GLAST Proposal Review

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GLAST Large Area Telescope Performance Safety
Assurance Joseph Cullinan SLAC Perform
ance Safety Assurance Manager cullinan_at_slac.sta
nford.edu [phone]
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4.1.A PSA Status August 2005

• DAQ/Electronics
• TEM/TPS
• Have now completed handoff of 14 TEM/TPS
  assemblies to IT
• MRB held to review replacement of TPS units
  currently installed in Bays 0 and 4.
• TPS units in the first two TEM/TPS assemblies
  installed in the Grid did not have CCA rework
  performed to eliminate voltage oscillation
  problem (NCR 397).
• MRB concluded to remove TPS units only from Bays
  0 and 4. Plan is to keep existing TEMs in Bays 0
  and 4. Pros and cons of five different options
  hardware removal (including use-as-is) were
  considered
• This option will allow for subsequent removal of
  TEM or TEM/CAL if replacement TPS fails to meet
  electrical or mechanical fit requirements
• Replacement TPS units with HV calibration
  constants similar to those of the TPS units to be
  removed have been selected from fully tested
  TEM/TPS assemblies
• TPS removal and replacement procedure being
  finalized and documented by IT
• Recalibration of new TEM/TPS telemetry and TKR
  and CAL detectors will be required following TPS
  replacement
• PDU
• T/V test started on 1st box, 2nd box delivered to
  SLAC for initial testing
• GASU
• GASU Power Supply boards and CCAs for 1st GASU
  completed rework at SLAC following initial
  testing
• Updating drawings and BOM to reflect changes
• Boards and CCAs for 2nd GASU still in assembly at
  Aeroflex

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4.1.A PSA Status August 2005

• DAQ/Electronics
• LCB/SIB/CPS boards
• Last month LAT QA observed workmanship issues
  with first SIB, LCB and CPS boards delivered and
  reviewed these issues with Aeroflex and SLAC
  source inspector
• Discrepancies were result of carelessness rather
  than unclear drawings or lack of technical
  expertise at Aeroflex
• Corrective action Aeroflex project management
  reviewed procedures with technicians to increase
  awareness of drawing requirements, hardware
  handling and workmanship requirements
• SLAC source inspector now documents all
  in-process and final inspections and forwards
  reports to LAT QA and DAQ for review.
• Discrepancies now are more clearly documented for
  evaluation. Any discrepancies that require
  rework is more quickly addressed by LAT/GSFC QA
  and DAQ, and if necessary additional corrective
  action can be implemented
• Cables
• Performing final inspection of remaining flight
  cables (including spares) at vendor facility
  (Cicon) this week.

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4.1.A PSA Status August 2005

• Integration and Test
• Supported completion of 6-tower and 8-tower
  testing
• Supported receipt and acceptance of ACD
• ACD final acceptance data package forthcoming
• Elevated 4 open ACD nonconformances to LAT level
  NCRs

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4.1.A PSA Status August 2005

• TKR
• Supported MRB presented by INFN on Tower 8 tray
  anomaly observed during T/V testing (INFN NCR
  551)
• Ladders in Tray M007 began to show excessive
  noise or dead channels when temperatures rose
  above 25 deg. C
• Similar failure was observed on Tray M010 on
  Tower 7. This tray was eventually removed and
  replaced, and Tower 7 retested
• Both trays were fabricated for Tower 0 and
  subsequently requalified and placed into Towers 7
  and 8
• MRB concurred to remove and replace tray M007
  from Tower 8, and followed by repeat of
  environmental testing
• Cause is unknown after considerable electrical
  testing on tray M010
• Testing on tray M010 to troubleshoot this problem
  appears to be exhausted currently INFN does not
  have additional testing planned for tray M007
• INFNs analysis indicates failure is typical of
  missing bias on Si detector and not wire bond
  intermittent failure
• Additional Tower 0 requalified trays L023 and
  B002 are installed in flight Towers 4 and 5 no
  anomalies have been observed with these trays
• INFN reported that insignificant performance
  degradation would result in Towers 4 and 5
  ifthese trays began to show similar problems with
  ladders
• Last flight tray (L015) from Tower 0 is now on
  hold at INFN

