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ENG File: P18000.eng
Discussion
Timeline
Here's a reconstruction of events based on video and physical evidence collected after the test:
•T-0: Motor ignites
•T+.5: Erosive burning spike settles down, but motor is now burning at a much higher pressure than expected
•T+.5 - 2.9: Thrust curve follows typical BATES profile
•T+2.9: Aft grain burns out, casting tube is ejected
•T+2.9: Interaction with casting tube event along with elevated thermal and mechanical stresses causes nozzle failure
•T+2.9-6.2: Motor continues to burn at lower pressure/thrust due to fewer grains, leakage at nozzle break
•T+6.2: Second grain from aft end burns out, unprotected liner at aft end is ejected due to high velocity gas passing over it
•T+7.8: Motor shuts down
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