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Explosion at Scaled Composites Kills 2, Injures 4
Posted by
CowboyNeal
on Thu Jul 26, 2007 10:27 PM
from the burning-up dept.
from the burning-up dept.
Animats writes "Details are scant at this time, but a explosion at the Scaled Composites rocket test facility has killed two people and seriously injured four more. The Los Angeles Times reports that the explosion was 'ignited by a tank of nitrous oxide.' This is Burt Rutan's facility, and the home of SpaceShip One and Virgin Galactic spacecraft development."
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First and foremost (Score:4, Insightful)
CNN (Score:3, Informative)
Oh, damn! (Score:5, Insightful)
No, they NEED zombies! (Score:4, Funny)
Parent
Strange for a hybrid motor (Score:5, Informative)
Usually mis-ignition will just cause rapid release of the N2O oxidizer, and designs are such that a clogged nozzle which would actually cause an explosion generally causes a safety valve to open and vent the excess pressure.
Yeah, everything I've seen on hybrid motors says they are non-explosive with a near zero TNT rating.
Re:Strange for a hybrid motor (Score:5, Informative)
They weren't firing the motor; apparently this was some sort of handling accident. Which also explains why people were close enough to be hurt. Why the fireball, I don't know. Also, nothing actually *detonated* here -- just a big fireball and modest overpressure. (At least, that's what informed commentary on the pictures I've seen says.)
It's also worth noting that given sufficient provocation, it is entirely possible for N2O to detonate by itself -- it's an energetic compound. It's just fairly non-reactive under most conditions, and even if it does start decomposing in a self-sustaining fashion it doesn't normally detonate. But it can, and if you have enough of it you don't even need a detonation to kill people.
Parent
Re: (Score:3, Informative)
Re:Strange for a hybrid motor (Score:5, Informative)
No, it most certainly does *not* need a fuel. It is an energetic chemical. In other words, 2N2O -> 2N2 + O2 + energy. Not TNT levels of energy, but not small amounts either. I don't have the numbers off hand, but the decomposition temperature is over 1000 Celsius. That reaction *can* happen in a detonation. However, the chemical is quite stable and relatively inert at normal temps (thermal decomposition starts a bit over 500C, iirc) -- at room temp it's far less reactive than oxygen. This accident may or may not have been that -- my understanding is it looks more like a pressure vessel burst and a fire from fuel + oxidizer, but we don't have enough details to know that. The trailer and tank you see overturned in that photo hold nitrous normally (I don't know what was full, or where the nitrous was at the time).
I've worked on that airport and seen these guys out testing. My condolences to the families.
Parent
Re:Strange for a hybrid motor (Score:5, Informative)
The activation energy is high, but it can be lowered by use of a catalyst.
Parent
A couple more details (Score:5, Informative)
I've been chasing news articles for a little while now.
Details are very scarce, but apparently this was a cold-flow test -- they weren't intending to light the motor, just flow nitrous through it. Tank ruptured, and a big fireball. Evidence visible from pictures etc suggests nothing detonated. Apparently people a couple miles away at the airport proper didn't hear an explosion -- they just saw clouds of dust and smoke, not abnormal for a motor test. I haven't seen anything about causes etc.
My condolences to the families.
Re:A couple more details (Score:5, Interesting)
Among the safety innovations of this rocket is that a single fiber optic cable is wound around and around the tank, so that if it ruptures anyplace it will cut the cable, and the rocket will be shut down immediately.
That said, in a cold-flow test, there shouldn't be anything burning.
I am sure that Burt and Richard Branson are terribly distressed by this. My deepest sympathies go out to the families of the killed and injured.
Thad Beier
Parent
Re:A couple more details (Score:5, Interesting)
Actually, this is standard in a lot of rocketry situations. On the space shuttle, the electrical wire that controls the hydrazine valve to the thruster is wrapped around the thruster bell. If something goes wrong, and the bell fails, it will cut power to the control valve, causing it to close, and thus shutting down the thruster.
This is the basic principle of "Fail Safe" design. To me, the problem with the fiber optic cable is that the fiber cable is just a data control. It would be better if they wrapped the power line around it, so that a failure would cut the power, and thus cause it to go safe.
Parent
Re: (Score:3, Interesting)
I did well in high school physics, but there is one thing I think I read/learned awhile back, and wonder if someone can confirm it, and its relevance to this event (if the parent poster quoted above is correct).
The thing is this: that things can explode simply through ra
Re:A couple more details (Score:5, Informative)
In non-technical usage, explosion can refer to a detonation or a deflagration. The distinguishing feature is a detonation has a supersonic reaction front, a deflagration is subsonic.
A pressure vessel rupture is an explosion for most purposes in terms of the results; ditto a deflagration. This appears to have been a deflagration -- damage is too light for a mass detonation on that scale.
Damage from explosions can come both from the overpressure, heat, flame, etc caused by the combustion, and also from the shock wave of a detonation. The shock wave will shatter hardened structures, the overpressure "just" moves things around. Also, with a detonation, the pressure rise time is *much* faster, and the overpressure can be *much* higher, so a comparable mass of substance will do much more damage if it detonates rather than deflagrates.
