tilt)
  • Continuous, active positioning by three linear
    actuators
  • Ability to alter surface shape to correct for
    figuring errors and other effects
  • Occasional correction
  • Interface with Mirror Cell
  • Provide means to align SSA in 6 DOFs
  • Compensate for mirror cell fabrication tolerances
    (/- 5mm any direction TBC
  • One-time adjustment during telescope integration
  • Ability to remove and replace MSA with specified
    repeatability
  • Quick replacement of segments without
    re-alignment of Subcell
  • Accommodate irregular/variable size segments with
    single support design
  • Uniform gaps lead to irregular and/or variable
    size hexagons
  • Provide means to extract segment out of M1 array
    for re-coating/maintenance
  • Lifting jack
  • Segment Lifting Talon
  • Interface with segment removal crane

23
Design Concept
Final Figuring
Polished Mirror Segment
3 ea Whiffletree
Cam Locks (3ea)
Diaphragm
Axial Support Rod Flexures
Guide Flexure
Edge Sensors (12)
Warping Harness Actuators, 21ea
Moving Frame
Tower
Mounted Segment Assembly (MSA)
Note Does not represent assembly sequence
24
Design Concept
3ea Adjustable Alignment Positioners (AAPs)
Actuator flexure
Actuator Output Shaft
Mirror Cell
Fixed Frame
3ea Actuators
SUBCELLACTUATORS
25
Design Concept
Lifting Talon
Segment Lifting Jack
MSA Placed on Jack
26
Design Concept
Actuator Flexure Clamped to Moving Frame (3
places)
MSA Attached to Subcell
27
Design Concept
Cam Locks Released
Diaphragm
Mirror Segment
3 ea Whiffletree
Guide Flexure
Axial Support Rod Flexures
Warping Harness Actuators, 21ea
Moving Frame
Tower
Fixed Frame
Mirror Cell
3ea Adjustable Cell Interface
MSA hold-down bolts
3ea Actuators
PSA Operational Configuration
28
SSA Design
PRELIMINARY DESIGN
29
Design Status
  • Segmentation scheme has been chosen
  • Scaling rule selected to minimize blank diameter
  • We have a detailed 1.44m Preliminary Design
  • 27-point mechanical whiffletree axial support
  • Central diaphragm lateral support
  • 21-actuator/segment, whiffletree-based warping
    harness
  • Correction for segment shape variations via
    custom WT joint locations
  • Repeatable interface, Subcell alignment, and
    actuator attachment
  • Extensive, coupled performance modeling has been
    performed
  • Complete FEA revision to reflect Preliminary
    Design is complete
  • Design satisfies nearly all requirements
  • Completing final changes required for Prototype
    SSA fabrication
  • Hardware designs being detailed
  • Detailed drawings for prototype in process

30
Current PSA Design
  • PSA attached to mirror cell

Mirror Cell
Actuator
31
Flexures Bonded to Segment
Central Diaphragm (bonded to segment)
Segment
Edge Sensor 12 ea.
Alignment Arrow Points to center of M1
Axial flexure assemblies 27 ea. bonded to segment
Note Does not represent assembly sequence
32
Small Whiffletree Triangles Attached
Small whiffletree triangle - 3 inner - 6
outer
Note Does not represent assembly sequence
33
Large Whiffletree Triangles Attached
Large whiffletree triangle
Note Does not represent assembly sequence
34
Sheet Flexures Added
Sheet flexure, 6ea In-plane connection between
Whiffletree Triangles and Moving Frame
Note Does not represent assembly sequence
35
Moving Frame Attached
V-Groove for lifting, 3 ea.
Moving frame
Sheet flexure, 6ea In-plane connection between
Whiffletree Triangles and Moving Frame
Note Does not represent assembly sequence
36
Warping Harness Added
Warping harness leaf-spring
Warping harness actuator
Note Does not represent assembly sequence
37
Tower Locks Installed
Tower Assembly with Repeatable Interface
Electrical Connector Bulkhead Panel
Note Does not represent assembly sequence
38
Fixed Frame Included
Fixed Frame
Note Does not represent assembly sequence
39
Installed on Mirror Cell
Actuator flexure
Actuator
Mirror Cell
Adjustable Alignment Positioner (AAP)
Note Does not represent assembly sequence
40
Sector Boundary
  • PSAs Clocked 60 degrees between sectors
  • Two fixed frame versions
  • Sufficient clearance at boundary

Adjacent actuators 35mm nominal clearance
Sector-A
Sector-F
41
Group of Segments
  • View of Seven Adjacent Segments Top View

