NASA Installing Shocks On Ares 293
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?"
fp (Score:2, Insightful)
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First thing to my mind: WTF?
Aren't ground-to-orbit vehicles really sensitive to weight? Shouldn't the design be about minimizing weight vs. compensating for shit by throwing an extra ton of dampers onboard?
cost? (Score:5, Insightful)
Re:cost? (Score:5, Interesting)
Just about anything can be a "weight". It's in their best interests to make the weights serve (another) function.
Also, the weights are almost all at the bottom of the rocket, so they should only affect the first stage.
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Still, that's where the most fuel is burned. For an historical example, by the time the Saturn V rocket had traveled its own length--360 feet--it had burned a greater weight in fuel than the weight of the command and service modules it was sending to the moon.
Where the fuel is burned doesn't matter... (Score:3, Interesting)
It's how much that weight has to be accelerated that matters. If you have to have dead weight, it's better to put it on the first stage than on a later one--you only have to accelerate that dead weight to first-stage burnout, rather than all the way to orbit.
The end effect is that a pound of dead weight in the last stage costs you a pound of payload... but a pound of dead weight on the first stage might only cost you a quarter of a pound in payload.
That's why many people propose making the first stage of a
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You know, the motors and controls could be *in* the canisters.
And considering the Ares V is such an improvement over older designs, a bit of dead weight is more than made up for by the overall efficiency of the vehicle.
The Ares V weighs 10% more than the Saturn V, but it carries 60% more payload. The Ares V weighs 50% more than the Space Shuttle, but it carries 700% more payload.
I doubt anyone will bemoan the loss of a tenth of a percent of the Ares V's ~200 ton payload capacity.
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Unfortunately the 1600lbs+ of kludge is going on Ares I not on Ares V. Saying that however, Ares V hasn't got any spare capacity for TLI either!
Re:cost? (Score:5, Informative)
a drop in the hat? (Score:2, Informative)
http://www.nasaspaceflight.com/content/?cid=5167
Constrained by the Ares I launch vehicle, the SRD lift-off weight target for Orion is set at 64,450 lbs...
2.5% of total weight, to offset "massive vibration issues" sounds worthwhile to me, particularly if something important might come loose (or worse, break).
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It's like trying to reduce the vibrations in your Chevette by encasing it in lead: probably effective, but your gas mileage is going to suck.
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Does someone have a car analogy?
Because they didn't design their engine very well, it now needs a very large harmonic balancer. [wikipedia.org]
Re:cost? (Score:4, Funny)
It's been considered. Leave the first stage on the ground. Launch with a cannon or railgun to get the initial acceleration instead of putting the engine and fuel on board. Non-living cargo can take considerable acceleration. You just need a longer railgun if you want to launch pesky humans.
As for this system, it seems like what they are doing is basically the same as noise-canceling headphones. Maybe they need a couple of giant bass speakers. Once in space they can switch them over to play techno.
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Gun launches still need an engine and fuel to run it. The orbit that the gun puts you in will necessarily intersect the atmosphere, so you need a circularization burn at the top to stay in space. It is of course much smaller than what you need to get to space using a rocket all the way, but you definitely need it.
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Bass and techno in space?
What a perfect way to get intelligent life to come destroy us all.
I wonder how you say get off my lawn in alien ?
The Hell! 1600+ pounds additional weight? (Score:3, Insightful)
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.
Funny coincidence... (Score:3, Funny)
In related news, did anyone notice the Oprah ad below the story (down on the left side):
"LOSE WEIGHT IN 2008! THE BESTLIFE DIET - JOIN NOW!"
Talk about context-sensitive advertising ;-))
Re:The Hell! 1600+ pounds additional weight? (Score:4, Interesting)
You forgot "plus the additional fuel needed to haul that 1600 pounds skyward".
That's the bitch about designing spaceships - for every ounce you add, you need at least an additional half-pound of fuel* to shove it upwards.
* depending of course on such details as specific impulse, fuel density, etc etc.
Re:The Hell! 1600+ pounds additional weight? (Score:5, Informative)
There's a much more informative article on Space.com from yesterday: http://www.space.com/news/080819-nasa-ares1-vibration-update.html [space.com]
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I remember reading about Apollo astronauts being amazed at how much they shook/vibrated - so much that they joked about not being able to make out controls (no one complained though for fear of loosing the missions)
Its not just the vibrations of the propellant exploding under their pants but the gimble of the engines to keep its trajectory that causes oscillations in the craft.. all being better absorbed by this awesome contraption.
