Attachment B RST-INT-SPEC-0315.pdf

Effective Date: March 24, 2022

National Aeronautics and Space Administration

Goddard Space Flight Center Greenbelt, Maryland

RST-INT-SPEC-0315, Revision -

Roman Space Telescope (RST), Code 448

Roman Space Telescope Vibration Isolation System (VIS)

Performance Specification (SPEC)

GSFC CM Office March 24, 2022

Released

Roman Space Telescope Reviewed – Not Subject to Export Control

Roman VIS Spec RST-INT-SPEC-0315, Revision -ii

Roman Space Telescope Vibration Isolation System (VIS)

Performance Specification (SPEC)

Review/Signature/Approval Page

Prepared by:

Joanne Baker

Approved by:

Doug McGuffey

Electronic Approval available on-line in the RST CM Tool file://gs448share/WFIRST/01.0%20Project%20Management/1.4%20Configuration-Data%20Mgmt/Templates/Document%20Templates/TDMS/Templates%20(boilerplates)/Historical/in iii

Preface This document is a Roman Space Telescope (RST, or Roman) Configuration Management (CM)-controlled document.

Note: Prior to May 20, 2020, the project name was Wide Field Infrared Survey Telescope

(WFIRST).

For the purposes of configuration management, the prefixes “WFIRST” and “RST” are completely interchangeable. For example, RST-MGMT-PROC-0024 is the same as WFIRST-

MGMT-PROC-0024.

Changes to this document require prior approval of the Configuration Control Board (CCB. Proposed changes shall be submitted to the Roman CM Office (CMO), along with supportive material justifying the proposed change.

In this document, a requirement is identified by “shall,” a good practice by “should,” permission by “may” or “can,” expectation by “will,” and descriptive material by “is.”

Questions or comments concerning this document should be addressed to:

Roman Configuration Management Office Mail Stop 448 Goddard Space Flight Center Greenbelt, Maryland 20771 iv

Change History Log

Revision Effective Date Description of Changes

(Reference the Reference the CCR & CCB/ERB Approval Date)

Revision - March 21, 2022 Initial release of document per RST-CCR-0521 v

Table of TBDs/TBRs/TBSs

Item No. Location Summary Individual/

Organization Actionee

Due Date

SVEN-112 Component Mass3.1.1

The SVEN shall meet all performance requirements while supporting a total weight of 1,750 kg (TBR) +0% / -10%.

L. Daly Contract Award

SVEN-113 3.1.1

Each VENU shall meet all performance requirements while supporting a total mass of 610 kg

(TBR) +0% / -10%.

L. Daly Contract Award

SVEN-114 3.1.1

Each VENU shall meet all performance requirements while be equi-spaced in a plane around a circle with radius 670 mm

(TBR).

L. Daly Contract Award

SVEN-131 3.1.3

The vendor shall provide 7 (TBR) interfaces for alignment reference targets on both mounting interfaces of each VENU, to be defined in the ICD.

L. Daly Contract Award

GVIS-112 4.1.1.1

The GVIS shall meet all performance requirements while supporting a total weight of 11,850 kg (TBR) +0% / -10%.

L. Daly Contract Award

GVIS-113 4.1.1.1

Each GVIU shall meet all performance requirements while supporting a total mass of 4120 kg (TBR) +0% / -10%.

L. Daly Contract Award

GVIS-120 4.1.1.24.1.1.2

Each GVIU shall not exceed a diameter of 0.915 m (TBR) and a height of 0.4 m (TBR).

L. Daly Contract Award

GVIS-131 4.1.1.3

The vendor shall provide 7 (TBR) interfaces for alignment reference targets on both mounting interfaces of each GVIU, to be defined in the ICD.

L. Daly Contract Award

GVIS-133 4.1.1.3

The GVIS to TVSS interface shall have a mechanical alignment tolerance of ±2 mm (TBR), to be defined in the ICD.

L. Daly Contract Award vi

Table of Contents

1 INTRODUCTION

1.1 Purpose

1.2 Scope

1.3 Related Documentation

1.3.1 Applicable Documents

1.3.2 Reference Documents

2 GENERAL

2.1 Test Configuration

2.2 System for Vibration Environmental Negation Description (Baseline)

2.3 Ground Vibration Isolation System Description

2.3.1 Ground Vibration Isolation (Option 1)

2.3.2 Ground Vibration Isolation System Adjustability (Option 2)

2.3.3 Ground Vibration Isolation System Hard Stop and Load Transfer (Option 3)

3 PERFORMANCE SPECIFICATIONS: SYSTEM FOR VIBRATION ENVIRONMENT

NEGATION (BASELINE)

3.1 Mechanical

3.1.1 Component Mass

3.1.2 Volume Constraint

3.1.3 Mounting and Alignment Interfaces

3.1.4 Mechanical Factors of Safety

3.1.5 Material Allowables

3.1.6 Proof Testing

3.1.7 Fail Safe and Locking

3.1.8 Venting

3.1.9 Viscous Damping

3.2 Frequency and Damping

3.2.1 Isolator Resonant Mode Frequency and Damping

3.2.2 Isolator Lateral and Internal Modes

3.2.3 Isolator Model Correlation

3.3 Thermal

3.3.1 Thermal Environment Description

3.3.2 Thermal Environment

3.3.3 Heaters and Telemetry

3.4 Electrical Grounding

3.5 Contamination

3.5.1 GSE Cleanliness

Materials Inaccessible Surfaces

3.5.2 Surface Contamination Levels at Delivery

Particulate and Molecular Contamination – Exposed Surfaces

3.5.3 Cleanability – Sensitive Surfaces

3.6 Verification Program

3.6.1 Verification Methods

vii

Inspection Analysis Test

3.6.2 Required Tests

Performance Tests

3.6.2.1.1.1 Performance Verification Over Temperature

Mass Properties Measurement Proof Load Test Thermal Vacuum Cycle Test

4 PERFORMANCE SPECIFICATIONS: GROUND VIBRATION ISOLATION SYSTEM . 20

4.1 GVIS Requirements – Applicable To All Options

4.1.1 Mechanical

Component Mass Volume Constraint Mounting and Alignment Interfaces Mechanical Factors of Safety Material Allowables Proof Testing Fail Safe & Locking Venting Viscous Damping

