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Design of Next-Gen NASA Rocket Showing Flaws
caffiend666 writes "According to an AP news article, NASA engineers are concerned about the design for the new rocket meant to replace the shuttle. Work on the project has revealed that the first few minutes of flight could see 'violent shaking', a serious flaw that might destroy the craft soon after launch. 'NASA officials hope to have a plan for fixing the design as early as March, and they do not expect it to delay the goal of returning astronauts to the moon by 2020. The shaking problem, which is common to solid rocket boosters, involves pulses of added acceleration caused by gas vortices in the rocket similar to the wake that develops behind a fast-moving boat.'
...before it's built. Seems like a non-story.
so they found a problem with a preliminary design. big deal. that's why they call it research and development.
how long did it take to design the saturn Ib/saturn V and make sure that they'd mate well with the apollo capsule? how long did it take to come up with skylab, an orbiting lab that could be mounted on a saturn V?
i expect it'll take about five to six years to bring the orion program to a complete first generation system.
when religion is no longer the opiate of the masses, governments will resort to real opiates.
You mean they didn't get the design of a prototype exactly right on the first try? Amateurs! Seriously though, where is the news here?
today is spelling optional day.
Certainly better than financials... I think they do awesome work. I have been proud of the rover project, and I think the knowledge gains from NASA missions have long tails.
If anyone else has read Diane Vaughan's Challenger Launch Decision, he or she will know that launch schedule pressure from upper management was a leading cause of the rationalization of risk that NASA undertook to justify flying with known Shuttle desgign flaws. Hopefully, in this case, the NASA senior managers are not applying the same mindless schedule pressures that leads to quick fixes and mindless workarounds at the expense of long term safety.
We all know what to do, but we don't know how to get re-elected once we have done it
How is it that astronauts managed to land on the moon in 1969 but the next mission to get people to the moon will take until 2020? With today's engineering tech - CFD software, advanced materials science, VR simulation, rapid prototyping technology - and lots of commercial sattelites shot into space every year, it should be much easier to get people to the moon and back safely than it must have been in the 60s. Unless of course that landing was faked as some people allege.
It's a harmonic vibration issue apparently, and these are generally solved quite easily. Adding or removing stiffness, a spiral wrap of an energy dissipating elastomer, isolation mounts, ading or removing mass (or simply moving mass around)... doesn't look like it's a severe issue at this early of the design stage. Someone's just being alarmist.
She can't hold much longer, captain!
Management....wants....a....launch....so....shut....the....fuck....up, Scotty!
Table-ized A.I.
Actually, NASA's ROI is pretty good at about $7 returned for every $1 spent. They also develop a lot of technology that doesn't have a financial ROI, but rather a simple non-tangible benefit to society as a whole. For example, they developed the CCD imager for use in the Hubble Telescope. That technology is now widely used in inexpensive digital cameras but is more importantly also used in medical imagers for detecting breast cancer. It has eliminated something like a half a million unneeded biopsies which not only save that cost, but also the pain from the procedure itself.
Bill
It's my Sig and you can't have it. Mine! All Mine!
Solid Rocket Boosters are sort of like strapping yourself to a firecracker. We can't have liquid ones?
Bruce Perens.
The first Saturn V rockets for the Apollo program had a similar problem with pogo oscillations. http://www.time.com/time/magazine/article/0,9171,902216,00.html . Engineers were able to solve the problem back then, I'm sure they can come up with solutions again.
This was brought up last NASA story. Somebody pointed out that just ONE of the technologies produced for the Hubble telescope lead to more money saved on machines scanning for breast cancer than it cost for the Hubble in its entirety, and that's just the price tag, not the lives that have been saved because of that alone.