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It's not like all that weight is gonna come free.
Yes, but if the alternative is to reduce the power of the engines to have less vibration in the first place, then the net loss of payload may be greater than simply using the more powerful engines with the extra weight and shock absorbers. I suppose that I could be mistaken, I am not a rocket scientist after all, but if the goal is to maximize payload (which appears to be the case) then some inefficiencies in other areas (like shock absorbers and weights) might be tolerable provided that such problems are n
Re:The Hell! 1600+ pounds additional weight? (Score:5, Interesting)
some inefficiencies in other areas (like shock absorbers and weights) might be tolerable provided that such problems are not the result of more fundamental design flaws in the Ares rocket.
Well that's the thing, see. These problems are the result of more fundamental design flaws in the Ares rocket -- specifically, designing the thing with a single solid first stage to start with.
Solids give a notoriously rough ride. Liquid fuel engines are fed a smooth flow of fuel and are fine tuned to keep out any combustion instability or oscillation. Solids are just a big chunk of almost-explosive with a hole drilled down the middle -- once you light it, that's it. Except for ammunition (ICBMs, artillery rockets, etc), traditionally solids have been used in multiples, usually together with a liquid-fueled core. The advantage is that the thrust variations of multiple solids tends to average out -- you still get vibration, but not as bad. But Ares 1 went with a single, huge, solid stage. That's like designing-in a vibration problem.
On top of that, the damn thing is a hammerhead design, wider at the top than at the bottom (look at the picture, it looks like a corn dog). Those are notoriously prone to stability problems of their own. With liquid fueled engines with some throttle range and gimballed for steering, that's a minor issue. With a solid whose idea of throttle control is cutting the right shape hole down the middle so as to expose different amounts of burning surface at different times, and whose gimballing ability is, well, limited at best -- you'd better hope you don't have any unexpected issues with that inherent hammerhead instability -- like wind shear, or oh say unexpected excessive vibration.
The whole thing is a freaking kludge, and adding a ton of active dampening is just yet another kludge. The manned spacecraft division of NASA jumped the shark a long time ago, this is just further proof.
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Except that liquid fueled engines weigh more than solid fueld engines...
Funniest, most wrong thing I've read on Slashdot today.
Hints: look up "specific impulse" and "combustion chamber wall thickness", among others. Hell, look at any kid's introductory book on rockets; it will explain in words short enough for you to understand why solids are (for a given delta-vee) so much heavier than liquids.
Re:The Hell! 1600+ pounds additional weight? (Score:4, Interesting)
Second point: If you look at the math for a two stage rocket, the effect of adding a pound to the first stage is inconsequential compared to the effect of adding a pound to the second stage. Sadly I'm away from my books (in a job transition at the moment) but the simple way to think of it is this: you only drag first stage with you for the first 2 or so minutes of flight, and then upper stage carries you for the next six minutes or so. So the weight is only with you for a short integrated length of time.
You can see this in effect when you consider the difference between first stage and second stage - first stage is essentially a modified Shuttle solid rocket motor, and second stage is essentially a re-designed external tank (yes, it's different, but the construction is the tank, thin wall aluminum with TPS).
First stage is thick, heavy steel, overdesigned for re-entry.
Second stage is thin, light aluminum.
The first stage is heavier, again, because of reuse and because mass isn't the design driver. Upper stage, however, since it nearly inserts orbit and is drug along the entire time is an incredible mass driver and must be as light as possible.
Sorry for rambling, and apologies for not showing the math, but in short, that's why adding 3/4 a ton to first stage isn't as big a deal as it sounds like. In the long run, it might effect maybe 10% of its weight in payload, if even...
Hooray for more weight... (Score:3, Interesting)
Oh, were we trying to lift stuff into space? (Score:2)
I thought we were trying to preserve jobs for Shuttle contractors while giving them a good excuse to stop doing risky things like launching Shuttles. If our primary goal was to lift stuff into space, we'd have designed our stuff to fit on a heavy Delta or Atlas, so as to be prepared for the worst if the Ares I fails and prepared for the best if the Falcon 9 succeeds.
