m1 assembly specification

Project Documentation SPEC-0007 Revision A

Advanced Technology Solar Telescope 950 N. Cherry Avenue Tucson, AZ 85719 Phone 520-318-8102 [email protected] http://atst.nso.edu Fax 520-318-8500

M1 Assembly Specification

Kerry Gonzales

24 May 2010

Name Signature Date

Prepared By:

Kerry Gonzales

Sr. Opto-Mechanical

Engineer

K. Gonzales 20 May 2010

Approved By Chen Liang

Sr. Optical Engineer C. Liang 20 May 2010

Approved By :

Eric Hansen

Optical Systems

Engineer

E. Hansen 20 May 2010

Approved By: Rob Hubbard

Systems Engineer R. Hubbard 20 May 2010

Approved By: Harvey Bass

Contracts Officer H. Bass 20 May 2010

Approved By:

Thomas Rimmele

ATST Project

Scientist

T. Rimmele 21 May 2010

Released By: Jeremy Wagner

Project Manager J. Wagner 24 May 2010


SPEC-0007, Revision A Page ii

REVISION SUMMARY:

1. Date: 21 May 2010 Rev: A Changes: Initial document for release.


SPEC-0007, Revision A Page iii

TABLE OF CONTENTS

1. SPECIFICATIONS OVERVIEW........................................................................................ 5

1.1 SCOPE OF THE DOCUMENT ................................................................................................ 5 1.2 RELATED DOCUMENTS ...................................................................................................... 5

1.2.1 Related ATST Project Documents ............................................................................. 5 1.2.2 Interface Control Documents and Drawings ............................................................ 5 1.2.3 Verification Methods ................................................................................................. 6

2. WORK BREAKDOWN STRUCTURE .............................................................................. 8

2.1 M1 ASSEMBLY DEFINITIONS ............................................................................................. 8

3. M1 ASSEMBLY REQUIREMENTS & SPECIFICATIONS ......................................... 10

3.1 M1 MIRROR POLISHING REQUIREMENTS & SPECIFICATION ............................................ 12 3.1.1 Scope ....................................................................................................................... 12 3.1.2 M1 Polishing Definitions ........................................................................................ 13 3.1.3 Environmental Conditions ...................................................................................... 13

3.1.4 Cleaning .................................................................................................................. 14 3.1.5 Coating Removal ..................................................................................................... 14

3.1.6 Coating .................................................................................................................... 14 3.1.7 Virtual Telescope Model ......................................................................................... 15 3.1.8 Optical Surface Specifications ................................................................................ 15

3.1.9 Interface Specifications ........................................................................................... 18 3.2 M1 CELL ASSEMBLY REQUIREMENTS & SPECIFICATIONS ............................................... 19

3.3 M1 SUPPORT SYSTEM ..................................................................................................... 20

3.3.1 Overview ................................................................................................................. 20

3.3.2 M1 Support System Functional Requirements & Specifications ............................ 21 3.3.3 M1 Support System Performance Requirements & Specifications ......................... 22

3.4 M1 CELL STRUCTURE ..................................................................................................... 23 3.5 M1 THERMAL CONTROL SYSTEM .................................................................................... 23

4. M1 ASSEMBLY CONTROL SYSTEM REQUIREMENTS & SPECIFICATIONS .. 25

4.1 M1 CONTROL SYSTEM DEFINITIONS ............................................................................... 25 4.2 M1 CONTROL SYSTEM DESIGN REQUIREMENTS ............................................................. 26

4.2.1 General Assembly Requirements ............................................................................ 26

4.2.2 Specific Assembly Requirements ............................................................................. 28 4.2.3 Performance Requirements ..................................................................................... 31 4.2.4 Operational Requirements ...................................................................................... 31

4.2.5 Interface Requirements ........................................................................................... 31

5. M1 ANCILLARY EQUIPMENT....................................................................................... 33

5.1 M1 APERTURE PLATE ..................................................................................................... 33 5.2 M1 WASHING EQUIPMENT .............................................................................................. 33

5.3 M1 LIFTER ...................................................................................................................... 34 5.3.1 Overview ................................................................................................................. 34 5.3.2 M1 Lifter Functional Requirements & Specifications ............................................ 34


SPEC-0007, Revision A Page iv

5.3.3 M1 Lifter Performance Requirements & Specifications ......................................... 35

5.4 M1 ASSEMBLY HANDLING CART .................................................................................... 36 5.4.1 Overview ................................................................................................................. 36 5.4.2 M1 Assembly Handling Cart Functional Requirements & Specifications.............. 36

5.4.3 M1 Assembly Handling Cart Performance Requirements & Specifications .......... 37 5.5 M1 MIRROR SHIPPING CONTAINER SPECIFICATIONS ........................................................ 37

6. GENERAL REQUIREMENTS.......................................................................................... 38

6.1 DESIGN AND ANALYSIS REQUIREMENTS & SPECIFICATIONS ........................................... 38 6.1.1 Drawings & Documents Requirements & Specifications ....................................... 38

6.1.2 Environmental Design Requirements & Specifications .......................................... 39 6.1.3 Structural Design Requirements & Specifications ................................................. 40 6.1.4 Electrical Design Requirements & Specifications .................................................. 40

6.1.5 Thermal Design Requirements & Specifications .................................................... 41 6.1.6 Reliability & Lifetime Requirements & Specifications ........................................... 42 6.1.7 Maintenance Requirements & Specifications ......................................................... 42

6.2 FABRICATION REQUIREMENTS & SPECIFICATIONS .......................................................... 42 6.2.1 Materials and Workmanship Requirements & Specifications ................................ 42

6.2.2 Stress Relieving Requirements & Specifications .................................................... 43 6.2.3 Surface Finish, Coatings, and Paint Requirements & Specifications .................... 43

6.3 METROLOGY, INSPECTIONS, & FACTORY TEST REQUIREMENTS & SPECIFICATIONS ....... 43

6.4 PACKING AND SHIPPING REQUIREMENTS & SPECIFICATIONS .......................................... 44


SPEC-0007, Revision A of 44

1. SPECIFICATIONS OVERVIEW

1.1 SCOPE OF THE DOCUMENT

This document consists of the requirements and specifications for the development, design,

analysis, procurement, fabrication, factory assembly, factory acceptance testing, disassembly,

packaging, transportation, delivery, site assembly, and site acceptance for the ATST M1

Assembly which includes the M1 Mirror, the M1 Cell Assembly, the M1 Lifter and M1

Assembly Handling Cart.

The Contractor shall be responsible for polishing the M1 Mirror and the detailed design,

analysis, fabrication, pre-assembly, factory acceptance testing, delivery, site assembly and site

testing of the M1 Assembly and all of its subsystems as specified in this document.

1.2 RELATED DOCUMENTS

1.2.1 Related ATST Project Documents

ATST DWG-00001 M1 Blank, Detail

ATST DWG-00099 M1 Mirror, Detail

SPEC-0005 Software and Controls Requirements

SPEC-0012 Glossary and Acronym List

SPEC-0014 Software Design Description

SPEC-0020 M1 Coating Procedure

SPEC-0022 ATST Common Services Users’ Manual

SPEC-0027 Coordinate System Definition

SPEC-0029 ATST Optical Prescription

SPEC-0034 Zerodur® Blank Specification

SPEC-0063 ATST Interconnects & Services Specification

SPEC-0065 Quality Assurance Requirements

1.2.2 Interface Control Documents and Drawings

It is the intent of the ATST project to integrate and interface the M1 Assembly with other major

ATST subsystems, such as the telescope mount assembly, and various high-level control

systems. Contractor shall be required to interact and work periodically with ATST Project

personnel and outside vendors that are providing these related subsystems. The purpose of these

interactions is to refine and manage required changes associated with the critical interfaces

between the M1 Assembly and these other subsystems, and to improve the overall design and

performance of the ATST.

The Contractor shall develop and implement appropriate metrology and measurement methods

that allow verification of these interfaces during factory acceptance testing. These methods shall

be developed in conjunction with ATST Project personnel and shall be subject to approval by

AURA.



The M1 Assembly shall provide interfaces for the following items that are not directly included

in this Contract. These interfaces are each specified in their respective Interface Control

Documents that are included as part of this specification:

ICD 1.1-1.2 Telescope Mount Assembly to M1 Assembly

ICD 1.2-2.3 M1 Assembly to Wavefront Correction Control System

ICD 1.2-4.4 M1 Assembly to Telescope Control System

ICD 1.2-4.5 M1 Assembly to Global Interlock System

ICD 1.2-5.0 M1 Assembly to Enclosure Interface

ICD 1.2-6.4 M1 Assembly to Coating and Cleaning Facilities

ICD 1.2-6.5 M1 Assembly to Handling Equipment

1.2.3 Verification Methods

Included in each major numbered specification listed herein this document is a requirement

verification method. These verification methods specify the minimum standards of verification

required by AURA to ensure that the individual requirements and specifications are met.

All verification activities are the responsibility of the Contractor; i.e., the Contractor shall be

solely responsible for providing any and all test equipment, analyses, inspections, and other

means necessary to verify that the specifications and requirements have been met.

Examples of verification methods include:

Design Review. Verification by design review shall mean that the Contractor

demonstrates to AURA during the appropriate design review that the equipment shall

meet the specification by way of its intrinsic layout and configuration.