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4.1.A PSA Status August 2005

• TKR
• Pioneer Flex Cables
• Supported in-process and final source inspection
  of cable assemblies at Pioneer
• Pioneer has delivered qty 29 finished cable
  assemblies qty 22 have been hand carried to
  INFN
• Minor workmanship issues have been observed
  during source inspections
• Omnetics connectors with damaged and bent pins
  from handling and worn test connector savers were
  removed and replaced without problems
• Missing conformal coating observed on some
  resistors
• On-site inspection and Pioneers responsiveness
  has allowed quick resolution of these workmanship
  issues. Causes were identified and corrective
  actions were put in place
• GSFC has not rejected any Pioneer test coupons to
  date
• Parlex Flex Cables Qualification Test Plan
• Reviewed relevant documentation on Qual plan with
  GSFC and TKR
• Will use flight and non-flight cables and coupons
  to complete qual testing
• Non-flight cables will be hand selected to ensure
  qual testing will not be impacted by
  nonconforming condition of cable. Non-flight
  cables with slight annular ring failures would be
  best candidates.
• Minor changes to the Parlex qualification test
  plan would include using cables instead of
  coupons for some tests.

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4.1.A PSA Status August 2005

• Mechanical Systems
• X-LAT Plate
• Delivered to SLAC in July still awaiting
  acceptance data package from Lockheed Martin.
• Lifting sling returned to LM for scheduled rework
  
• Radiators
• T/V testing initiated

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LAT NCR Metrics 8/26/05
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4.1.A PSA Status August 2005

• Software QA
• Supporting reviews of FSW test procedures
• Supported the IT release of LATTE R4.10.0
  including VV and documention review for LAT
  Docs.
• Met with GSFC Software QA (Randy Worden) to
  discuss LAT QA processes for FSW oversight
• QA requirements for FSW were reviewed
• Randy provided recommendations for the LAT QA
  process overseeing FSW documentation and approval
• SLAC reviewing these recommendations for
  implementation

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Issues and Concerns

• Pioneer Flex Cables
• Must ensure that coupon testing at GSFC keeps up
  with cable production and delivery to INFN, so we
  dont end up waiting for a test report before a
  cable can be installed on a tower.
• GSFC has provided exceptional support in
  prioritizing coupon testing in response to a
  highly accelerated delivery schedule for Pioneer
  cables, so the process is working so far.
• Tower testing
• TKR, INFN and LAT QA need to closely follow the
  process for removing non-flight cables used to
  support tower environmental testing, and the
  subsequent replacement of flight cables
• Towers 7, 8 tray anomalies observed in T/V
• Cause is still unknown, and currently there are
  no known additional tests or analyses on removed
  trays to determine cause

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4.1.A PSA Planned Accomplishments September
2005

• Support PDU, GASU testing
• Support electronics assembly at Aeroflex
• Support flex cable production at Pioneer
• Support flex cable qual testing at Parlex

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Cost Report
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Cost Variance Explanation

• Why overrun/underrun?
• Did not reduce headcount to follow planned FTE
  dropoff due to extended production runs through
  end of July at Teledyne and General Technology
  with full time source quality engineers. Also
  required same headcount as last month to support
  subsystem production and testing.
• What will be done to correct?
• Source quality engineers at Teledyne and General
  Technology have rolled off as of end of July (2
  FTE)
• Look to consolidate QA headcount at SLAC in
  September as subsystem production (cables, flex
  cables, incoming inspection) ramps down

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FTE Report (DOE/NASA-funded only)
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FTE Variance Explanation

• Why overrun/underrun?
• Source QA support was needed longer than expected
  at Teledyne and General Technology to support
  production. Also needed to continue current
  level of QE support at SLAC
• What is the impact?
• 2 FTE required to support extended production
  cycles at these two vendors
• What will be done to correct?
• Roll off of 2 source QEs at end of July is
  reduction of 2 FTE for August. Will also see
  additional reduction of approximately 1 FTE in
  August due to vacations. Also look to consolidate
  FTE at SLAC in September as vendor production
  runs near completion.