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Solar Sail Design and Fabrication Assessment

Applications and Design

Preliminary Solar Sail Design and Fabrication Assessment
Spinning Sail Blade
Square Sail Blade
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Authors:
J B Daniels
D M Dowdle
D W Hahn
E N HIdreth
D R. Lagerquist
E J Mahagnoul
J B Munson
T F Origer
Jet Propulsion Laboratory
California Institute of Technology
146 Pages

Open: Solar Sail Design and Fabrication Assessment

Introduction

Sheldahl's efforts and activities under the original Statement of Work of Contract No. 954721 were directed to a study and evaluation of designs and fabrication methods, equipment, facilities, economics, schedules, etc., for the square sail sheet alternate. Those efforts and the work accomplished, until redirected to focus attention on the spinning sail blade alternate, are documented in Section II of this report.

Section I contains a report of Sheldahl's preliminary assessment of the Astro Research Corporation baseline for the spinning sail blade design and related fabrication issues, performed under the revised Statement of Work of Contract Unilateral Modification No. 1.

Four primary areas of interest are discussed:
1. Blade Design Blade design aspects most affecting producmbility and means of measurement and control of length, scallop, fullness and straightness requirements and tolerances were extensively considered. Alternate designs of the panel seams and edge reinforcing members are believed to offer advantages of seam integrity, producibility, reliability, cost and weight.

2. Manufacturing Methods and Processes Analyses assumed that the base film (.1-mil Kapton or equivalent), battens and flight reels would be furnished by NASA. Approaches to and requirements for unique and highly specialized metalizing methods, processes and equipment were studied and preliminarily identified.

Alternate methods of sail blade fabrication and related special machinery, tooling, fixtures and trade-offs were studied. A preferred and recommended approach is preliminarily identified. Quality Control plans, inspection procedures, flow charts and special test equipment associated with the preferred manufacturing method were analyzed and are discussed.

3. Economic, Schedule, Facility Considerations Special facilities requirements and ROM program plans, schedules and costs for the spinning sail blade were evaluated and are included in this report.

4. Areas Requiring Further Study A number of areas requiring further study, refinement of definitions and requirements, conceptual or preliminary designs, and/or test and evaluation, etc., are identified.

Several are of particular importance from a schedule and lead time point of view. Others are presumed to be matters under study at JPL or other agencies, but are included so as, in any event, to avoid being overlooked. Sheldahl will be pleased to provide further particulars and furnish cost and schedule inputs for extension of the blade design and fabrication assessment areas suggested.

Some of the items are common to both the spinning sail blade and square sheet and are included in both Sections I and II.

MATERIALS STUDIES
While NASA JPL has prime responsibility for the design and specification of materials, bonding and seaming methods and is obtaining support from other NASA agencies and from other organizations under subcontract, Sheldahl also funded initial investigations of candidate adhesive systems, sealing equipment,
methods and conditions, fabricated sample specimens; and conducted tests.

Two primary purposes were envisioned:
(1) To obtain preliminary working knowledge of materials and seaming equipment and methods as it pertained to the design and fabrications study, and

(2) To provide information and test data to JPL as a measure of support, to add to the total body of knowledge concerning candidate sail materials, seaming and bonding methods, etc., all ultimately for consideration in JPL material system design, development and specification purposes.

Results of the preliminary Sheldahl Materials Study to date are included as an appendix to this report.

TOC

SECTION I
SPINNING SAIL BLADE DESIGN AND FABRICATION ASSESSMENT
Title Page
Introduction and Summary 1
SPINNING SAIL BLADE DESIGN 5
Baseline Design 5
Deviations from Baseline .5
Manufacturing/Assembly, Packaging and Quality Assurance . .. 6
Accuracy Requirements 6
Batten Design 7
Weight Estimates 7
Sealed Versus Sewn Seams . .. 7
Longeron Tapes 7
Rip-Stop 7
Packing Methods 8
Baseline Design . .8
Alternate Longeron Design 10
Level Wind-Preferred Approach 11
Blade Weight Estimates 12
Seams (Panel Joints) .. 12
Edge Tendons (Tapered Edges) 13

