[AR] Re: Damascus AR Incident
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Thu, 19 Jan 2017 15:18:29 -0500 (EST)
On Mon, 16 Jan 2017, David Spain wrote:
1) Would it have been possible to have sent the PTS team to the lower
level in an attempt to patch shut the leak long enough to have pumped
the fuel out of the missile's first stage? Or would the pressure of the
escaping fuel been too high to patch the rupture by hand?
As others have already mentioned, their protective gear wasn't rated for
anything like that hydrazine environment. Worse, hydrazine is not just
toxic and flammable -- it's also corrosive and prone to catalytic
decomposition. There definitely was a fair bit of decomposition going on
in the silo: it caused enough of a temperature and pressure rise in the
other tanks to justify activating a water-spray system to cool things
down. (Unfortunately, the water supply was limited...) Altogether a
*very* hostile environment, even neglecting the possibility of missile
collapse or large-scale hydrazine ignition.
Also, patching the leak wouldn't have been easy. The hole was only about
half an inch across, but it was spewing a gallon of fuel every few
seconds, so the flow rate was sizable. I'd be very surprised if anybody
had thought enough about such a scenario to have even sorted out the
materials and techniques needed for a patch -- it wouldn't be simple.
2) Could the missile's fuel been pumped out even with the leak on-going
had the folks in the LCC been warned at the get go of the leak?
Since Titan II was meant to be fueled at all times except for maintenance,
the silo didn't have umbilicals connected to the rocket's tanks, nor did
it have tanks that could hold a full missile-load of propellants. To
unload the tanks, you needed guys in the silo connecting hoses, and tank
trucks up on the surface to receive the propellants. It couldn't be done
by just pushing buttons in the control room.
(If we were building such a facility nowadays, stuff like that might get
included to reduce propellant-handling hazards. But remember that the
Titan silos were designed in great haste at a time when such issues didn't
get as much attention.)
...According to the documentary the last order carried out by Livingston
was to activate exhaust fans. I can't help but wonder if the cause of
the explosion was because he was successful. Sparks from a fan's
commutator would have been sufficient I would think...
He only activated one exhaust fan, near the exit the team had left by.
(Whether he actually had orders to do this is unclear.) It does seem
likely that the combination of doors left open during the re-entry, and
airflow from that fan, helped bring a fuel/air mixture to whatever the
ignition source was. There was a lot of electrical gear still running in
the silo -- there were things that might spark during shutdown, so trying
to shut it all down wasn't necessarily a good idea, and nobody had ever
studied how best to handle such a situation. And hydrazine doesn't even
really need a spark to ignite it -- mere contact with a strongly catalytic
surface can do that.
(The fuel/air explosion, by itself, would have done damage but not total
destruction. However, among the damage it did was to rupture the
first-stage oxidizer tank, dumping tons of liquid oxidizer into the liquid
fuel, and *that* produced the real explosion.)
Seems like extremely bad judgement. The documentary led me to believe
that part of the problem was because SAC command was dominated by former
pilots not missile people.
Once the leak started, the silo was a volcano waiting to erupt. Closing
things up and getting the hell out was basically the right thing to do.
Even without complications like non-missile people in charge, any attempt
to defuse the situation would have been improvised, with failure not at
all unlikely.
(Details from David Stumpf's book "Titan II".)
Henry
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