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Time to dust off the Apollo capsule design and mount it on top of a Delta or Atlas then? :-)
OK - I haven't checked the figures, they may be too small for the Apollo capsule - in which case it's time to dust off the blueprints for Saturn V too!
The basic construction of these aren't flawed, but there are many points where they can be improved. And the instrumentation can be a bit more modern than it was back in the 60's.
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...that's 1600lbs that could have been used to lift more fun stuff in to space.
Or ten lawyers?
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You're clearly no engineer.
If you were, you'd realize that all we need to do is starve them for a few months and, bam, double the capacity for hurtling lawyers into space.
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I'm not a rocket scientist (Score:5, Interesting)
But adding 1600 lbs plus weight of electric motors to the weight of a space craft, seems like a last resort option.
Nothing else worked?
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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.
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I thought the Ares was being built with a free hand, and that the Jupiter [space.com] system was the one thrown together from spare parts.
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Not with the meager budget they're getting.
You mean the engineers are paid less for coming up with a bad idea?
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But adding 1600 lbs plus weight of electric motors to the weight of a space craft, seems like a last resort option.
Nothing else worked?
Well, from the information I gathered from the previous article, [slashdot.org] the issue is with the solid rocket booster. It has a phenomenon known by rocket scientist as pogo. [wikipedia.org]
In a liquid fueled rocket, pogo can be managed by damping [wikipedia.org] the fuel supply. You can't do that when the fuel is solid. They basically had the option of putting a big tuned mass damper on it, or scrapping the single solid rocket engine for either a liquid one, or a hybrid of the two. The other two options would warrent a big "I told you so" fr
Not absorbing vibrations (Score:2)
Re:Not absorbing vibrations (Score:4, Informative)
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No, they are dampening the vibrations because vibrations from SRBs are too unpredictable to be canceled out in the way you describe.
A) Then why do they need electric motors?
B) Tuned mass dampers (what you are describing) work much better if you know the frequency you are trying to dampen.
Perhaps what they are using aren't traditional electric motors, but more like Magneto rheological dampers [wikipedia.org] or some other electric damper. That would make much more sense.
Shock absorbers? (Score:2)
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Gateship. Because it's a ship, that goes through the gate.
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Interesting tweak (Score:4, Interesting)
That's great. Use a solid rocket to save a couple bucks, then add 1600 pounds of dead weight (not dead, really, but still needed because the solids vibrate too much) to make the thing work.
This Ares thing is getting more shuttle-ish by the minute.
Would the Apollo survivors please come back from retirement? Looks like the new folks are having some trouble with the problems you already solved.
I know the whole Ares thing is to reuse shuttle parts, but it seems that there is very little left from the shuttle that's worth saving and even less that's being saved. The Ares V core is wider, the solids are longer... Couldn't they just build an improved Saturn V and pretend the shuttle never happened?
I bet Kerosene/LOX would be cheaper too.
Re:Interesting tweak (Score:5, Insightful)
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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You think the Saturn V didn't have many tons of anti-vibration structure, anti-pogo devices, and other such things? Get real!
Actually, with a liquid fueled rocket you can put a small damper in the fuel line. [wikipedia.org]
Similar fuel pulse problems occur in diesel engines, I deal with it every day.
Re:Interesting tweak (Score:5, Interesting)
How much do you suppose a "small" damper on the fuel line weighs on a 6.7 million pound rocket? I couldn't find any answers, but it would not surprise me if the Saturn V's "small" pogo suppressors weighed over 1600 pounds in total.
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Also, there is a fallacy in your logic.
it would not surprise me if the Saturn V's "small" pogo suppressors weighed over 1600 pounds in total.
The Saturn V is a much bigger rocket than Aries I.
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I would like some actual evidence that 1600 pounds is abnormally large for vibration suppression. I don't know enough about the field to say whether it is or not, but from everything I've read about it, that number does not strike me as particularly bad. These rockets are big. For comparison, although the total weight of the rocket is not yet determined, this 1600 pound damping system will account for roughly one tenth of one percent of the total weight of just the first stage.
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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
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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
Re:Interesting tweak (Score:4, Insightful)
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 [wikipedia.org] they read as kids.
