Orbital Sciences Rocket Explosion

[Vortex11]

I guess that's a new launch pad needed too.

I wonder if it will be traced to the 40+ year old engines?

[dr.s.lartius]

The videos on YouTube support that; an asymmetrical fault low on the first stage.

It is amusing to note that many written reports say that it failed seven seconds after lift-off, whereas the first sign of trouble that I have seen in the videos is at about fourteen seconds.

[Martin Brown]

It was an impressive failure mode. The engine was at full nominal output power but the vertical thrust clearly failed completely.

You actually see a donut sheet of yellow flame down the outside of the main engine exhaust so looks to me like the main fuel tank ruptured (38s into BBC video stream). It then stalls and explodes.

[hernibles]

I think this has 2 engines side by side, so clearly any single engine failure will have an asymmetric and catastrophic result.

SpaceX has 9 engines (designed by them in the 21st century) and claims system can tolerate up to 2 engines out. Seems rather more robust to me.

[Brian Gaff]

Well its too early to tell, I'd suggest. Nobody has even ventured into the zone yet. Considered too dangerous at night of cours.

The engines may well be old, but they will have been put through the same tests as new engines. They should not really deteriorate after all. Being Russian I think you can be fairly confident they are over engineered. For those who don't know they were intended for the Russian Moon missions that never flew as the launcher kept blowing up, not due to engines though, due to the sheer size of the rocket and mainly the vibration etc, of all the plumbing. I think they found out there are major issues with upscaling rockets beyond a certain size.

Now I did not see the pictures, but listening to the sound there were two distinct explosions. the second one was probably the range safety destruct explosion, which under the circumstances, was probably not needed. the first seems to have been about 10 seconds after ignition, and apparently damaged some internal structures and put a hole in one side. Looks like some problem with plumbing maybe, but I'm sure we will know eventually. as for the pad, as I say, at least at the press conference the folk did not know themselves how bad the damage was. They are warning the public to report any debris and not touch it. I think they are mainly worried about any solid fuel or hypergolic fuels that might have been hurled outside of the fireball and hence still be in a dangerous state. Brian

[Brian Gaff]

Exactly, but the telemetry might have indicated something earlier than it was visible or audible.

Bear in mind that these engines have flown on this rocket before and have also worked in test firings, so if it were an engine fault, it might be something that was done when it was actually put into the vehicle. Brian

[Brian Gaff]

Just cannot get a reliable plumber when you need one, obviously! 200 million dollars of rocket gone in less than 20 seconds. Sure has bonfire night beat. Brian

[Brian Gaff]

Yes Orbital have a track record of poor fault tolerance. Remember all the Pegasus failures? They also of course tend to use bits and pieces from all sorts of sources, like when they were using decommissioned Minuteman missiles as Taurus launchers with a modified Pegasus on top of it.

I'm not saying they are wrong, but it is what happens if you do not have the whole thing as an integrated in house design. Often its the critical interfacing of items due to poorly understood modes of vibration or g forces that causes the problems. Brian

[Martin Brown]

Since you can't see the video I will describe it. Lift off looks normal and then after clearing the pad there is a sudden change in the flame plume behind the rocket (from a normal engine exhaust to something 3x fatter). A small flash bang at the base of the rocket and it stops rising. It was two maybe three times higher than a water tower by then.

The final bang is as the entire thing drops back in free fall onto the launch pad and the fuel released detonates in a major explosion. I don't think the range safety officer had any time to react at all.

A few small bits fly high into the air classic shell burst style.

All in all a very expensive firework!

[hernibles]

Nice info on the original Russian N1 rocket here:

This used the engines now evolved and used by Orbital. 30 of them on the first stage alone!

4 launches and 4 failures. All catastrophic!

[newshound]

I was initially puzzled by the relatively prolonged fire on the launchpad after the initial Whoomf from the kerosene and the LOX, until I looked it up and found it had a solid fuel second stage.

[Brian Gaff]

Also of course there were two explosions, one for the initial problem and a second from the self destruction system operated by range safety.

There are now some aerial pictures and a press release about the first inspection of the pad on the web sites I understand. Most damage looks relatively light according to those who have looked, but of course its not a large area in the shot apparently. Brian

[Nick]

In message , Brian Gaff writes

A bit of description to, I hope, assist Brian. The BBC video shows the launch from one perspective with the rocket moving (slowly) away from the camera as it ascends. The only photo I've seen from the NASA press release earlier is taken from almost the opposite direction. In that, the ocean is to the left with some blast marks and no obvious debris around the sea wall area. Most damage is presumably either behind the camera position, in the water or on other bits of land further to the left (the first press release did mention extensive property and vehicular damage).

HTH,

[Cursitor Doom]

Whatever. Let's just blame the Russians.