4.1.2 Thermal

Thermal Environment Heaters and Telemetry

4.1.3 Electrical Grounding

4.1.4 Contamination and Cleanliness

Materials Inaccessible Surfaces Surface Contamination Levels at Delivery Cleanability – Sensitive Surfaces

4.2 GVIS Isolation (Option 1)

4.2.1 Mechanical

4.2.2 Frequency and Damping

4.2.3 Thermal

4.3 GVIS Adjustment Features (Option 2)

4.3.1 Mechanical

4.4 GVIS Hard Stop and Load Transfer (Option 3)

4.4.1 Mechanical

4.5 Verification Program

4.5.1 Verification Methods

4.5.2 Inspection

4.5.3 Analysis

4.5.4 Test

4.5.5 Required Tests

Performance Tests

4.5.5.1.1.1 Performance Verification Over Temperature

viii

Mass Properties Measurement Proof Load Test Thermal Vacuum Cycle Test Load Transfer

APPENDIX A ABBREVIATIONS AND ACRONYMS

ix

List of Figures

Figure 1. IPA TVAC Optical Test Configuration Figure 2. The SVEN provides isolation between the chamber Dome hardware and the OLAFS. . 4 Figure 3. Block diagram of the SVEN in relation to the TVAC facility and GSE Figure 4. TVAC Chamber Test Flow Figure 5. The GVIS provides isolation between the L-GESHA (on the chamber floor) and the

TVSS + IPA

Figure 6. Block diagram of the GVIS in relation to the TVAC facility, flight hardware, and GSE.

List of Tables

Table 1. Applicable Documents Table 2. Reference Documents Table 3. SVEN Design Factors of Safety Table 4. SVEN Loads and Environments Table 5. SVEN Isolator Frequency Requirements Table 6. Thermal Vacuum Test Parameters Table 7. GVIS Design Factors of Safety Table 8. GVIS Loads and Environments Table 9. GVIS Isolator Frequency Requirements Table 10. Thermal Vacuum Test Parameters

1 INTRODUCTION

1.1 Purpose

The Roman Space Telescope (RST or Roman) is a mission responding to the 2010 National Research Council New Worlds, New Horizons (NWNH) Astronomy and Astrophysics Decadal Survey top priority recommendation in the large space mission category. The science program includes two dedicated investigations to tackle outstanding questions in dark energy research and exoplanet exploration, and includes a substantial General Observer program to enable targeted investigations of astrophysical phenomena to advance other goals from the Decadal Survey. The system undergoes extensive testing throughout integration to ensure proper alignment before launch, including an Integrated Payload Assembly (IPA) Thermal Vacuum (TVAC) optical test.

In order to properly conduct the test, two Vibration Isolation Systems (VIS) are required. This document defines the requirements for both the Ground Floor VIS (GVIS) and the System for Vibration Environment Negation (SVEN).

1.2 Scope

This document establishes the performance, design, test, and verification requirements for the Ground Vibration Isolation System (GVIS) and System for Vibration Environment Negation (SVEN) to be used in testing the Roman Integrated Payload Assembly (IPA). The latest versions of all documents below should be used. Roman Space Telescope documents can be obtained from RST Technical Data Management System (TDMS).

1.3 Related Documentation

RST documents can be obtained in the RST CM Tool.

1.3.1 Applicable Documents

The following documents are referenced within this document and are directly applicable or contain policies or other directive matters that are binding for the contents of this document. In the event of conflict between an Applicable Document and the content of this document, the applicable Roman Project Configuration Change Board (CCB) has the final authority for conflict resolution.

Table 1. Applicable Documents

Document Number Title RST-SYS-SPEC-0031 Math Model Guidelines Document IEST-STD-CC1246E Product Cleanliness Levels- Applications, Requirements and

Determination 540-PG-8700.2.1 Design and Certification of Dollies, Stands, and Shipping

Containers NASASTD-8719.9 Lifting Standard

1.3.2 Reference Documents

The following documents are referenced herein and amplify or clarify the information presented in this document. These documents are not binding on the content of this document.

Table 2. Reference Documents

Document Number Title RST-INT-PLAN-0052 IFA/IPA I&T Plan RST-INT-PLAN-0353 IPA TVAC Test Plan GSFC-STD-1000G Goddard Open Learning Design (GOLD) Rules RST-SMA-REQ-0032 RST Mission Assurance Requirements

2 GENERAL

2.1 Test Configuration

NASA/GSFC requires Ground Support Equipment (GSE) isolation systems for the IPA TVAC optical test; this optical test is particularly challenging given the tight optical stability requirements, chamber noise, vacuum, and thermal test conditions. The test configuration will require passive vibration isolation systems in two places to reduce disturbances induced by vacuum pumps as well as other dynamic perturbations external to the chamber (e.g. surrounding road noise and test activities) that are transmitted into the chamber. The first – GVIS – to minimize disturbances to the IPA and the second – SVEN – to minimize disturbances to the chamber dome subsystem (consists of an auto-collimating flat (ACF) and associated support structure). The test layout of the chamber can be seen in Figure 1.

Figure 1. IPA TVAC Optical Test Configuration

2.2 System for Vibration Environmental Negation Description (Baseline) The System for Vibration Environmental Negation System, henceforth known as “SVEN,” will be used to provide structural support for the Optical Large Aperture Flat System (OLAFS) and adaptor plate, and vibration isolation between the OLAFS / adaptor plate assembly and the Upper Support Frame (USF). A single unit of the SVEN assembly may be referred to as a Vibration Environment Negation Unit, or “VENU”. The SVEN shall be comprised of three VENUs, which can consist of one or more separate pieces of hardware that provide isolation to the OLAFS, and will be mounted to the GSFC-designed adaptor plate and to the USF. The entire set shall be considered one System for Vibration Environmental Negation.

