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Orbital Sciences Antares rocket explodes after liftoff

nasa.gov

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Re: Orbital Sciences Antares rocket explodes after liftoff

#181

Post by nikanj »

blhack wrote: post #9

I had a close friend who worked on this. Everybody in our lab stopped working this afternoon to watch it launch, and to cheer our friend on. Definitely went from "YAY!" to sad really quick. It's been said other places in this thread, but to echo it again: I really feel for all the engineers involved in this. That's got to be devastating. To everybody: failures suck, but big spectacular failure is directly correlated…

A lot of people are trying to build mechanical perpetual motion engines, and have failed for thousands of years. Failure doesn't always signal you're doing something right.

Re: Orbital Sciences Antares rocket explodes after liftoff

#182

Post by cromwellian »

gedmark wrote: post #137

Using 50 year old Russian engines was a risky move on Orbital's part, but in fairness the NK-33's are a pretty amazing piece of technology. The US has still yet to build anything matching its performance: http://en.wikipedia.org/wiki/NK-33 297 seconds of Isp is huge. The Saturn V's F1 engine only had 263 seconds. And the closest we've come since to that level of performance in a Lox/RP-1 engine is the Merlin 1D which…

"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.

Re: Orbital Sciences Antares rocket explodes after liftoff

#184

Post by easytiger »

nikanj wrote: post #181
blhack wrote: post #9

I had a close friend who worked on this. Everybody in our lab stopped working this afternoon to watch it launch, and to cheer our friend on. Definitely went from "YAY!" to sad really quick. It's been said other places in this thread, but to echo it again: I really feel for all the engineers involved in this. That's got to be devastating. To everybody: failures suck, but big spectacular failure is directly correlated…

A lot of people are trying to build mechanical perpetual motion engines, and have failed for thousands of years. Failure doesn't always signal you're doing something right.

These guys, whom i believe to be an investment scam, are the most recent:

http://www.steorn.com/ http://en.wikipedia.org/wiki/Steorn

They've erased some of the history from their website and interest hasn't been high enough for full exposure of their nonsense. Yet a decade of failure hasn't shut them down. I feel sorry for the people who poured €11 million into them. Never seeing that back.

Re: Orbital Sciences Antares rocket explodes after liftoff

#185

Post by solistice »

klodolph wrote: post #173
solistice wrote: post #123

Earlier quoted context omitted.

As I've understood it, it means that the scale of your ambitions is right. Consider a continuum of things that you can do, divided up by difficulty. For some part of it, you allways succeed, for some part of it, it's a mix of sucess and failure, and for some even more difficult part, you always fail. Now in order to succeed at something consistently, you need to master it, which also means that the things you always…

I think the generalization is overbroad. Risk of failure should be weighed against the consequences of failure. If I'm writing code for robots as a hobby and my robots behave exactly as I intended all of the time, then I'm probably not learning anything, and I should try to make the robots do more sophisticated tasks. The consequences of failure are minimal, so the optimum failure rate is high. If I'm at work writing…

Oh, I absolutelty agree with you, and did think about including the concept of failure costs in the above post, but decided against it since I believed it would make the post a little more convoluted. Even with hobby robotics there's a maximum failure cost you can stomach, there's only so many servos you can burn through, and you only have finite time to program, which limits the number of attempts you can make.

One great way to lower the amount of expesive failures is to hedge it with a number of cheaper failures, whether that'd be models, prototypes or testing rigs for individual components of an airplane or rocket. If you look at the early stages of avionics, there were many failures, some of them expensive, deadly or embarrasing. But over time, we did build up a repertoire of testing methods to verify a given airplane design. Does that mean our airplanes don't fail? No. Does that mean we aren't trying to develop even better airplanes because of the risk involved? No. But all in all, it's a considerable improvement. We'll get there for rockets, just like we did for cars, ships, airplanes or computers.

Re: Orbital Sciences Antares rocket explodes after liftoff

#186

Post by swatkat »

cromwellian wrote: post #182
gedmark wrote: post #137

Using 50 year old Russian engines was a risky move on Orbital's part, but in fairness the NK-33's are a pretty amazing piece of technology. The US has still yet to build anything matching its performance: http://en.wikipedia.org/wiki/NK-33 297 seconds of Isp is huge. The Saturn V's F1 engine only had 263 seconds. And the closest we've come since to that level of performance in a Lox/RP-1 engine is the Merlin 1D which…

"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

Re: Orbital Sciences Antares rocket explodes after liftoff

#187

Post by Stolpe »

_kst_ wrote: post #131
_kst_ wrote: post #80

Earlier quoted context omitted.

There wouldn't have been much point in a self destruct. The rocket launched, then it looked like there was an explosion in or near the boosters (which apparently caused a loss of thrust), then it fell back onto the pad and exploded. Blowing it up at a higher altitude just would have spread the debris a little farther.

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?

Re: Orbital Sciences Antares rocket explodes after liftoff

#188

Post by dingaling »

gedmark wrote: post #137

Using 50 year old Russian engines was a risky move on Orbital's part, but in fairness the NK-33's are a pretty amazing piece of technology. The US has still yet to build anything matching its performance: http://en.wikipedia.org/wiki/NK-33 297 seconds of Isp is huge. The Saturn V's F1 engine only had 263 seconds. And the closest we've come since to that level of performance in a Lox/RP-1 engine is the Merlin 1D which…

> but in fairness the NK-33's are a pretty amazing piece of technology

And we wouldn't have any at all if Kuznetsov hadn't ignored a direct order from Moscow to destroy all the engines and tooling, as part of the erasure of the N-1 launcher from official history.

IIRC the OKB knocked them off their inventory as them as 'surplus components' and stored them in a warehouse under plastic sheeting.

Re: Orbital Sciences Antares rocket explodes after liftoff

#189

Post by teekert »

GrinningFool wrote: post #86
blhack wrote: post #9

I had a close friend who worked on this. Everybody in our lab stopped working this afternoon to watch it launch, and to cheer our friend on. Definitely went from "YAY!" to sad really quick. It's been said other places in this thread, but to echo it again: I really feel for all the engineers involved in this. That's got to be devastating. To everybody: failures suck, but big spectacular failure is directly correlated…

"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…

Success is the ability to go from one failure to another with no loss of enthusiasm. -Winston Churchill

Personally I think he meant that eventual success is often achieve by applying this strategy.

Re: Orbital Sciences Antares rocket explodes after liftoff

#190

Post by CmonDev »

pbreit wrote: post #160
trothamel wrote: post #31

The 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.

Most of those smart folks are probably retired now - need more immigrants:

http://xkcd.com/984

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