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Orbital Sciences Antares rocket explodes after liftoff
201–210 of 264 posts
Re: Orbital Sciences Antares rocket explodes after liftoff
#202The first stage engines that exploded were AJ-26 engines. These are remanufactured NK-33 or NK-43 engines built in the Soviet Union in the late-60s or early-70s for the N-1 moon rocket, but never used. In May, an AJ-26 exploded on the test stand at Stennis space center in Mississippi, severely damaging the test stand.
It seems so bizarre that we're using 40 year old, Russian-made engines. I'm sure there are plenty of smart folks who will say not too worry, but I wonder.
It is a fascinating case of uneven technological development.
The Soviet Union went so far with staged combustion engines in the sixties that that level of technology has not yet been reached elsewhere.
USA, Europe and Japan went with hydrogen staged combustion but that's quite different.
The ULA/Blue Origin decision about new indigenous US first stage engine development gets a huge boost from this problem.
It's just what can be reached when you put resources into it. Coming from the IT world it might seem strange that the investment has not lost its value, but it has not. It might be quite a lot easier to duplicate nowadays, but not child's play at all.
Sometimes it's chilling to think what kind of still secret projects were funded by the huge US defense budgets during the cold war. There are some public sides and declassified parts on things like very good glide ratio hypersonic vehicles, but officially they never went far and the space shuttle was the thing. ( http://www.456fis.org/THE%20B-52/FS-011-DFRC_popup6.jpg )
Re: Orbital Sciences Antares rocket explodes after liftoff
#203Earlier quoted context omitted.
According to the press conference just now, the range safety officer apparently did send a destruct signal. The signal probably would have been sent very close to the time the rocket hit the ground. In my relatively ignorant opinion, it was going to blow up one way or another. We'll probably get more details later.
Out of curiosity, what does this signal actually trigger?
Each rocket contains conventional explosives which are used to destroy the vehicle if attitude control is lost during flight. It's to prevent the rocket from causing more damage by possibly crashing into a populated area.
Re: Orbital Sciences Antares rocket explodes after liftoff
#204Earlier quoted context omitted.
"The US has still yet to build anything matching its performance" The Space Shuttle Main Engines had an Isp of 452s and 500,000 lb of thrust, easily the most efficient rocket engines ever built.
NK-33 is RP/LOX, whereas SSME is LH2/LOX. LH2/LOX cryogenic engines have higher Isp compared to other solid and liquid engines. ISRO's CE-7.5 LH2/LOX engine[1] has an Isp of 454s. [1] http://en.wikipedia.org/wiki/CE-7.5
Was anything about cromwellian's statement inaccurate, such that it should have been downvoted? I'm pretty sure I understand everything being discussed here but I don't understand THAT.
Re: Orbital Sciences Antares rocket explodes after liftoff
#205More discussion on spacex reddit: http://www.reddit.com/r/spacex/comments/2km5vq/ot_orbitals_a...
Reddit thread is interesting. Pulled this off there... wow https://www.youtube.com/watch?v=Zl12dXYcUTo
Interesting in that case that the range officer didn't destroy the rocket, or waited a really long time.
Re: Orbital Sciences Antares rocket explodes after liftoff
#206Earlier quoted context omitted.
Comparing their rockets to "the punchline of a joke" is definitely bad mouthing, just factual badmouthing. Despite that, I don't blame him. Being factual is what's important.
And of course it's ridiculous that engines like NK-33 are considered bad just because they sit in a hangar for some 40+ years :) . It's not milk, they aren't that easily spoiled. Elon just used this time reference to make the decision look good - for somebody who doesn't know better. So factually he's right - but also misses the point. Here I should admit that Elon says more than he does - but he does quite a bit too…
> And of course it's ridiculous that engines like NK-33 are considered bad just because they sit in a hangar for some 40+ years
I took his comment to be more in the "that's your business model? buying and selling old Russian hardware?" vein. It's not that the hardware is bad, per se.
Although the hardware might be bad. I imagine they're looking into that...
Re: Orbital Sciences Antares rocket explodes after liftoff
#207Earlier quoted context omitted.
"If you're failing, you're doing something right." I didn't think people said this and meant it. If you succeed, it means you've done the critical things right. If you're failing, it means that you didn't do something right. Or several somethings. Yeah, you can learn from it and do better, and that's great - but that doesn't mean it's a success. It's a failure and - in some cases - a chance to do better the next time…
For me the essence of the idea that failure is part of (and maybe even required for) eventual success is expressed in Theodore Roosevelt's "Man in the Arena" The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive…
Failure can contribute to longer-term success, there's no doubt. But it's not a measure of success in its own right. Even re-reading OP's post today, that remains my interpretation of both what he said, and the more general sense in which the failure-related 'wisdom' is getting spread about the startup community.
Re: Orbital Sciences Antares rocket explodes after liftoff
#208How do they root cause something like this when so much of the evidence is blown to pieces?
Wondering the same thing. In addition to incidents like this, every once in a while, a story pops up that describes how programming error was the cause of rocket crash that happened TWENTY years ago... How? Just how can people be sure that it was programming error? It's not like you can debug a burnt piece of a microcontroller, can you? Guess we've come a long way from a magnifying glass investigations :)
I entered an engineering school 5 years after Ariane V.
Each single professor explained us why their subject was the reason for Ariane V to explode. The physics one went about how the imperial/metric discrepancy was the cause, the mechanics one went about how error margin management wad the cause, the CS one about integer overflow... Each of them made it clear that their course was the center of the world, but altogether it didn't look smart.
I chose that the CS guy was right ;)
Re: Orbital Sciences Antares rocket explodes after liftoff
#209Earlier quoted context omitted.
If the insurance company is doing its job right, this was priced into its rates.
Then it cost millions to a lot of people.
Which is understood by all those people when they purchase insurance. This isn't news. Spreading the risk around is why people buy insurance in the first place.
Re: Orbital Sciences Antares rocket explodes after liftoff
#210Earlier quoted context omitted.
"If you're failing, you're doing something right." I didn't think people said this and meant it. If you succeed, it means you've done the critical things right. If you're failing, it means that you didn't do something right. Or several somethings. Yeah, you can learn from it and do better, and that's great - but that doesn't mean it's a success. It's a failure and - in some cases - a chance to do better the next time…
I'm going to get up from my chair and go to the water cooler to fill up my water bottle. I bet I will succeed at it. How is this different to you than launching rockets? It's different to me because launching rockets is much more difficult. There are many more things that can cause you to fail catastrophically. To me , failure is to be expected when you're doing something that is difficult. That is the definition of…
That's a fair point, and one I don't disagree with. Where I do disagree is the idea that failure is a measure of success or even the potential for success.
It's a potential indicator of either the difficulty of the task, the abilities of the people performing the task, or both[1]. It's also an indicator that no matter how many things were done right, one or more things were done wrong.
I feel that your original post and subsequent reply reflect the pervasive perception that failure is a requirement for doing something big successfully. I think that's a misconception that's running rampant in the startup community. Failure can happen and it can be learned from, but success is possible without it.
1. In this case I'm going with 'difficult' and 'some things not done right'. Strongly suspect incompetence was not a factor :)