A close-up of the SVEN and surrounding hardware can be seen in the images below. The SVEN is represented with three teal boxes, suspended from the light grey USF and connected to the blue adaptor plate supporting the dark grey OLAFS.

Figure 2. The SVEN provides isolation between the chamber Dome hardware and the

OLAFS.

SVEN

OLAFS

USF

Adaptor Plate

Z

X

Y

Figure 3. Block diagram of the SVEN in relation to the TVAC facility and GSE.

2.3 Ground Vibration Isolation System Description

The Ground Floor Vibration Isolation System, henceforth known as “Ground VIS” or “GVIS,” will be used to provide vibration isolation between the Lower GESHA and the TVSS. A single unit of the GVIS assembly may be referred to as a Ground Vibration Isolation Unit, or “GVIU”.

The GVIS shall be comprised of three GVIUs; each GVIU can consist of one or more separate pieces of hardware that provide structural support and isolation to the Unit Under Test (UUT), which consists of the Integrated Payload Assembly (IPA) and test support equipment. The entire set will be considered one Ground Vibration Isolation System.

Figure 4. TVAC Chamber Test Flow

2.3.1 Ground Vibration Isolation (Option 1)

The main function of the GVIS is to provide isolation to the Unit Under Test during TVAC testing. This system can consist of one or more isolator at each of three locations, as seen in Figure 5. The GVIS will minimize noise from the chamber and any outside sources during optical testing of the IPA.

2.3.2 Ground Vibration Isolation System Adjustability (Option 2) The GVIUs may require small adjustment capabilities in order to level the IPA. These adjustment features will be used to adjust the Unit Under Test level to gravity as needed during integration and test activities in the SES. This height adjustment feature must be in line with the isolation load path and must be capable of functioning while supporting the full load of the UUT, as adjustments may be required after transferring the UUT mass onto the isolated load path. This feature will be only be procured as an add-on to Option 1, not as a separate entity.

2.3.3 Ground Vibration Isolation System Hard Stop and Load Transfer (Option 3) A safe harbor location is required such that the UUT can be set down in the test chamber on a rigid and stable surface, in order to facilitate test hardware preparations. This functional requirement can be achieved through several different modular packaging methods, including but not limited to a redundant isolator lockout or a separate rigid load path. The mass of the UUT must be transferrable from the rigid load path to the isolated load path in a safe, controlled, and measurable manner, as specified in Section 4.4. This feature will only be procured as an add-on to Option 1 + Option 2, not as a separate entity.

A close-up of the GVIS and surrounding hardware can be seen in the images below. The GVIS is represented with three yellow cylinders representing the envelope of available volume, sitting on the gold L-GESHA and supporting the light grey TVSS.

Figure 5. The GVIS provides isolation between the L-GESHA (on the chamber floor) and the TVSS + IPA.

GVIS

L-GESHA TVSS

Z

X

Y

Figure 6. Block diagram of the GVIS in relation to the TVAC facility, flight hardware, and

GSE.

Roman VIS Spec

RST-INT-SPEC-0283, Revision -

3 PERFORMANCE SPECIFICATIONS: SYSTEM FOR VIBRATION

ENVIRONMENT NEGATION (BASELINE)

3.1 Mechanical

3.1.1 Component Mass

SVEN-110: The total mass of the SVEN shall be less than or equal to 225 kg.

Note: This assumes an individual equal mass of 75 kg per unit for each of the three locations.

Note: If this requirement drives significant additional engineering effort, the government should be informed in order to assess potential relaxation of the requirement.

Note: The “total mass” includes: the isolators, mount hardware, soft structure (i.e. blankets), harnessing, and cabling within the vacuum chamber.

SVEN-111: The total mass of the SVEN shall be measured to within 0.2%.

SVEN-112: The SVEN shall meet all performance requirements while supporting a total weight of 1,750 kg (TBR) +0% / -10%.

Rationale: The SVEN must support the OLAFS and adaptor plate as suspended loads in the SES chamber dome.

Note: This requirement assumes operation at a worst-case mass, with the potential to reduce the system mass during future design updates. This mass will be updated ARO.

SVEN-113: Each VENU shall meet all performance requirements while supporting a total mass of 610 kg (TBR) +0% / -10%.

Rationale: The OLAFS system has a tip/tilt feature; the composite CG has an associated range that will change the force on each individual VENU.

Note: The CG of the OLAFS is assumed to fit within a 150 mm box centered in the Payload Coordinate System (PCS). It is assumed that the individual VENU isolators will be equi-spaced in a plane around a circle with radius 670 mm.

SVEN-114: Each VENU shall meet all performance requirements while be equi-spaced in a plane around a circle with radius 670 mm (TBR).

3.1.2 Volume Constraint

SVEN-120: Reserved

SVEN-121: Each VENU shall not exceed a height envelope of 0.30 m in the axial direction.

Rationale: Driven by volume constraints of the SES chamber dome subsystem test architecture.

Note: The individual VENU isolators will be equi-spaced in a plane around a circle with radius 670 mm.

Note: If this requirement drives significant additional engineering effort, the government should be informed in order to assess potential relaxation of the requirement.

3.1.3 Mounting and Alignment Interfaces

SVEN-130: The mechanical interface shall be defined in the Interface Control Document (ICD), which will be developed by the contractor with NASA GSFC input.

Rationale: A vendor-provided ICD allows the vendor to set the interfaces such that they are compatible with any heritage systems that may be used for this procurement.

Note: The ICD can contain both documents and drawings, per contractor discretion.

SVEN-131: The vendor shall provide 7 (TBR) interfaces for alignment reference targets on both mounting interfaces of each VENU, to be defined in the ICD.

Rationale: Alignment reference interfaces will allow GSFC to measure the position, alignment, and levelness, between SVEN, the USF, and the OLAFS adaptor plate.

