Par Chart Template

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STS-107 FRR JSC - SHUTTLE SAFETY MISSION
ASSURANCE TECHNICAL DISCUSSION ISSUES/CONCERNS
JANUARY 07, 2003
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JSC SIGNIFICANT EVALUATION ACTIVITIES STS-107
(OV-102) FRR TAGUP
DISCUSSION ITEMS OV-103 BSTRA CRACK BY HUGO
MARTINEZ ONE PAGE SUMMARIES
AS OF 01/06/03 DAVE BROWNE SEA-J-0101
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OV-103 BSTRA CRACK STS-107 FRR TAGUP
AS OF 01/06/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0100
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• SUMMARY
• At the STS-107 PAR SRQAs recommendation was
  that the OV-103 Ball Strut Tie Rod Assembly
  (BSTRA) ball crack is a constraint to STS-107
  (OV-102).
• Testing is underway in an attempt to clear
  cracked BSTRA balls for flight with margin.
• Demonstrate that cracks are caused by thermal
  cycling under load.
• Demonstrate that cracks arrest after a given
  number of cycles.
• Analysis will attempt to prove that any FOD
  liberated from the BSTRA balls will not cause
  particle ignition or otherwise adversely impact
  Orbiter MPS or SSME operation.
• A risk assessment is underway to determine the
  probability of crack initiation as well as the
  probability of generating a piece of debris large
  enough to cause a catastrophic failure.
• Design and fabrication of inspection tools to
  remotely rotate and inspect the BSTRA balls on
  the vehicles is in work.
• Constraint to STS-107.

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0101
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• ISSUE
• During Orbiter Maintenance Down Period (OMDP)
  inspections of the OV-103 17-inch feedline BSTRAs
  a crack was observed on a Liquid Oxygen (LO2)
  BSTRA ball.
• IMPACTS/EFFECTS
• Worst case effect of a malfunctioning BSTRA joint
  is feedline rupture/leakage due to increased
  stresses on the feedline bellows and other
  components resulting from lack of feedline
  angulation (Criticality 1/1 CIL Catastrophic /
  Remote / Accepted Risk Hazard).
• Worst case effect of a piece of debris liberated
  from a cracked BSTRA ball is catastrophic SSME
  failure (Criticality 1/1 CIL Catastrophic /
  Remote / Accepted Risk Hazard).

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0102
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• BACKGROUND
• BSTRA balls were only inspected for surface
  defects during manufacturing.
• All BSTRA balls in flight spares will be
  inspected for subsurface defects.
• Subsurface defects found on 3 of 15 balls
  inspected at KSC.
• A test program was initiated at Huntington Beach
  (HB) to
• Demonstrate crack initiation due to thermal
  stresses.
• Demonstrate crack arrest (Tests 2a 2b).
• In parallel to HB testing, MSFC investigated
  means of cracking balls for use in Tests 2a 2b.

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0103
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• BACKGROUND (contd)
• Testing to date has shown
• A ball with subsurface defects can be cracked in
  a flight-like thermal gradient.
• A 1.75 ball cracked during ambient-to-LN2
  testing.
• FOD can be generated in an off-nominal thermal
  gradient.
• Testing is continuing to
• Determine if cracks arrest in a flight-like
  (combined thermal and mechanical) environment.
• Cracks on two test balls have not grown
  throughout 18 flights worth of testing (30
  flights planned).
• Determine if FOD can be generated in a
  flight-like environment.
• Testing to date has not resulted in FOD
  generation.
• Analysis will attempt to prove that any FOD
  liberated will not cause particle ignition or
  otherwise adversely impact Orbiter MPS or SSME
  operation.

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0104
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• BACKGROUND (contd)
• 100 borescope inspection of any BSTRA ball is
  now possible.
• Prototype tools to remotely rotate the ball and
  view its entire surface are being developed.
• Subsurface inspections via eddy current may also
  be possible.
• Orbiter must be demated from ET without SSMEs
  installed.
• Analysis is in work to
• Determine the probability of crack initiation in
  flight-like environment.
• Determine the probability of generating a piece
  of debris large enough to cause particle ignition
  or other catastrophic SSME failure.

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0105
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP

• ROOT CAUSE
• Root cause is under investigation. Most probable
  cause is attributed to the brittle properties of
  the BSTRA ball material combined with thermal
  cycling, possibly initiated by an undetected flaw
  in the ball.
• RECOMMENDATION
• Constraint to STS-107 pending successful
  completion of
• HB testing on the 1.75 ball that cracked during
  ambient-to-LN2 testing.
• Crack arrests prior to the ball cracking in half.
• Cracking does not result in unacceptable step at
  crack location.
• No FOD generation beyond acceptable level (FOD
  criteria TBD).
• 100 surface inspection of cracked OV-103 ball.
• No evidence of particle liberation.
• No surprises (i.e. crack is consistent with most
  probable cause).

MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0106
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BACKUP
MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0107
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP
MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0108
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP
MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0109
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OV-103 BSTRA CRACK STS-107 (OV-102) FRR TAGUP
MEETING DATE 01/07/03 HUGO MARTINEZ SPECIAL
TOPIC-J-0110