More untested principles (Score:5, Interesting)
Lets review what we have so far:
1. First attempt at building a man rated launcher with an entirely solid fueled stage
2. Largest solid rocket booster ever flown
3. First (I believe) aerodynamically unstable man rated launcher
4. And now, first use of shock absorbers to dampen an otherwise lethal vibration in a launcher
Considering how reverting to capsules was seen as a safe bet, and as taking advantage of existing technology and production lines, there is an increasing amount of experimental new technology involved.
With the Shuttles headed towards retirement and the only remaining source of access to the ISS in jeopardy due to chilly relations with Russia, now doesn't seem like the best time to be getting experimental. Functional will do just nicely.
I honestly think that a manned ATV might fly before Orion at this rate.
Re:More untested principles (Score:4, Informative)
3. First (I believe) aerodynamically unstable man rated launcher
Dunno about that one... The Gemini program's launch vehicles tended to suffer what was called the "Pogo" effect [everything2.net] once they reached a certain speed and altitude. Tended to scare the shit out of the first astronauts to experience it.
The Apollo program had solved that.
Re: (Score:3, Interesting)
Pogo isn't due to an aerodynamic instability, it's due to feedback cycles in the fuel/engine system. Simply put, the more G's the rocket experiences, the faster the fuel wants to flow into the engine, increasing thrust, increasing G's, etc. Now, the fuel system is designed to limit that for obvious reasons. Pogo happens when the control mechanisms don't react quite as fast as the feedback cycle and overcorrect. Another cause of pogo (serious on Saturn V until they figured it out) is hydraulic effects in
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Huh? First off, Pogo is experienced to some degree or another by practically ever booster of significant size. The best you can do is dampen it below danger levels, as it is an
Re:More untested principles (Score:5, Informative)
3. Basically all space rockets are aerodynamically unstable. This is absolutely nothing new.
4. Before it was eclipsed by an even worse event, Apollo 13 briefly scared the crap out of everyone involved when the center engine of the second stage nearly ripped the entire rocket to little pieces. It was experiencing pogo oscillation [wikipedia.org], flexing the massive thrust frame by three inches at 16Hz, experiencing 68 gees. Just before this incredible vibration destroyed the entire craft, a fuel sensor was falsely tripped and shut the engine down, saving the ship.
Saturn V and Apollo were full of problems. Rocket science is hard, remember? I suggest that you get a clue before you mindlessly criticize.
Re:More untested principles (Score:5, Insightful)
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.
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Apollo 13 briefly scared the crap out of everyone involved when the center engine of the second stage nearly ripped the entire rocket to little pieces. It was experiencing pogo oscillation, flexing the massive thrust frame by three inches at 16Hz, experiencing 68 gees.
You're greatly exaggerating the Wikipedia entry, which itself exaggerates the actual facts. (What, Wikipedia not accurate? I'm shocked!)
There was a known pogo issue on the center S-II engine, observed at 18 Hz on Apollo 8, apparently limite
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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
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3. First (I believe) aerodynamically unstable man rated launcher
Actually most if not all manned and unmanned commercial rockets are aerodynamically unstable. They require active guidance systems to stay flying straight. (You couldn't manually pilot them without computer control, similar to modern fighter jets from F-16 onward.)
Model rockets have fins in order to be stable without this active guidance.
Pendulum Rocket Fallacy [wikipedia.org]
Also check this article on Little Joe II [wikipedia.org], the apollo abort test platform. It has f
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The vibrations are not lethal. They are 5-6 Gs, which is enough to temporarily impair the functionality of the astronauts (blurred vision, etc), but not enough to seriously injure or kill.
from the Space.com article:
Why have they left it this late? (Score:4, Informative)
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This isn't pogo, which you linked to, which affects only liquid-fueled rockets. This is an "organ pipe" oscillation characteristic of solid rocket boosters.
Still an old problem, but not quite what you describe.
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This isn't pogo, which you linked to, which affects only liquid-fueled rockets. This is an "organ pipe" oscillation characteristic of solid rocket boosters.
Mod parent up please. This explanation makes much more sense. The length of the SRB makes the gases inside resonate to a specific frequency. If that frequency is close to the natural frequency of the craft, it breaks.
