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GLAST Large Area Telescope: Cost/Schedule Review November 3, 2004

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Gamma-ray Large Area Space Telescope. 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 [email protected]

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Presentation Transcript
slide1

Gamma-ray Large Area Space Telescope

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

[email protected]

[email protected]

significant accomplishments
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)
fabrication assembly and testing status
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

1

Detector Flexures (366+20 spares)

Base Electronics Assembly (BEA) From next page

Composite Shell Assembly (1)

fabrication assembly and testing status1
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 (8+2 spares) – All in

Base Frame Assembly (1)

– in and assembled

Chassis and connector frames (8) – All in

Connectors (32) – All in

tsa i t
TSA I&T
  • 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.
i t flow
I&T 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

I&T in B7

Install & test

1st & 2nd flight

Chassis onto

ACD

Install & test

remaining six

flight

Chassis onto

ACD

1/27/05 – 2/10/05

2/23/05 – 3/4/05

2/11/05 – 2/23/05

2/10/05

1/25/05 – 1/27/05

1/14/05 – 1/25/05

1/14/05

ACD Subsystem

Efficiency

Verification test

(include rotate

ACD 90 degree)

Vibration Test

EMI/EMC Test

Pre-

Environmental

Review (PER)

Install Thermal

Blanket &

MMS

ACD Full

Functional

Test

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)

Acoustic Test

Thermal Balance/

Thermal-Vac

Test

Post-ship

Checkout &

Full Functional

Test at SLAC

ACD ship

to SLAC

interdependencies
Interdependencies
  • EGSE/G3 – Ongoing development with I&T 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.
issues concerns documentation qual program
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 PR’s Closed
        • 2 PFR’s Closed
        • 10 PR’s Open
        • 6 PFR’s Open (1 black, 3 yellow, 2 red)
acd schedule variances
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 I&T (-$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.
acd cost variances
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
acd cost variances1
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 I&T (-$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
threats to schedule and cost
Threats to Schedule and Cost
  • GASU/G3 EGSE
  • PMT Assembly
  • Electronics assembly and test
  • Minor Technical Issues that require manpower and time to resolve.
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