42
Group of Segments
  • View of Seven Adjacent Segments Bottom View

43
SSA Design
AXIAL SUPPORT SYSTEM
44
Axial Support System
  • Two level, 27-point whiffletree system
  • All-Aluminum design (nearly)
  • Triangles and sheet flexures Aluminum
  • Rod Flexures Stainless Steel
  • Analysis shows high CTE of Aluminum to be
    acceptable
  • Lower machining costs and corrosion resistance a
    plus
  • Triangles nested for compactness

Pivot Flexures at Moving Frame Connection
Mirror Support Rod Flexures
Rod Flexures at pivot locations
45
Axial Support System
  • Whiffletrees Ride on Moving Frame
  • Moving Frame 6061 Aluminum weldment

Pivot Flexure
Actuator Rod Flexure Clamp
Handling Feature
46
Axial Support System
  • Sheet Flexures
  • Concept introduced by SALT
  • Stabilize whiffletrees in XYSSA plane
  • Pivots (Kz) Sheet Flexures (Kx, Ky, Rz) provide
    4 Degrees of Stiffness
  • Tip/Tilt (Rx Ry) remain compliant
  • Whiffletree mass is nominally balanced about
    sheet flexure plane
  • Aluminum 7075-T651, 0.508mm (0.020) thick

Pivots 3 per WT
Sheet Flexures 2 per WT
Sheet Flexure Attachment to Moving Frame, Typical
No further discussion of Sheet Flexures Questions?
47
Axial Support System
Bondline
  • 27-Mirror support rod flexures
  • Invar pucks bonded to mirror using 3M EA-2216
    Epoxy
  • Well characterized adhesive
  • JPL heritage for Invar/Zerodur bonds (documented
    process )
  • 0.250mm nominal bondline (0.010)
  • Stainless Steel rods connect pucks to triangles
  • 304V Cold drawn 94 CW
  • 250 ksi yield strength
  • Threaded end connections
  • Stiff, strong, adjustable removable

Mirror
Vent Hole
Invar Puck
Flexure 2.1mm OD x 143mm Long
Vent Hole
Small WT Triangle
Detailed discussion PDR Volume-5
48
Axial Support System
  • 9-Small whiffletree triangles
  • Extruded Aluminum 6061 T6
  • Low cost
  • 12 per extruded blank, in production qty.
  • 3-Large load-spreader triangles
  • Cast Aluminum (A356 T51)
  • Lowest manufacturing cost
  • Complex shapes large size ideal for casting

No further discussion of Triangle
design Questions?
49
Axial Support System
  • Optical Performance
  • Whiffletree support points and pivot locations
    determined by optimization
  • Pivot locations unique for each of the 82 segment
    types
  • See PDR Volume-2 for details
  • Axial support gravity print-thru
  • Figured out at ?seg0
  • Springs-back as 1-cos(?seg)
  • Surface error amplitude 10 nm RMS (?seg90)
  • See PDR Volume-3 for details

50
SSA Design
LATERAL SUPPORT SYSTEM
51
Lateral Support System
  • Lateral Support Design
  • Simple Flat Central Diaphragm
  • Low cost
  • Compact (space limited by 45mm thick mirror)
  • no decoupling flexures
  • Diaphragm material Invar 36 (one piece)
  • Baseline for optical performance analysis
  • Prefer to use INOVAR from Imphy Alloys (Fr.)
  • High purity, w/Low Carbon content
  • Low CTE 1/2 of regular Invar (0.65 PPM/C)
  • Better temporal stability
  • Bonded directly to mirror
  • Adhesive 3M EA-2216,
  • 0.250mm bondline (0.010)
  • Diaphragm dimensions
  • Rim OD 150 mm OD, Hub OD 60 mm
  • Flexure region OD 130mm, 0.350 mm thick
  • 10 mm wide outer rim bonded to glass
  • Mirror Pocket ?156 mm by 25.5 mm deep

Central hub t8.5mm
Rim t3mm
Flexure t0.350mm
Detailed discussions PDR Volumes-3 -5
52
Lateral Support System
  • Diaphragm Cross-Section View

Diaphragm
Adhesive Bond Diaphragm to Glass
Mirror Segment
Adhesive layer
Moving Frame
53
Lateral Support System
  • Moving frame concept isolates diaphragm
  • Makes operating diaphragm deflections small
  • High strength material not required
  • Lateral Support gravity print-thru
  • Lateral support gravity print-thru
  • Zero out at ?seg0
  • Springs-back as sin(?seg)
  • Surface error amplitude 12 nm RMS (?seg90)

