[AR] Re: arocket Digest V4 #217

  • From: qbert@xxxxxxxxxxxxxxx
  • To: arocket@xxxxxxxxxxxxx
  • Date: Sun, 11 Sep 2016 15:32:31 -0600

The problem with the theory is that there should have been relevant telemetry data to that
happening and SX seems to be adamant that all systems showed nominal leading up to
the explosion.

I'm assuming that the would the Falcon9 and or the strong back have sensors for movement
placed around them and if even they did not show anomalies then what ever let go would have
likely not been connected to them.

Robert

At 01:52 PM 9/11/2016, you wrote:

On Sat, Sep 10, 2016 at 10:08 PM, George William Herbert
<george.herbert@xxxxxxxxx> wrote:

> Ok, I have a theory.
>
> They were loading RP-1, Supercooled LOX, and GHe.
>
> LOX tank was chilled but the Kero tank was not. Aluminum gets stronger at cryo temps.
>
> Partway through loading a GHe tank lets go.

That would certainly account for the disaster.

Someone has mentioned that the GHe tanks are composite.  I don't know
if that is actually the case, but it seems possible that a composite
He tank might generate enough heat in a rupture to ignite the organic
components in the oxygen.  Rupturing the GHe tank would ruin their day
in any case, but if the composite tank did start to burn in the LOX
tank, it might explain some of the subsequent events.

It might be interesting to pump one of those GHe tanks till it
ruptured in a vat of LOX.

But when you think about it, the GHe is about the only large source of
energy available to start some kind of destruction cascade.

I wonder what the loading sequence is?  The thermal stress would be
awful on a sphere where half was a room temperature and the other half
was at LOX temp.

Keith

> The flight kaboom some time back had a full LOX tank so little space for the GHe to go, blew the LOX tank. This time, half-full LOX tank is enough expansion space (just) to avoid blowing the tank immediately. But the warmer tank bottom or feed line down weren't as well chilled and are therefore weaker, and rupture. *ping*. And pressure drops in LOX tank.
>
> So the LOX and GHE drop into the RP-1 tank. They don't have time to mix much to detonable mixture.


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