GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 1 GLAST Large Area Telescope: Electronics, Data Acquisition & Instrument Flight Software Mechanical & Thermal March 19-20, 2003 David Nelson Stanford Linear Accelerator Center (650) Gamma-ray Large Area Space Telescope

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 2 Mechanical & Thermal Outline Overview View of boxes Team Requirements Mass Allocation Enclosures Material List Manufacturing Flow Presented in Jerry’s Clinton’s presentation Thermal Vibration Interfaces Verification & Test (QA) Summary

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 3 Overview GRID CAL BASE PLATE TEM 1 OF 16 TEM POWER 1 OF 16 SIU PDU EPU 1 OF 3 GASU EMPTY 1 OF 5 +X +Y +Z

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 4 Team David Nelson Joby Noriel Jim Stanfield Gary Guiffre Bruce Wakayama DATT Research (Thermal Consulting Firm)

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 5 Requirements/ Documents LAT-DS Electronics LAT Interface Definition Drawing LAT-MD LAT Program Instrument Performance Verification Plan LAT-SS Electronics-LAT Mech/Therm ICD REF: LAT-SS GLAST LAT Environmental Specification * Random Vibration at Qualification Test levels will produce most severe environment and boxes will be designed and evaluated for these levels.

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 6 Mass Allocation

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 7 Global Trigger ACD Signal Unit (GASU)

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 8 Power Distribution Unit (PDU)

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 9 Spacecraft Interface Unit (SIU) 3U cPCI BAE RAD750 TYPICAL cPCI 6U MODULE

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 10 Event Processor Unit (EPU) 3U cPCI BAE RAD750 TYPICAL cPCI 6U MODULE

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 11 Tower Electronics Module (TEM) TEM – PSU Stack Tower Electronics Module

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 12 Power Supply Unit (PSU)

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 13 Power Supply Assembly Drawing

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 14 TEM Assembly Drawing

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 15 TEM & Power Supply Assembly

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 16 TEM Assembly

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 17 Thermal Vacuum Chamber Stand & Vacuum system TEM, TPS Calorimeter Tracker LID with view port

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 18 Materials List

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 19 Thermal Power total hot case360 watts –TEM 3.4 watts –TEM Power Supply11.7 watts –GASU24.9 watts –PDU18.1 watts –EPU24.3 watts –SIU27.2 watts Stackups –TEM, TEM Power Supply, EPU -> 39.4 watts –TEM, TEM Power Supply, SIU-> 42.3 watts –TEM, TEM Power Supply, PDU-> 33.2 watts –TEM, TEM Power Supply, GASU ->27.5 watts Special stack up

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 20 Thermal Assumptions Thermal boundaries for the T&DF –-40C to +55C for Qualification –Uniform thermal connection to X-LAT plates –Only thermal conduction considered –No thermal conduction to calorimeter base plates. –100 O C maximum Si junction temp Thermal Resistances/Conductance's –Al W/m-K –Polyimide 0.33 W/m-K –CV2943 adhesive 1.26*W/m-K –Wedge-Lok 0.14 O C/W, 2 each 6” –Actel FPGA 6.2 O C/W J-C –Thermal Via, 12 mil, 2*10 3 O C/W each 3.4 O C/W for an array of 64X8

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 21 Power Distribution +Y Side LAT Radiator Bay 12 EPU-B Bay 13 Empty Bay 14 Empty Bay 15 Empty Bay 12 EPU-B Bay 13 Empty Bay 14 Empty Bay 15 Empty Bay 8 PDU-B Bay 9 GASU Bay 10 GASU Bay 11 SIU-B Bay 8 PDU-B Bay 9 GASU Bay 10 GASU Bay 11 SIU-B X Side Bay 4 PDU-A Bay 5 GASU Bay 6 GASU Bay 7 SIU-A +X Side Sun Side -X Side Bay 4 PDU-A Bay 5 GASU Bay 6 GASU Bay 7 SIU-A +X Side Sun Side Bay 0 EPU-A Bay 1 Empty Bay 2 Empty Bay 3 EPU-A Bay 0 EPU-A Bay 1 Empty Bay 2 Empty Bay 3 EPU-A Boxes94.4 -Y Side LAT Radiator Boxes Y Side LAT Radiator TEM/TPS:191.7 TEM/TPS:241.0 X-LAT Tot286.2LAT Top View X-LAT Tot359.9LAT Top View

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 22 Bolted Interface Contact Resistances

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 23 SIU Stackup TEM, TEM-PSU, and SIU/EPU/EMPTY Stack 10x Typical

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 24 SIU Thermal Analysis BAE Rad 750 –Temperature at Wedge-Lok rail interface must be < 70C for maximum junction temperature of 100C SIB – Provided by Dennis Silver, Silver Engineering –The PWB is inch thick Polyimide Epoxy-glass with a total of four internal 2-oz Cu power and ground planes. The board includes thermal vias under several components and under the wedge-lock retainers. The total board heat dissipation used in the analysis is 1.78 watts –Average board temperature 65.1 o C with a chassis base temperature of 55 o C LCB –Construction similar to SIB. Total power 2.7 watts. –Average temperature predict = 70C with chassis base of 55 o C

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 25 SIB Thermal Analysis – Provided by Dennis Silver, Silver Engineering

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 26 SIU/EPU Stackup Temperatures SIU 27.2 W/ EPU 24.3W PSU 11.7 W TEM 3.4 W Top & bottom covers are 0.08 in Al Side walls are 0.15 in 6061 Al Temperatures –TEM = 0.2 O C Rise –PSU = 0.7 O C Rise Thermal resistance for box below -> 0.11K/watt –SIU = 2.0 O C Rise Thermal resistance for box below -> 0.17K/watt –Total temp rise (3.4*.11)+2+(11.7*.17) = 5.2 O C Rise CASE 1