Analysis. Verification by analysis shall mean that Contractor analytically demonstrates

that the design meets the specification. Such analyses may include finite element

methods, computational fluid analyses, closed form analyses, etc. All analyses shall be

provided to AURA in written report form, in both electronic (e.g., MS Word) and paper

copy format.

Inspection. Verification by inspection shall mean that the Contractor visually

demonstrates to AURA personnel that the specification has been achieved on the as-built

equipment during factory acceptance testing.

Test. Verification by test &/or measurement shall mean that Contractor empirically

demonstrates that the as-built equipment meets the specification. Testing may be required

in the factory during factory acceptance testing and/or at the Site during Site acceptance

testing.

At a minimum, the specification compliance matrix provided by Contractor as part of the Work

shall use the verification method(s) listed in each of the requirements sections below.

All analyses, test results (with test error analysis) and other verification reports shall be provided

to AURA in written report form, in both electronic (e.g., MS Word or Excel) and paper copy

format. For each Test method used for acceptance testing, the Contractor shall perform a test

error analysis. All potential errors effecting the measurement shall be listed and their influence



on the test results evaluated. The required measurement value shall be adjusted so the Test shall

yield a 99% or greater certainty that the specification has been met after taking the test error

analysis into account.



2. WORK BREAKDOWN STRUCTURE

2.1 M1 ASSEMBLY DEFINITIONS

The M1 Assembly shall be comprised of the following major systems, subsystems, and

components. Specific details, requirements, and specifications of these items are specified in

more detail later in this document.

WBS 1.2 M1 Assembly

The M1 Assembly contains the M1 mirror and subsystems which controls its optical figure

and temperature over the telescope operating conditions.

WBS 1.2.1 M1 Mirror

The M1 Mirror is the primary light-collecting mirror in ATST. The M1 Mirror is

composed of low expansion glass or glass ceramic and its optical surface is polished as

an off-axis parabola.

WBS 1.2.2 M1 Cell Assembly

Assembly containing the M1 mirror, M1 support system, M1 thermal control system,

cooled aperture plate and M1 control system

WBS 1.2.2.1 M1 Support System

The M1 Support system supports the weight of M1 and maintains nominal surface

figure over operational zenith angles and thermal conditions.

WBS 1.2.2.2 M1 Cell Structure

The M1 Cell Structure is the base that supports the M1 Support System, M1 Thermal

Control System and the cleaning and washing hardware.

WBS 1.2.2.3 M1 Thermal Control System

The M1 Thermal Control system maintains the temperature of the M1 surface and

aperture plate close to ambient temperature to prevent self-induced seeing.

WBS 1.2.2.4 M1 Safety Restraint System

The M1 Safety Restraint System provides protection of M1 in the event of seismic

activity.

WBS 1.2.2.5 M1 Control System (M1CS)

The M1 Control System controls application of the active forces to M1, and controls

the thermal management system. It includes hardware to run the software. The M1CS

communicates with the Telescope Control System (TCS).

WBS 1.2.3 M1 Aperture Plate

The M1 Aperture Plate provides an aperture stop to limit the incoming optical beam and

provides active cooling within the M1 Thermal Control System.

WBS 1.2.4 M1 Washing Equipment



The M1 Washing Equipment is installed on the M1 Assembly to remove effluent during

the in-situ washing process.

WBS 1.2.5 M1 Lifter

The M1 Lifter is a steel structure with articulated beams and lifting pads used with a

crane to install and remove the M1 from the M1 Assembly, coating chamber support and

wash-cart support.

WBS 1.2.6 M1 Assembly Handling Cart

The M1 Assembly Handling Cart is a steel structure capable of lifting the M1 Assembly

for installation and removal from the Telescope Optic Support Structure. The M1

Assembly Lifting Cart will engage the M1 Assembly at the rear of the M1 cell, lower it

from the Telescope Optics Support Structure and move the M1 Assembly from the

telescope floor area to the transport area within the observatory facility.



3. M1 ASSEMBLY REQUIREMENTS & SPECIFICATIONS

1.2.0-0005 Commonality of Designs

Wherever possible, Contractor shall utilize identical equipment and designs throughout the M1

Assembly as well as the ATST facility. The purpose of doing this is to lower costs associated

with design effort, spares and maintenance.

Verification: Design Review & Inspection

Requirement Origin: Engineering

1.2.0-0010 Reliability

The lifetime of the ATST telescope is expected to be in excess of forty years. The objective of

the facility is to allow maximum telescope availability and performance for the given weather

conditions of any day of the year. The remote nature of the site puts a premium on having robust

systems that are easily repaired.

Wherever possible, all assemblies, subassemblies, components, parts, and mechanical systems

shall be designed to exceed the lifetime of the facility. Contractor shall identify any and all items

not designed to exceed this lifetime, and maintenance procedures and spares lists shall be

provided for them.

Failure modes of all critical components, including support system actuators and thermal control

system blowers and heat exchangers, shall be evaluated and the design of all systems shall be

such that failure of a single component shall result in a minimal performance reduction of the

system.

Verification: Design Review


1.2.0-0015 Maintainability

Routine maintenance of the M1 Assembly shall cause minimum loss of observing time. The M1

Assembly shall be designed such that routine preventative maintenance will be completed in less

than four hours per month, without removal of major components from the M1 Assembly, at

night under enclosure interior lighting. Repairs of all failures arising as a result of normal

operations of the M1 Assembly shall be accomplished in no more than 8 hours by trained

personnel. Major maintenance must be accomplished within one week on at most a yearly basis.

To the extent possible, the M1 Assembly shall be designed to be maintained using standard tools

and test equipment. Any special tools or equipment required for this operation shall be designed

and furnished by the contractor, along with detailed instructions for their use.

The M1 Assembly design shall ensure that all necessary maintenance operations can be

effectively carried out without risk to personnel or hardware. Special care must be taken in the

design of any hardware that would require maintenance personnel to work around the M1 Mirror

to avoid risk to the M1 Mirror optical surface.



Critical components, such as actuator control modules, shall be replaceable at the module level to

minimize down-time. Maintenance, replacement and repair schedules will be provided for all

components of the M1 Assembly, listing frequency and type of maintenance required.

The Contractor shall provide all special tools and equipment necessary for initial set-up,

maintenance, and servicing operations required throughout the operational life of the M1

Assembly. This excludes common hand tools such as wrenches, sockets, Allen keys, etc.

Custom stands, sights and instruments necessary for initial set-up of the system, debug, and

regular maintenance shall be delivered as special tooling and equipment. Any special handling

fixtures, such as spreader bars, necessary for handling parts of the M1 Assembly shall be

deliverable. Special tools shall be marked with the part number. For ease of installation, a lifting

feature shall be provided for any removable subassembly having a mass exceeding 15 kg.

Verification: Design Review, Inspect


1.2.0-0020 Removal for M1 recoating

For periodic re-coating of the M1, the M1 Mirror shall be capable of being easily removed from

the Telescope. The M1 Assembly shall be capable of removal from and installation to the

telescope by 4 technicians in 4 hours. The M1 Mirror shall be capable of removal from and

installation to the M1 Assembly by 4 technicians in 4 hours.



1.2.0-0025 Stresses

Stresses in all members shall be maintained within safe working values for all combinations of

fabrication, assembly, operation and survival conditions. Unless specified otherwise, all stresses

shall remain below the Precision Elastic Limit of the material under any combination of

Operational and Survival Conditions.

Consideration of fatigue shall be given to all structural members and connections subjected to

regular stress fluctuations over the lifetime of the facility.


Requirement Origin: Engineering, Safety



3.1 M1 MIRROR POLISHING REQUIREMENTS & SPECIFICATION

3.1.1 Scope

This section, defines the requirements for the ATST M1 Mirror. The ATST M1 Mirror is an off-

axis paraboloid, a circular section of a larger Ø 12 meter on-axis paraboloid. The relationship of

M1 Mirror with respect to its parent optical axis and to M2 Mirror, the secondary mirror, is

shown in Figure 1 below.

Figure 1. ATST M1-M2 optical design

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3.1.2 M1 Polishing Definitions

Bidirectional Reflectance Distribution Function (BRDF). BRDF is a four-dimensional

function that defines how light is reflected at an opaque surface.

Conic Constant (K). The Conic Constant is required to define the shape of the primary mirror

with the radius of curvature. The Conic Constant k is related to the surface height (Z) as a

function of primary mirror radial position (r) from the parent vertex and Radius of Curvature (R).

Figuring. Figuring is the process used to achieve the desired shape of an optical surface.

Generating. Generating, or Generation, is the first step in figuring an optical surface and rapidly

removes material using fixed-abrasive grinding.

Optical Surface. The Optical Surface of the M1 is the polished surface shown in the referenced

drawings.

Polishing. Polishing is the optical fabrication process that creates a finished surface on the

primary mirror.

M1 Mirror. The M1 Mirror is the 4 meter diameter ATST primary mirror.

M2 Mirror. The 0.65 meter diameter concave mirror in the ATST.

Paraxial Radius of Curvature (R). The Paraxial Radius of Curvature is the center radius of the

M1 parent surface, which along with the Conic Constant, is required to define the shape of the

primary mirror.

Virtual Telescope Model (VTM). VTM is a software model of the ATST optical system. The

VTM is capable of modeling comprehensive M1 surface figure errors as well as compensators

such as correctability of M1’s active axial support and focus of M2. The VTM can be used to

predict system-level image degradation contributed by M1, and it will be used to determine M1’s

compliance to requirement.

Zenith Angle. The Zenith Angle is the angle between the primary mirror parent optical axis and

the vertical axis.

