1. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy1 GLAST Large Area Telescope: Mechanical Systems Peer Review 27 March 2003 Section 4.1 - Radiator Mechanical Design John Cernac Lockheed Martin Mechanical Design Engr john.d.cernac@lmco.com Gamma-ray Large Area Space Telescope

2. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy2 Topics Requirements compliance matrix Materials and construction Mechanical envelope & interfaces Handling integration & test Status & further work

3. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy3 Driving Design Requirements Based on:Radiator Level IV Design Specification, LAT-SS-00394-1-D6, Draft, Dated 5 Mar 2003 LAT Mechanical Systems Interface Definition Dwg, Radiator-LAT Interface, LAT-DS-01221, Draft, Dated 25 Feb 2003 Verification Methods A: Analysis, I: Inspection

4. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy4 Blank Panel Exploded Outer Facesheet VCHPs Honeycomb Core Inner Facesheet Doublers Reservoir Support Bar 1.56 m 1.82 m

5. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy5 Panel Construction The blank panel is oversized in + & -X The excess at the edges will be trimmed & used for verification The panel facesheets are 6061-T6 Al –Outer: 1.60 mm (.063”) thick –Inner:.79 mm (.031”) thick The panel core is 5000-series Al with a higher density around the mounting points

6. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy6 Heat Pipe Installed The heat pipes are positioned with tooling and bonded to the outer facesheet The honeycomb core is machined to match the heatpipe The outer facesheet with heatpipes, the core, and the inner facesheet are bonded together in an autoclave OUTER FACESHEET REMOVED

7. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy7 Reservoir Mount Installed The reservoir mount serves three purposes –Provides mechanical support at reservoir end mount –Accommodates manufacturing tolerances in x, y, & z –Thermally isolates the reservoir from the radiator structure

8. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy8 Isolating Bushing Installation

9. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy9 Radiator Panel Doublers 2.3 mm (.090”) thick doublers are bonded over the facesheets at the mounting points The doublers include doublers on the trim strips at the edges of the panel for quality verification.

10. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy10 Radiator Mounting Interfaces Each interface accepts 4 fasteners –5/16 fasteners at the upper mount –#10-32 at the lower Insulating shim.25” (6.35 mm) thick G10 glass epoxy material and G10 washer under screw head provides thermal isolation at upper mount brackets

11. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy11 Panel Edge Closeouts The +/- x and +z edges are closed out with tape. –x-axes panel edges perforated –+z-axis panel edge solid The –z edge is closed out by the reservoir support bar and where required, perforated tape Thermal control film (FOSR) is applied to the outer facesheets Y

12. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy12 Radiator Static Envelope The radiator maximum static envelope is specified per LAT-DS-01221, Draft The physical size and features of each radiator panel are located from datum points at the radiator mounting interfaces The radiator is sized, dimensioned and toleranced to be within the static envelope with the exception of the MLI (TBD) ENVELOPE RADIATOR RADIATOR IN THE ENVELOPE

13. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy13 Venting for Ascent Pressure Decay The general venting solution is to provide 0.5 sq in of vent area per cubic foot of volume - ref IDC TSS-622. The panel volume is 3.4 cubic feet therefore 1.7 sq in required 1.5 sq in is provided by perforated tape at +/-X & -Z edges 0.8 sq in is provided by vent holes in the reservoir closeout Total general vent area = 2.3 sq in; 0.6 sq in/35% margin Two each 0.03 cubic feet core volumes require venting: Required venting area = 0.015 sq in Four 0.093 diameter holes are placed in the inboard face sheet at each volume & vent to the thermal blanket which directs venting to the edges. This provides 0.027 sq in vent area; 0.012 sq in/80% margin

14. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy14 Panel Design Verification Test Testing of inserts potted in panel sections identical in characteristic to the Radiator panels is planned Standard test in shear & tension will be performed This data will be used to define verification test acceptance criteria

15. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy15 Handling With Z Axis Up Normal integration is planned for handling with +z axis up. The handholds are weights which provide cg adjustment of the load as required to offset the pick- up point so the cables clear the instrument grid.

16. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy16 Handling With +X Axis Up Radiator installation and removal can be performed with +x axis up. The same sling and sling attaching hardware will be used as used for z axis up –Radiator interface is 2 inserts per lifting lug attachment

17. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy17 Radiator Lifting Adapters The lifting adapters are made of stainless steel to provide the required ballast characteristics The lifting adapters are fitted with ¼ inch captive fasteners – no loose pieces

18. GLAST LAT ProjectDOE/NASA Mechanical Systems Peer Review, March 27, 2003 Section 4.1 - Mechanical Systems Radiator Assy18 Drawing Tree