High Performance MLI for Cryogenic Hardware Leslie Buchanan Steve Buerger March 13, 2003

Today’s Talk The nature of MLI - theory vs practice Basic principles High performance MLI Results Conclusions 2/5/2019

Theory vs Practice Simple, versatile technology. Radiation shields to minimize heat transfer Customized for wide range of applications. Implementation degrades performance. Seams to facilitate installation and access Penetrations to accommodate supports, plumbing, cabling, and venting Fastening devices to attach blanket to hardware Real estate limitations cause tight clearance IRAS SBIRS HEO TCS PRSA 2/5/2019

MLI (Multi-Layer Insulation) - A Versatile, Effective Technology Purpose - Create Adiabatic Surface Cryogenics-Insulate cold surface from warm electronics S/C-Insulate warm electronics from space Construction Inner Layers 10 min to 50 max Double Aluminized Mylar, .25 mil thick Dacron Net Spacers Outer Layers Space Exposure Maintain Temperature Provide ESD prevention Provide atomic oxygen and micrometeoroid protection Protect inner layers during installation and handling 2/5/2019

Minimize Heat Leak Through MLI MLI - Basic Principles Minimize Heat Leak Through MLI radiation shield theory through thickness lateral 2/5/2019

MLI - Basic Principles Radiation Shield Theory Parallel planes, no shield Multiple Shields 1 2 1 2 N 2/5/2019

MLI Best Practices Wherever Possible High Performance MLI Low emissivity surfaces on layers Optimize number of layers Maximize loft adequate clearance CTE considerations Minimize effect of seams, gaps, and penetrations Provide vent paths Minimize temperature mismatches 2/5/2019

Application – Test Unit for Cryogenic Cooling System Requirements Design high performance MLI Critical to mission success Requirement: Goal: Provide ease of disassembly Facilitate post MLI installation hardware changes Meet tight schedule Design and produce MLI in parallel with hardware 4 months start to finish 2/5/2019

Number of Layers Optimized for Available Clearance and Ease of Installation Design Goal Reference - C.W. Keller, Thermal Performance of Multilayer Insulation, Final Report, prepared for NASA Lewis Research Center Contract NAS3-12025, Lockheed Missiles and Space Company, Sunnyvale, CA, 1971, NASA CR-72747. 2/5/2019

Number of Layers Optimized for Available Clearance and Ease of Installation Design Goal SBIRS GEO Test Data Reference - C.W. Keller, Thermal Performance of Multilayer Insulation, Final Report, prepared for NASA Lewis Research Center Contract NAS3-12025, Lockheed Missiles and Space Company, Sunnyvale, CA, 1971, NASA CR-72747. 2/5/2019

Seam Selection Criteria Thermal Performance Minimize radiation line-of-sight Match temperature profiles of adjacent edges Minimize compression of shields in joint formation Allow gas venting Producibility Edges easily fabricated Facilitate fastening techniques Ease of assembly/disassembly on hardware 2/5/2019

Sub-Blanket Fastening Device Selection Criteria Thermal Performance Minimize conduction through fasteners Minimize radiation through fastener penetrations Allow interstitial gas venting Structural Integrity Resistance to tensile loading Resistance to shear loading Allow clearance for loft Control ballooning Producibility Ease of assembly/disassembly 2/5/2019

Blanket-to-Hardware Attachment Selection Criteria Thermal Performance Minimize conduction through fasteners Minimize radiation through fastener penetrations Allow interstitial gas venting Structural Integrity Resistance to tensile loading Resistance to shear loading Allow clearance for loft Control ballooning Producibility Ease of assembly/disassembly 2/5/2019

Penetration Selection Criteria Thermal Performance Minimize radiation line-of-sight Minimize radiation from penetration into layers Minimize conduction from MLI to penetration Allow gas venting Producibility Ease of installation on hardware 2/5/2019

Ball MLI Center Charter – Develop and Communicate MLI Technology We design, fabricate, and install MLI blankets Standard performance MLI, s/c High performance MLI, cryogenics Standard processes company wide Documented in Quality Business System MLI team Thermal Engineer MLI Designer/Production Engineer MLI technicians 00-114d 2/5/2019

Full-up MLI Fabrication Capability Controlled facilities, clean rooms Capacity: 80 feet of lay-up tables, 2 sewing stations, 12 cutting stations CAD templates Cutting techniques Hot knife Laser cutter (high quantity jobs) Capable of processing all insulation materials including Mylar, Kapton, Teflon, beta-cloth, net/mesh films with all metallized finishes such as aluminum, gold, silver, and inconel Processes used include stitching, venting, attachment (snaps, grommet, Velcro, bonding), and ground strap installation 2/5/2019

MLI Best Practices Applied on Test Unit Component MLI Design Performance Minimize Radiation Lines-of-Sight through MLI Minimize Conductive Paths through MLI Minimize Lateral Conduction along MLI Layers Minimize radiation from penetration into MLI Maximize Loft Allow Gas Venting Maximize Ease of Assembly and Disassembly Maximize Ease of Fabrication Blanket-to-Hardware Attachment Method High Moderate N/a Sub-blanket Attachment Method Seams Clearance Blanket Pattern Contouring Material Shrinkage at Cryogenic Temps Penetrations (Support Struts, Cold Rods, Windows) Low (GSE Cooling Lines, Cables) 2/5/2019

Tips and Tricks Number of layers optimized using Lockheed correlations Developed seam and penetration treatments to minimize performance degradation Optimized seam locations Facilitate ease of installation and disassembly As few as possible Layer temperature profiles matched at interfaces Used streamlined design and production processes company standard 2/5/2019

MLI Performance Exceeded Design Goals 2/5/2019

Conclusions Best MLI practices wherever possible Work concurrently with mechanical to develop “MLI friendly” configuration Compromises made to simplify implementation, facilitate disassembly, and where high performance unnecessary Test unit excellent opportunity to verify concepts 2/5/2019