Nitroglycerin doesn't "ignite" in that there isn't a "flame", but the reaction that occurs is a combustion reaction -- the complex molecule ends up as a mix of N2, H2O, CO2, CO, etc. That reaction propagates at supersonic speeds. Interestingly, it will burn quietly if lit -- there's no pressure wave, just thermally-induced decomposition, and it won't transition on its own.
Parent
Re:A couple more details (Score:4, Insightful)
It just looks like that one tank trailer fell over, but in fact it has to have rolled over 270 degrees to be where it's lying now. Also, the container just past it was both hit really hard in the side by expanding gas, and knocked over.
But there's no massive fragmentation damage or burn mark anywhere to be seen.
What is instructive however, is that there's something missing, and something else tipped over. The other thing tipped over is the test stand itself, which is a large blue steel truss structure, which is now about 10 feet away from where it started and lying on its side.
What's missing, is a large (roughly 7 foot diameter and 10 foot long) composite "flight tank" which would hold the nitrous oxide for the motor during a test or flight, and any sign of the injector or a chamber assembly. They're just out and out gone.
The missing tank, test stand knocked over, lack of fire or fragmentation damage seems to indicate that nothing burned much if at all, and nothing detonated. This has all the hallmarks of a large pressure vessel explosion.
I for one am going to try to attend the memorial service.
Parent
shame (Score:4, Insightful)
Complacentcy (Score:3, Insightful)
Quick Turnaround (Score:4, Funny)
http://www.scaled.com/ [scaled.com]
It Happens (Score:5, Insightful)
The first thing that occurred to me was whether Rutan was there. He wasn't, but he could have been. It's his way to keep his hands in things. That would have been an enormous loss to aero- and space development. He's one of the all time geniuses of all things flyable. Any really good aerospace engineer could write a definitive book on composite construction. It took genius to do so in 28 pages. It'd be damn hard for Scaled to go on without him, even with Northrup buying them out.
The second that occurred to me was that it'll put a damper on hybrid motor development and use. The motors are much safer than solid or liquid, but the handling equipment isn't safe by any stretch. Amateur rocketry has been using them for years, but nobody is willing to break the high-power certification barrier and make them available to low and mid-power rockters due to the liability factor from the ground equipment. It may come to nothing more than headlines for the media and PR for some politicians, but I expect a call for the FAA's Office of Space Transportation to rethink certifying of hybrid powered human rated craft.
Please, Burt (Score:4, Insightful)
Not unexpected (Score:5, Insightful)
Most people (other than the safety engineers and insurance folks) rarely stop and think about what it costs in human lives to move forward. But there is a cost.
In a perfect world it would never happen, but we are imperfect and it will always happen. People make mistakes. Equipment malfunctions. Bad weather. Mislabeled products. Acts of nature.
The people that do this work benefit their species; a true higher calling. Take a moment to think about their sacrifice and thank them.
New planet definition.... (Score:4, Funny)
Parent
Sabot is French, Luddites were English (Score:3, Informative)
The entymology I am more familiar with, and would seem more believable, is rooted in the Fench revolution. The French peasants trampled the landlords' crops by stamping on them with their sabots. Much more believable!
Re:Sabot is French, Luddites were English (Score:5, Funny)
Parent
Re:what the shit... (Score:5, Funny)
Parent
Re: (Score:3, Funny)
Ah, just wait till the Russians show off their Lindsay Lohan type shit...
Re:Not surprised... (Score:5, Insightful)
All I have to say on the matter is that rocket science is dangerous business, the same goes for any kind of challenging engineering. Sometimes people die because other people fuck up, sometimes people die in spite of every sane precaution that could possibly be taken. I just hope this is the latter and not the former. I just hope it isn't symptomatic of a corporate mentality takeover after the buyout.
Parent
Re: (Score:3, Informative)
Re: (Score:3, Insightful)
Re:Not surprised... (Score:5, Insightful)
Parent
Re: (Score:3, Insightful)
Re:Not surprised... (Score:4, Insightful)
Hindsight is 20/20. From this initial report, it sounds like this particular incident was a result of known factors, and thus avoidable. The Challenger and Columbia incidents were the result of factors which, while known, were under-appreciated. The Challenger factors were managerial, while the Columbia factors were the result of engineering.
There's also the matter of economics. It's simply not economically possible to guard against every threat. If it were, then someone on this planet would be nigh-immortal.
Parent
Re:Not surprised... (Score:5, Insightful)
Parent
Re: (Score:3, Interesting)
Re:sorry (Score:5, Insightful)
"Where's the kaboom?.. There was supposed to be an earth shattering kaboom"
Man, I can usually appreciate sympathetic dark humor but that joke just comes across as so dickish and it isn't even funny in an inappropriate "NASA=need another seven astronauts" kind of way.