Note: Interfaces assumed to be precision tapped holes to accommodate metrology standoffs and targets.

SVEN-132: Each VENU shall incorporate lifting and handling points for integration of the GVIS to be defined in the ICD.

Note: Hardware assemblies under 22kg do not require lift points, if dimensions allow for personnel handling.

3.1.4 Mechanical Factors of Safety

SVEN-140: Positive Margins of Safety (MS) shall be demonstrated analytically for the SVEN Assembly, including interfaces to MGSE, using the MS formula below with the appropriate Factors of Safety (FS) in Table 3 applied to the loads and environments defined in Table 4.

Rationale: This critical GSE will be suspended over flight hardware, and must analytically prove to be safe.

MS is defined as follows:

𝑀𝑀𝑀𝑀 =

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐿𝐿𝐴𝐴𝐿𝐿 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆 ∗ 𝐹𝐹𝑀𝑀

− 1

Table 3. SVEN Design Factors of Safety

Type of Hardware Inertial, Thermal Metallic Yield 2.0 Metallic Ultimate 3.0 Stability/Buckling Ultimate 3.0

Table 4. SVEN Loads and Environments

Configuration Inertial Load (g) Temperature (K) Vertical Lateral

Installed in SES at ambient

-1.6/+0.6 ±0.25 293 ± 3

Installed in SES at worst case temperature

-1.0 0.1 [Worst Case Test Temperatures/Gradients or Temperature Maps]

Reference thermal environment per

Section 3.3.2, SVEN- 320.

Note: Mirror normal and lateral loads are applied simultaneously. Lateral loads should be applied along both axes simultaneously.

Note: Minus sign denotes downward for vertical load. Vertical loads include gravity (-1g).

3.1.5 Material Allowables

SVEN-150: Material allowables and stiffness shall be

• At least A or S-basis for metallic materials as defined in MMPDS or B-basis values tested under the appropriate environments.

• At least B-basis for composite materials as defined in CMH-17, or B-basis values tested under the appropriate environments and representative of the processes used in the fabrication of the components while accounting for strength degradation due to thermal cycles.

• B-basis values for glass/ceramics based on Weibull distribution, or using a test verified threshold stress, or a value of 6.9 MPa (1 ksi. Used in the absence of test data).

Rationale: Traceable allowables are required to assure that stress analysis results are appropriately conservative.

Note: This requirement does not apply to GFE.

3.1.6 Proof Testing

SVEN-160: The SVEN assembly shall be proof tested at ambient to 1.5 times the loads defined in Table 4, assuming the isolators are suspending the full mass defined in Section 3.1.1.

Rationale: Proof testing is required because this critical GSE will be suspended over flight hardware.

Note: Duration of test to be 3 minutes.

Note: Lateral loads may be tested in only two directions.

3.1.7 Fail Safe and Locking

SVEN-170: Reserved

SVEN-171: Reserved

SVEN-172: Reserved

3.1.8 Venting

SVEN-180: All enclosed cavities shall be vented, including pin holes.

Rationale: Venting holes are required when we operate in a vacuum chamber to mitigate pressure failures.

SVEN-181: Venting shall be directed away from the article under test.

Rationale: Venting away from flight hardware and optical GSE reduces contamination risks.

Note: As shown in Figure 1, the article under test lies directly above the OLAFS and the Integrated Payload Assembly in the SES chamber test configuration.

SVEN-182: If the volume being vented is larger than 100 cubic centimeters, the vent hole must be covered with a 35 micron mesh filter.

Rationale: Filter eliminates need to verify cleanliness of inaccessible internal surfaces.

3.1.9 Viscous Damping

SVEN-190: For hardware which maintains a seal (e.g., viscous damper), hardware shall meet its requirements after exposure to all environments without leakage or rupture.

Rationale: Maintaining integrity of the seal vital to the operation of the hardware. Leakage or rupture can results in failure or contamination issues.

Note: Inspection after each environment is required to verify no leakage has occurred.

Note: For joints that maintain seal through fasteners, minimum prealod for each fastener should be assumed in analysis/design.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-18.

SVEN-191: All viscous dampers shall be evacuated to preclude entrapment of air.

Rationale: Small amounts of entrapped air can greatly affect the performance of the damper.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-43.

SVEN-192: All viscous dampers shall allow changes in fluid volume and viscosity with temperature.

Rationale: Resistance is dependent on fluid viscosity and orifice size in the damper. Performance must be met under all temperature conditions the damper will operate in.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-44.

3.2 Frequency and Damping

3.2.1 Isolator Resonant Mode Frequency and Damping

SVEN-210: The fundamental modes of the SVEN shall be less than or equal to the frequencies defined in Table 5, over the operational temperature range as specified in Section 3.3.2.

Table 5. SVEN Isolator Frequency Requirements

Mode Name Frequency Requirement Mode Description Rocking Mode ≤ 3.0 Hz (TBR) Rotation of the lateral (Y/Z) plane Lateral Mode ≤ 9.0 Hz (TBR) Translation in the lateral (Y/Z) plane Axial (bounce) Mode ≤ 7.0 Hz (TBR) Translation in the vertical (X) direction

Rationale: The isolator bounce mode sets isolation required to meet test jitter requirements.

Note: This requirement will be met over mass and temperature ranges as specified in Sections

3.1.1 and 3.3.2. Thermal control system is permitted to meet frequency requirements.

SVEN-211: The fundamental modes of the SVEN as defined in Table 5 shall achieve a damping level of 4% critical, over the operational temperature range as specified in Section 3.3.2.

Rationale: High damping is required to minimize isolator mode response.

Note: Thermal control system is permitted to meet damping performance requirements.

3.2.2 Isolator Lateral and Internal Modes

SVEN-220: All lateral or local mode frequencies of the isolator shall be greater than 350 Hz, over the operational temperature range as specified in Section 3.3.2.

Rationale: Setting SVEN internal mode above 350 Hz avoids exciting OLAFS mirror first bending mode.

Note: All lateral or local mode frequencies of the Isolator will be evaluated when the ends are fully constrained in translation and rotation at the interface.