3.1.3 Environmental Conditions

3.1.3.1 Operating Environment

The M1 Mirror, while operating as a part of the ATST, shall be capable of sustained and

continuous operation in complete conformance with the requirements of this specification

throughout the expected life of the observatory while being continuously subjected to any

combination of environmental conditions given in 6.1.2, under Operating Environment.



3.1.3.2 Survival Environment

The M1 Mirror shall meet the requirements of 3.1.3.1 above, without damage or requirement for

repair, after being subjected to any combination of environmental conditions specified under

Survival Environment in 6.1.2 below for any duration of time during any number of occurrences

throughout the expected life of the observatory:

3.1.3.3 Transportation Environment

The M1 Mirror shall meet the requirements of Section 3.1.3.1 above, without damage or

requirement for repair, after being subjected to any combination of environmental conditions

specified below for any duration of time during any number of occurrences while packaged in a

shipping container:

Altitude: sea level to 4500m

Ambient temperature: -20 to +50 C

Relative Humidity: 0 to 100% (condensing with salt spray)

Wind speed: 0 to 70 m/s

Gravity Orientation: Optical Surface facing up

Shock and Vibration: 10.0 g in any direction

3.1.4 Cleaning

The Optical Surface of the M1 Mirror will be subject to periodic cleaning throughout the life of

the observatory. The M1 Mirror shall meet the requirements of Section 3.1.3.1 above, without

damage or requirement for repair, after being subjected to cleaning with any combination of CO2

snow, alcohol, acetone, detergents and water.

3.1.5 Coating Removal

The coating on the M1 Mirror will be subject to periodic removal and replacement throughout

the expected life of the observatories using the procedures outlined in SPEC-0020. The M1 shall

continue to comply with all the requirements of Section 3.1.3.1 above, without damage or

requirement for repair, after being subjected to any number of coating removals. Materials that

may be used without limitation are; Hydrochloric acid, Cupric Sulfate, Potassium Hydroxide,

Nitric Acid, Ceric Ammonium Nitrate, Calcium Carbonate, Potassium Ferrocyanide solutions,

and Sodium Thiosulfate solutions.

3.1.6 Coating

The Optical Surface of the M1 Mirror will be subject to regular coating throughout the life of the

observatory. The M1 shall continue to comply with the requirements of Section 3.1.3.1 above,

without damage or requirement for repair, after being subjected to any number of such re-

coatings. Materials to be used for such coatings include, without limitation, aluminum, silver,

silicon nitride, nickel chromium, silicon and hafnium oxide. Processes used during coating may



include, without limitation, evaporation or sputtering, which require vacuum environments in the

range of 10-5

microns Hg pressures. The Optical Surface may be coated while facing either up or

down.

3.1.7 Virtual Telescope Model

The Virtual Telescope Model (VTM) is a software model of the ATST Optical System in Zemax.

The VTM will model comprehensive M1 surface figure error caused by factors such as residual

polishing error, thermal induced deformation, structure-induced deformation, and gravity

induced print-though. The VTM will also model compensators such as bending of the M1

optical surface by its active axial support actuators and focus of M2. The VTM will be capable

of predicting system level image degradation contributed by M1 surface figure error after active

compensation.

3.1.8 Optical Surface Specifications

1.2.1-0005 Optical Surface Description

The theoretical M1 Mirror parent optical surface is a conic surface of revolution described by the

following equation:

Z = r2/(R(1+(1-(1+K)r

2/R

2)0.5

)) with:

R = Radius of Curvature,

K = Conic Constant, and

r = distance from the parent optical axis.

Verification: Acceptance Test


1.2.1-0010 Paraxial Radius of Curvature

The paraxial radius of curvature of the M1 mirror shall be:

R = 16 m 15.0 mm.

Verification: Acceptance Testing


1.2.1-0015 Conic Constant

The Conic Constant of the primary mirror shall be:

K = -1.000



1.2.1-0020 Surface Figure Accuracy

The Optical Surface of the M1 Mirror shall depart from the theoretical shape by less than 25 nm

RMS after the following compensations have been applied: removal of tip tilt and piston errors



and active adjustment of M1 axial actuator support forces. A maximum correction force of 30 N

is allowed for correction of surface figure errors of all spatial frequencies due to polishing.

Verification: Acceptance Test, The vendor will verify that the Optical Surface complies with the

surface figure accuracy by performing full aperture interferometry. The spatial resolution of the

phase map shall be a minimum of 500 by 500 pixels. The vendor will additionally verify the

surface figure accuracy via a second method. This second method shall be independent of the

primary interferometric test and is intended to exclude possible systemic errors in the primary

test method. This second method is preferably non-interferometric in nature.

The Optical Surface specifications shall apply over a 4000 mm diameter projected onto the

Optical Surface of M1Mirror, parallel to the optical axis of the parent parabola. It is important

to note that the optical surface is not perpendicular to the incoming solar beam, but tilted at an

angle of approximately 14°; this tilt causes the projected Ø 4000 mm clear aperture to become

an elliptical footprint when projected onto the M1 Mirror.


1.2.1-0021 Surface Figure Accuracy, Higher Spatial Frequency Error

The Optical Surface of the M1 Mirror shall depart from the theoretical shape by less than 8 nm

RMS total, for higher spatial frequency error with spatial period from 1mm to 100mm, after the

following compensations have been applied: removal of tip tilt and piston errors and active

adjustment of M1 axial actuator support forces. A maximum correction force of 30 N is allowed

for correction of surface figure errors of all spatial frequencies due to polishing.

Verification: Acceptance Test, The vendor will verify that the Optical Surface complies with the

surface figure accuracy for higher spatial frequency error by performing Sub-aperture

interferometry. Sub-aperture interferometer measurements shall concentrate particularly at

support locations and M1 edges.


1.2.1-0025 Aspherical Surface Slide

The aspherical surface profile of the M1 mirror shall coincide with the optical axis of the M1

parent mirror to within 2 mm.



1.2.1-0030 Encircled Energy

The M1 mirror, while supported on the M1 Cell Assembly shall be such that the calculated

Encircled Energy (EE) concentration using the VTM, after removal of tip tilt and piston errors,

and applying active adjustment of the M1 axial actuator support forces, shall degrade, compared

to an ideal telescope, by less than:



Wavelength: 1600 nm 50% EE Degradation Diameter < .020 arcsec

This Encircled Energy specification shall be met over the full range of operational gravity

orientations and potential temperature distributions within the M1 Cell Assembly as well as

vibrations due to the M1 Thermal Control System. A maximum correction force of 30 N is

allowed for correction of support system errors. A maximum correction force of 30 N is allowed

for correction of thermal control system induced errors.

Verification: Acceptance Test (this test is expected to be performed at a single elevation angle at

or near Zenith Pointing), Analysis (Analysis will be required to estimate and remove error

contributions present in normal operation but not present in optical testing from the overall

requirement to derive the required optical test result)


1.2.1-0040 Optional Horizon Pointing Testing

As an option, the M1 Mirror Surface Figure Accuracy and Encircled Energy shall be tested at a

Horizontal Pointing angle of approximately 75 degrees (with the M1 approximately vertical).

Verification: Optional Factory Test During this approximately horizon pointing test, the M1

Mirror shall be supported during testing on the M1 Cell Assembly.


1.2.1-0045 Surface Imperfections

The Contractor shall use its best efforts to minimize the number of surface imperfections in the

Optical Surface. Within the Optical Surface, no surface imperfections of surface area larger than

5.0 square millimeters shall be allowed, and a maximum of 200.0 square millimeters shall be

allowed for the summation of all defective areas within the Optical Surface. No subsurface

damage shall be allowed to remain in any surface imperfection. Cracked material shall be

removed by a combination of grinding and etching.



1.2.1-0050 Surface Roughness

As a requirement, the Optical Surface shall be polished to less than 20 Angstroms RMS surface

roughness.

As a goal, the Optical Surface shall be polished to less than 10 Angstroms RMS surface

roughness.

Verification: Acceptance Test of minimally 20 arbitrary locations, chosen by AURA, distributed

over the entire Optical Surface and covers a total area > 0.01% of the Optical Surface.




1.2.1-0055 Surface Scatter

The Optical Surface shall yield a Bidirectional Reflectance Distribution Function (BRDF) of less

than 1.0 sr-1

at 0.002 radians from the specular direction.

Verification: Acceptance Test of 20 arbitrary locations, chosen by AURA, distributed over the

entire Optical Surface. This test shall be conducted with AURA representative present.


1.2.1-0060 Local Decenter and Rotation of the Optical Surface

The position accuracy of the Optical Surface relative to the M1 Mirror support interface features

(mounting hardware) shall be less than 2 mm in X-Y decenter and less than 2.0 arc minutes in

rotation about the Z axis.



3.1.9 Interface Specifications

1.2.1-0085 Configuration

The Vendor shall Generate, Figure and Polish the M1 Blank ensuring that the finished Optical

Surface be contained entirely within the “critical zone” of the M1 Blank as defined in ATST

DWG-00001.



1.2.1-0090 M1 Mirror Support Interface Hardware

The M1 Mirror shall consist of all actuator attachment hardware bonded to the M1 Mirror. All

hardware bonded to the M1 Mirror shall be provided as part of the M1 Support System so as to

be compatible with the axial and lateral support actuator designs of that subsystem. The Vendor

shall select adhesive, bond joint design and install the M1 Mirror lateral and axial support

interface pads as defined on drawing ATST-DWG-00099. The bonded lateral and axial support

interfaces shall be suitable for safe operation of the finished M1 Mirror while being subjected to

any combination of the Operating and Survival Conditions listed in Section 2 above while

installed in the ATST as well as Coating and Cleaning processes.