Diaphragm Attached to Moving Frame
Detailed discussion PDR Volume-3
54
SSA Design
Tower, Guide Flexure, Locks and Registration
55
Tower Guide Flexure
  • Tower Guide Flexure
  • Provide lateral load-path for SSA
  • Connect Moving Frame to Subcell (Fixed Frame)
  • Accommodate segment piston/tip/tilt
  • Guide flexure details in PDR Volume-5
  • Tower assembly includes
  • ½ of the registration interface
  • ½ of the SSA lock system
  • Tower 6061-T6 Aluminum weldment

Guide Flexure Attached to Tower at OD
Guide Flexure Attached to MF at ID
Guide Flexure
SSA Lock 3 ea.
Moving Frame (MF)
Registration 3 ea. at 120 deg
Tower
56
Tower Guide Flexure
Attached to MF
Guide Flexure
Attached to Tower
Mirror Segment
Convolution for piston compliance
Moving Frame
Clearance hole for Mirror Support Rod Flexure
57
SSA Locks
  • Locks
  • Three per SSA
  • Secure Moving Frame to Tower
  • Permanently installed
  • Enable safe handling, installation removal
  • Support segment during actuator change-out
  • Latched by spring-plunger detent
  • Hardened cam keyed to handle
  • Hardened insert mounted in moving frame

Cam
Spring Plunger
58
SSA Lock Positions
  • Locked
  • Moving frame pushed to Neutral position
  • Nominal Clearance 0.250 mm
  • MSA can be installed, removed and handled
  • Actuator can be replaced
  • Unlocked
  • Moving Frame and Tower not in contact
  • Act as Piston/Tip/Tilt hard-stop
  • Nominal clearance /-3 mm SSA range of travel
  • outside range of actuator hard stops (/-2.5mm)

Moving Frame
No further discussion of Lock design Questions?
Moving Frame
59
Registration
  • Requirements Goals
  • Repeatability /-0.050mm in-plane
  • Stiff connection in all DOF
  • Face-to-face axial registration with thru-bolt
  • Strong, stiff and easy to dimensionally inspect
  • Lateral registration features not in axial load
    path
  • Sufficient strength to position segments at 14.5
    deg inclination during installation
  • 0.25g lateral load plus friction
  • Cycles Assume one Installation Removal per
    year for 50 years (50 cycles)
  • Implies a near-kinematic design
  • Design concept
  • Set of 3 tangential and axial contacts, 120 deg
    apart
  • Lateral registration features
  • Tapered pin in V-groove with small in-plane
    radial clearance when assembled
  • Clearance allows Tower to move slightly in X,Y,
    Clocking
  • Axial registration features
  • Mating flat surfaces clamped by thru bolt
  • Friction joint during operation

60
Registration Hardware
  • Registration mating sequence (typical 3 places _at_
    120 deg)

Tower Separated From Fixed Frame
Tower Lowered to Fixed Frame
Captive Bolt Tightened to Clamp Joint
Conical Pin
V-groove
61
Registration
  • Tapered pin
  • Material Ti 6Al-4V Annealed Nitrided
  • 120 ksi base metal
  • TiN Rc70 surface coating for galling resistance
  • Insert ring
  • Material 17-4 PH Condition H1025
  • 145 ksi yield strength
  • Contact stress
  • Contact force 1009N
  • 210 kg at 14.5 deg inclination with sliding
    friction coefficient of 0.5
  • 60 ksi max subsurface von Mises stress
  • FSy 2.0
  • Result
  • Durable interface that will not Yield or Gall

62
Registration
  • Pin-Insert clearance
  • Cost
  • Machine shop quote 400/set, in quantity

No further discussion of Registration
design Questions?
63
SSA Design
WARPING HARNESS SYSTEM
PDR Volume-4 Dedicated to Design and Analysis of
Warping Harness
64
Warping Harness Approach Architecture
  • Purpose
  • Allow automated periodic correction of low order
    surface distortions
  • Residual errors from polishing
  • Coating stress distortion
  • Seasonal mean-value of thermal distortion
  • Segment positioning errors within the array
    (Focus and Astigmatism)
  • etc.
  • Fundamental Approach
  • Extension of the Keck design
  • Re-figure the mirror by bending it in a
    controlled manner using whiffletree
  • Bending moments introduced into whiffletree by a
    set of moment actuators
  • Actuators are motorized, instrumented and tied
    into the M1CS
  • Architecture
  • 21 whiffletree joints are fitted with
    moment-actuators
  • Lead screw pushes against an instrumented
    leaf-spring to create a moment
  • Stepper motor drives lead screw to permit
    automation