Parent
Re:sorry (Score:5, Insightful)
Parent
Re:sorry (Score:4, Insightful)
Parent
Re: (Score:3, Insightful)
This is a non-convincing argument. Pro-war people say the same thing "Oh how many people get murdered each year?" Rapists say "at least I didnt kill anyone." Murders say "at least I'm not a pedophile." This is moral relativism and a slippery slope. If you cant defend private enterprise launching millionares into space as something to die for then that should tell you about how weak your position is.
Well, first of al
Re:sorry (Score:4, Insightful)
The grandparents point is simply that a death is a death, although when their is something unique or spectacular about it we make it a bigger deal than if it's simply a "routine" death. Now I don't mean routine to the family, but routine in a page 26 kind of way, as opposed to something that makes the front few pages.
And I would expect that sending someone to orbit is a very noble calling to many. How many non-goverment employees have ever sent someone to orbit? I'm guessing not very many.
Pretty quick of you to assume that safety wasn't a concern. It was actually a cold test run when it happened. There were bunkers onsite to ensure safety. That's just the from the story we know now. When it's been determined that safety wasn't a high priority then I'll be on your side but for now you are just assuming....
Parent
Re: (Score:3, Interesting)
This is a non-convincing argument. Pro-war people say the same thing "Oh how many people get murdered each year?" Rapists say "at least I didnt kill anyone." Murders say "at least I'm not a pedophile." This is moral relativism and a slippery slope.
Oh grow up. You are comparing someone making a morbid joke with murders and rapists.
Get off your high horse. Moral relativism, my ass.
And I'm someone who's first action on reading the headlines (before slashdot even noticed them) was to call a friend who has been closely involved with the x-prize and scaled composites to make sure she wasn't one of the ones hurt.
Re:sorry (Score:4, Insightful)
Chuck you, Farley.
At the end of the day, these people died so Burt could launch millionaires (instead of billionaires) into near orbit for $250K a pop (instead of $30M a pop).
Given the situation in Unistat, and the likelihood of "The Moon is a Harsh Mistress" (TANSTAAFL is something Heinlein derived as a likely result of living in a hostile environment) coming true after a critical mass of humans is achieved outside of earth orbit, I'm willing to bet that the people working at Scaled Composites were on their way towards doing more for human freedom than NASA did in the past 40 years.
Until NOC bought them out, of course, ending all hope of cheap civilian access to space.
> Now, I fully expect the government to come in and regulate these guys. At least put in some real NASA-level safety precautions.
Chuck you again, and the horse you rode in on, Farley.
Columbus and those who followed him didn't cross the Atlantic because they thought it was safe. They did so because he thought he could make a fuckload of money by doing so.
NASA safety precautions are appropriate for people who will sue you if your spaceship blows up.
The meek (and that's you, Farley) can have the earth. The rest of us only want the right to sign a waiver that we may take our chances with the stars.
Parent
Re: (Score:3, Informative)
Re:sorry (Score:4, Interesting)
Context is everything...
Why does the needless death of a beautiful baby in a war torn nation touch us or tug harder at our heart strings than the equally tragic death of an old man in a traffic accident? Part of it is the loss of possibility, a life unfulfilled. Part of it is the sadness of losing something innocent to something so depraved and heartless as a snipers rifle or terrorists bomb.
In the same way, we are especially touched by the loss of heroes. Heroes of the mind who force back the darkness, heroes of the will who challenge what's possible for people, and heroes of the heart who throw themselves fiercely at life's dare. Along the way we lose some of these heroes and a little piece of us dies with them, and that's why we mourn, that's why their passing is something special.
It doesn't diminish the humanity or worth of others, it doesn't diminish the depth or breadth of the trajedy of losing others. It is however a special loss, and these men and women deserve our acknowlegement, our respect, and our tears at their passing. It will always be hardest when we lose that which is the best of ourselves.
Who we make heroes... and how we mourn there passing more than anything else says something about who we are.
Parent
Re:sorry (Score:5, Funny)
Parent
This has NOTHING to do with NASA (Score:3, Interesting)
My condolences to the families.
Re:This has NOTHING to do with NASA (Score:4, Informative)
Rutan is fine.
Parent
Rutan was not killed (Score:3, Informative)
Burt Rutan is not one of the casualties. [ksby.com] He's spoken to the press since the accident. All six casualties were Scaled Composites employees.
Pull out of forklift-aided transportation (Score:5, Funny)
While corporations are profiting from increased handling capacity, our brave young men and women are dying unnecessarily.
Ban forklifts! [youtube.com]
Parent
Not at all (Score:4, Insightful)
Look, this sort of thing happens every day in the private sector. Fisherman drown, taxi drivers get shot, construction workers die in falls, and life goes on, with hardly missing a beat. If you want space to be really privatized, the right way to look at this whole accident is to say, yeah, it sucks that they died, but, back to work people.
Parent
Burt's a great guy, but ... (Score:3, Interesting)
He is right that the little guys have their chance at space - look at Armadillo