When stationary, the air must have a net velocity in excess of 400 mph for the engine to retain efficiency - which a turbine can easily do if there are no other complications. Eventually, the turbine gets in the way, hence the need for a really good bypass system. White Knight avoided the need for TAR by having the first stage as an actual aircraft, but a conventional aircraft isn't going to be capable of carrying the weight needed for true orbital flight, let alone interplanetary flight. Affordable space flight is probably going to require TAR engines.
(Other alternative launch-assist methods include using linear accelerators - basically strap the rocket onto something akin to a bullet train and then get the train up to the critical speed, or using a very powerful gas cannon to fire the rocket into the air at the critical speed. The first would likely end up more expensive to operate than a TAR, the latter would require a very sophisticated multi-charge arrangement if it is to avoid killing everyone onboard, but might end up being another viable method.)
One thing I think can be said for certain - by 2020, no sane engineer will be designing launch vehicles for space that use a rocket first stage. I'll give it a 40/60 chance that by 2020 commercial space flight will have surpassed NASA in terms of cost-per-unit-mass-launched, and 20/80 that hobbyist space flight will have done likewise. If NASA persists in long-outmoded next-gen launch vehicles, then somewhere in the 2030-2050 timeline, NASA will be redundant. Government-run organizations make sense for bleeding-edge work because that is generally too expensive for everyone else. However, once everyone passes said Government agency's technology, it has no value or merit. To have value for money, NASA should be working on systems that will become bleeding-edge in 2020, not what were bleeding-edge in 1920. R&D is the expensive work, everything else is meccano tech.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Seriously, this was known about forty years ago and are called pogo oscillations. They are generally disastrous, and they were the cause of Apollo 13's fifth engine shut down after liftoff.
In general, I'm pretty non-plussed by NASA's moon landing attempts. Their design is basically Apollo rehashed plus forty years (fifty years if it actually launches - pretty depressing), the vast majority of it isn't reusable (I haven't got a clue how they can call it a shuttle replacement) and it really doesn't get us any further forwards in terms of making getting into space easier, safer and something that can be done on a regular basis.
""I hope no one was so ill-informed as to believe that we would be able to develop a system to replace the shuttle without facing any challenges in doing so," NASA administrator Michael Griffin said in a statement to The Associated Press."
Well, duh, the whole point of the 'shuttle-derived' Stick design was that it was supposed to be safe to fly and fast and cheap to develop because the shuttle technology would avoid these kind of 'challenges'.
But instead of building a capsule that could fly on the shuttle-derived launcher they've expanded it into an orbital RV which requires major changes to the launcher design to have any chance of reaching orbit.
This is a non-story. Rockets explode during their development.
The difference being that, at the time, the entire population rallied behind NASA. Our domination of the Space Race was needed to establish our position over the Soviets during the cold war. People had no problem allowing the government to pump money into a program that would prevent the Soviets from establishing a foothold above us in space.
Unfortunately, the population doesn't have that kind of motivation (or fear) anymore. You can damn well bet though that if al-qaeda started launching men into space and two the moon our asses would be back there by the end of the week.
In an effort to conform with internet communication standards, please note that the above comment is 100% biased opinion
"Link?"
I believe you'll find it's another made-up statistic to justify NASA based on 'spin offs'; most of those arguments turn out to be bogus when you actually look for proof.
In addition, if you want CCDs, you'd be better off spending the money to develop them and skipping over the entire mult-billion dollar HST thing. Now, I think the HST is a good thing, but it has to stand on its own merits, not on the basis of some possible 'spin offs'.
http://freakonomics.blogs.nytimes.com/2008/01/11/is-space-exploration-worth-the-cost-a-freakonomics-quorum/
My ism, it's full of beliefs.
>they do not expect it to delay the goal of returning astronauts to the moon by 2020.
of course not, what's going to delay going to the moon again by 2020 is the fact that congress has no intention whatsoever of paying for that, and no one, not even Bush takes the program seriously.
Why are they wasting money on programs that are going to be thrown right out the window, never to be heard of again, as soon as the next president takes office?
