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NASA Installing Shocks On Ares
caffiend666 writes "In order to abate the massive vibration issues of their new Ares I spacecraft, NASA is installing shock absorbers. 'The plan is to install 16 canisters in the bottom of the rocket with 100-pound weights attached to springs. Battery-powered motors will move the weights up and down to stop vibrations. Those are essentially remote-controlled shock absorbers, said Garry Lyles, who headed the team of NASA engineers tackling the shaking problem.' So, when the spaceship is a rocking, don't come a knocking?"
sounds like the design is a massive failfuck.
Will they then have to haul nearly a ton into space? That sounds like a very costly improvement to the shuttle.
So they're loading down the first stage with at _least_ 1600 pounds of weight (plus motors, plus batteries, plus cannisters) to dampen vibration?
That's pretty crazy, I would think. It's not like all that weight is gonna come free.
Please understand there is a big difference between American engineering and government controlled American engineering.
The people are far better than their government, thats why the government mostly treats them as villians
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Nothing else worked?
Not with the meager budget they're getting. We'll either do the job cheap, or we'll do it right. Looks like we chose "cheap". And on the long run it won't be cheap either. Just like the way the shuttle turned out. A horrible expensive kludge. I hope they at least put in a better escape system...like what they had on the old expendable rockets.
What?
Ares being cheap is a false economy. By trying to essentially throw together a rocket from spare parts, they are now costing more money making it work than if they had just built a launcher with a free hand.
If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
Tell Gus Grissom, Ed White and Roger Chaffee how well the original Apollo design worked for them. Oh wait you can't - they're dead.
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That extra weight seem really to be a waste of resources. There must be a better way to solve that problem. All the vibrations has to originate from somewhere and maybe it's all about tuning the rockets or change the engine configuration.
Please mod up parent a bit, it's a little flamebait, but also insightful.
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"..their building this thing with not even half the money of the Apollo program.." (sic)
Actually, elegance in engineering doesn't cost any more, and can even be cheaper. What costs more is finding problems half way through a project and then solving them by throwing extra weight and complexity at it. That will cost more money, more time, and, if it creates more critical failure points, more lives....
This sounds like more than the shock absorbers found in your car and other mechanical systems. Those are passive spring-mass-damper systems. These sound like active vibration control systems, that try to cancel out one shaking by producing an equal and opposite shaking. It's fairly straightforward, the sort of thing you can learn in an undergraduate control theory class, but getting it to work robustly, even on a test stand, takes a fair bit of tuning. Getting it to work on a complex system like Ares seems to be asking for trouble.
If nothing else, it's certainly a very heavy fix. My rocket science is a little rusty, but the 1600 lbs of active weight in the first stage probably doesn't translate into 1600 lbs of lost payload (if it were in the crew capsule, then yes, but the first stage doesn't go all the way to orbit). Even so, it's some lost payload capacity, and does nothing to tackle the root cause of the problem. Back to the drawing board, guys!
Ever get the feeling they're building a kludge all over again? Space Shuttle II -- Revenge of Thousands of Glued On Tiles and Strapping It to the Side an Ice-Covered Tank.
There was no way to passively dampen the vibrations? A simpler, cheaper solution? So instead they'll introduce another ton of lift weight and 17 additional motors and batteries to fail.
My prediction: in the first 50 launches this system will fail and the rocket will either shake the astronauts and payload apart (failure to dampen) or spectacularly shake the rocket apart (oscillate lopsidedly or out of synch with the vibrations).
With luck Slashdot will archive this long enough. Given that this is a NASA project, that might not be likely.
Get off my lawn.
You think the Saturn V didn't have many tons of anti-vibration structure, anti-pogo devices, and other such things? Get real!
Clueless computer types such as yourself might think that a rocket should be fuel tanks and an engine and nothing else, but that's not how it actually works in the real world. There's a reason that "rocket science" is used as an idiom to indicate something that's extremely hard, you know.
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Not going to talk about your "Germans" comment, but...
Apollo had at least 2 major incidents, killing 3 astronauts, and endangering 3 others.
Shit happens when you are pushing the envelop. Mercury, Gemini, Apollo, Shuttle, Salyut, Soyuz, Mir, all had their fatal or near fatal incidents.
And each have/had "inelegant design flaws".
Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong fix.
To an outsider it seems that the US did a terrible mistake then they abandoned rockets in favor of the Space Shuttle. Yes it looks cool but its very expensive and not really the best tool for the job. The fastest way to get up to speed would be to side with some country that has good rocket technology instead of trying to build it themselves. It feels like this has more with politics than practical reasons.
This rocket has epic fail written all over it. If vibrations are an issue fixing those vibrations should be priority one, not mitigating them.
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The Apollo missions definitely weren't entirely safe... but people didn't really care about it as much as they do today. They were driven to succeed at almost any cost, and to do so before the Russians.
Now we have this culture of protection and safety that's we're too afraid to (accidentally) sacrifice a human even at the prospect of settling on the moon. Not saying it's wrong, but it complicates things more.
