WFIRST-IC-SPEC-0069-.pdf

Effective Date: July 3, 2019 Expiration Date: July 3, 2024

CHECK https://ipdtdms.gsfc.nasa.gov

TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.

National Aeronautics and Space Administration

Goddard Space Flight Center Greenbelt, Maryland

WFIRST-IC-SPEC-0069, Revision -

Wide Field Infrared Survey Telescope (WFIRST), Code 448

Requirements Specification for

Composite Laminate Thermal Conditioning

GSFC WFIRST CMO

July 8, 2019

Released https://ipdtdms.gsfc.nasa.gov/

Requirements Specification for Composite Thermal Conditioning WFIRST-IC-SPEC-0032, Revision -ii

Requirements Specification for

Composite Laminate Thermal Conditioning

Review/Signature/Approval Page

Prepared by:

Wes Alexander

Approving Signature Authority:

Wes Alexander

Electronic Approval available on-line at: https://ipdtdms.gsfc.nasa.gov

Requirements Specification for Composite Thermal Conditioning WFIRST-IC-SPEC-0069, Revision -iii

Preface This document is a Wide Field Infrared Survey Telescope (WFIRST) Configuration Management (CM)-controlled document. Changes to this document require prior approval of the applicable Signature Authority or designee. Proposed changes shall be submitted to the WFIRST 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:

WFIRST 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 Signature Authority Approval Date)

Revision - July 3, 2019 This was approved by the WFIRST Signature Authority via WFIRST-SCoRe-0163 on the effective date shown.

v

Table of TBDs/TBRs/TBSs

Item No. Location Summary Individual/ Organization

Actionee

Due Date

TBR1 2.1 Minimum cold temperature for thermal conditioning

WFIRST 11/19/2019

vi

Table of Contents

1 INTRODUCTION

1.1 Purpose

1.2 Scope

2 REQUIREMENTS

2.1 General

2.2 Ramp Rate

2.3 Hold Time and Temperature Tolerance

2.4 Instrumentation

2.5 Edge Protection

3 QUALITY ASSURANCE PROVISIONS

APPENDIX A ABBREVIATIONS AND ACRONYMS

1 INTRODUCTION

1.1 Purpose

The purpose of this specification is to define the requirements for thermal conditioning composite laminate billets, parts, and assemblies.

1.2 Scope

All composite laminate billets, parts, and assemblies used on the Wide Field Infrared Survey Telescope Instrument Carrier (IC) shall be thermally conditioned for coefficient of thermal expansion (CTE) stabilization. This specification defines the ramp rates, hold times, and instrumentation requirements for this thermal conditioning.

2 REQUIREMENTS

2.1 General

The requirement for thermal conditioning is called out on the engineering drawings. The drawings shall call out the temperature range of the cycling and the number of cycles required. In general, all composite parts are cycled 5 times from room temperature (~293 ⁰K) to 77 ⁰K (TBR1). This cycling is done at the billet level prior to testing process control specimens. The engineering drawing may also call out thermal conditioning at the assembly level.

2.2 Ramp Rate

The ramp rate shall not exceed 10 ⁰K per minute from room temperature (~293 ⁰K) to 200 ⁰K and 5 ⁰K per minute below 170 ⁰K. Slower ramp rates are acceptable.

2.3 Hold Time and Temperature Tolerance

The hold time at the temperature extremes shall be until the part temperature reaches the extremes called out on the drawing, including allowance for any gradients as described in Section 2.4. The tolerance on the temperature extremes is ±10 ⁰K for the warm temperature and +0/-5 ⁰K for the cold temperature. Part gradients shall be controlled such that the difference between minimum and maximum temperature is less than 50 ⁰K during all stages of the thermal conditioning, regardless of part size and type.

2.4 Instrumentation

Calibrated silicon diodes with an accuracy of ± 1.0 ⁰K (from 293 ⁰K to the lower cycling limit) shall be used to monitor the part temperature. A sufficient number of diodes shall be used to demonstrate that the part temperature has reached the requirements. A demonstration part with multiple diodes may be tested using the intended test configuration may be used to show that part gradients are small, thus requiring only one diode for further monitoring of thermal conditioning.

A recording of temperature versus time is required for each thermal cycle.

2.5 Edge Protection

To ensure that edge defects do not propagate during the thermal conditioning, either of the following shall be employed: 1) apply edge coating prior to cycling on all free edges per WFIRST-IC-SPEC-0067, or 2) allowances shall be made to remove a minimum of 1.0” of material off each end of tube billets or 1.0” of material off the perimeter of a flat laminate upon completion of the cycling.

3 QUALITY ASSURANCE PROVISIONS

A pre and post thermal conditioning visual inspection shall be performed on all free edges to ensure there are no edge defects or delaminations. This inspection shall be performed using 10x magnification. Any indications shall be noted and dispositioned according to the Quality Assurance Implementation Plan.

Appendix A Abbreviations and Acronyms

Abbreviation/ Acronym

DEFINITION

GSFC Goddard Space Flight Center IC Instrument Carrier CTE Coefficient of Thermal Expansion TBD To Be Determined TBR To Be Revised TBS To Be Scheduled WFIRST Wide Field Infrared Survey Telescope