1. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 1 GLAST Large Area Telescope: Tracker, W.B.S 4.1.4 August Status Meeting Robert Johnson rjohnson@scipp.ucsc.edu Gamma-ray Large Area Space Telescope

2. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 2 Flight-Tower Assembly Status Tray Panel status: –All flight tray panels are completed –About half of the tray panels for the 17 th tower were also delivered before Plyform went on holiday. The rest are close to completion. –All bottom trays for 18 towers have been delivered. Sidewall status –Completed for 17 towers MCM status: –Production is stopped. –Flight quality MCMs delivered for 17+ towers –The 18 th tower will have to include non-flight (NCR) MCMs but will be only slightly less efficient than the flight towers. Tray and tower assembly status: –All 16 flight towers have been assembled –However, some flight cables are still missing (next slide)

3. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 3 Tracker Flight-Tower Status TowerAssemblyVibeT/VStatus A,B,1-6  Integrated into the Grid 7  Needs a C6 cable installed, then ship 8  11Replace 1 noisy tray, install 3 cables, and repeat both vibe and T/V testing 9  Replace 3 cables and ship 10  At Alenia ready for vibe; replace 3 cables 11  In T/V testing; needs 2 cables replaced 12  Add 1 flight cable after env. testing 13  In T/V testing; needs 2 cables added 14  Has all 8 flight cables; in vibration testing

4. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 4 Tower 7 and 8 Rework Each of these two towers had one tray with high noise on one side when at elevated temperature. –Both trays were originally in “Tower-0”, so they were two of the first trays built. –They differ from following trays primarily in that the wire bonds from MCM to SSDs and bias circuit are encapsulated with silicone. The encapsulation was removed from the process because it was catastrophic for heavy trays (hundreds of wire bonds failed during thermal cycles). The problem with the thin-converter mid trays is subtle and was not realized until the towers went into T/V testing. The symptoms are consistent with intermittent connection of the bias current to the SSD ladders, but up to now direct measurements of the bias current have not confirmed this. Some more tests are in progress on the Tower-7 tray.

5. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 5 Tower 7 and 8 Rework The bad tray in Tower 7 was replaced, and the tower has by now completed a second round of environmental testing. –It should be ready to ship next week after installing a C6 cable. The bad tray in Tower 8 will (probably) be replaced in the next week. If so, the tower will go back into environmental testing after installation of the remaining flight cables. –This will therefore be the last flight tower to be shipped. –We are hoping to test Tower-15 in parallel with it, in order to have a true flight spare tower. Note that two towers already installed in the Grid each have a single Tower-0 tray. –In those cases, however, they are a top tray and bottom tray, which differ greatly from mid trays in terms of mechanical/thermal response. –They showed no problems, even in T/V testing. –If they should develop the same problem in the future, the performance impact would be slight, and the trigger would be unaffected.

6. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 6 Tracker Flex-Circuit Cable Status I expect to have all of the flight cables by the end of next week. The cables needed to complete Towers 8, 9, 10 should be carried to Italy this weekend. Parlex projects 9 additional cables (not shown here) by the end of next week, but they will almost certainly be a week later, at least. Still, they may provide the C3 and C5 cables for Tower 15.

7. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 7 Tracker Environmental Testing Schedule

8. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 8 Estimated Tower Ship Dates Tower 7September 9 Tower 8September 9 if we don’t replace a tray. End of September if we do. Tower 9September 9 Tower 10September 14 Tower 11September 23 Tower 12September 23 Tower 13September 23 Tower 14September 16

9. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 9 Cost/Schedule Reports for 4.1.4 Tracker Presentation July 2005 Month End Gamma-ray Large Area Space Telescope

10. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 10 Level 3 Milestone Count

11. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 11 Level 3 Milestone List

12. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 12 Cost Report

13. GLAST LAT ProjectMonthly Review, September 1, 2005 4.1.4 Tracker SubsystemR. Johnson 13 FTE Report (DOE/NASA-funded only)