An interesting summary <https://youtu.be/mBcoTqhAM_g> from a
commentator who, previously, I only knew from his Kerbal Space Program
videos. But he seems to have a pretty good handle on the reported
probable cause, and does an (IMO) pretty decent explanation for the
laypeople in the audience.
https://youtu.be/mBcoTqhAM_g
On 1/2/2017 3:44 PM, (Redacted sender monsieurboo for DMARC) wrote:
Reference: http://www.spacex.com/news/2016/09/01/anomaly-updates
"each COPV consists of an aluminum inner liner with a carbon overwrap. The recovered COPVs showed buckles in their liners ... investigators concluded that super chilled LOX can pool in these buckles under the overwrap."
Based on their description, it's the inner aluminum liner that's buckling, and the phrase "under the overwrap" strongly suggests LOX (or SOX) is accumulating between the liner and overwrap. While I understand and don't disagree with their analysis of what happened subsequently, what's unclear to me is how any LOX could get behind that liner. I can't picture this happening unless the integrity of the inner liner was breached, although this isn't stated explicitly.
The update specifies changes to their helium loading procedure that will minimize the risk of SOX formation -- which is well and good -- and that they will alter their tank fabrication method to try to prevent buckling in future tanks. But it seems to say that they're willing to use already-fabricated tanks that their own investigation indicates may have flaws up to and including breaches in the inner liner that would still potentially allow LOX to come into contact with a source of fuel. That seems like a bit of a crapshoot.
I also wonder, if these tanks were examined via ultrasound or x-ray post fabrication as would certainly seem prudent, how it is that the buckling wasn't discovered.
Cheers,
Mark L.