1.2.1-0095 M1 Mirror Stresses

The M1 Mirror shall not incur stresses exceeding 0.7 MPa through any interface hardware.

Special attention should be given to the interface hardware design to minimize stresses imparted

to the substrate.

Verification: Design Review, Analysis




1.2.1-0100 Alignment Targets

The Vendor shall design and install alignment target registration features on the M1 Mirror to

accurately locate the Optical Surface for the purpose of installation and alignment using a laser

tracker measurement system (i.e. FARO or API laser tracker systems). The location of the targets

are defined on the drawing ATST-DWG-00099. The location of these targets relative to the best

fit theoretical optical surface shall be delivered as part of acceptance test documentation. The

accuracy in position of these targets shall be within 100 microns of their reported position

relative to the measured Optical Surface geometry.

Verification: Design Review & Factory Test


3.2 M1 CELL ASSEMBLY REQUIREMENTS & SPECIFICATIONS

1.2.2-0005 Scope

The general requirements of the M1 Cell Assembly are as follows:

Accurately support, locate and maintain position of the M1 within the required tolerance

over the full range of operational conditions.

Maintain the M1 optical surface figure within the required tolerance over the full

operational range of the telescope.

Maintain the M1 optical surface temperature within the required tolerance over the full

range of operational conditions.

Provide active optics correction capability using the M1 axial actuators for control of the

M1 surface figure.

Allow straightforward removal of the M1 from the M1 Assembly for periodic re-coating

of M1.

Allow removal of the M1 Assembly from the Telescope Mount Assembly

Allow in-situ cleaning and washing of the M1 reflective surface.

Provide earthquake protection of the M1 in the event of seismic shock.



1.2.2-0010 Performance Modeling

Many individual factors contribute to the final optical performance of the ATST M1 Assembly.

A detailed and balanced error budget shall be generated that lists the individual contributions to

M1 Assembly contributions to overall telescope wavefront error, and these errors shall be

combined in an appropriate manner to demonstrate the M1 Assembly meets the Encircled

Energy specification (1.2.1-0030) under all operating conditions.





1.2.2-0015 Electronic Heat Sources

It is essential to avoid heat sources on or near the telescope, which could thermally disturb the

M1 or the air in the optical path. All heat sources larger than 10 W located on or near the M1

Cell Assembly, including control electronics, shall be insulated in an enclosure and actively

cooled. The maximum total heat input into the local environment from the M1 Cell Assembly

shall be no greater than 30 W.



1.2.2-0020 Thermal Mass

The M1 Cell Assembly constitutes a large thermal mass in the system. It is essential that the

temperature of the external surfaces be controlled to avoid “seeing” disruptions in the optical

path. The external surfaces of the M1 Cell Assembly shall remain within ±2ºC of the ambient

temperature at all times.

Verification: Design Review & Factory Test. At a minimum the Factory Acceptance Test will be

performed at one (1) ambient temperature condition for all M1 Assembly operational modes.


3.3 M1 SUPPORT SYSTEM

3.3.1 Overview

1.2.2.1-0005 Scope

The M1 Support System shall contain 120 axial support actuators arranged in five circular rings.

Support pads at the upper end of each actuator are bonded to the back of the M1 Mirror; these

support pads shall be made of a material that closely matches the M1 Blank thermal properties

and shall have a connection joint between the actuator rod and support pad for assembly and

disassembly of the axial support system. The axial supports shall attach to the rear surface of the

M1 cell and shall be easily removed for servicing and removal of the M1 Mirror for recoating.

Axial support forces shall be adjustable to control the M1 Mirror optical surface figure.

The M1 Support System shall contain 24 lateral supports arranged at intervals around the outside

diameter of the M1 Mirror and attached to the M1 cell structure. Support pads at the end of each

actuator shall be bonded to the outside diameter of the M1 Mirror; these support pads shall be

made of a material that closely matches the M1 Blank thermal properties and shall have a

connection joint between the actuator rod and support pad for assembly.

The M1 Support System shall control the position of the M1 Mirror in six degrees of freedom

and control the M1 Mirror optical surface figure at the direction of the M1 Control System.





1.2.2.1-0010 Basic Requirements

The M1 support system shall accurately support, locate and maintain the position of the M1

Mirror within the required tolerance over the full operational range of the telescope. It shall also

maintain the M1 Mirror optical surface figure within the required tolerances.

The M1 Support System shall be insensitive to thermal distortions and flexure of the M1 Cell

Structure. Changes in shape of the M1 Cell Structure shall not cause the position and surface

figure requirements of the M1 Assembly to be exceeded under operational conditions.


Requirement Origin: Safety, Engineering, Science Requirements

3.3.2 M1 Support System Functional Requirements & Specifications

1.2.2.1-0015 Seismic Safety

The M1 Support System shall ensure that the M1 Mirror survives the seismic conditions of this

specification without damage by providing passive restraint.



1.2.2.1-0020 Actuator Failure Condition

Safety of the M1 Mirror is a critical requirement of the M1 Support System; the actuator designs

shall limit the maximum force that can be applied. No failure, or combination of failures, is

allowed that can damage the M1 Mirror or impart a local stress of greater than 0.7 MPa in the

M1 Mirror.

(As a goal, actuator failure would result in a fixed minimum force applied to the M1 Mirror

leading to the ability for correction of the resulting optical surface error by adjusting the forces

applied to adjacent actuators.)



1.2.2.1-0025 Actuator Replacement Capability

Each M1 Support System actuator shall be capable of removal and installation from the M1

Assembly by 1 technician in less than 2 hours.


Requirement Origin: Safety

1.2.2.1-0030 Hysteresis

The operational requirements of the M1 Assembly demand that support forces will vary from

positive to negative and back again over a day tracking the sun. The design of the axial and

lateral support system shall minimize hysteresis and dead-zone effects due to this force direction

change.





3.3.3 M1 Support System Performance Requirements & Specifications

1.2.2.1-0035 M1 Figure Adjustment

The M1 Support System shall be able to accurately adjust the M1 Mirror optical surface figure

by applying arbitrary orientation Zernike correction terms to correct for telescope errors external

to the M1 Assembly. The minimum actuator force available for these corrections shall be 75 N

above or below the nominal support force. Specific corrections with the ranges and tolerances

specified below shall be demonstrated:

Term Absolute Minimum

Adjustment (microns RMS)

Residual error (nm RMS)

Astigmatism 10 30

Coma 1 36

Spherical 1 56

Trefoil 1 17

Quatrefoil 1 26

All motions shall be smooth, free of vibration and precisely controlled. The figure correction

shall be accomplished and stable within five (5) seconds of receiving the command.

Verification: Design Review, Factory Test. M1 Zernike correction terms shall be tested using

full aperture interferometry.

Requirement Origin: Science Requirement Flow-down

1.2.2.1-0045 M1 Figure Stability

The M1 Support System shall stably maintain any commanded optical surface figure of the M1

Mirror, with RMS figure change at a rate of less than 10 nm RMS over any 10 minute period, for

any combination of static or changing operational conditions.

Verification: Design Review & Factory Test. M1 Figure Stability shall be tested using full

aperture interferometry.


1.2.2.1-0050 M1 Mirror Position

The M1 Support System shall be able to define and adjust the M1 Mirror position with the

ranges and tolerances specified below:

Motion: Range: Repeatability:

De-center motion (X or Y) ± 500 μm ± 2 μm

Piston (Z) motion ± 1000 μm ± 2 μm



Tip-tilt motion (about X or Y) ± 50 arc seconds ± 0.5 arc seconds

Z axis rotation ± 15 arc minutes ± 2 arc seconds

All motions shall be smooth, free of vibration and precisely controlled. These specifications

include the effects of the M1 Cell Structure and the M1 Support System. The position correction

shall be accomplished and stable within sixty (60) seconds of receiving the command.



1.2.2.1-0055 M1 Support Stiffness

The M1 Mirror axial supports shall have a minimum stiffness of 20 N/micron. The M1 Mirror

lateral supports shall have a minimum stiffness of 40 N/micron.



3.4 M1 CELL STRUCTURE

1.2.2.2-0005 Scope

The M1 Cell Structure is a structural steel weldment that interfaces to the Telescope Mount

Assembly and all of the M1 Assembly subsystems. It provides a mounting surface and load

reaction for all of the axial and lateral support actuators. It houses the M1 thermal control system

hardware and also provides a mounting location for sensors, facility interface panel(s), M1

Assembly Handling Cart and the M1 Lifter.




The M1 Cell Structure shall be designed to provide high resonant frequencies relative to all

excitation sources and minimum deflection with changing gravitational loading. The M1 Cell

Structure shall have minimum thermal mass and heat capacity consistent with the required

mechanical performance. The M1 Cell Structure shall provide adequate access for maintenance

and service of the support actuators and thermal control system hardware contained within the

M1 Cell Structure.


Requirement Origin: Safety, Engineering

3.5 M1 THERMAL CONTROL SYSTEM

1.2.2.3-0005 Scope

The M1 Thermal Control System controls the optical surface temperature of the M1 Mirror. It

consists of all equipment required to monitor and control the optical surface temperature.