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 27 TEM Temperature Profile GCCC ASIC GTCC ASIC ACTEL FPGA

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 28 TEM Component Thermal Data TEM Cooling; Hottest single component –PWB mounted flat to 2 mm 6061 Aluminum FPGA 3.1 O C J/C for ½ watt –Polyimide PWB 0.33 W/m-K Using 9 cm 2 footprint 2.7 O C for ½ watt –CV W/m-K 0.23 O C for ½ watt –Temperature rise from edge of TEM box to center of TEM box 2.1 O C Total Delta T for FPGA Junction Temperature = XLAT interface + SIU + PSU+ TEM + TEM Center + FPGA – Delta T = = O C 10 mil CV mil PWB 10 mil CV mm Aluminum FPGA

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 29 GASU Component Thermal Data

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 30 GASU and PDU case CASE 2 GASU Stack Temperatures –TEM = 0.2 O C Rise –PSU = 0.7 O C Rise –GASU = 10.0 O C Rise –Total Temp = –Delta T X-LAT interface to TEM hottest FPGA = = 11.1 O C CASE 3 PDU Stack –TEM = 0.2 O C Rise –PSU = 0.7 O C Rise –PDU = 6.1 O C Rise –Total Temp 8.1 O C Rise –Delta T X-LAT interface to TEM hottest FPGA = = 13.3 O C CASE 2 ½ GASU 12.5 W PSU 11.7 W TEM 3.4 W XLAT Interface PDU 18.1 W PSU 11.7 W TEM 3.4 W CASE 3 XLAT Interface Cable Mt

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 31 Acceptance Level Vibration

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 32 QUAL Level Vibration

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 33 QUAL Level Response Curve SDOF Response Q=10

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 34 Mounting Bolt Stresses Assumptions: Analysis based on input dynamic loads input at electronic box baseplate. Bolts are high tensile strength A ksi fasteners. Dynamic Loads derived from maximum expected response of a SDOF system to the QUAL level random environment of Grms with a Q=10 in all three orthogonal axes. Maximum CG location in Z-Axis is used for conservatism in overturning moment calculation. Safety Factor of 1.4 used on Ultimate Material Strength. Worst Case Combined Stresses are shown where applicable. Coefficient of Friction assumed to be.30 for Electro-less Nickel. Margins on Based Combined Stresses

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 35 Typical FEM Model Analysis Approach - Plate, Brick and Beam Elements - Model Weight 31.4 lbs. (14.3 kg) - Fundamental Mode > 500Hz - Machined Aluminum 6061-T6 - Ultimate Strength psi - Conservative Simplified Approach to Application of Dynamic Load Factor - Applied Maximum Response of SDOF to QUAL Level uniformly to each of the three orthogonal axes - 3 s Load Levels used to account for peak excitation. - Ignored Mass Participation Effects and Non-uniform Distribution of acceleration loads throughout the structure. - Q = 10 - Safety Factor of 1.4 x Ultimate Strength - Applied Acceleration Load Grms (44.84 Grms peak) GASU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 36 Y-Axis Load Case Displaced Shape and Stress Contour Maximum Stress ~ 2599 psi X-Axis Load Case Displaced Shape and Stress Contour Maximum Stress ~ 2792 psi GASU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 37 Z-Axis Load Case Displaced Shape and Stress Contour Bottom View Z-Axis Load Case Displaced Shape and Stress Contour Top View Maximum Stress ~ psi GASU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 38 Typical FEM Model Analysis Approach - Plate, Brick and Beam Elements - Model Weight 21.6 lbs. (9.82 kg) - Fundamental Mode > 500Hz - Machined Aluminum 6061-T6 - Ultimate Strength psi - Conservative Simplified Approach to Application of Dynamic Load Factor - Applied Maximum Response of SDOF to QUAL Level uniformly to each of the three orthogonal axes - 3 s Load Levels used to account for peak excitation. - Ignored Mass Participation Effects and Non-uniform Distribution of acceleration loads throughout the structure. - Q = 10 - Safety Factor of 1.4 x Ultimate Strength - Applied Acceleration Load Grms (44.84 Grms peak) PDU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 39 Y-Axis Load Case Displaced Shape and Stress Contour Maximum Stress ~ 3390 psi X-Axis Load Case Displaced Shape and Stress Contour Maximum Stress ~ 1850 psi PDU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 40 Z-Axis Load Case Displaced Shape and Stress Contour Top View Maximum Stress ~ psi Z-Axis Load Case Displaced Shape and Stress Contour Bottom View PDU Stress Model

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 41 GASU & PDU Covers FEM Model GASU & PDU Covers FEM Model PDU Cover Natural Frequency 197 Hz Modal Participation Factor1.64 Input22.2 Grms Dynamic Deflection 3 s.028 inches Typical FEM Model Plate Elements Fixed Edge Boundary Conditions Flexure of Box Side Walls not considered. Design Goal > 100Hz GASU Cover Natural Frequency 157 Hz Modal Participation Factor1.64 Input 19.8 Grms Dynamic Deflection 3 s.039 inches

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 42 Verification & Test (QA)

GLAST LAT ProjectDOE/NASA Peer Critical Design Review, March 19-20, 2003 D. Nelson 43 Summary Mechanical design of majority of DAQ flight enclosures completed Assembly drawings in progress Sixteen sets of TEM DAQ and TEM power supply engineering model enclosures fabricated and are part of EGSE test-stands used by DAQ and sub-systems GASU in fabrication Mechanical analysis presented and show sufficient margin Thermal analysis well advanced –Thermal vacuum chamber being fabricated at SLAC to support verification