
Update: In-Flight Abort Static Fire Anomaly Investigation - runesoerensen
https://www.spacex.com/news/2019/07/15/update-flight-abort-static-fire-anomaly-investigation
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knd775
It's really interesting that they managed to encounter an interaction between
NTO and titanium that has never been known to occur before.

It seems that no one really knew that titanium could ignite.

edit: Maybe not. Looks like this was a known failure mode for titanium
[https://apps.dtic.mil/dtic/tr/fulltext/u2/613553.pdf](https://apps.dtic.mil/dtic/tr/fulltext/u2/613553.pdf)

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magicalhippo
> Looks like this was a known failure mode for titanium
> [https://apps.dtic.mil/dtic/tr/fulltext/u2/613553.pdf](https://apps.dtic.mil/dtic/tr/fulltext/u2/613553.pdf)

The gist of it, as I could see:

\-----

Several instances have been reported of violent reactions of titanium and
liquid oxygen which appeared to be related to impact. The impact sensitivity
of titanium in LOX has been investigated rather extensively. It appears that
the ignition of titanium under impact occurs in the following sequence:

(1) The impact exposes fresh metal and results in some gaseous oxygen being
formed at the point of impact.

(2) The gaseous oxygen reacts with the fresh metal in an exothermic reaction.

(3) The heat generated raises the metal temperature sufficiently to result in
localized dissoluton of any TiO2 film that might form.

(4) Thus a protective oxide film does not build up and the reaction proceeds
rapidly between the base metal and oxygen.

Ignition of massive titanium is observed in gaseous oxygen at liquid-oxygen
temperatures at pressures of about 100 psi and above. This critical pressure
limit is lowered only slightly as the temperature of the oxygen is raised to
ambient temperature.

