1. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 1 SPP FIELDS MEP Main Electronics Package Mechanical Packaging Bill Donakowski billd@ssl.berkeley.edu UCB/SSL MAVEN PFDPU Flight Unit SPP MEP Baseline Design SPP MEP EM Hardware

2. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Agenda Requirements Design Overview Interlocking Frame Design Details Daughter Board Details Thermal Design FEM Design Analysis Mass Properties Vibration Testing Ongoing Issues 2

3. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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 3

4. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP Project Requirements Requirements per EDTRD, 7434-9039 Analysis/Design –Materials selection, dynamics analysis, structural analysis, venting, EMI/EMC, grounding Testing/Verification –Mass Properties, Vibration, TVAC, Bakeout, Cleanliness 4

5. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP Box Overview 5 Attach surface to Spacecraft Panel 10” 6.85” 8.25”

6. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP Box Overview 6 6x Skewers MEP Overview 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 Connectors on 3 sides of box

7. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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) 2X Center Posts

8. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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)

9. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Interlocking Frames Design 9 Individual Frames bolted together with 6X skewers Detail showing Frame Interlocking Features Each Box can be Pulled From Stack

10. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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

11. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Thermal Design S/C environment is hot –Testing Operational: -25 to +60 –Testing Survival: -30 to +65 (Temps at baseplate) Boards screwed to Frames at perimeter 2X Screws at PCB center to EMI shield w/ integral posts Attachment frame wet mounted to S/C (CHO-SEAL, APL Provided) 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) Baseplate

12. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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

13. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP FEM Dynamic Analysis and Test 13 ComponentRequirementAnalysisTest ResultsRemarks Box Structure Fn > 100 Hz600 Hz450 Hz TBD -MEP EM Hardware (w/ dummy masses) -February 2014 (w/ EM PWAs installed) 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 February 2015 Modal Analysis, Axis Perpendicular to PCBs

14. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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

15. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Mass Properties Current Masses (Measured EM Units) 15 ComponentCBE Mass (Kg) DCB.495 RFS.100 TDS.435 DFB.437 AEB1.362 AEB2.362 MEP Chassis3.202 LNPS1.900 LNPS2.620 Internal (Box to Box) Harnessing.229 MEP BOX CBE TOTAL7.142 Kg (NTE MASS: 7.856 Kg)

16. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical 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 –DCB and DFB request for taller components below DFB Board Design under evaluation/ Appears to be simple change EM Testing –Fit checks of Frames/Weighing PWA –Verification of flatness on bottom of frames –Some limited Thermal Vac Testing, January 2015 –If hardware allows, vibration (sine sweep) test, February 2015 16

17. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP Status and Schedule S/C Interface –MICD produced No outstanding issues with APL –SSL has approved APL’s baseline spacecraft panel inserts design 17

18. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical MEP Concerns Machining Details Critical –Fit of Frames to each other –Frame Flatness and coplanarity at interface to Spacecraft panel Final Assy needs to preclude preloading/warping frames 18 Full inspection of machined parts and adequate assembly tooling should alleviate potential fit problems on Flight Build

19. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Backup Slides 19

20. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Electronics Board Layout Control Drawing 20 Drawing Maintained by SSL Distributed to Electronics Designers Main Document for Design Consistency between EE and ME aspects

21. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical Connectors Fastening 21 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

22. B. Donakowski UCB/SSLFIELDS iCDR – MEP Mechanical PCB Attach Method 22 Custom UCB designed insert Stainless Steel, Silver Plated Spiralock Threads provide Locking Device Insert soldered to PCB Traces UCB will provide to outside groups