GLAST Large Area Telescope: Mechanical Systems Peer Review March 27, 2003

1. Gamma-ray Large Area Space Telescope GLAST Large Area Telescope: Mechanical Systems Peer Review March 27, 2003 Section 5.3 – Fabrication & Assembly Plans Bill Olson SLAC Mechanical Engineer marcc@slac.stanford.edu

2. Topics Agenda • Procurement plans • Identify critical component need dates vs. delivery dates • Summarize procurement contract status • Long lead part requirement/procurement • Fabrication plans • Mech Parts and Materials plan • Material approval status/readiness • Assembly plans • Assembly sequence • MGSE • Performance and Safety Assurance plans • Further Work

3. Procurement Plans • RFP for 4 x 4 Grid & Grid Box Machining • Issue by 4/21/03 • Place contract by 5/15/03 • Long Lead Materials • PR for 2 Grid billets is in process now • Lockheed has ordered heat pipe extrusions

4. Mechanical Parts & Materials Plan • Material requirements flow down from the Mission Assurance Requirements 433-MAR-0001 and the Mechanical Parts Plan LAT-SS-00107-01. • LAT Material selection of low outgassing and flight heritage • Outgassing specs: TML < 1% CVCM < 0.1% • Important Procedures and Guidelines for Material selection • Fastener Integrity Requirements (541-PG-8072.1.2) • Metallic Materials for Stress Corrosion Cracking Resistance in Sodium Chloride Environment (MSFC-STD-3029) • Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials for Outgassing (ASTM-E-595)

5. Mechanical Parts & Material: Status • Submitted to SLAC IPO as of 3/19/03

6. Legend Accepted Hardware Test activity Assembly activity Grid Box Assembly Overview Grid Assy Grid Box Base Assy Grid Box Assy Grid Ready for Test Radiator Mount Bracket Spacecraft Interface (Wing) EMI Skirt Details Heat Pipe Patch Panels X-LAT Plates Heat Pipes CAL Plates (Temporary) Purge Groove Cover Grid Box Assembly Configuration

7. Grid Assembly The Grid Assembly consists of; • 4 x 4 Grid • Spacecraft mounting interface (Wing) which is located at the bottom center of each side of the Grid • Radiator Mounting Brackets - 2 as shown and 2 opposite. Grid Assembly Radiator Mounting Bracket

8. The Grid Box Base Assembly is the next level assembly, and is the configuration delivered to I&T. It consists of: Grid Assembly Heat Pipe Patch Panels, 2 as shown and 2 opposite Heat Pipes 5 Top Flange Heat Pipes (TFHP) 12 Downspout Heat Pipes (DSHP) 2 Purge groove covers Flight heaters, thermostats & thermistors on Grid Once this assembly is put together, it is not intended to be taken apart. Grid Box Base Assembly Grid Box Base Assembly Heat Pipe Patch Panel

9. Grid Box Assembly The Grid Box Assembly is the Mechanical Systems’ top assembly test configuration. It consists of: • Grid Box Base Assembly • Remaining EMI skirt parts • 4 Center EMI Shields • X-EMI Shields, 2 as shown and 2 opposite • 2 X-LAT plates with heat pipes • X-LAT Mid-plate • 16 Temporary Calorimeter plates. Grid Box Assembly X-EMI Shield Center EMI Shield

10. Grid Fabrication Plan The Grid is a complex machined part that requires special consideration and handling. Tapemation outlined their plan, which basically is; • Rough mill, leaving approximately 0.200” extra all around • Heat treat to remove stresses and temper to T6 condition • Face Datum-A and the opposite side to 0.100” away from the finished surfaces • Mill all four sides to approximately +0.100” • Stress relieve • Finish mill inside (bay) features from Datum-A side • Finish mill all four sides

11. Grid Fabrication Plan (Cont) • Finish mill all features on side opposite Datum-A • Finish drilling, tapping, and all other features on Datum-A side • Finish mill Datum-A surface • Deburr and clean part • Inspection – Coordinate Measurement Machine (CMM) • Alodine • Install all inserts and hardware • Perform proof load test on inserts • Ready for Grid Box Machining.