The M1 Thermal Control System shall provide cooling to the M1 Mirror, minimizing convective

heat transfer to the ambient air from any surface that may contribute to local seeing effects. The

temperature control shall be done in such a way as to allow all other requirements of the M1 Cell

Assembly to be met while the Thermal Control System is operating under any combination of

operational environmental conditions.

The M1 Thermal Control System shall be designed so that the failure of one component such as

a blower or heat exchanger shall result in a minimal performance reduction of the system.

Critical components of the M1 Thermal Control System shall be monitored during operation and

any change in their health status shall be directed to the telescope control system.

The M1 Thermal Control System shall provide, at a minimum (TBR), six (6) additional thermal

sensor inputs that can be populated by AURA after acceptance of the system. The M1 Control

System shall have the ability to read and convey the data from these additional inputs to the TCS

as required.



1.2.2.3-0015 Temperature Range

The M1 Thermal Control System shall be capable of maintaining the surface temperature of the

M1 Mirror within 2ºC of the temperature of the surrounding ambient air during any and all

operating conditions.


Requirement Origin: Engineering, Science Requirement Flow-down

1.2.2.3-0020 Temperature Response

The optical surface shall be capable of an average temperature change of 5° C in 8500 seconds

with uniformity of ±0.5° C. This temperature change shall be accomplished using liquid coolant

at 15° C cooler than the ambient air. The initial blank temperature shall be at ambient

temperature and be uniform over the entire mirror to within ±0.5° C.



1.2.2.3-0025 Temperature Uniformity

The M1 Thermal Control System shall provide cooling to the M1 Mirror in such a way as to

maintain temperature uniformity of any point of the M1 Mirror optical surface within ±0.5° C

under any combination of operational conditions.

Verification: Design Review & Analysis




1.2.2.3-0030 Vibration

The M1 Thermal Control System shall not create vibrations that degrade telescope imaging

performance. Any M1 Mirror optical acceptance testing results using the M1 Cell Assembly

shall include any and all vibration effects from the M1 Thermal Control System.



1.2.2.3-0035 System Safety

The M1 Thermal Control System shall include all necessary hardware to detect fault conditions

within the M1 Assembly as described in ICD 1.2/4.5 and transmit them to the GIS, including but

not limited to leak detection, over temperature conditions, flow and pressure loss etc.

The M1 Thermal Control System shall be capable of responding to all GIS commands as

described in ICD 1.2/4.5, including but not limited to being depowered separately from the

remainder of the M1 Assembly when commanded by the GIS.



4. M1 ASSEMBLY CONTROL SYSTEM REQUIREMENTS & SPECIFICATIONS

4.1 M1 CONTROL SYSTEM DEFINITIONS

The following definitions are used throughout this section.

Controller. A controller is a computing component that executes software to close servo loops,

read external sensors, and interface with higher level software.

Engineering User Interface. The engineering user interface is a graphical user interface (GUI)

that provides control and status information to a user for a particular subsystem. An engineering

user interface may be instantiated on a remote computer via a network connection. More than

one engineering user interface may be open.

Index Position. The index position is a specific location within the range of travel of a

mechanism. It has a unique sensor or marker to identify it to a mechanism controller.

Interlock. An interlock is a hardwired connection between two systems or mechanisms that

provides time-critical safety information.

Interlock Condition. An interlock condition exists if a system or mechanism raises an interlock

connection because it has detected a possible safety conflict.

Interlock Override. An interlock override is a manually set condition to inform a system to

ignore a particular interlock condition.



Observatory Control System (OCS). The OCS is the highest level software system,

responsible for coordinating observations and providing system services.

Telescope Control System (TCS). The TCS is responsible for control of all telescope

subsystems.

Wavefront Correction Control System (WCCS). The Wavefront Correction Control System

is responsible for determining and transmitting corrective values for observed errors in the

wavefront delivered by the telescope.

4.2 M1 CONTROL SYSTEM DESIGN REQUIREMENTS

The M1 Control System (M1CS) is one element of the M1 Assembly, along with the M1 Mirror,

M1 Cell Structure, M1 Thermal Control System, and others.

From a software systems point of view, the M1 Control System (M1CS) is a subsystem of the

ATST Telescope Control System (TCS). While the TCS is responsible for the overall operation

of the telescope, it delegates responsibility for the operation of the M1 Assembly to the M1CS.

The M1CS is required to accept input demands from the TCS and apply them to its own internal

components. Additionally the M1CS is responsible for all internal operations, i.e., those

activities that are wholly performed inside the M1 Assembly or are initiated by the M1CS.

Commands to the M1CS are sent through the ATST Common Services, defined in the ATST

Common Services User’s Manual (SPEC-0022-1).

4.2.1 General Assembly Requirements

The M1CS has a number of general requirements placed upon the entire system, but not

necessarily applicable to specific subassemblies. These requirements define the basic functional

and performance requirements of the M1CS as they apply to the M1 Assembly. Additional

requirements placed upon the software define operational and interface requirements. Finally,

there are a set of general requirements for software standards, documentation, and testing.

1.2.2.5-0001 Control

The M1CS shall control all actuators, sensors, and other mechanical and optical components

associated with the M1 Assembly. No other system or controller shall operate these components

without using the M1CS to control them. Control of the M1CS shall be through the approved

TCS/M1CS interface (ICD 1.2/4.4).


Source: Software Concepts

1.2.2.5-0005 Status

The M1CS shall maintain and provide status information on all actuators, sensors, and other

components associated with the M1 Assembly. Status information shall include position, rate,

forces, temperatures, wavefront correction input and any other information required to determine

the condition of the M1 Assembly, the M1CS, and its components. Status information shall be



updated at rates necessary to perform both manual and automatic control processes as specified

herein. Status information shall be made available to requesting systems through the TCS-to-M1

Assembly interface (ICD 1.2/4.4).

In general, status information is pertinent and expected to be sent from the M1CS if it contains

any information on the current condition of the hardware and software within the M1 Assembly

and is useful for diagnostics, operating control loops, or possibly indicative of errors or problems

within the M1 Assembly. The information found in the M1CS status reports is defined by the

TCS to M1 Assembly Interface Control Document. This information shall be inserted, modified,

and reviewed as part of the design process.



1.2.2.5-0010 Default state

The default state of any equipment shall be an inert, non-moving, non-powered condition.

Equipment within the M1 Assembly shall take this state on an interlock condition, initialization,

shutdown, or when demanded through the software interface.


Source: Software Concepts, Engineering, Safety

1.2.2.5-0015 Restart

The M1CS shall perform all requests sent through its interface without need of reboot or re-

initialization, unless the request demands such an operation.


Source: Software Concepts, Engineering

1.2.2.5-0020 Health

The M1CS shall be able to determine if the current state of the M1 Assembly is within

operational specifications. The M1CS shall report this current state as its “health”. The health

shall be determined and reported at least every three seconds through the ATST Common

Services health reporting mechanism, as specified by SPEC-0022-1.


Source: Software Concepts, Operational Concepts

1.2.2.5-0025 Logging

The M1CS shall log pertinent data to the ATST facility log mechanism. Pertinent data shall

include state changes, configuration changes, errors, alarms and warnings, and any other

information that may assist in reconstructing the operation of the M1CS. The M1CS logging

level shall be user selectable for the depth of information, per the ATST logging facility

definitions of logging levels, as specified by SPEC-0022-1.




Source: Software Concepts, Operational Concepts

1.2.2.5-0030 Availability

The M1CS shall always be available to accept or reject commands. It shall not block any

command request while processing another command request.

This requirement prevents the M1CS from processing a command in only one thread, essentially

blocking subsequent commands until the first one is completed. This behavior is necessary to

effect commands such as stop and pause after an initial start command; otherwise it would be

difficult to stop an ongoing operation.



1.2.2.5-0035 Persistence of data

Static information required by the M1CS to operate shall be recoverable after a restart or reboot.

This information may include, but is not limited to, zero points, lookup tables, and configuration

parameters. Dynamic information, such as current position and state, may be reset or recovered

after initialization. Static information shall be stored through the ATST Common Services

mechanism for default configuration storage.



4.2.2 Specific Assembly Requirements

1.2.2.5-0100 Control of the axial and lateral support actuators

The M1CS shall control the operation of the M1 Support System. The M1CS shall define the

position of the axial and lateral support actuators and maintain that position under all operating

conditions per specification.

The M1CS is the sole controller of mirror support and resulting mirror figure during normal

operations. It is the responsibility of the M1CS to provide accurate and responsive values to the

actuators to keep the mirror position within specification, in all defined operating modes (open

loop, closed loop) and at all mirror elevation angles.

Verification: Factory Test


1.2.2.5-0105 Open-loop correction

The M1CS shall perform open-loop correction of the M1 Mirror figure for the current zenith

angle, temperature, temperature gradient, or any other variable operating condition that

influences M1 Mirror figure. The correction forces shall be predetermined and applied as

necessary to maintain the M1 Mirror figure. The M1CS shall be commanded to enable or disable

the open loop-correction. The current zenith angle shall be used to determine the corrective

forces for each axial and lateral actuator, along with any other information (i.e., temperature,

azimuth angle, etc.) needed to maintain M1 Mirror figure.



