Re: The reaction.... was simply not expected
well the titanium part was in a HELIUM system, and the nitrogen-based oxidizer ended up in there. I expect that the helium system works very well for HELIUM, not explosive liquids like NTO.
apparently a small amount of NO is often mixed with the NTO to limit stress corrosion of titanium (it's in the article).
So the real problem is HOW the *FEEL* did the NTO get into the helium system in the FIRST place?
(worth pointing out, titanium is chemically and physically a LOT like aluminum but a lot of people probably do not know this)
Anyway, that much is probably obvious. Captain Obvious definitely thinks so.