12. Ready for Grid Box Machining Legend Fabrication activity Inspection/test Assembly activity Grid Fabrication Grid NDT plate (x-ray, UT, other) Procure aluminum Roughmachine Grid Stress-relieveheat treat Finish machine Grid Test samples Clean Grid Remove, mach test samples Repair as required Inspect Grid Inserts Procure inserts, mount h’ware Alodine Install inserts Proof inserts Final Inspection SLAC Buy-off

13. Grid Box Machining • Grid Box Machining is a temporary assembly for machining: • EMI shields coplanar for X-LAT plate mounting • Each pair of Radiator Mounting Brackets coplanar • Control relative positions of Radiator & X-LAT locating pins to Grid datum’s so 3 sets of heat pipes will mate properly • Install the EMI Skirt components on Grid • Machine bottom edges of the EMI Skirt components co-planer • Machine X-LAT locating pin holes and fastener holes in the EMI Skirt components • Machine mounting features & locating pins holes in Radiator Mounting Brackets • Install locating pins and Helicoils • Mark parts for specific location on Grid X-LAT Pins Radiator Pins

14. Legend Fabrication activity Inspection/test Assembly activity Grid Box Machining EMI Skirt Grid Procure aluminum Grid Machine Radiator Brkts Machine Patch Panels Machine Center EMI Shields Machine X-EMI Shields Inspect Clean EMI Skirt Components Install inserts in EMI Skirt Parts Inserts Procure inserts, mount h’ware Repair as required Install Radiator Brkts, Patch Panels, Center EMI Shields, & X-EMI Shields on Grid Repair as required Drill Pin and Bolt Holes in EMI Skirt Parts & Radiator Brkts Machine Radiator mounting surface features in Radiator Brkts Inspect Machine EMI Skirt Co-planer Clean Assy Install inserts in EMI Skirt Parts Deliver To SLAC

15. Grid Assembly Procedure The Grid Assembly is assembled per the following procedural steps: • All components are inspected, cleaned, bagged, and staged when received. This is true for all components that make up the Grid Box Assembly • Lay Grid top side down on a flat table • Install Spacecraft wings • Install the Radiator Mounting Brackets

16. Grid Box Base Assembly Procedure The Grid Box Base Assembly is the core assembly, and is not intended to be disassembled below this level. The procedural steps are; • Leave the Grid Assembly top side down • Install the Heat Pipe Patch Panels so the Downspout Heat Pipe mounting surfaces on the Grid and Patch Panels are co-planer • Turn the Grid Assembly top side up • Locate the Downspout Heat Pipes (DSHP) relative to Radiator locating pins with tool • Bond the DSHPs to Grid • Bond Grid Top Flange Heat Pipes into Grid • Bond the Purge Groove Cover Plates. • Install flight heaters, thermostats, & thermistors to Grid • Wire heaters, thermostats, & thermistors • Attach the Grid Perimeter Ring, which is for handling the LAT during all phases of operation, other than flight, to make handling the assemblies easier and safer.

17. Grid Box Assembly Procedure The Grid Box Assembly is the final assembly level for Mechanical Systems. The procedural steps for assembly are; • Place the Grid Box Base Assembly top side down • Install temporary Calorimeter plates • Install the Center EMI Shields • Install the X-EMI Shields • Mount the X-LAT plates on the EMI Shields and fasten the heat pipes to the Patch Panels • Mount the X-LAT Mid-plate on the EMI Shields.

18. Mechanical Systems MGSE

19. Performance Assurance System • Mechanical Systems will comply with the following: • LAT Performance Assurance Implementation Plan (PAIP), LAT-MD-00039 • LAT Quality Manual, LAT-MD-00091 • Configuration Management Plan, LAT-MD-00068 • Instrument Performance Verification Plan, LAT-MD-00408 • Calibration Program, LAT-MD-00470 • System Safety Program Plan (SSPP), LAT-MD-00078 • Additionally, above requirements have been flowed down to Suppliers and Subcontractors.

20. Further Work • Finalize Wing design • Finalize Spacecraft Mount configuration with Spectrum • Optimize stress and mass of EMI Skirt components • Detail design of assembly MGSE • Get Grid vendor under contract