At a minimum, the M1CS shall keep open-loop correction tables for the following sets of mirror

natural mode coefficients (mm1..20):

Static +

(mm1 .. mm20) * cos(el) +

(mm1 .. mm20) * sin(el) +

(mm1 .. mm20) * (T – T0) +

(mm1 .. mm20) * (dT/dz) +

(mm1.. mm20)* solar flux +

(mm1.. mm20)* TBD,

Where Static defines the non-changing set of actuator force values to correct for static errors

such as polishing or support position errors. The variable correction is supplied by coefficients

which are scaled; cos(el) and sin(el) define the cosine and sine accumulative error due to

changing elevation angle el; (T - T0) defines the cumulative error due to the difference in the

current temperature of the optical surface (T) and the nominal temperature (T0); and dT/dz

defines the temperature gradient (dT) through the mirror perpendicular to the optical surface (dz).

The Contractor shall define the static force values and additional open-loop correction tables for

other parameters if they are necessary to maintain the optical performance specification.


Source: Engineering

1.2.2.5-0110 Closed-loop correction

The M1CS shall be capable of closed-loop correction of the M1 Mirror figure. The M1CS shall

use information from the ATST Wavefront Correction Control System (WCCS) and any

necessary look up table values to calculate and apply the appropriate force adjustments for each

axial support actuator to provide closed-loop figure correction. The M1CS shall be commanded

to enable or disable the closed-loop correction through the TCS interface.

If the open-loop mode operation is enabled after operating in closed-loop mode, the last closed-

loop demands applied will be used to calculate a zero point offset (difference between closed

loop and LUT demand) which will be added to all LUT position and or figure demands.

While closed loop correction is enabled, if updates from the WCCS are not received within a

user definable period between 10 seconds and 10 minutes, actuator forces shall be updated by the

M1CS based on the last available closed-loop support force set with open-loop look up table

(LUT) adjustments made to compensate for changes in telescope position, temperature, etc.


Source: Engineering



1.2.2.5-0112 WCCS controlled closed-loop correction

The M1CS shall be capable of closed-loop correction of the M1 Mirror figure using only

information from the WCCS to calculate and apply the appropriate force adjustments for each

axial support actuator to provide closed-loop figure correction. The M1CS shall be commanded

to enable or disable this WCCS controlled closed-loop correction through the TCS interface.


Source: Engineering

1.2.2.5-0115 Control of the M1 Thermal Control System

The M1CS shall control the operation of the M1 mirror thermal control system. Control shall

include the ability to enable and disable the M1 mirror thermal control system, maintain optical

surface temperatures within specification relative to ambient air temperature, create a

temperature profile within the M1 that is based upon the projected ambient temperature of the

next day’s observations (as provided by the TCS), and read and report all temperatures and other

sensors involved in the operation of the M1 thermal control system.

Verification: Design Review, Factory Test

Source: Operational Concepts, Engineering

1.2.2.5-0120 Observing Mode: Thermal Control System

The M1CS shall execute closed-loop control of the thermal control system by reading

temperature sensors and applying an appropriate response with the blowers, coolant control

valves, and other thermal equipment. The control loop shall maintain the optical surface mirror

temperature equal to that of the ambient environment within specification.

While in the Observing Mode the M1CS interface shall have the following control options:

Closed-loop control using measured temperatures to maintain the system at ambient

temperature.

Open-loop control that provides maximum cooling at all times.

Open-loop control that can apply any combination of tabulated cooling data (for example

based on diurnal cycles, telescope position, etc.) that is populated by the user at anytime.

No-Control (Off) setting that provides no thermal control.



1.2.2.5-0125 Preconditioning Mode: Thermal Control System

The M1CS shall execute thermal control of the M1 Mirror to prepare it for Observing Mode. The

M1CS shall create temperature set points based on the time until observations are scheduled to

begin and the ambient temperature expected at the start of observations which will be supplied

by the TCS, or based on data from the previous dawn stored by the M1CS.

While in the Preconditioning Mode the M1CS interface shall have the following control option:

Fixed duration preconditioning prior to set start time.





1.2.2.5-0130 Loss of an actuator

The M1CS shall be able to operate with removed or disabled actuators, under the condition the

removed or disabled actuators shall apply no force to the M1 mirror. The M1CS shall have the

capability to adjust forces on other actuators to minimize the performance degradation due to the

loss of a single actuator.

Verification: Test

Source: Engineering

4.2.3 Performance Requirements

1.2.2.5-0200 Update mirror forces at rates between 0.1 and 1 Hz

The M1CS shall continuously update the forces on the M1 Mirror at a rate between 0.1 Hz and 1

Hz. The rate shall be externally controllable through the public interface with the TCS.


Source: Science Requirements

4.2.4 Operational Requirements

1.2.2.5-0300 Engineering user interface

The M1CS shall provide a Graphical User Interface (GUI) that controls all required functionality

of the M1 Assembly. This engineering user interface shall use the same interfaces specified for

the TCS (ICD 1.2/4.4) and WCCS (ICD 1.2/2.3).

Verification: Inspection, Factory Test


1.2.2.5-0305 Time

The M1CS shall use International Atomic Time (TAI) in all calculations. It shall use TAI in all

data distribution.

Verification: Inspection

Source: Engineering

4.2.5 Interface Requirements

1.2.2.5-0400 Common Services Framework

The M1CS shall provide a software interface that conforms to the ATST interface for the

Common Services Framework (SPEC-0022). The Common Services Framework interface shall

be controlled by the ATST; the M1CS shall use the interface defined by the ATST.

Description: The Common Services Framework defines three levels of component interface: (a)

the containers and container managers the M1CS components shall operate within, (b) the



controller model the M1CS components shall implement, and (c) the services the M1CS shall

employ to interact with the ATST software system.



1.2.2.5-0405 Telescope Control System

The M1CS shall accept and act upon commands and configurations from the ATST Telescope

Control System (TCS) for all operational and engineering activities. The commands,

configurations, and events shall be defined in the interface control document ICD 1.2/4.4.

Description: The TCS commands the M1CS to perform in a specified wavefront mode, such as

closed-loop wavefront correction, or a particular thermal mode, such as closed loop thermal

correction. The TCS also requires the M1CS to broadcast status events at regular intervals or

upon state changes. In addition, the engineering GUI uses the same interface to perform the

above activities and additional ones as necessary for testing, diagnosis, and performance

monitoring.



1.2.2.5-0410 Wavefront Correction Control System

The M1CS shall accept and act upon wavefront correction information from the ATST

Wavefront Correction Control System (WCCS). The wavefront correction information format,

type, and rate are specified in the interface control document ICD 1.2/2.3.

Description: Wavefront information is broadcast by the WCCS to all subscribed listeners. The

M1CS shall be one of the subscribed listeners and shall act upon the information sent by the

WCCS to correct its mirror figure.


Source: Science Requirements, Software Concepts

1.2.2.5-0415 Interlock

The M1CS shall respond to a global interlock signal by placing itself and its subsystems in a

safe, default state. The default state shall prevent the M1CS from moving any mechanisms or

equipment while the interlock condition exists. The M1CS shall reject commands while the

global interlock signal is active. The action currently underway when the interlock condition

occurred should be aborted.

The M1CS shall respond to the release of a global interlock signal by accepting new commands.

The M1CS shall not exit the default state until commanded by the TCS or the engineering user

interface.



Description: The M1CS needs to listen for broadcasted interlock conditions and place itself in a

safe state when it detects an interlock condition. Upon the release of the interlock condition the

M1CS needs to be able to resume processing commands and performing actions.

The broadcast interlock condition is not the same as the hardware GIS interlock used by the

mechanical systems in the M1 Assembly. It is a software event sent by the Observatory Control

System when it determines that a hardware interlock is ongoing and may impact operations. It

shall not be used for personnel or equipment safety reasons.


Source: Safety, Engineering

5. M1 ANCILLARY EQUIPMENT

5.1 M1 APERTURE PLATE

1.2.3-0005 Scope

The M1 Aperture Plate is a continuous ring that defines the clear aperture of the M1, the entrance

aperture of the ATST.



1.2.3-0010 Basic Requirements

The M1 Aperture Plate shall be located immediately in front of the M1 Mirror optical surface,

and will define the 4 meter circular clear aperture of the incoming optical path as viewed along

the optical axis of the telescope. The M1 Aperture Plate shall have a thickness no greater than 75

mm. The sunward facing surface of the M1 Aperture Plate shall be illuminated by direct

sunlight. The absorbing surface shall be painted black with an average solar absorption of greater

than 95%. The temperature of the M1 Aperture Plate shall be maintained at ambient temperature

within a range of +/-1° C.


Requirement Origin: Engineering, Science Requirements

5.2 M1 WASHING EQUIPMENT

1.2.4-0005 Scope

The M1 Washing Equipment consists of equipment used to collect and remove the effluent

accumulated at the lower edge of the M1 Mirror during the in-situ washing process.

Verification: Design Review & Inspect



The M1 Mirror will be washed in-situ periodically at a near horizon pointing position. The

mirror surface will be washed using a liquid soap solution and rinsed with distilled water. The



M1 Washing Equipment shall include equipment around the lower half of the M1 Mirror to

contain the liquid effluent and prevent its damaging M1 Cell Assembly components. Features in

the design will be provided to verify that no leakage has occurred past any seal during the

washing process.




M1 Aperture Plate removal or relocation and any M1 Washing Equipment installation required

in preparation for in-situ washing shall be capable of being accomplished within one hour by

four technicians



5.3 M1 LIFTER

5.3.1 Overview

1.2.5-0005 Scope

The M1 Lifter is a steel structure with articulated beams and lifting pads used with a crane to

install and remove the M1 Mirror from the M1 Assembly, coating chamber and wash-cart.




