GLAST LAT Presentation

1
GLAST Large Area Telescope Cost/Schedule
Review November 3, 2004 AntiCoincidence Detector
(ACD) Subsystem WBS 4.1.6 David J.
Thompson Thomas E. Johnson NASA Goddard Space
Flight Center Subsystem Manager/Instrument
Manager David.J.Thompson_at_nasa.gov Thomas.E.Johnso
n_at_nasa.gov
2
Significant Accomplishments

• Started flight PMT assembly. 16 units are
  completed, 10 are being coated, 20 additional
  units beginning assembly.
• Completed vibration testing of the Spare/Qual
  Electronics Chassis.
• Installed fiber ribbons on the flight structure.
• Successfully completed all mechanical
  qualification testing of the new PMT mounting
  design.
• Completed Spare/Qual Electronics Chassis
  functional testing.
• Made preparations to go to EMI testing.
• Received 36 new PMTs from Hamamatsu.
• Completed the assembly and functional testing of
  all (4) single row Electronic Chassis (minus the
  PMTs)

3
Recent Accomplishments - Electronic Component
Status
ITEM Quantity Required Flight (Spare) Assembly Complete Functional Testing Conformal Coating Thermal Testing Ready for next assembly
Front End Electronics Boards 12 (4) 16 16 16 16 16
High Voltage Bias Supply 24 (6) 30 30 30 30 30
Photomultiplier Tube Assembly 196 (40) 16 10 0 10 0
4
Fabrication, Assembly and Testing status
Number needed in parenthesis
STATUS KEY
6
Prototyped
130
Clear fiber cables (130)
In Fabrication or Ordered
130 (All)
Received
In assembly
12 All 89 spares All All 45
Assembled
Tested
ACD Assembly (1)
Detector assemblies - TDA - (4 basic types, 89
needed total)
1
8
8
8
8
Tile Shell Assembly TSA (1)
8
Fiber ribbon detectors (8)
8
360
360, All
1
Detector Flexures (36620 spares)
1
Base Electronics Assembly (BEA) From next page
Composite Shell Assembly (1)
5
Fabrication, Assembly and Testing status
1
1
1
1
1
1
1
1
1
1
Base Electronics Assembly (1)
Electronics Chassis (8) (4 double 4 single)
Photomultiplier Tube rails (8 2 spares) All in
Power distribution board (82 spares) All in
Base Frame Assembly (1) in and assembled
Chassis and connector frames (8) All in
Connectors (32) All in
6
TSA IT

• Fiber Ribbon Installation Complete
• Resolved issues with overall length (they were
  too long) and supporting the ribbons (they
  sagged)
• All 25 TOP TDAs INSTALLED and GAPS MEASURED
• Data Assessment Showed Some Vertical Gaps Too
  Large And Some Too Small
• Large Gaps Affect ACD Performance
• Small Gaps Could Lead To Tiles Interference
  During Vibration Environments
• Mechanical, Science And Systems Teams Met And
  Agreed To A Plan For Accepting Predicted Final
  Gaps
• Reduced Minimum Allowable Gap From .035 To .024
• Allowed Largest Gaps at Outer Tile Locations
• FINAL GAP PLAN ESTABLISHED
• FINAL INSTALLATION OF TDAs IS UNDERWAY.

7
IT Flow
10/4 11/30
11/25 12/7
12/2 1/11
Qual Electronics Chassis Environmental Test
1st flight chassis Environmental Acceptance
Test
The remaining Seven Flight Chassis
Environmental Acceptance tests
12/29/04 1/14/05
6/10 11/19
12/14 1/13
12/7 12/13
Assemble last 2 rows of TDAs WSF (124-130,
224-230, 324-330, 424-430) onto TSA
Initial TDA/TSA IT in B7
Install test 1st 2nd flight Chassis onto ACD
Install test remaining six flight Chassis
onto ACD
1/27/05 2/10/05
2/10/05
1/14/05 1/25/05
1/14/05
1/25/05 1/27/05
2/11/05 2/23/05
2/23/05 3/4/05
ACD Subsystem Efficiency Verification
test (include rotate ACD 90 degree)
EMI/EMC Test
Vibration Test
Pre- Environmental Review (PER)
ACD Full Functional Test
Install Thermal Blanket MMS
ACD Integration complete
4/12/05-4/19/05 (was 3/26/05 4/2/05)
3/4/05 3/10/05
3/10/05 4/7/05
4/7/05 4/8/05
4/11/05
4/19/05 5/17/05
Mass Properties
Pre-ship Review (PSR)
Thermal Balance/ Thermal-Vac Test
Acoustic Test
Post-ship Checkout Full Functional Test at
SLAC
ACD ship to SLAC
8
Near Term Milestones
Milestone Description Date New Date Status/Notes
Complete PMT Assembly January, 2004 11/05/04 First group completed mid-October. See back up material for more information on PMT issue
Complete Qualification Unit Electronics Chassis Assembly 5/20/04 10/1/04 COMPLETED
Complete Flight Mechanical Drawings September 12/1/04 One assembly drawings remains. Designer has been focused on problem resolution, revisions, and EOs.
Complete installation of 25 top TDAs 10/15/04 11/10/04 Initial installation and measurement verification complete. Final installation underway.
Complete vibration testing of Spare/Qual Electronics Chassis 10/8/04 COMPLETE
Complete qualification testing of new PMT mounting design 10/15/04 COMPLETED ON 10/26
EMI Testing of Qual/Flight Spare Electronics Chassis 11/29/04 Continuing to work on defining requirements that can be tested effectively and efficiently.
Complete environmental and functional testing of first 10 flight PMTs 11/10/04 PMTs in conformal coating.
Complete 34 PMTs for first dual row Electronic Chassis 11/19/04
Thermal vacuum test Qual/Flight Spare Electronic Chassis using fully functional EGSE 12/15/04
9
Interdependencies

