Sea Launch vehicle explodes on launch pad, Sea Launch Zenit 3SL vehicle, carrying the NSS 8 satellite Options

[ugordan]

Yes, there's definitely something happening to the left of the platform. I'd think if it were a regular shockwave, the water surface would not be disturbed upwards but would turn white, remaining flat. It would also quickly diffuse into other directions. This looks like something fast impacting into the water or maybe even the RD-171 exhaust disturbing the area. Not very nice, whatever it is.

[spdf]

http://www.interfax.com/3/236235/news.aspx

Experts divided over consequences of Zenit rocket failure
MOSCOW. Jan 31 (Interfax-AVN) - Analysis of video footage of the
abortive launch of a Russian-Ukrainian Zenit launch vehicle early on
Wednesday morning has not helped determine the total scope of damage
caused to the floating platform from which rocket blasted off,
spacecraft expert Igor Lisov told Interfax-AVN.
"Video footage of the launch makes us presume the worst
consequences for the floating platform. Judging from the film, instead
of taking off the rocket fell through a hole on the launch pad.
Afterwards, several hundred tonnes of rocket fuel components, including
oxygen and kerosene, most likely exploded under the platform, he said.
However, no fire broke out on the launch pad after the accident. It
means that no fuel was spilt on the platform itself, he said.
Other experts said that the accident had not caused major damage to
the platform and the launch complex could resume operations soon.
"There are no complaints about the performance of the systems of
the launch pad or units responsible for the launch," a source in the
Transport Machine Building Design Bureau, which helped build the Sea
Launch platform, told Interfax-AVN.
"The accident will most likely entail minimal consequences for the
launch complex because no fire broke out after the launch," he said.
The cause of the accident and its consequences will be announced by
a commission of U.S.-based Sea Launch Corporation, which was founded by
the United States, Russia, Ukraine and Norway.

[nprev]

Maritime oil platforms are pretty structurally robust...they have to be just to survive the sea, to say nothing of the risks of explosions/fires inherent to that business. I suspect that Odyssey's superstructure is okay, but the launch complex will need a lot of work to restore.

[ugordan]

I hear kerosene is a bit nasty to clean, if there is any of it unburned left after the mishap.

[djellison]

I would have thought there would be left-over fuel and oxidiser in the storage on the platform as well. A hazardous job to clear up.

Doug

[Guest_Zvezdichko_*]

My personal opinion about the failure is a pump valve failure.

EDIT: A friend of mine said that when we see a dark smoke during ignition, it surely means bad oxidizing of the fuel. So the engines can't reach maximum trust and the rocket will fall apart ( this is what we saw during launch ).

[stevesliva]

Maritime oil platforms are pretty structurally robust...they have to be just to survive the sea, to say nothing of the risks of explosions/fires inherent to that business. I suspect that Odyssey's superstructure is okay, but the launch complex will need a lot of work to restore.

This photo:
http://www.boeing.com/special/sea-launch/i...r-sealaunch.jpg

Makes me think that the platform probably survived in with most all structure intact as well, since the rocket collapsed in the better direction... but how badly scoured that superstructure and the underside of the platform are will be interesting to see.

[ugordan]

But that's where the flight computer or whatever comes in. There is an engine ready (close to T=0) point by which the RD-171 should have attained nominal thrust, so the clamps holding down the rocket can be released. If the engine fails to achieve full thrust by then, it should automatically shut down and safe itself. What you're describing seems a more likely scenario if the vehicle managed to lift off and then lose thrust -- obviously this was not the case.

[Guest_Zvezdichko_*]

I'm also curious how the explosion happened. Kerosene can't be ignited easily. I'm sorry If my question is dumb, can somebody answer me?

quoting spdf:"Afterwards, several hundred tonnes of rocket fuel components, including
oxygen and kerosene, most likely exploded "

[ugordan]

I think explosion is the wrong word here. More likely rapid mixing of RP-1 and LOX, which obviously burns very well (everything does with LOX!). It probably happened once the tanks ruptured on the way down. The effect would be akin to the Challenger accident. The only really energetic part of the equation is the RD-171 engine, churning gas out at several km/sec it can be regarded as a directed-effect bomb, but it was most likely pointed downward and then abruptly shut down. Personally, I don't believe the engine exploded.

The term "explosion" might come from watching too many Hollywood movies where they always equate to big fireballs.

[Guest_Zvezdichko_*]

It's spaceflightnow.com refer to the accident:

http://www.spaceflightnow.com/sealaunch/nss8/

"fiery explosion"

[tty]

I think explosion is the wrong word here. More likely rapid mixing of RP-1 and LOX, which obviously burns very well (everything does with LOX!).
----
The term "explosion" might come from watching too many Hollywood movies where they always equate to big fireballs.

Well it is an explosion. What the ordnance people call a FAE (fuel-air explosive). Such explosions cause a massive overpressure within and close to the fireball and are therefore very effective for killing people but it is a rather slow low-grade explosion with little fragmentation effect. I would expect extensive damage to buildings on deck etc, but the basic structure of the platform is probably more or less intact. The fire damage might not be too bad either. With all that LOX around I expect all the kerosene went up in that one big whoosh.

[BPCooper]

I'm not sure what is being implied here, but LOX and Kerosene are not hypergolic. They do not ignite on contact. Mixing them together cannot do anything unless a source is there to start the explosion in the first place.

[tty]

Indeed not and a Fuel-Air mixture will only explode when the mixture is just right. FAE bombs therefore usually have several pyrotechnic fuses which go off in succession so at least one will hit the right interval.
However in this case there would be plenty of ignition sources. A red-hot and possibly still firing rocket engine for one thing. Bits of metal hitting each other at high speed. Electric circuits shorting out.
From the result it seems clear that at least one timed it juat right.

[jamescanvin]

Interesting information and thread over at nasaspaceflight.com

They also have an image from a webcam on Odyssey *after* the event (doesn't show much, but shows it's still there!)

They also have a better quality video (you need to be registered)

James