The M1 Lifter shall safely and accurately install the M1 Mirror on the M1 Cell Assembly

supports, coating chamber supports and wash-cart supports. The M1 Lifter shall be capable of

being stored on a horizontal surface while holding the M1 Mirror. During use, stresses within

the M1 Lifter and M1 Mirror shall be within safe limits. The M1 Lifter shall incorporate a cover

to protect the M1 Mirror from falling objects while it is in use.



5.3.2 M1 Lifter Functional Requirements & Specifications

1.2.5-0015 Protective Cover

The M1 Lifter shall incorporate a protective cover, shielding the M1 Mirror from damage due to

dropped items weighing up to 1 Kg from heights of 10 meters.

Verification: Design Review, Factory Test




1.2.5-0020 Handling Safety

The M1 Lifter shall incorporate alignment guides that preclude possible damage to the M1

Mirror due to mishandling of the M1 Lifter while being lowered over the M1 Mirror.



1.2.5-0025 Storage

The M1 Lifter shall be capable of being stored on the M1 Handling Cart.




The M1 Lifter shall be capable of being configured into a state ready to lift the M1 Mirror by

three technicians within ten minutes from the time it is lowered onto the M1 Cell Assembly.



5.3.3 M1 Lifter Performance Requirements & Specifications

1.2.5-0035 M1 Stress Levels

Safety of the M1 substrate is critical to the operation of the M1 Lifter; the design shall include a

mechanism that limits the maximum force that can be applied. No failure, or combination of

failures, shall be allowed that can damage the M1 Mirror or impart a local stress of greater than

0.7 MPa in the M1 Mirror.



1.2.5-0040 Safety Factors

Safety of the M1 Mirror substrate is critical to the operation of the M1 Support System; the

design shall use a minimum safety factor of 4 for all components. The load rating shall be

stenciled on the M1 Lifter and visible from 10 meters.



1.2.5-0045 Repeatability

The M1 Lifter shall be capable of reinstallation of the M1, after the repeated lifting operations

required by the coating process, to within an accuracy that allows reconnection to the M1 Cell

Assembly actuators without the need to adjust actuator positions.





5.4 M1 ASSEMBLY HANDLING CART

5.4.1 Overview

1.2.6-0005 Scope

The M1 Assembly Handling Cart is a self propelled steel structure capable of lifting and

transporting the M1 Assembly as needed by integration, coating and maintenance procedures

through the observatory facility.




The M1 Assembly Handling Cart will engage the M1 Assembly at the bottom of the M1 Cell,

lower the M1 Assembly from the telescope, and move the M1 Assembly from the observing

floor to the receiving area within the observatory facility.



5.4.2 M1 Assembly Handling Cart Functional Requirements & Specifications

1.2.6-0015 Lifting Capacity

The M1 Assembly Handling Cart shall be capable of lifting and lowering the M1 Assembly for

installation and removal from the telescope. The lifting capacity of the M1 Assembly Handling

Cart shall be a minimum of two times its expected nominal load. The raise and lower speed shall

be adjustable between 1 and 5 mm/s.



1.2.6-0020 Transport Capacity

The M1 Assembly Handling Cart shall be capable of transporting the M1 Assembly up a two

percent grade over an even surface containing concrete expansion joints, 25 mm wide gaps

between floor surfaces and 5 mm height changes in self propelled operation. The transport speed

shall be adjustable between 10 and 100 mm/s in both the forward and reverse directions. The M1

Assembly Handling Cart shall be steer-able with a minimum turning radius of 4 meters measured

at the centerline of the M1 Assembly Handling Cart. The M1 Handling Cart shall utilize wheels

with rubber tires for transport.



1.2.6-0025 M1 Accessibility

The M1 Assembly Handling Cart shall allow access to all M1 Assembly components for

disassembly and reassembly of the M1 Support System required by the recoating process. All

disassembly and reassembly procedures shall be possible with the M1 Assembly on the M1

Assembly Handling Cart.





1.2.6-0030 Control

The M1 Assembly Handling Cart shall be manually controlled using a hand paddle with a 5

meter cable. Guides that allow precise location of the M1 Assembly Handling Cart with respect

to fixed posts and rails that are installed in the facility floor shall be incorporated in the design

and supplied with the Handling Cart hardware.



1.2.6-0035 Power Source

The M1 Assembly Handling Cart shall be capable of being connected to the facility power

sources specified in the relevant ICD while traveling between the telescope and transport area.

The M1 Assembly Handling Cart is required to be able to be disconnected from power while

carrying the M1 Assembly to transit in an elevator. Brakes shall be automatically applied in the

event of a power loss.



5.4.3 M1 Assembly Handling Cart Performance Requirements & Specifications

1.2.6-0035 Seismic Loading and Safety Factors

Safety of the M1 substrate is critical to the operation of the M1 Assembly Handling Cart; the

design shall use a minimum safety factor of 4.0 for all components. The load rating shall be

stenciled on the M1 Assembly Handling Cart and visible from 10 meters.

Verification: Design Review & Analysis


5.5 M1 MIRROR SHIPPING CONTAINER SPECIFICATIONS

1.2.1-0055 General

The Vendor shall design, fabricate and deliver a reusable shipping container that is suitable for

safely transporting the M1 Blank and coated M1 Mirror while being subjected to any

combination of the Transportation Conditions listed in Section 2 above.



1.2.1-0060 Envelope

The size of the shipping container shall not exceed an envelope five (5) meters square on a side

and two (2) meters in height.





1.2.1-0065 Lifter Compatibility

The design of the shipping container shall allow use of a lifting fixture to remove and install the

M1 Mirror that attaches to the M1 Mirror at six (6) places equally spaced around the outer

diameter of the M1 Mirror as shown in ICD 1.2/6.5.



6. GENERAL REQUIREMENTS

6.1 DESIGN AND ANALYSIS REQUIREMENTS & SPECIFICATIONS

To the extent possible, subsystems that are off the shelf or previously designed, built, and tested

by Contractor or by AURA should be used to minimize cost and to optimize the ability to

maintain and procure spare parts. Design of components should be achieved using the most

efficient and effective manufacturing processes to simplify all components and ensure the lowest

cost and highest reliability without sacrificing performance.

Wherever possible, the M1 Assembly subsystems shall be organized into modules for ease of

mounting/dismounting and servicing. Written instructions for the removal, installation, servicing,

alignment, and adjustment shall be provided by Contractor for all subsystems.

Contractor shall supply all mechanical and electronic hardware associated with each mechanical

system, and shall provide all necessary amplifiers, wiring, utility routing, hangers, cable trays,

and connections to the appropriate control system to operate the systems. Design of all utility

routing shall be subject to approval by AURA.

Unless stated otherwise, all requirements and specifications stated in this General Requirements

& Specifications shall be subject to verification via design review and inspection.

6.1.1 Drawings & Documents Requirements & Specifications

All detail design drawings shall conform to AMSE Y14.5M-2009.

All detail design drawings shall be in System International (metric) units with Imperial (inch)

secondary units shown in parentheses as required. All analyses shall be performed in the System

International system (metric).

All detail design drawings shall be generated in (or transferable to) the latest commercially-

available version of SolidWorks. These drawings, along with printed hard copies, shall be

provided to AURA upon completion of the Work.



All computer aided design (CAD) 3d solid models of the M1 ASSEMBLY shall be provided to

AURA in the latest commercially-available version of SolidWorks format upon completion of

the Work.

Four sets of manuals shall be prepared, containing all information related to maintenance and

operation of the pertinent M1 Assembly, so that the information in the Manuals will be adequate

to enable ATST project personnel to perform the full range of expected operating and regular

maintenance functions related to the M1 Assembly without the need to seek information from a

source other than the manuals.

The manuals shall have the maintenance and operating information organized into suitable sets

of manageable size, which shall be bound into individual binders properly identified on both the

front and spine of each binder, which is indexed (thumb-tabbed) and includes pocket folders for

folded sheet information. The Manuals shall also be supplied in electronic form.

Such information shall include, but not limited to, all information related to normal operations

and procedures, emergency operations and procedures, normal maintenance and procedures,

emergency maintenance and procedures, spare parts, warranties, wiring diagrams, inspection

procedures, performance curves, shop drawings, product data, and similar applicable

information. The maintenance tasks to be covered in the Manuals include, but are not limited to:

Removal and reinstallation for recoating the M1 Mirror,

Cleaning and washing of M1 Mirror,

Replacement and calibration of position, pressure or temperature sensor equipment as

well as axial and lateral actuators, and thermal control system components,

Adjustment and tuning of PID parameters for actuator and temperature control loops,

Troubleshooting system failures

6.1.2 Environmental Design Requirements & Specifications

The ATST observatory Site is located at an elevation of approximately 3050 meters (10,000

feet).

Local air pressures will be influenced by the Site altitude and by exposure of the observatory to

local weather conditions. All M1 Assembly subassemblies, parts and components shall be vented

so that changes in pressure when transporting from sea level to the observatory site shall not

cause damage or failure.

Any equipment designed to operate at normal atmospheric air pressures and incorporating air

cooling shall be de-rated for the reduced air density at the Site.



There are two separate environmental conditions that shall be used by the Contractor when

performing the Work. These are the Operating Conditions and Survival Conditions. The

following subsections describe these two conditions.

Operating Conditions

The following data represents the range of environmental conditions expected during daytime

hours when the facility will be in use. The M1 Assembly and all of its subsystems shall remain

fully operational throughout the range of conditions indicated.

