Report of the PRESIDENTIAL COMMISSION
on the Space Shuttle Challenger Accident
Volume 5 Index
Hearings of the Presidential
Commission on the Space Shuttle Challenger Accident: February 26,
1986 to May 2, 1986.
MARCH 7, 1986 SESSION (part 2 of
2)
[1190] [Ref. 3/7-64 1 of
2] Scenario 1.
SCENARIO NO. 1
FAILURE MECHANISM:
- DEFECT IN THE AFT SEGMENT MOLDED INHIBITOR
(HOLE)
- ALLOWS IGNITION OF THE PROPELLANT (HOT GAS
THRU THE HOLE)
- SUB-SURFACE PROPELLANT BURNING DEGRADES
CASE INSULATION AT THE MEMBRANE WALL RESULTING IN A CASE BURN THRU
AT (OR NEAR) 60 SECONDS
ASSESSMENT METHOD:
- REVIEW BUILD AND PROCESS RECORDS OF 51-L
RH AFT SEGMENT INHIBITOR
- REVIEW EXPERIENCE BASE WITH THESE
INHIBITORS
- ASSESS FAILURE MECHANISMS/CHARACTERISTICS
WITH OBSERVED 51-L DATA
- DETERMINE BY ANALYSIS THE HEAT EFFECT ON
INSULATION AND CASE MEMBRANE
FINDINGS TO DATE:
- THE MOLDED INHIBITOR IS LAYED-UP AS 8
PLIES OF RUBBER AND VULCANIZED ALONG WITH CASE INSULATION
- LOW PROBABILITY OF A FLAW THRU 8 PLIES
OF RUBBER
- NO PREVIOUS EXPERIENCE WITH PROBLEMS AT
THIS INHIBITOR
- ANALYSIS INDICATES THAT 2.5 TIMES NOMINAL
HEAT TRANSFER WOULD BE REQUIRED TO DEGRADE THE INSULATION AND HEAT
THE CASE TO BORN THRU IN APPROXIMATELY 60 SECONDS
- THIS FAILURE MECHANISM WOULD NOT EXPLAIN
THE "SMOKE" AT LIFT-OFF
- THIS FAILURE MECHANISM IS NOT
PROBABLE
Back