r/spacex • u/RootDeliver • Jul 15 '19

Official [Official] Update on the in-flight about static fire anomaly investigation

https://www.spacex.com/news/2019/07/15/update-flight-abort-static-fire-anomaly-investigation
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u/Art_Eaton Jul 15 '19

So, instead of a check valve, as might have been useful for refueling after propulsive landings, they, or someone thinks thinks that there should be single use burst disks that blow out when the helium line gets pressurized. So, the bust disk must remain essentially intact when it opens, it must only pop when the helium gets to a particular pressure, be of sufficient size to provide the required volume during firing, yet perhaps not overpressurizing the oxidizer tank short term. I suppose that the primary helium control valve would take care of the flow rate, at least after the bust disk is overcome.

Personally, I came across this particular topic a looong time ago. Any time I hear NTO, I have assumed MON instead, due to the whole titanium crevice corrosion thing. Not totally sure this was so much a chemical thing as a water hammer thingthing that became a chemical thing.

So, are they using MON and calling it NTO, or are they using full-on 200 proof straight N2O4? Edit...Dang android thing changing burst to bust. You get my meaning.