20 HANDLING AND FABRICATION PLAN. 15
Government Furnished Equipment 15
Film Metalizing .. . 15
Key Equipment and Processing Considerations .. 15
Major Equipment Design Areas . .. 16
Sail Blade Manufacture 20
Fabrication Concepts 20
Panel Seaming 23
Edge Reinforcement 24
Tailoring . 25
Section Joining and Batten Installation 26
Tensioning. .. 28
Measurement and Control 28
Repair, Splicing Technique ..... 29
Film Cutting Methods 31
Flight Reel, Cannister Packing. 34
Quality Assurance and Inspection ... 35
Quality Assurance Plan 35
Test Equipment/Problems 41

ECONOMIC, SCHEDULE AND FACILITY CONSIDERATIONS 45
Existing Facilities and Equipment .. 45
New Facilities and Equipment . 47
Program Plans and Schedule . .. 45
ROM Cost Estimates .... 51
AREAS REQUIRING FURTHER ATTENTION 51

SECTION II SQUARE SAIL SHEET DESIGN AND FABRICATION ASSESSMENT
Introduction and Summary 55

SAILSHEET DESIGN 59
JPL Baseline Design 59
Reinforcement and Attitude Control 59 1
Corner Design 60
Center Design 67
Gore Tailoring 70 14 Stowage and Deployment .79
Packing Configuration 79
Packing Factors 79
Cannister Design 82
HANDLING AND FABRICATION PLAN 83
Materials Procurement. .. 83 2 2 Film Metalizing .. .83
Key Equipment and Process Considerations 83
Major Equipment Design Areas ... 84
Sail Fabrication .. .. ... .. 89
Fabrication Concepts 89
Fabrication Methods. 91
Inspection, Splicing, Rip-Stop Installation . 95
Gore Tailoring .. . 97
Sealing and Folding. 99
Repair and Rework Techniques 107
Film Cutting Methods. 108
Canister Packing . .. 111
Qualit Assurance and Inspection . 112
Quality Assurance 112
Test Equipment/Problems .. . 119

LIST OF FIGURES
Section I
SPINNING SAIL BLADE
Title Page 1-1 Spinning Solar Sail Blade Section Fabrication 21
1-2 Spinning Solar Sail Blade Assembly 22
1-3 Typical Longeron Joint 30
1-4 Film Cutting Methods 32 and 33
1-5 Inspection Characteristic Flow Plan 36
1-6 Inspection Characteristic Flow Plan 37
1-7 Spinning Sail Blade Fabrication Study . 46
1-8 Spinning Sail Blade Configuration Program Plan 48

Section II
SQUARE SAIL SHEET
I1-1 "Brute Force" Reinforcement Scheme, Corner Outhaul Line 61
11-2 Stiff Edge Tendons 62
11-3 Deeper Scallop 63
11-4 Modified Scallop . 64
11-5 Stress Contours 65
11-6 Reduction of Corner Film Stress 66
11-7 Sail Center Mast Attachment 68
11-8 Center Attachment, Symmetrical Case 69
11-9 Uniform Stress Field 71
11-10 Center Cutout Scallop Design 72
I1-11 Center Cutout Scallop Design 73
11-12 Sail Center, Unsymmetrical Case 74
11-13 Sail Center, Unsymmetrical Case, Translated 10 m 75
11-14 Initial HYPAR Quadrant. 77
11-15 Gore Tailoring Requirements . 78
11-16 Solar Sail Packing Configuration . 80
11-17 Solar Sail Packing Configuration 81
11-18 Solar Sail Fabrication Concepts 90
11-19 Solar Sail Fabrication -850 m Square Sail 92
11-20 Inspection/Rip-Stop Installation 96
11-21 Gore Tailoring 98
11-22 Reel-to-Reel Fabrication Concept 100
11-23 Half Table Fabrication Concept . 103
11-24 Final Diagonal Seam Sealer Concept .105
11-25 Final Diagonal Seam Sealer Concept 106
11-26 Film Cutting Methods 109 and 110
11-27 Inspection Characteristic Flow Plan (Long Table, Half Sail) 113
11-28 Inspection Characteristic Flow Plan (Long Table, Half Sail) • 114
11-29 Inspection Characteristic Flow Plan (Reel-to-Reel) 115
11-30 Solar Sail Facilities 122
11-31 SolarSail Facilities Half Sail 123
11-32 Solar Sail Facilities Reel-to-Reel 124
11-33 Program Plan, Half Sail Method 127