1 SPP FIELDS MEP Main Electronics Package Peer Review Bill Donakowski UCB/SSL 18 NOV 2014 MAVEN PFDPU Flight Unit SPP MEP Baseline Design B. Donakowski SPP MEP EM Hardware

MEP PDR Overview Requirements Design Heritage Design Overview Interlocking Frame Design Details Daughter Board Details Thermal Design FEM Design Analysis Mass Properties Vibration Testing Ongoing Issues 218 NOV 2014 B. Donakowski

MEP Functional Requirements Provide Packaging for 9 different Board Assemblies in common box – LNPS1, LNPS2, MAGo, MAGi, RFS/DCB, DFB, AEB (2x), TDS Modular box arrangement allows individual boxes to be built up independently and taken apart a/r Design/Coordinate/Fab Box Frames with responsible groups – UCB/MN/LASP/GSFC.060” thick Aluminum walls for Radiation Shielding One plane mounting interface to Spacecraft Adequate Structure Integrity (Strength, Dynamics) Optimal thermal path to Spacecraft Electrical Ground to S/C 318 NOV 2014 B. Donakowski

MEP Project Requirements Requirements per EDTRD, Analysis/Design – Materials selection, dynamics analysis, structural analysis, venting, EMI/EMC, grounding Testing/Verification – Mass Properties, Vibration, TVAC, Bakeout, Cleanliness 418 NOV 2014 B. Donakowski

MEP Box Overview 5 Attach surface to Spacecraft Panel 18 NOV ” 6.85” 8.25” B. Donakowski

MAVEN Design Heritage 6 6x Skewers Top EMI Shield over Card- Card Harnesses S/C Bracket Box Vents Connectors on 3 sides of box MAVEN Electronics Box 11 Separate Cards sharing common Frame details Bolted to S/C Bracket on one Box face Box Size: 8.1” Wide x 6.2” Tall x 9.3” Long SPP FIELDS Electronics Box 9 Separate Cards sharing common Frame details Bolted to S/C on one Box face 10x Attach feet to S/C (every other Frame) #8 Fasteners (no shear panels) Box Size: 9.4” wide x 6.5” Tall x 8.0” long 2x Skewers Connectors on 3 sides of box B. Donakowski 2 Shear Panels 18 NOV 2014

MEP Typ Box Frame Assy 7 FrameInstrument Connectors EMI Shield Mounting Surface to Spacecraft Intrabox Connectors Screws and Custom Inserts at PCB perimeter Card PWA 6.2” x 9.2” Daughter Board (DCB, DFB, TDS) 18 NOV 2014 B. Donakowski 2X Center Posts

Box Machined Open Frame Design 8 Box Frame walls.060” Multiple PCB attach screws to Frame to increase PWB stiffness and provide good thermal conduction path Machined 6061 T6 Al Alloy Machined Frame.85” Pitch (Frame to Frame) Feet for attachment to S/C LNPS Boxes are 5-sided 6X Skewers (#8 Threaded Rod) (OPEN) B. Donakowski 18 NOV 2014

Interlocking Frames Design 9 Individual Frames bolted together with 6X skewers Detail showing Frame Interlocking Features Each Box can be Pulled From Stack B. Donakowski 18 NOV 2014

Daughter Board Details DB Module to be designed/built by SSL Large Chip (RJEX4000 CCGA) at Center Used on DCB, TDS, DFB 10 Custom threaded tool thru threaded inserts applies gentle force at corners to remove DB from MB 4X Custom Tools EM Hardware built and working well B. Donakowski 18 NOV 2014

Thermal Design S/C environment is hot—testing at 75 C Boards screwed to Frames at perimeter 2X Screws at PCB center to EMI shield w/ integral posts Attachment frame wet mounted to S/C (TBC) All Exterior Walls painted with Black Paint (Aeroglaze Z307) Black Anodize Interior Walls Alodine 600 Treatment at Box interfaces (to PCB, SC, other Frames) 11 S/C PCB screwed to EMI Shield (2x) B. Donakowski 18 NOV 2014

PWB Thermal Design Consider entire heat path Component To Board – All components dissipating more than 50 mW should be looked at by thermal engineer Thermal / Ground / Power Planes – Board dissipated power needs to travel to the frame via conduction in thermal (or ground) planes, then to the frame Board Mounting to Box – Need a good path from thermal planes to standoffs / box lip / – 2 Oz Copper Layers 12 B. Donakowski 18 NOV 2014

MEP FEM Dynamic Analysis 13 B. Donakowski 18 NOV 2014 ComponentRequirementAnalysisTest ResultsRemarks Box StructureFn > 100 Hz600 Hz450 HzMEP EM Hardware Mother Board (DCB) Adequate (2X) Separation from Structure 195 Hz210 Hz (MAVEN) 235 Hz (DFB) MAVEN Board similar in design DFB test run by LASP on EM (NOV 2014) Daughter Board (DCB) Adequate (2X) Separation from MB 850 HzTBDSine Survey Test DEC 2014 Modal Analysis, Axis Perpendicular to PCBs

FEM Analysis 14 PCB/Spacers/EMI Shield Assy Fixed at Perimeters (to Frame) Fn=195 Hz Entire MEP Box Assy (PCBs/Frames) Fixed at Attach Feet (to S/C) Fn > 600 Hz B. Donakowski 18 NOV 2014

Mass Properties Current Estimate: Kg Contingency (20%): Kg Current Best Estimate: Kg – (Intrabox Cables included, S/C cables not included) 15 B. Donakowski 18 NOV 2014

MEP Status and Schedule EM Hardware – All Mechanical hardware fabrication complete – Hardware In-house and part of box build-up Required Design Changes for FLIGHT (not incorporated in EM design) – Change in connectors due to survival heater scheme change All Drawing changes complete – Increase in TDS Box width due to component height increases below board All Drawing Changes complete – LASP request for taller components below DFB Board Design under evaluation/ Appears to be simple change Final FEM Analysis – December 2014 EM Testing – Fit checks of Frames/Weighing PWA – Some limited Thermal Vac Testing, December 2014 – If hardware allows, vibration (sine sweep) test, January B. Donakowski 18 NOV 2014

MEP Status and Schedule S/C Interface – SSL has approved APL’s baseline spacecraft panel inserts design 17 B. Donakowski 18 NOV 2014

Backup Slides 18 B. Donakowski 18 NOV 2014

Electronics Board Layout Control Drawing 19 Drawing Maintained by SSL Distributed to Electronics Designers Main Document for Design Consistency between EE and ME aspects B. Donakowski 18 NOV 2014

Connectors Fastening 20 UCB Custom Connector Nutplate Easier than nuts to assemble no need to get wrench to hold nuts during jackpost torquing Standoffs can be removed one-by-one D-Connector OTS Jackposts Spiralock tapped holes Desirement: Allow Jackposts to be Removed from outside of Box without opening box Material: 6061 T6 Aluminum B. Donakowski 18 NOV 2014

PCB Attach Method 21 Custom UCB designed insert Stainless Steel, Silver Plated Spiralock Threads provide Locking Device Insert soldered to PCB Traces UCB will provide to outside groups B. Donakowski 18 NOV 2014