Sept. 2008EFW INST+SOC PDR IDPU Chassis Mechanical Design and Development Bill Donakowski Mechanical Engineer UCB/SSL

Sept. 2008EFW INST+SOC PDR IDPU Chassis Requirements Functional –Provide Mechanical Packaging for 4 EFW electronic boards in one card cage box –BEB/DFB/DCB/LVPS Boards –Allow removal of each board layer separately –Provide structure and attachment to S/C –All access to test points following board installation into box Structural –Positive strength margins –First natural frequency greater than 50 Hz Radiation Shielding –External walls to have.35” equivalent thickness Aluminum –LOS requirement from outside to boards Venting –Allow proper venting on ascent Thermal –Alodined Box attach face is conductively attached to S/C Panel 5 –All other outer surfaces black anodized to radiatively couple to inside of S/C –Temperature range: -35° C to +65° C (preliminary) EMI Shielding –Provide metal shielding between each board layer

Sept. 2008EFW INST+SOC PDR IDPU Chassis Design Description Standard card-cage design –Standard 6U format circuit boards (160mm x 230mm) –Similar to THEMIS –Aluminum 6061 T6 panels bolted together –gaps prevented at panel interface by step in edges Separate layers for individual boards to slide into box –Each card layer consists of PCB, wedgelocks, connectors, and EMI shield –Cards held in place by wedgelocks on sides and fasteners on front panels –Each panel can be removed by unscrewing bolts, loosening wedgelocks, and sliding out Separate, removable radiation shield over connectors and cables –Installed for testing and at integration to S/C –Aluminum 6061-T6

Sept. 2008EFW INST+SOC PDR IDPU Chassis Overview LVPS DFB DCB BEB REMOVABLE RADIATION SHIELD HOLES FOR BOLTING TO S/C PANEL #5 (10-32 bolts) ALL CABLES TO S/C MATE TO FRONT OF BOX TOTAL MASS: CBE 8.3 Kg 10” VENT 3.5” 7.5” 4.2”

Sept. 2008EFW INST+SOC PDR IDPU Chassis Overview WEDGELOCKS ON EACH BOARD EDGE (manuf: CALMARK) EACH BOARD CAN BE REMOVED INDIVIDUALLY (without removing others)

Sept. 2008EFW INST+SOC PDR IDPU Chassis Overview REMOVABLE RADIATION SHIELD (INSTALLED FOLLOWING BOX INTEGRATION ONTO S/C) BACKPLANE CONNECTOR ACCESS PANEL TO TEST POINTS ON BOARDS 8 x ATTACH BOLTS (8-32)

Sept. 2008EFW INST+SOC PDR RBSP Chassis Radiation Shielding All external aluminum panels provide shielding –.35” thickness –Interlocking steps to prevent any gaps at connections Removable Radiation Shield covers connectors and cables on front of box –Radiation Shield installs following box installation onto S/C –Provides.35” equivalent thickness radiation shielding line of sight to boards Volume for cable run to S/C EMI SHIELDS BETWEEN LAYERS ( 3 SHIELDS)

Sept. 2008EFW INST+SOC PDR IDPU Chassis Radiation Scheme for Cables Radiation LOS Maze allows simple cable runs.90” Pass-thru for cables to S/C

Sept. 2008EFW INST+SOC PDR IDPU Chassis Analysis Structural –Thick wall sections for radiation shielding makes for very robust box –Preliminary strength analysis strength margins >.7 on yield (100G) Venting –Volumetric analysis to confirm –Vent size 1 in 2 for every 1 ft 3 Volume –Size vent accordingly Preliminary FEM output Showing Von Mises Stresses

Sept. 2008EFW INST+SOC PDR IDPU Chassis Status ICD drawing submitted to APL –Overall box geometry –Cable routing –Keep-out zones to allow radiation shield installation on S/C Individual Board ICDs completed –Showing connectors, board geometry –Allowing electrical components layouts to begin Mechanical Box detailing ongoing –Weight relieving of.35” walls to be implemented where possible

Sept. 2008EFW INST+SOC PDR IDPU Chassis Issues and Concerns Thick walled construction produces rapid mass gain if box grows

Sept. 2008EFW INST+SOC PDR IDPU Chassis (backup) Materials 6061-T6 Aluminum Alloy –Yield Strength: 37,000 psi –Ultimate Tensile Strength: 42,000 psi Delrin –Ultimate Tensile Strength: 8,000 psi