1. 1 GLAST LAT ProjectMechanical Systems Mechanical Systems November 2003 GSFC Status Marc Campell, Subsystem Manager

2. 2 GLAST LAT ProjectMechanical Systems Accomplishments Accomplishments during November/December –Heat treatment and straightening of Grid #1 complete. Heat treat samples tested and exceed all requirements. –Billet #2 ultrasonic inspected (no flaws) and shipped to Tapemation for storage. –Grid Spacecraft insert and Grid-CAL insert EM strength testing complete. –Released 33 of 35 Mech drawings for Grid Manufacturing package. All model changes have been made to the Grid drawing – awaiting final approval for release. –Grid Box Top Assembly drawings 1 st draft complete. –Closed 20 open issues in preparation of Grid MRR on 12/18 –Issued Rev 2 of Grid Machining SOW to Tapemation. –X-LAT Plate design review held. Design approach approved. –CCB approved MECH mass increase.

3. 3 GLAST LAT ProjectMechanical Systems Accomplishments (Cont.) Accomplishments during November/December –Supported LM preparations for Radiator MRR 12/16 –Downspout and Top Flange Heat Pipes complete. Awaiting SLAC buyoff (Jan 04). –Radiator Acoustic analysis with LAT model complete. Loads are about the same and will not impact design. –Radiator insert and spool testing completed.

4. 4 GLAST LAT ProjectMechanical Systems 3 Month Milestones Dec - Feb

5. 5 GLAST LAT ProjectMechanical Systems 3 Month Milestones (cont)

6. 6 GLAST LAT ProjectMechanical Systems Issues & Concerns Close last remaining issues prior to the start of detailed machining of the grid – need successful MRR. Grid to I&T delivery date – schedule continues to compress. To maintain schedule Grid Box Assy tests are being performed on Grid #2 after start of I&T or deleted. This increases risk. X-LAT plate & Radiator delivery schedule due to late starts. 1 x 4 Grid delivery date to I&T. –Need to resolve and implement modified Grid – TRK interface

7. 7 GLAST LAT ProjectMechanical Systems Open Flight Design Issues Grid-TRK interface - define Grid datum & TRK tooling interface –Working group in progress RFA’s closure –Working with Pat Hascall & Bernie Graf Radiator integration sequence –Study underway – drawing analysis indicates feasibility. Radiator VCHP Helium leak rate may impact ACD PMT’s –How to evaluate the impact in a timely manner (dispersion analysis) –LM can substitute another inert gas, but it impacts ground performance (not on-orbit). –LM ready to start VCHP’s now. Heat leak from Grid to Radiator may exceed values used in LAT thermal analysis. In analysis, a Ti Radiator Mount Bracket (RMB) was assumed instead of Alum. –Re-run thermal model to determine impacts to Grid heater power. 2 options if it is a problem Allocate more heater power for Grid Reduce thermal isolator size & re-analyze Radiator loads

8. 8 GLAST LAT ProjectMechanical Systems Open Flight Design Issues (Cont) TCS – location of Grid heaters, thermostats, RTD’s and associated wiring needs to be resolved Define GBA Static Load test requirements & plans –Prelim plan presented at Peer Review LAT integration sequence affects MECH drawing tree & testing –DSHP’s & all EMI Skirts may be removed at start of I&T

9. 9 GLAST LAT ProjectMechanical Systems Schedule Budgeted Cost Work Scheduled$6.276M Budgeted Cost Work performed$6.236M Schedule Variance $40K

10. 10 GLAST LAT ProjectMechanical Systems MECH Critical Path

11. 11 GLAST LAT ProjectMechanical Systems MECH Critical Path (Cont)

12. 12 GLAST LAT ProjectMechanical Systems Program Threats Top 6 threats to maintaining schedule –Highly compressed, success oriented schedule –Interdependencies on other Subsystems –Manpower availability (Engr’s & Tech’s) –Closure of open items for Grid manufacturing –EM tests and flight designs are being performed in parallel – increases impact of any EM test failure –LM does not get their requested information in a timely manner Top 3 threats to staying within cost –Interdependencies on other Subsystems –TCS costs Prototype may require PDU, SIU & GASU boards Much of work being performed by ELEC –EM program taking longer than budgeted