3.2.3 Isolator Model Correlation

SVEN-230: The model correlation shall be valid from 0.1 to 400 Hz and over the operational temperature range specified in Section 3.3.2.

SVEN-231: The transmissibility characteristics of the correlated Isolator model shall yield frequencies and resonant peaks to within 5% of the measured frequencies and response amplitudes.

3.3 Thermal

3.3.1 Thermal Environment Description

The SVEN will be connected to the USF and a GSFC adaptor OLAFS plate, both of which will be held to 293K within a 170K radiative environment. The SVEN will be blanketed to ensure proper thermal control of the environment.

3.3.2 Thermal Environment

SVEN-320: The SVEN shall function within specification after exposure to the RST Test radiative environment survival temperature range of 160K to 313K and conductive environment survival temperature range of 210K to 313K.

Rationale: The SVEN must survive exposure to the hot and cold survival limits.

SVEN-321: The SVEN shall meet all performance requirements under a radiative environment of 235K – 275K and a conductive environment of 273K ±10K.

Rationale: The SVEN must survive exposure to the radiative environment.

3.3.3 Heaters and Telemetry

SVEN-330: SVEN heaters shall be sized for a maximum power supply of 150V with no more than 5 W/sq in. at maximum power.

Rationale: The maximum power supply available to the TVAC test is 150V.

SVEN-331: SVEN heaters shall include lead wires of 1 m in length accessible post-delivery.

Rationale: The leads on any SVEN heaters must be long enough for the GSFC team to appropriately connect them to the thermal control system, and ideally will be oriented “up and out” e.g. in the +Z direction.

SVEN-332: Vendor shall include a minimum of (1) type T thermocouple per heater circuit with leads for heater control feedback.

Rationale: Type T thermocouple is supported by GSFC thermal chambers.

SVEN-333: The SVEN design shall accommodate blanketing after delivery to GSFC.

Rationale: GSFC will install blanketing around SVEN after receipt of the hardware.

3.4 Electrical Grounding

SVEN-400: The DC resistance of the mechanical contact between two conductive mating surfaces (internal to the component) shall be less than or equal to 2.5 mΩ DC resistance.

SVEN-401: Ground straps shall be used to connect hinged joints.

SVEN-402: When ground straps are required across hinged joints, the DC resistance across the hinge shall be less than or equal to 2.5 mΩ DC.

SVEN-403: All ground straps shall have a length-to-width ratio of less than 5 to 1, be made of copper at least 1 mil thick, and still be flexible enough to allow for bending to occur.

3.5 Contamination

3.5.1 GSE Cleanliness

Materials

SVEN-511: All materials, including lubricants, used in the SVEN Assembly and vacuum harnesses shall meet the ASTM E-595 criteria of < 1% TML and < 0.1% CVCM.

Note: This requirement is to be met at the time of delivery.

Inaccessible Surfaces SVEN-514: Surfaces which are not accessible for cleaning after assembly shall be cleaned prior to assembly.

Rationale: Ensure compliance with contamination limits on the RST flight hardware.

3.5.2 Surface Contamination Levels at Delivery

Particulate and Molecular Contamination – Exposed Surfaces SVEN-520: The SVEN Assembly surfaces shall meet IEST-STD-CC1246E Particulate Cleanliness Level 300 R1 and shall also be visually inspected and meet Level VC-0.5-1000 + UV, or equivalent, when inspected with both UV and white light in a darkened room prior to be integrated into the SES chamber.

Rationale: Ensure compliance with RST contamination standards.

3.5.3 Cleanability – Sensitive Surfaces

SVEN-530: Any surfaces that are not cleanable with Isopropyl alcohol and polyester wipes or light vacuuming shall be identified on the MICD. Alternate cleaning methods shall be identified and appropriate documentation provided for any surfaces that are not cleanable with Isopropyl alcohol.

3.6 Verification Program

SVEN-600: The contractor shall conduct a government-approved verification program that demonstrates the component design is qualified.

Note: Applicable models of the SVEN including (CAD/FEM/STOP) will be shared with GSFC for test development.

3.6.1 Verification Methods

Verification methods include inspection, analysis, as well as environmental, functional, and performance testing, or a combination of these techniques.

Inspection

Verification by inspection includes (but is not limited to) visual inspection, simple physical manipulation, gauging, measurement, and documentation examination.

Analysis Verification by analysis will be used to show design margins. Also, when the particular tests required for verification are impractical, risky, unacceptably long, or prohibitively expensive, analysis may be used instead of testing, as noted in the verification matrices.

Analysis, including simulations where applicable, will also be used to guarantee that the SVEN and their components will perform as expected under worst-case conditions.

Test Verification by test includes, but is not limited to, the evaluation of performance by use of special equipment or instrumentation, simulation techniques, and the application of established principles and procedures to determine compliance with requirements.

3.6.2 Required Tests

The following tests are required for each VENU to provide assurance that the SVEN meets all requirements. Each test or demonstration is described below:

• Performance Testing

• Mass Properties

• Proof Load Test

• Thermal Vacuum Cycle Test

Performance Tests

All Isolator Units shall be tested to demonstrate adequate function prior to, during and following exposure to the environmental testing in this document. Performance testing shall include all major performance characteristics of the Isolator.

Performance tests shall be structured to demonstrate that the Isolator is operating correctly in order to verify all performance requirements.

Data from performance tests prior to environmental testing shall be compared with the corresponding data from tests following environmental testing in order to verify that no damage or degradation in performance has occurred.

3.6.2.1.1.1 Performance Verification Over Temperature

Function of critical performance characteristics shall be verified over temperature to the extent possible. This specifically includes but is not limited to:

a) Frequency and damping

b) Heater and Temperature Sensors (if applicable)

c) Structural Testing

The Contractor shall propose a specific verification test program to achieve these objectives.