Move all sig!
Maybe the vibrations are originating from multiple sources. It may be far more effective and cheaper to add active damping than to redesign the engines, the gimbals, the fuel pumps, the launch pad, and whatever else could be contributing to inducing these vibrations.
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That is exactly what I have been saying. Apollo was the heaviest lifter we had, it worked, and it worked great. What's wrong with pulling out the blue prints, updating some components and building a newer improved version of the Apollo system? Why is this so hard to figure out? It's certainly better than wasting 1600+++ pounds on shock absorbers, damn that is just plane stupid. It's not like this is rocket..oh wait...but still!
Because the blueprints and designs don't give you everything. There's a ton of additional work such as tools, dies, machinery, etc. needed to make the parts that are no longer around and which would need to be rebuilt and debugged.
Any modern system such as rockets, cpus, chips, etc. have a lot of ancillary things that are needed to build them. And that's ignoring the little tips and experience with what techniques work which is probably only known by the original engineers and builders.
Even today, if you were to give a company like TSMC or UMC the chip layout and designs for something like a pentium chip, there would still need to be a fairly long experimentation time (e.g. 1 year) before they could manufacture the chip in quantities because the company would have to fiddle around with chip masks and the making the chip to figure out the quirks and gotchas in making the chips. The Saturn V is a lot more complicated and a lot harder to debug than a cpu.
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Well... We have to be cautious here. The Saturn V flew, I think, less than 10 times. The shuttle solids flew a couple hundred times (there are two in every shuttle). This design is derived from the shuttle ones and should, by now, be thoroughly understood. They have a far longer track record than the Saturn series. I am baffled someone did not predict the vibration problem before day 1.
Besides, there is no way to build a Saturn V now. The factories and processes that built the parts are gone. It would have to be redesigned. The whole point is, it would not need to be redesigned from scratch and could follow a pattern that, it seems, worked better than this.
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I'd hesitate to say it 'worked great', given the very few flights the Saturn V (to give it it's proper name) flew. They didn't mostly solve the vibration problems until Apollo 14, for example (they never did completely solve them), and they were making significant modifications right up to the last flight. In particular, they fiddled extensively with the retrorockets on the first and second stages to reduce weight while ensuring proper separation and no recontact.
Mostly because it isn't a matter of updating 'some components'... For one example - the electronics in the Saturn V IU (Instrument Unit) are hopelessly out of date, you can't simply 'update them' because they interconnect with everything else on the booster. Even just updating the electronics on the IU means redoing the cooling system and wiring harness, not to mention that all the vibration, structural, cooling, etc. etc. analysis will have to be redone as well.
When it comes to the Apollo capsule itself, I've seen credible work that indicates that the weight of its power and electronic would shrink by over 90%! Which means the cooling system is now way oversized... The CG of the capsule also moves radically, which means rejiggering the RCS to account for the changed aerodynamic performance... Etc. Etc.
There's a reason why the Soviets update the Soyuz only infrequently.
It's only easy when you don't understand the issues involved. Very few Slashdotters seem to know much about the history and engineering of the Apollo program beyond the extremely simplified panegyrics they read as kids.
You are very confused, I'm afraid.
First, no Saturn V stage had six engines. It is therefore nonsensical to talk about "two affected engines" and "the other four engines". The first and second stages both had five engines.
Second, Apollo 13 only had one engine shut down due to pogo. There was an unmanned flight that lost two engines, Apollo 6. This also happened due to totally unanticipated violent pogo. Pieces were seen falling off the rocket at about two minutes after launch due to the intense vibration in the first stage. The second stage then experienced two premature engine shutdowns. The remaining three (not four!) engines burned for about a minute longer to compensate, but this was still not enough, and the third stage also had to burn for about half a minute longer. All of this combined to place the vehicle in the wrong orbit, although this was not a disaster and the mission was still abel to meet many of its goals.
Launch disaster during Apollo 13 was not averted due to an intentional cut-off as you state. A low fuel pressure sensor was tripped by the violent vibration, tricking the flight control computer into thinking that there was a fuel pressure problem and causing it to shut down the engine. This was all by accident. The computer was not programmed to deal with pogo in any way, and this sensor could have easily not tripped if things had gone just a little bit differently.
Saturn V pogo was never really solved, although after the modifications which were in place for Apollo 14 it became much less severe. Apollos 11 and 12 experienced pogo in the same engine as 13, but in a slightly different mode which happened to be much less violent. Significant pogo also happened on the third stage of Apollo 10 and the first stage of Apollo 6. Less violent pogo happened on essentially every flight of the Saturn V run. As a result, the Saturn V was being continually modified and refitted to deal with the different pogo oscillations which presented themselves after each new flight. In fact a fix for the Apollo 13 pogo was already in the pipeline (having been already observed on 11 and 12), but it was deemed too expensive to retrofit to the Apollo 13 launcher.
Calling this hodgepodge of guess-and-check which never really solved the problem "elegant", while calling a nifty, light, active damping system a 'kludge" is simply stupid.
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