The first couple minutes really suck. Those SRB's shake bad. Once they burn out, the ride is really smooth. Solid rockets are that way, I am sorry, but you can't have fuel moving up the tube and the flame following it and have a smooth ride. Think of the solid fuel, it doesn't move, only the pressure. The farther it moves up the more the pressure changes here and there. POGO is something else. That is more from liquid fuel sloshing around, not presenting and even pressure. As the fuel is falling it adds more weight causing more thrust, and as the fuel splashes up, then there is less weight and pressure, meaning the engines are working to compensate. Someone will come up with something to make the ride some what tolerable. I don't think I'd ever want to ride that big long SRB into orbit. That will be more jarring 8 minutes of your life! ick.
IANARS, but these do not blow up. Heck even the challenger did not blow up. A seal popped open that allowed the exhaust to hit the fuel tank. The simple fact is that these are VERY safe. It has only several issues; The mix is hard to get right. Considering that it is the same mix that has gone into all 120+ x 2 shuttles, I am not too worried. The second is that once lit, there is no stopping it, and there is no throttling it (other than building it into the mix). This is not like strapping yourself to a fircracker, but to a simple bottle rocket that does not pop.
I prefer the "u" in honour as it seems to be missing these days.
I wish NASA would put more effort into developing gaseous core nuclear rocket engines. There was a nuclear engine project in the late 60s using a solid core reactor, but gaseous core reactors have not been thoroughly explored. Whereas solid reactors melt above about 3500C, a "light bulb" type of reactor consisting of a hollow quartz bulb with a cloud of gaseous nuclear fuel confined in the center could operate at 25000 C, radiating in the ultraviolet range instead of heat per se. In an engine based on this type of reactor, hydrogen flowing past the outside of the bulb would be superheated and expelled as rocket exhaust. No chemical combustion, no radioactive emissions, just heat transfer.
Check out this interesting article, part 10 of a series, about a hypothetical design for a non-polluting, 100% reusable nuclear rocket based on the Saturn V form factor. Using existing engineering apart from the gaseous core reactor, it could lift 1000 tons of payload into orbit (6 times the capacity of the proposed single-use Ares 5 cargo rocket, and 30 times that of the shuttle), and then return 1000 tons of cargo to a powered vertical landing. No expendable fuel tanks, no solid booster recovery, just a big old Flash Gordon style rocketship. This is heavy lifting power that could take up a space hotel or moon base in one shot. It could power enormous ships to Mars in 3 months, not merely to explore but to colonize, carrying hundreds of people at a time, hundreds of tons of equipment and supplies, and highly effective radiation shielding.
I know it's the "N" word, but this rocket wouldn't be a nuclear disaster waiting to happen. If such a ship crashed or exploded and released its entire nuclear fuel load into the atmosphere, the nuclides released would be 1% of what came out of a single 1950s bomb test (and there were many of those).
Let's however get back from engineering dreamland and take a cold hard look at political reality. Anything with the word "nuclear" in it scares the shit out of the vast majority of people. Most people seem to be convinced that every nuclear device is a potential nuclear weapon waiting to go off, and that any nuclear accident will inevitably result in thousands of deaths and an area the size of Texas rendered uninhabitable.
I am perfectly well aware that the actual situation is nothing like that (and, furthermore, the results of a chemical rocket malfunctioning aren't pretty either). But nuclear rocketry in Earth's atmosphere is a nonstarter for the next couple of decades at least.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
With this new rocket we see the same idiotic non-scientific design. The rocket will be unstable folks. You know it, we know it. Make it look like Soyuz. Nothing will happen, but lives will be saved.
You proved the world that you can live with non-metric non-scientific Imperial measurement system (inches, pounds, arrow flights, feet, elbows, miles, stones, etc.), that the religion is the "best" spiritual foundation of the state. But maybe it is time to say: enough is enough, put the pride on the shelf, and do it right at long last?
http://www.transterrestrial.com/archives/010396.html#010396
What exactly is the issue? The problem is that any structure has a resonant frequency at which it naturally vibrates. If you excite the structure at that frequency, you can develop a positive-feedback system that will literally shake it apart (the Tacoma Narrows Bridge is the classic example).