Mass Properties Measurement Measurement of the weight and center of gravity of each hardware component will be made to show compliance with requirements and to provide accurate data for the IPA TVAC mass properties control program. If measurements of components are not reasonably feasible, analytical mass property predictions are acceptable for individual components. Measurement of the weight and center of gravity of each final VENU assembly will be made to show compliance with requirements and to provide accurate data for the IPA TVAC mass properties control program. Center of gravity will be referenced to the component to USF mounting interface.

Proof Load Test The strength of each VENU shall be demonstrated through a static load proof test of 1.5x the loads listed in Table 4. The assembly must be fully loaded for a minimum of 3 minutes.

Thermal Vacuum Cycle Test Thermal vacuum cycle testing shall be conducted in accordance with the requirements written in Table 6.

During Thermal Vacuum testing, the VIS shall be in operational configuration.

Note: This is meant to indicate that the unit is fully assembled and has the heater and temperature sensors that will be delivered with the unit installed. MLI is not expected to be on during testing.

Table 6. Thermal Vacuum Test Parameters

Parameter Component Level Chamber Pressure After Evacuation < 1 x 10-5 Torr Number of Cycles to Survival Temperatures 3 Minimum Dwell Time (at cold and hot Survival Temps)

2 hrs

Use of heater delivered with unit Must be used at max voltage during transitions to the warm plateaus and to hold soak temperatures

Use of thermocouples delivered with unit Read out during the entire test

Temperature Tolerance for Soak +/- 2K of survival limit

4 PERFORMANCE SPECIFICATIONS: GROUND VIBRATION

ISOLATION SYSTEM

4.1 GVIS Requirements – Applicable To All Options

The GVIS will be comprised of three GVIUs, which can consist of one or more separate pieces of hardware that provide isolation to the Unit Under Test. The entire set will be considered one Ground Vibration Isolation System. The requirements listed in Section 4.1 apply to all options.

4.1.1 Mechanical

Component Mass GVIS-110: The total mass of the GVIS shall be less than or equal to 1050 kg.

Note: This assumes an individual equal mass of 350 kg per unit for each of the three locations.

Note: The “total mass” includes: the isolators, mount hardware, soft structure (i.e. blankets), harnessing, and cabling within the vacuum chamber.

Note: This is the full mass allocation for the combined Options 1, 2, and 3. If Options 2 and/or 3 are not selected, this mass allocation for the isolators will be reduced upon contract award such that a full system can still be packaged in the available space.

GVIS-111: The total mass of the GVIS shall be measured to within 0.2%.

GVIS-112: The GVIS shall meet all performance requirements while supporting a total mass of 11,850 kg (TBR) +0% / -10%.

Rationale: The GVIS must support the mass of the Unit Under Test on the floor of the SES chamber.

Note: This requirement assumes operation at a worst-case mass, with the potential to reduce the system mass during future design updates. This mass and CG will be updated ARO.

GVIS-113: Each GVIU shall meet all performance requirements while supporting a total mass of 4120 kg (TBR) +0% / -10%.

Rationale: The CG of the Unit Under Test is not centered in the SES chamber. Each GVIU must be capable of supporting the worst-case offset CG.

Note: The CG of the Unit Under Test fits within a 200 mm box centered in the Payload Coordinate System (PCS).

Volume Constraint

GVIS-120: Each GVIU shall not exceed a diameter of 0.915 m (TBR) and a height of 0.4 m

(TBR).

Rationale: Driven by volume constraints of the SES chamber floor subsystem test architecture.

Note: This is the full volume allocation for the combined Options 1, 2, and 3. If Options 2 and/or 3 are not selected, this volume allocation for the isolators will be reduced upon contract award such that a full system can still be packaged in the available space.

GVIS-121: Reserved

Mounting and Alignment Interfaces GVIS-130: The mechanical interfaces shall be defined in the Interface Control Document (ICD), which will be developed by the contractor with NASA GSFC input.

Rationale: A vendor-provided ICD allows the vendor to set the interfaces such that they are compatible with any heritage systems that may be used for this procurement.

Note: The ICD can contain both documents and drawings, per contractor discretion.

Note: If Options 2 and/or 3 are not selected, this ICD requirement may be removed such that NASA GSFC controls the interfaces of the system.

GVIS-131: The vendor shall provide 7 (TBR) interfaces for alignment reference targets on both mounting interfaces of each GVIU, to be defined in the ICD.

Rationale: Interfaces for alignment reference targets will allow GSFC to measure the position, alignment, and levelness between the GVIS, the lower GESHA, and the TVSS during test integration.

Note: Interfaces assumed to be precision tapped holes to accommodate metrology standoffs and targets.

GVIS-132: Each GVIU shall incorporate lifting and handling points for integration of the GVIS to be defined in the ICD.

Note: Hardware assemblies under 22kg do not require lift points, if dimensions allow for personnel handling.

Note: If Options 1, 2, and 3 are packaged into a single system, this requirement applies to the entire system. If Option 3 is separately-integrated hardware, this requirement applies to both Option 1 (the isolation load path) and Option 3 (the rigid load path).

GVIS-133: The GVIS to TVSS interface shall have a mechanical alignment tolerance of ±2 mm (TBR), to be defined in the ICD.

Rationale: The GVIS assembly will hold both test hardware and optical flight hardware, and must have high repeatability on the placement of that hardware in order to assure proper optical alignment of the system.

Mechanical Factors of Safety GVIS-140: Positive Margin of Safety (MS) shall be demonstrated analytically for the GVIS Assembly, including interfaces to MGSE, using the MS formula below with the appropriate Factors of Safety (FS) in Table 7 applied to the loads and environments defined in Table 8.

Rationale: This critical GSE will be supporting flight hardware, and must analytically prove to be safe.