Operating wind speeds: Up to 5 m/s (11 mph) from any direction.

Operating temperature range: -2 to 22C (28 to 72 F)

Temperature change rate: +/-2 ºC/hr maximum

Operating humidity range: 0 to 70 percent relative humidity

Gravity Orientation 0 to 75 telescope Zenith angle

Survival Conditions

The following data represent the extreme environmental conditions the M1 Assembly must be

able to withstand without damage, and with the ability to return to operation within all

specifications upon return to an Operating Condition. The M1 Assembly shall not be required to

operate in these Survival Conditions.

Survival air temperature range: -10 to 27 C (14 to 81 F)

E-Stop or Seismic acceleration: 2 g in any direction added to nominal conditions

Survival wind speed 0 to 20 m/s from any direction

Survival humidity range: 0 to 95 percent relative humidity

Gravity orientation 0 to 90 telescope Zenith angle

6.1.3 Structural Design Requirements & Specifications

Stresses in all members shall be maintained with safe working values for all possible

combinations of fabrication, erection, operation, and survival conditions. Unless specified

otherwise by AURA, a minimum Factor of Safety of 4.0 under any combination of operational

and environmental loading shall be used during the course of the Work.

Gravity loads, temperature effects, wind effects, and seismic loads shall be combined per an

approved standard when determining the critical cases for maximum stresses and deflections.

All mechanical and electrical components of the telescope are to be selected so as to prevent

their exciting vibration (i.e., resonances) of the telescope in any mode.

6.1.4 Electrical Design Requirements & Specifications

Power to the M1 Assembly shall be provided at each major subsystem location. All

electronic/electrical equipment must have over-current protection (thermal breakers, fuses,

lightening arresters, ground-fault interrupts, surge protection, etc.). Fuses must be easily



accessible for replacement. All electronic/electrical equipment must have a main line circuit

breaker or power switch, and a controlled light indicator for power status.

All electrical/electronic installations must comply with National Electrical Code where

applicable.

All electronic/electrical equipment in the M1 Assembly must have safety grounds.

The M1 Assembly and its components should minimize electromagnetic interference (EMI) with

scientific instruments and other telescope systems. Emissions and immunity to EMI must be

considered in every part of the M1 Assembly design. Electronic equipment used in the telescope

area must be EMI certified and comply with FCC regulation Part 15, Class B limit for emissions.

For equipment used in the control or computer room, Class A limit is acceptable. All electronic

equipment must be certified IEC 1000-4-2 or better for electrostatic discharge (ESD) immunity

and, IEC 1000-4-3 and IEC 1000-4-6, or better, for radio frequency interference (RFI) immunity.

Immunity to power-line disturbances (IEC 1000-4-9, IEC 1000-4-13), electrical fast transient

(IEC 1000-4-4), and surges (IEC 1000-4-5) is also desired.

All power and signal cables and leads shall be shielded.

Contractor shall define and provide electrical connectors, cabling, and tubing consistent with

high reliability operation and EMC constraints. Connectors shall be capable of being rapidly

disconnected for service of all assemblies of the M1 Assembly. Connectors shall be keyed so that

incorrect connection is not possible. Proper and appropriate strain relief shall be provided to

ensure reliability and to minimize effect of cabling loads on the M1 Assembly. Only high-quality

rough-service connectors may be used.

Power and signal cables should be shielded for low and high frequency interference. Whenever

possible, power and signal wires must be routed separately. The cabling design must avoid

ground loops. Cables and tubing shall be compatible with use with the cable wraps with

acceptable flexibility, size, weight, and life cycles considered. All cables which go through the

cable wrap systems must resist cork-screwing, and be capable of withstanding multiple reverse

bends. The jacketing material must be smooth and friction-free enough to move easily within the

cable wraps, be able to slide easily over neighboring cables, be resistant to oil and abrasion, and

remain flexible at low temperatures. The jacket material should be molded onto the conductors,

eliminating any possibility of the conductors shifting inside the cable.

All utilities shall be strain relieved at all disconnects and end points.

Shielded cables and armored fiber optic cables shall also meet the above requirements. Cables

designated for power must also meet the specifications for voltage and amperage capacities as

per the U.S. National Electric Code.

6.1.5 Thermal Design Requirements & Specifications

It is essential to minimize heat sources on or near the M1 Assembly that could thermally disturb

the air in the optical path.



Any and all equipment that is cooled shall be designed in such a way that external or internal

condensation does not occur.

6.1.6 Reliability & Lifetime Requirements & Specifications

The design lifetime of the ATST facility shall be 50 years. The objective of the facility is to

allow maximum high-performance telescope usage for the given weather conditions of any day

of the year. The remote nature of the site puts a premium on having robust systems that are

highly reliable and are easily and quickly repaired.

Due consideration of fatigue shall be given to all enclosure structural members and connections

subjected to stress fluctuations over the lifetime of the facility.

Wherever possible, all assemblies, subassemblies, components, parts, and mechanical systems

shall be designed to exceed the lifetime of the facility. Contractor shall identify any and all items

not designed to exceed this lifetime, and their application and use shall be subject to approval by

AURA.

Friction and wear components not expected to provide reliable performance over the design

lifetime shall be easily replaced. Servicing instructions shall include inspections of such

equipment to evaluate conditions on a periodic basis.

6.1.7 Maintenance Requirements & Specifications

The M1 Assembly shall be configured such that all necessary maintenance operations can be

easily carried out without risk to personnel or to the telescope.

The M1 Assembly shall be configured such that all maintenance requirements are minimal. All

maintenance procedures shall be approved by AURA.

6.2 FABRICATION REQUIREMENTS & SPECIFICATIONS

6.2.1 Materials and Workmanship Requirements & Specifications

All materials used in the Work shall be new and of high grade commercial quality. They shall be

sound and free from defects, both internal and external, such as cracks, laminations, inclusions,

blow holes or porosity.

Workmanship shall be of a high grade of commercial practice and adequate to achieve the

accuracies and surface finishes called for on all drawings and in the specifications.

All manufacturing processes, such as plating, welding or heat treatment, shall be specified and

performed in such a manner as to achieve the strength and properties required without

introducing any material defects such as hydrogen embrittlement, excessive grain growth, or

residual stress concentrations.



All metal edges shall be free of burrs and sharp corners. No sharp edges that might constitute a

hazard to personnel or equipment (e.g., cabling) shall remain on the finished components.

Materials used by Contractor shall be consistent with all requirements including life cycle,

reliability, and maintainability. Substitution (e.g., to obtain improved performance or reduced

cost) is subject to written approval by AURA.

6.2.2 Stress Relieving Requirements & Specifications

All welds shall be stress relieved after welding and/or prior to final machining.

Shop drawings shall include heat treatment specifications for all parts requiring treatment to

meet the performance and functional specifications required of the M1 Assembly. Temperature-

time charts and records of heating, quenching treatments, material tests, etc., shall be kept and

identified with the parts and submitted to AURA as required for approval.

All welded parts, unless specified or approved otherwise by AURA, shall be fully stress relieved

prior to final machining operations.

6.2.3 Surface Finish, Coatings, and Paint Requirements & Specifications

All exposed machined surfaces, unless specified otherwise, shall have a surface finish of 64-

microinches or better.

Surface finishes are to be approved by AURA as suiting the location and function of each

member. These finishes shall not adversely affect the functioning of the telescope, nor require

additional maintenance during the life of the telescope.

All parts of the telescope shall be finished so as to promote cleanliness of the telescope and to

avoid contamination of any mirror surface or instrument. It is of prime importance that all

protective coatings are of high quality and long life due to the high cost of recoating and the

resulting interference with telescope operation. AURA reserves the right to inspect all surface

preparation for each individual coating prior to application.

All metallic surfaces, other than mating machined surfaces, shall be painted or otherwise

permanently protected against atmospheric corrosion.

All exterior surfaces of the M1 Assembly shall be finished with a highly durable paint or an

equivalent coating approved by AURA applied per Federal Standard 595, color TBD by AURA.

All finishes shall be durable against atmospheric and sun exposure, airborne dust impact,

personnel access on and around the structure, and any other expected wear conditions.

6.3 METROLOGY, INSPECTIONS, & FACTORY TEST REQUIREMENTS & SPECIFICATIONS

All equipment and standards used in acceptance testing shall be calibrated and traceable to

established standards to ensure accuracy and integrity of testing. These tests shall be



satisfactorily performed to demonstrate compliance with the stated requirements in this

specification.

Failure to meet all acceptance test requirements to the satisfaction of AURA shall result in

rework or other corrective actions by Contractor until the requirements are met.

The final deliverable cables and hoses shall be used in all acceptance testing at Contractor’s

facility.

6.4 PACKING AND SHIPPING REQUIREMENTS & SPECIFICATIONS

Contractor shall be responsible for all aspects of shipping, including shipping arrangements,

shipping, handling, and storage costs, transportation permits, customs and port of entry fees,

taxes, and all other costs associated with transporting the M1 Assembly components from the

Contractor’s facility to the Site.

All materials and equipment for shipment shall be prepared in such a manner as to protect them

from damage in transit and storage. Special care shall be taken with electrical and electronic

components, which shall be packed with a dehumidifying agent to effectively deal with

condensation.

Proper identification of parts and adequate provision for slinging and handling of equipment

without damage shall be made.

All packaging, packing materials, slinging, and handling equipment design shall be approved by

AURA.