Solid rocket motors don't run particularly smoothly (compared to well-designed or even poorly designed liquids) and large solid motors provide a very rough ride. Everyone who has ever ridden the Shuttle to orbit has commented on how much smoother the ride gets after staging the SRBs.
Now, one way to mitigate this is to damp it out with a large mass. The Shuttle does this by its nature, because even though it has two of the things, they are not directly attached to the orbiter--they are attached to a large external tank with one and a half million pounds of liquid propellants in it, and it can absorb a lot of the vibration. Moreover, the large mass has a frequency that doesn't resonate with the vibration.
As I understand it (and I could be wrong, and I'm not working Ares, but this is based on discussions, many off the record and all on background with insiders on the program), there is a very real concern that the upper stage on top of the SRB in "the Stick" will be excited at a resonant frequency, but that even if not, the stage will be too small to damp the vibrations of the huge SRB below.
If this is the case, there is no simple solution. You can't arbitrarily change the mass of the upper stage--that is determined by the mission requirement. Any solution is going to involve damping systems independent of the basic structure that are sure to add weight to a launch vehicle that is already, according to most reports, underperforming. Or it will involve beefing up the structure of the upper stage and the Orion itself so that they can sustain the acoustic vibration loads. In the case of the latter, it is already overweight, with low margins.
So this constitutes a major program risk, that could result in either cancellation, or a complete redesign (that no longer represents the original concept, because the problem is fundamentally intrinsic to it).
Now, let's take apart the response a little:
Thrust oscillation is...a risk. It is being reviewed, and a mitigation plan is being developed. NASA is committed to resolve this issue prior to the Ares I Project's preliminary design review, currently scheduled for late 2008.
The problem is that NASA can "commit" to resolve it until the cows come home, but if it's not resolvable, it's not resolvable. They can't rescind the laws of physics, and we're approaching a couple of anniversaries of times when they attempted to do that, with tragic results.
Now this next part is (to put it mildly) annoying:
NASA has given careful consideration to many different launch concepts (shuttle-derived, evolved expendable launch vehicle, etc.) over several years. This activity culminated with release of the Exploration Systems Architecture Study in 2005. Since then, the baseline architecture has been improved to decrease life cycle costs significantly.
NASA's analysis backs up the fact that the Ares family enables the safest, least expensive launch architecture to meet requirements for missions to the International Space Station, the moon and Mars. NASA is not contemplating alternatives to the current approach.
The problem is that NASA didn't give "careful consideration" to the previous analyses after Mike Griffin came in. As far as can be determined, all of the analysis performed under Admiral Steidle's multiple CE&R contracts, performe
ALL of our early missiles from the 50's were liquid based. All of our space program has been liquid based. Mercury was based on Atlas. Gemini was based on Titans. Apollo used the Mighty Saturn V. ALL of these engines were liquid based. Some are kerosine/LOX, and others are Hydrogen/LOX. The main boost of the Shuttle is based on the SSME. The main boost of the Ares V will be liquid. Likewise, even spacex's engines are liquid based. The brits abanded their missles and their launch systems BECAUSE they had so many problems. Even to this day, ALL of their missiles are produced from America.
I prefer the "u" in honour as it seems to be missing these days.
I see the problem here being one of opportunity cost.
This of course assumes the technology would never have been discovered if we didn't spend the initial investment; but by beating the would-be discoverer to the punch, we get the return soonerBut what technologies are discovered later because we are inefficiently allocating resources via NASA? You can say that solar cells, fuel cells, and velcro came sooner because NASA helped invent them. But NASA has been wasting money for decades. You don't see what's missing.