MS is defined as follows:

𝑀𝑀𝑀𝑀 =

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐿𝐿𝐴𝐴𝐿𝐿 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆 ∗ 𝐹𝐹𝑀𝑀

− 1

Table 7. GVIS Design Factors of Safety

Type of Hardware Inertial, Thermal Metallic Yield 2.0 Metallic Ultimate 3.0 Stability/Buckling Ultimate 3.0

Table 8. GVIS Loads and Environments

Configuration Inertial Load (g) Temperature (K) Vertical Lateral Tipping

Installed in SES at ambient

-1.0 ±0.1 0.5 Survival Temperatures (per

Section 4.1.2.1, GVIS-210)

Note: Mirror normal and lateral loads are applied simultaneously. Lateral loads should be applied along both axes simultaneously.

Note: Minus sign denotes downward for vertical load. Vertical loads include gravity (-1g).

Note: For tipping, an analysis ultimate Factor of Safety of 1.0 (minimum) shall be used.

Note: Requirement flowed from Design and Certification of Dollies, Stands, and Shipping Containers 540-PG-8700.2.1E, Revision E, Effective Date: December 10, 2018, Table 1, “Static Stand/Dolly (Stationary on casters, jacks, or feet).

Material Allowables GVIS-150: Material allowables and stiffness shall be

• At least A or S-basis for metallic materials as defined in MMPDS or B-basis values tested under the appropriate environments.

• At least B-basis for composite materials as defined in CMH-17, or B-basis values tested under the appropriate environments and representative of the processes used in the fabrication of the components while accounting for strength degradation due to thermal cycles.

• B-basis values for glass/ceramics based on Weibull distribution, or using a test verified threshold stress, or a value of 6.9 MPa (1 ksi. Used in the absence of test data).

Rationale: Traceable allowables are required to assure that stress analysis results are appropriately conservative.

Note: This requirement does not apply to GFE.

Proof Testing GVIS-160: All load paths shall be proof tested independently at ambient conditions to 1.5x the loads defined in Table 8, assuming the load path is supporting the full mass defined in Section 4.1.1.1.

Rationale: Proof testing of all load paths is required because this critical GSE will be supporting flight hardware.

Note: This applies for both the isolated load paths and the rigid load paths.

Note: Duration of test to be 3 minutes.

Note: Lateral loads will be tested in only two directions.

Fail Safe & Locking GVIS-170: Reserved

GVIS-171: Reserved

GVIS-172: Reserved

Venting

GVIS-180: All enclosed cavities shall be vented, including pin holes.

Rationale: Venting holes are required when we operate in a vacuum chamber to mitigate pressure failures.

GVIS-181: Venting shall be directed away from the article under test.

Rationale: Venting away from flight hardware reduces contamination risks.

Note: As shown in Figure 1, the article under test supports the Integrated Payload Assembly from below in the SES chamber test configuration.

GVIS-182: If the volume being vented is larger than 100 cubic centimeters, the vent hole must be covered with a 35 micron mesh filter.

Rationale: Filter eliminates need to verify cleanliness of inaccessible internal surfaces.

Viscous Damping GVIS-190: For hardware which maintains a seal (e.g., viscous damper), hardware shall meet its requirements after exposure to all environments without leakage or rupture.

Rationale: Maintaining integrity of the seal vital to the operation of the hardware. Leakage or rupture can results in failure or contamination issues.

Note: Inspection after each environment is required to verify no leakage has occurred.

Note: For joints that maintain seal through fasteners, minimum preload for each fastener should be assumed in analysis/design.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-18.

GVIS-191: All viscous dampers shall be evacuated to preclude entrapment of air.

Rationale: Small amounts of entrapped air can greatly affect the performance of the damper.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-43.

GVIS-192: All viscous dampers shall allow changes in fluid volume and viscosity with temperature.

Rationale: Resistance is dependent on fluid viscosity and orifice size in the damper. Performance must be met under all temperature conditions the damper will operate in.

Note: Requirement flowed from Mechanical System Specification RST-SYS-SPEC-0042, Revision B, Effective Date: August 6, 2020, Requirement MSS-44.

4.1.2 Thermal

The Ground VIS system will be connected to the L-GESHA and the TVSS, both of which will be held to 250K within a 200K radiative environment. The GVIS will be blanketed to ensure proper thermal control of the environment.

Thermal Environment GVIS-210: All GVIS hardware that is not removed ahead of TVAC testing shall function within specification after exposure to the TVAC test radiative and conductive environment temperature range of 180K to 313K .

Rationale: The GVIS must survive exposure to the hot and cold survival limits and radiative environment.

Heaters and Telemetry GVIS-220: GVIS heaters shall be sized for a maximum power supply of 150V with no more than 5 W/sq in. at maximum power.

Rationale: The maximum power supply available to the TVAC test is 150V.

GVIS-221: GVIS heaters shall include lead wires of 2 meters in length accessible post-delivery.

Rationale: The leads on any GVIS heaters must be long enough for the GSFC team to appropriately connect them to the thermal control system, and ideally will be oriented “down and out” e.g. in the -Z direction.

GVIS-222: Vendor shall include a minimum of (1) type T thermocouple per heater circuit with leads for heater control feedback.

Rationale: Type T thermocouple is supported by GSFC thermal chambers.

GVIS-223: The GVIS design shall accommodate blanketing after delivery and installation at GSFC, to be defined in the ICD.

Rationale: GSFC will install blanketing around the GVIS after receipt and installation of the hardware.

4.1.3 Electrical Grounding

GVIS-300: The DC resistance of the mechanical contact between two conductive mating surfaces (internal to the component) shall be less than or equal to 2.5 mΩ DC resistance.

GVIS-301: Ground straps shall be used to connect hinged joints.

GVIS-302: When ground straps are required across hinged joints, the DC resistance across the hinge shall be less than or equal to 2.5 mΩ DC.

GVIS-303: All ground straps shall have a length-to-width ratio of less than 5 to 1, be made of copper at least 1 mil thick, and still be flexible enough to allow for bending to occur.

4.1.4 Contamination and Cleanliness

Materials GVIS-410: All materials, including lubricants, used in the GVIS Assembly and vacuum harnesses shall meet the ASTM E-595 criteria of < 1% TML and < 0.1% CVCM.

Note: This requirement is to be met at the time of delivery.

