Does anyone have better wind data for the Cape that morning? I only have
the hourly ticks from wunderground. In Big Blue's case, winds did turn out
to be a factor: https://failures.wikispaces.com/Big+Blue+Crane+Collapse
Slightly better start times for messing with your mind. My brain keeps
trying to correlate the sound of the crane's failing brakes with something
squealing on the strongback, when they aren't the same design. Shut up,
brain. ;-)
https://youtu.be/8pE_93hw-oM?t=64
https://youtu.be/Gjib_I_ab84?t=40
Steve
On Sat, Sep 10, 2016 at 10:33 AM, Steve Traugott <stevegt@xxxxxxx> wrote:
https://youtu.be/8pE_93hw-oM?t=60
Close your eyes, forget it's a rocket, and play from 1:00. Sounds like a
crane coming apart off in the distance. Strut or steel cable X snapping,
striking structure, then X or other stuff breaking, swinging, and
bouncing. Not as likely to be as much telemetry on those strongback
components.
*If* that's the scenario, then:
- 1:05 Squeak may be X letting go or may be unrelated. Could be a
bird; I grew up in Florida but don't recognize it. A wetlands biologist
might.
- 1:06 Bang is either initial snap or X hitting something.
- 1:07-1:09 X is still swinging against structure, damping as it
settles, and/or other stuff is letting go.
Just to really mess with your mind, compare and contrast with the the Big
Blue collapse: https://youtu.be/Gjib_I_ab84?t=20
Steve
On Sat, Sep 10, 2016 at 9:25 AM, George William Herbert <
george.herbert@xxxxxxxxx> wrote:
I was thinking just a few seconds. Mentally playing that sequence with
his synced audio worked for me.
Thom's sequence:
1:00 : faint clicking sound, continues thru explosion
(No idea)
1:05 : musical sound
(GHe lets go the muted tuh-wing as the tank pressurized immediately)
(Lower dome stressed to beyond yield point and stretching but has not
failed)
1:06 : clunk sound
(Lower LOX dome rupture big Ping)
1:07 : click sound
(Mixing quiet)
1:09 : symbol clap sound
(Mixing quiet)
1:11 : explosion
Sent from my iPhone
On Sep 10, 2016, at 9:07 AM, Craig Fink <webegood@xxxxxxxxx> wrote:
Good theory, but it takes too long and leaves a long trail of data. Seems
SpaceX is still grasping at all the straws because they have no (or very
little) anomalous data. SpaceX recently asked the general public for videos
to help them identify (triangulate) a noise 4 seconds before the explosion.
To me it sounded like the squeak, bang, rattle of a dump truck dumping
dirt. Or, they have plenty of data and are just being quite.
https://youtu.be/_BgJEXQkjNQ?t=1m16s
Also, SpaceX has been working hard to get NASA comfortable with loading
fuel with Astronauts onboard.
http://www.floridatoday.com/story/tech/science/space/2016/07
/29/nasa-orders-second-spacex-crew-mission-iss/87672158/
`McAlister also said that NASA continues to assess SpaceX's new method
for fueling upgraded Falcon 9 rockets just a half-hour before launch. That
timeline would put astronauts on top of the rocket while fuel is loaded
.... “We are getting more comfortable with it, but we are not yet ready
to say we’re good,” McAlister said of SpaceX's procedure. “We’re still
working through that.”`
So, I can imagine NASA has been expressing concerns and SpaceX has been
addressing them, maybe even making changes in the fuel loading procedures
to get NASA "comfortable"
If the GHe COPV tank let go it would send a cloud of carbon/resin dust
into the lox, the dust would be the fuel. At 6000psi the COPV tank is going
to have thick wall and lots of thermal mass.
https://www.youtube.com/watch?v=5UdVnO10J3U
On Sat, Sep 10, 2016 at 3:48 AM, 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. 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. Mixture of ongoing GHE venting and LOX boiling
from the RP-1 raises combines tanks pressure again and the warmest barrel
sections, the RP-1 tank outer walls, rupture. Possibly, a small volume
reached explosive mixed conditions and turbulence or static or impact
detonates a small explosion in a bigger mass of still mixing materials.
Some of what's ejected out is LOX - white fluffy non burnie cloud that
evaporates in the heat. Some is RP-1 and just burns. Some is mixing
RP-1/LOX and burns REALLY WELL.
When the RP-1 hoop section lets go you have say 100 PSI times pi/4 times
144 squared or say 1.6 million pounds downwards force on the lower RP-1
tank dome and the Vacuum Merlin, held up by the interstage. The Interstage
structure fails due to gross overload, Merlin and tank dome are forced down
into Stage 1 LOX tank and destroying the first stage.
Sent from my iPhone
--
Craig Fink
WeBeGood@xxxxxxxxx <WeBeGood@xxxxxxxxx>