This leaves NASA with a few options:
A) Change the frequency of the booster. (Use two shorter SRBs so they resonate at higher frequencies.)
B) Change the natural frequency of the vehicle. (add or remove mass)
C) Use a totally different kind of engine.
Can someone at NASA... (Score:3, Informative)
Active Control System (Score:3, Insightful)
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!
it keeps getting better and better (Score:2)
Wow, what a mess. Tell me again about all the cost savings involved in reusing components versus starting from a clean sheet?
Treating The Symptoms (Score:2)
In medicine, it's called "allopathic", treating the symptoms. Doctors frequently do this because they're working from complaints and tests, not from a theoretical understanding of the systems. You can take aspirin for a headache. It'll probably work. You can't know without extensive testing whether that headache is due to a brain tumor (obSchwartzenneger: "It's NOT a tumah! It's NOT!").
A 4G vibration that's not felt by the astronauts but still occur in the vehicle could still rip the booster apart.
The DIREC
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You think that existing rockets don't have vibration problems? Get real!
Funny you should mention Apollo 13. On launch it came within seconds of total destruction due to a pogo oscillation in the second stage center engine that was vibrating at 68 gees, flexing the thrust frame by 3 inches at 16Hz. By complete, pure luck, a fuel sensor tripped and shut the engine down literally seconds before the entire rocket was destroyed.
Apollo 13 was also a huge failure of engineering. Remember all that improvisation the
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Yes, they are treating symptoms rather than the whole system,
but no, that's only what "allopathic" means if you're a homeopath itching for a fight.
Overcomplicated! (Score:4, Insightful)
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.
Inertial dampers, the only way to go (Score:2)
Seems to me it is about time NASA contacts Area 51 and puts an order in for those inertial dampeners we keep hearing about in Star Trek, Star Wars, BSG. My favorite is EE Doc Smith's Enertia-less drives.
Putting shock absorbers in a space craft just sound wrong. What's next? Fuzzy dice in the command module?
save the 1600lbs (Score:3, Informative)
Fly EELV instead - make Orion a much simpler and more robust capsule. Delta IV Heavy can already lift the ISS-bound version of Orion without trouble. Ares is a joke, a joke played by ATK, Mike Griffin and Scotty Horowitz on the US taxpayer.
The other problem with ESAS/Ares/VSE as currently implemented by NASA is that they choose the launcher (vaporware Ares based on SRBs) and are trying to shoe-horn the payload into it. This is 100% backwards from how most missions are designed, with the payload dictating the launcher.
Between this and the trouble that Orion development is experiencing, it would appear that the Chinese or even US private firms will be on the Moon before NASA. Go Bigelow!
For the astronauts? (Score:2)
I knew us Americans were growing obese...but was this really necessary?
Orion? NASA? Shock absorbers? (Score:3, Funny)
Go NASA!! (Score:2)
Awesome. Leave it to NASA to install more and more complicated parts on something until it's almost completely useless and costs a billion dollars per launch.
Next, failing to learn from other previous design mistakes, they'll install heat resistant tiles all over the thing.
Read that dyslexically (Score:3, Funny)
I read that headline dyslexically and thought it said "NASA Installing Shocks on Arse"
I thought it was about some new kind of employee training program involving electrified chairs so that managers could BZZZT someone not working :P
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Nooooo problem! They'll just add another segment to the booster! :)
Next : (Score:5, Funny)
Chrome rims and a spoiler. We might not be alone, so dress to impress!
Btw, not 16, "a 17th shock absorber will be a ring of weights and springs near the middle of the rocket".
Might not have a cannister though, or a switch ; )
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Yeah, they would only have to use 45.359237 kilo weights.
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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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Major Kludge (Score:4, Informative)
>big, clunky, and with no regard for elegance.
Dealing with a vibration problem by adding nearly a ton of lead bouncy weights is not a great solution; especially when your mission is climbing out of a deep gravity well. They need to be looking for and fixing the source of the vibration.
Fortunately, they are. From Wired [wired.com]: "In the long term, Gary Lyles, associate director for technical management at NASA's Marshall Space Flight Center, said they are planning cold flow testing to learn more about the source of the vibration within the motor design itself. The next step would be sub-scale hot flow tests with solid rocket motors. If the tests prove conclusive, NASA will be able to look at doing a block upgrade to the motor and adding design changes to the full scale motor that will result in less vibration being produced. This would solve the problem without adding on extra weight to compensate for the problem."