Inaccessible Surfaces GVIS-420: Surfaces which are not accessible for cleaning after assembly shall be cleaned prior to assembly.

Rationale: Ensure compliance with contamination limits on the RST flight hardware.

Surface Contamination Levels at Delivery GVIS-430: The GVIS Assembly surfaces shall meet IEST-STD-CC1246E Particulate Cleanliness Level 300 R1 and shall also be visually inspected and meet Level VC-0.5-1000 + UV, or equivalent, when inspected with both UV and white light in a darkened room prior to be integrated into the SES chamber.

Rationale: Ensure compliance with RST contamination standards.

Cleanability – Sensitive Surfaces GVIS-440: Any surfaces that are not cleanable with Isopropyl alcohol and polyester wipes or light vacuuming shall be identified on the MICD. Alternate cleaning methods shall be identified and appropriate documentation provided for any surfaces that are not cleanable with Isopropyl alcohol.

4.2 GVIS Isolation (Option 1)

The requirements listed in Section 4.2 apply only to Option 1, the isolated load path of the GVIS.

4.2.1 Mechanical

GVIS-1100: Each GVIU shall include load measurement capabilities with a resolution of less than or equal to 2.5 kg / 5.5 lbs for the isolation load path during ambient operations.

Rationale: GSFC requires knowledge of interface loads for final test configuration alignment and load transfer to the isolation system.

Note: English units are acceptable for measurement capabilities.

Note: The load measurement capability can be output in units of mass or strain.

Note: If this load measurement system is an integral part of the isolation system (e.g. cannot be removed), it must survive the environment described in Section 4.1.2.1.

4.2.2 Frequency and Damping

GVIS-1200: The fundamental modes of the GVIS shall be less than or equal to the frequencies defined in Table 9, over the operational temperature range as specified in Section 4.2.34.1.2.1.

Table 9. GVIS Isolator Frequency Requirements

Mode Name Frequency Requirement Mode Description Rocking Mode ≤ 2.7 Hz Rotation of the lateral (Y/Z) plane Lateral Mode ≤ 8.0 Hz Translation in the lateral (Y/Z) plane Axial (bounce) Mode ≤ 6.5 Hz Translation in the vertical (X) direction

Rationale: The isolator bounce mode sets isolation required to meet test jitter requirements.

Note: This requirement will be met over mass and temperature ranges as specified in Sections

4.1.1.1 and 4.2.3. Thermal control system is permitted to meet frequency requirements.

GVIS-1201: The fundamental modes of the GVIS as defined in Table 9 shall achieve a damping level of 1% critical, over the operational temperature range as specified in Section 4.2.3.

Rationale: High damping is required to minimize isolator mode response.

Note: Thermal control system is permitted to meet damping performance requirements.

GVIS-1202: All lateral or local mode frequencies of the isolator shall be greater than 450 Hz, over the operational temperature range as specified in Section 4.2.3.

Rationale: Keeping GVIS internal mode high avoids interaction between GVIS and Roman Observatory jitter sensitive optical modes.

Note: All lateral or local mode frequencies of the Isolator will be evaluated when the ends are fully constrained in translation and rotation at the interface.

GVIS-1203: The model correlation shall be valid from 0.1 to 450 Hz and over the operational temperature range specified in Section 4.2.3.

GVIS-1204: The transmissibility characteristics of the correlated Isolator model shall yield frequencies and resonant peaks to within 5% of the measured frequencies and response amplitudes.

4.2.3 Thermal

GVIS-1300: The GVIS shall meet all performance requirements under a radiative environment of 235K – 265K and a conductive environment of 250K ±10K.

Rationale: The GVIS must be operational under the SES temperature limits and radiative environment.

4.3 GVIS Adjustment Features (Option 2)

The requirements listed in Section 4.3 apply only to Option 2, the vertical adjustment features of the GVIS. These requirements should be considered an addition to the hardware described in Option 1; the combined system must meet the requirements laid out in Section 4.1.

4.3.1 Mechanical

GVIS-2100: The GVIS assembly shall have a vertical adjustment range of ≥ 12 mm.

Note: It is assumed that the individual GVIS isolators will be equi-spaced in a plane around a circle with radius 2.28 m. The vertical adjustment provides a tip/tilt range of ≥ 0.15 deg (0.30 deg total) when the center of rotation is the center of the circle.

Note: Performance of the adjustment feature applies while the GVIS assembly is supporting the Unit Under Test mass.

Note: The maximum extended length of the adjustment range shall fit within the allocated design volume.

GVIS-2101: The GVIS assembly shall have a vertical adjustment resolution of ≤ 0.4 mm.

Note: It is assumed that the individual GVIS isolators will be equi-spaced in a plane around a circle with radius 2.28 m. The vertical adjustment provides a tip/tilt resolution of 0.01 deg when the center of rotation is the center of the circle.

Note: Performance of the adjustment feature applies while the GVIS assembly is supporting the Unit Under Test mass.

GVIS-2102: The GVIS shall meet all adjustment capability requirements while supporting the full mass of the Unit Under Test.

Rationale: This adjustability function will be used to level the Unit Under Test in the SES chamber during chamber buildup.

4.4 GVIS Hard Stop and Load Transfer (Option 3)

The requirements listed in Section 4.4 apply only to Option 3, the rigid load path and load transfer features of the GVIS. These requirements should be considered an addition to the hardware described in Option 1 and Option 2; the combined system must meet the requirements laid out in Section 4.1.

4.4.1 Mechanical

GVIS-3100: Each GVIU shall incorporate hard mount features for rigid structural support of the test configuration, to be defined in the ICD.

Rationale: There must be a configuration of the GVIS that allows for a safe stopping point for chamber integration operations before engaging the isolation feature.

GVIS-3101: Each GVIU shall incorporate features that facilitate a load transfer from the rigid load path to the isolated load path and from the isolated load path to the rigid load path.

Rationale: The UUT must be placed on a rigid interface for hardware and personnel safety during test preparations.