• EGSE/G3 Ongoing development with IT and
  Electronics groups.
• LAT team to arrive at Goddard tomorrow.
• ICD, IDD, etc Rich Bielawski is helping track a
  set of needed changes.
• Another IDD (LAT-DS-00309) update has been sent
  to us for review. It is currently being reviewed
  by the mechanical team.

10
Issues, Concerns, Documentation, Qual Program

• Issues
• PMTs
• EGSE/Electronics Chassis testing
• Concerns
• EGSE/Electronics Chassis testing
• PMTs
• Numerous minor technical issues causing
  schedule and cost concerns.
• Documentation
• Recent upgrades to the CM system have caused
  several issues. This comes at an especially bad
  time since we have an ISO audit on November 19.
• Status of PR/PFRs
• 88 PRs Closed
• 2 PFRs Closed
• 10 PRs Open
• 6 PFRs Open (1 black, 3 yellow, 2 red)

11
ACD Schedule Variances

• 4.1.6 ACD Subsystem (-574K cum, -176 current)
• 4.1.6.1 Management/Science/Systems (-28K cum,
  -10K current) LOE tasks scheduled incorrectly
  in PMCS
• 4.1.6.2 Safety and Mission Assurance (-37K
  cum, -23K current) LOE tasks scheduled
  incorrectly in PMCS
• 4.1.6.3 - TSA Schedule Variances (0K cum, 1K
  current)
• 4.1.6.4 BEA Schedule Variances (-239K cum, -30K
  current)
• All variance is due to the PMTs.
• 4.1.6.7 ACD IT (-243K cum, -114K current)
• Technical issues have delayed progress. PMCS
  schedule has the ACD in TVAC this month. This
  will continue to get worse, unless rebaseline or
  CR action is taken.
• 4.1.6.B GSE (-23K cum, 0K current)
• (23K) Shipping container work being pushed out
  to reduce manpower.

12
ACD Cost Variances

• 4.1.6 ACD (-42K cum, 93K current period)
• 4.1.6.1 ACD Project Management/Sys Eng/Science
  (213K cum, 24K current period)
• Science support lower than planned. This is one
  area that has been identified as needing
  additional support in the form of a Grad student.
• 4.1.6.2 Safety and Mission Assurance (-81K cum,
  -69K current period)
• (-44K) - Materials support on the PMT anomaly
  was assessed to 4.1.6.2 instead of 4.1.6.4
• 4.1.6.3 Tile Shell Assembly (-122K cum, -70K
  current period)
• (-76K) - Design and analysis manpower
• (-46K) - Fabrication charge backs higher than
  planned

13
ACD Cost Variances

• 4.1.6.4 Base Electronics Assembly (-92K cum,
  197K current month)
• CCB action corrected majority of cost variance
  this month
• (-44K) - SLAC ASIC charges.
• 4.1.6.5 MS/TB (35K cum, 5K current month)
• 4.1.6.6 ACD Mech Qual and Cal Unit (-33K cum,
  -2K current month)
• 4.1.6.7 IT (-66K cum, -17K current month)
• Have not received credit for the amount of work
  done.
• 4.1.6.B Ground Support Equipment (104K cum,
  25K current month)
• (38K) Labor. Costs lagging on mechanical
  design and EGSE support.
• (66K) Materials. Not billed for work
  completed

14
Threats to Schedule and Cost

• GASU/G3 EGSE
• PMT Assembly
• Electronics assembly and test
• Minor Technical Issues that require manpower and
  time to resolve.