Re:This is not going to increase efficiency.... (Score:4, Insightful)
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The flammable Apollo Command module was designed by North American Aviation, not by the imported German rocket scientists who worked on the Saturn V booster.
(The Apollo capsule was considered by many to be bloated and technically inferior to the earlier Gemini capsules.)
Re:This is not going to increase efficiency.... (Score:5, Informative)
Their demise wasn't caused by a flaw in the rocket itself, it was because the capsule was using pure oxygen under low pressure in order to save weight.
Unfortunately - materials that were flame-retardant or flameproof in normal air became extremely volatile in the 100% oxygen atmosphere in the capsule. They changed to a different mixture after that accident.
Their accident also happened while on the ground during a test and not in space. Their accident was actually to honor them being designated Apollo 1. (as from what I have understood from at least one source, other sources does claim that it already was designated Apollo 1). So the only in flight accident with the Apollo program was Apollo 13 - and they did survive.
So this actually tells us - beware us from accountants.
Re:This is not going to increase efficiency.... (Score:5, Interesting)
Close, but there's a bit more to it than just being a 100% Oxygen environment. One of the things being tested was that the capsule would function properly experiencing the same outward pressure that it would experience in orbit. When the craft was in space, it would be pressurized at about 2-3 psi or pure Oxygen. To simulate that on the ground, the cabin was pressurized to 18 psi, 2 psi more than air pressure at see level.
In the aftermath, they realized just how stupid that was; at that pressure of pure O2, a bar of Aluminum would "burn like wood". Almost anything will burn, and many things will burn spontaneously. To make matters worse, almost every exposed surface of the module was covered in velcro for ease of use in zero-g. The problem is, the velcro was literally explosive at the Oxygen density used during the test.
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Unfortunately - materials that were flame-retardant or flameproof in normal air became extremely volatile in the 100% oxygen atmosphere in the capsule. They changed to a different mixture after that accident.
Close but not quite. The materials were also flame-retardant or resistant at 100% oxygen atmosphere at the pressure specified for flight, about 3 psi. (The same as the partial pressure of O2 in normal air.) This they did not change after the accident.
The accident happened because they wanted to run t
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Sounds like the Apollo program had a lot more bugs than just that particular one.
It was a litany of disasters that brilliant crews, both in space and on the ground, handled very well, otherwise there would have been a lot more deaths.
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Yeah, where do you find living Nazi-Era German Rocket Scientists these days?
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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, Sal
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Oh, it was WAY worse than that... just off the top of my head:
1) When landing on the moon, during the final (and most tricky) phase the computer controlling the LEM effectively turned off - Neil landed manually, with the computer yelling abort all the way.
2) Apollo 15 (I think) they tried decreasing the number of thrusters used to separate the stages - the stages almost collided, nearly killing everyone aboard.
3) Apollo 13, the center engine entered a pogo oscillation on launch that was about to destroy the
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The US government oversaw Apollo. US enterprise is currently overseeing a crappy suborbital space plane and an even crappier low payload rocket.
If the current incarnation of NASA has a problem, it is that like many modern government agencies it is trying to emulated private enterprise too much.
Re:Hey there! (Score:4, Informative)
Hilariously the apollo program had some pretty serious pogo oscillation problems. Pogo is shaking the rocket up and down makes the propellant flow increase and decrease making the oscillations worse.
In the apollo era, as per http://www.clavius.org/techsvpogo.html [clavius.org] they used plumbing style water hammer chambers to eliminate the fluid surges. Let the vehicle shake but prevent the ability for shaking to cause thrust variations.
The modern solution is apparently dynamic shock absorber technology on the vehicle.
The modern solution eliminates the shaking, the old solution allowed it to shake but patched around it so it didn't have negative effects.
The modern solution is better, which makes the comparisons to Apollo kind of funny to those who know...
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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....
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Ewe muss bee knew hear!
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That's not being a grammar nazi - he used the wrong word so that the sentence no longer makes sense.
Wood ewe be a grammar nazi to point out that the first two words of this sentence are wrong even though they happen to *sound* like the right words?
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