65
Design Concept
  • Actuator Schematic
  • Stepper motor driven screw displaces end of
    leaf-spring
  • Strain gauge on leaf-spring provides feedback for
    motor control
  • Motors will be mounted on the large whiffletree
    triangles and to the moving frame

Axial Support Flexure
Nut
Screw
Large Triangle
WT Joint Flexure (sheet flexure not shown)
Stepper Motor
Strain Gauge
Leaf-spring
66
Optical Performance Analysis
  • Actuator Layout
  • 21 Actuators

Mx My Large Triangles, 3ea (Only Mq
required)
Mx My Outer Triangles, 6ea
Mq, Inner Triangles, 3ea (Mr not required)
67
Optical Performance Analysis
  • Actuator Layout
  • 21 Actuators integrated into axial support system

Leaf Spring (Typ.)
Actuator (Typ.)
68
SSA Design
SUBCELL
Fixed FrameAAPsActuator Flexure
69
Subcell Design
  • Fixed Frame
  • Provides a stiff, stable interface between MSA
    and Mirror Cell
  • Construction Welded 6061-T6 Aluminum (2
    versions due to segmentation)
  • Interfaces
  • Mirror cell (via AAPs)
  • MSA (via tower registration features)
  • Actuators (bolted and pinned joints at ends of
    Fixed Frame)
  • Segment lifting jack (at center post) See PDR
    Volume 6 for details
  • Deep cross-section required to meet 35 Hz for
    Lateral mode
  • Optimized to reduce mass

Fixed Frame
AAP
Actuator Attachment
NEXT SLIDE
70
AAP Design
  • AAP Requirements/Features
  • Range of Travel
  • /-8mm adjustment in-plane
  • Mirror Cell mfg. tolerances (5mm) plus
    segmentation effects (3mm)
  • /-5mm vertical adjustment
  • Aligned one time during construction and
    permanently locked/pinned
  • Jam nuts and match-drilled dowel pins
  • Smooth adjustment (resolution)
  • 30mm post diameter required for stiffness
  • 35 Hz lateral mode
  • Welded Stainless Steel Post bolted to Mirror Cell
  • Brass Spherical Nuts
  • Stainless Steel Spherical Washers
  • Special tools required to torque assy.

Dowel Pins Match drilled at assy. 2 ea.
Threaded Post bolted to truss
Spherical Washer 2ea.
Spherical Nut 2ea.
Lock Nut 2ea.
Cross Section of AAP
Fixed Frame integration discussed in PDR
Volume-6 Alignment budget discussed in PDR
Volume-2
71
Subcell Design
  • Fixed Frame (Top plate removed)

Jack Center Shaft Support and Bushings See PDR
Volume-6 for Jack Design
Registration Pins 3 ea.
Tower Clocking Pin See PDR Volume-6
Jack Center Shaft Guide Retention Pin See
PDR Volume-6
AAP attach hole
Actuator Attachment Castings
Holes for surveying target holders 3ea. See PDR
Volume-6
72
Actuator Flexure
  • Design Overview
  • Actuator Rod Flexure Design See PDR Volume-5
    for Details

Knurled
Flexible Region 7.23mm OD x 115mm Long
73
Summary
  • Just Presented
  • M1 Overview
  • SSA Project Overview
  • Key Requirements
  • Subsystem Designs
  • Additional Presentations to Follow
  • Volume-2 System Level Calculations
  • Volume-3 System-Level Finite Element Analysis
  • Volume-4 Warping Harness Design and Analysis
  • Volume-5 Flexure Design and Analysis
  • Volume-6 Handling and Integration
  • Volume-7 Summary and Future Plans
  • Additional Comments Questions?

74
Acknowledgements
Acknowledgements The TMT Project gratefully
acknowledges the support of the TMT partner
institutions. They are the Association of
Canadian Universities for Research in Astronomy
(ACURA), the California Institute of Technology
and the University of California. This work was
supported as well by the Gordon and Betty Moore
Foundation, the Canada Foundation for Innovation,
the Ontario Ministry of Research and Innovation,
the National Research Council of Canada, the
Natural Sciences and Engineering Research Council
of Canada, the British Columbia Knowledge
Development Fund, the Association of Universities
for Research in Astronomy (AURA) and the U.S.
National Science Foundation.
75
BACKUP SLIDES
76
SSA Materials
  • Material Properties for Key Components
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