NASA Lessons Learned: External Tank (ET) and Solid Rocket Booster (SRB) Demating Operations

PLLS Database Entry: 0116

Lesson Info

• Lesson Number: 0116
• Lesson Date: 28-jul-1992
• Submitting Organization: KSC
• Submitted by: Lisa L. Musgrave

Subject/Title/Topic(s):

External Tank (ET) and Solid Rocket Booster (SRB) Demating Operations

Description of Driving Event:

While demating the ET from the SRB’s during OMI S0033, TPS FOAM damage occurred on the +Y forward crossover area. Scraping noises were heard and interference was observed. The operation was stopped while a deviation to the OMI was written to allow north movement of the crane in an attempt to relieve the interference. The operation proceeded but FOAM damage was unavoidable due to insufficient clearance. This insufficient clearance was due to incorrect installation of support brackets caused by inaccurate OMI procedures.

Lesson(s) Learned:

Improper installation of support brackets creates insufficient clearance between ET and SRB’s during demating operations.

Recommendation(s):

Update OMI to reflect correct support bracket installation, including caution of clearance limitations if improperly installed.

Evidence of Recurrence Control Effectiveness:

• N/A

Applicable NASA Enterprise(s):

• Human Exploration & Development of Space

Applicable Crosscutting Process(es):

• Provide Aerospace Products & Capabilities: Implementation

Additional Key Phrase(s):

• Flight Equipment
• Ground Operations

Approval Info:

• Approval Date: 02-jun-1994
• Approval Name: James G. Kline
• Approval Organization: KSC/HEI
• Approval Phone Number: 407-867-7614