But we can say whether vibrational loads will ever cause a problem. Vibrational testing is one of the hot "test items" that is performed for launch vehicles. Many, if not all, launch vehicles are modeled, simulated, tested, and characterized before they ever get fueled and launched.
The vibrational problem is well understood. To give an example, active force-feedback flight control sticks are used in the Apache. One of their tests is a vibration test. As part of that vibration testing, all conceivable vibration inputs are considered. The big ones are: engine noise, sustained impacts from enemy munitions, and firing of the apache's weapons with the emphasis on the machine gun under the cockpit. A vibration on the pilot's seat caused by the pilot farting isn't really considered because it's understood that such a vibrational input has very little impact on the Apache's flight controls (unless it tickles, I guess). But it's understood that the fart won't do much because the system is almost fully characterized (testing will help to fully characterize it).
All rockets shouldn't be grounded. I'm a bit biased on that, since I'm a rocket scientist. But it seems clearly reasonable to make sure that the rocket is understood as much as possible so suprise situations don't arise often.
As for the falling foam being understood by NASA, ANY person with a background in fluid mechanics would have pointed out the impulse that such an impact could impart to the wing would be much greater than anticipated. That's a management issue too: not putting the right people in place, or not consulting with the right people to get the answers.
No offense to any mechanical engineers, but I believe that the first thoughts concerning the foam were put forth by mechanical engineers with NO experience with aerodynamics. If I recall correctly, the prevailing thought was, "foam is soft, it'll just bounce off".
orca2 stated well the issue with not acknowledging the 10th engineer in his reply to your post.
The main thing that NASA's management forgot about the shuttle is that it was a EXPERIMENTAL vehicle. Even though it had a proven track record, it was still experimental. I now work in an environment that involves experimental stuff. And I'll tell you what... we make damn sure that all of the safety issues are addressed. We even have people unrelated to the program, but still proficient in areas related to the program, come in and examine how we go about test safety. Even though a lot of the stuff that we do has never been done before, we still make sure as much as we can that nothing will happen. We'd rather have our test personnel come back, and lose the experiment or lose data, than see our test personnel come back in a body bag.
That's part of the issue here... NASA didn't want to scrub the mission for fear of losing money and face, so they lost money and life.
As for the Italian company's work, NASA signs NDAs all the time. And JPL was where mission control was for Cassini, they had a powerful voice in the mission (and still do).
As for NDAs... At least at my former employer, we did TONS of NASA contracts and each time NASA had no problem signing an NDA. They are a bit different when the government is involved, but the government CAN'T take your company's technology/idea and go to another company and develop it cheaper, or publish your data (it's proprietary). There are strong laws against that.
In all seriousness, NASA has a way of pulling through. They'll figure out how to implement proper safety procedures and checks. And they'll figure out how to do those safety items without stalling their programs. I'm actually very suprised that NASA would forego the lives of its astronauts by NOT implementing good safety measures, even on experimental vehicles.
I did the same thing as NASA... minus the vector math.
The patched conic method is how you visualize the vector math, and those two together are only an approximation. The vector math is kind of the mortar between the patched conic approach. Patched conics offer visualization, but to figure out the actual direction and magnitude of the velocities, you need to do vector math. =)
Hill's equations are solved if you want a more precise orbit calculation.
In both cases, the managers became complacent. It's the same idea as, "the sun rose yesterday, and today, it's GOING to rise tomorrow!" There is no evidence that says the sun WILL rise tomorrow; only evidence that says that it has, and that it's very likely that it will again.
But the common thread to both of your paragraphs is that NASA had some info tucked away somewhere and didn't have it out.
Though I do agree with the fact that NASA didn't really explore the foam impact until after Columbia.
It's still true that NASA declined DoD imagery which would have easily spotted the shuttle's damage. Then at least they would have known. Though there was no way for the shuttle's crew to do anything about it, really... the next shuttle wasn't ready, and the next resupply vehicle was a month away. But they would have had better information about the problem, which is what NASA's management problem is.
NASA managers seem to put too much faith in their QA process. NASA managers also have the whole attitude of "I've been here XX years, I know what's going on!" or "I have 9 engineers telling me 'GO' and one saying 'NOGO!'; 9 in favor... it's a GO!"
Those attitudes pervade EVERY program over at NASA. Just look at the swedish engineer that found the doppler shift problem with the Hyugens probe. JPL just accepter the italian contractor's work without question. That's something that a good manager would NEVER do.
NASA also has the whole backstabbing, take your work and call it my own, ALWAYS put a good face on me attitudes amongst most of their managerial staff. That kind of thing is counter-productive especially when they are doing primarily R&D or T&E work.
What gravity assists do can be thought of in this way:
Think of ALL orbits as ellipses (this will avoid confusion).
Realize that the ellipse pictured in your head is the path that you will travel as you orbit something, with one focii of the ellipse at the center of mass of the object you are orbiting.
The result of one of the ellipse's focii being the object you are orbiting is that you will have a maximum and minimum altitude relative to that planet. (A result of this thought experiment, rather.)
You will swing really fast around the planet you are orbiting when you are closest to it. Then you will be sent on your way away from the planet, only to fall back down.
BUT! Let's say you added another planet at the OTHER focii. But let's make it simpler (in terms of the big picture) and say that the planet will be at the focii when you get near it. In other words, that other planet's orbital path puts it dead center on the focii of your orbit's ellipse just at the time that you happen to be close to that ellipse.
What will happen is that the gravity of this new, second planet will influence you more and more as you get closer to it. It gets to a point where your orbit will be changed so much by this new planet that you are travelling in a different direction.
If done properly, your gravity assist comes when you happen to swing around this second planet. Remember that as you get close to the body you are orbiting, you gain speed. And since as you get closer to the second planet, you are orbiting it more and more, this new speed you encounter can increase or decrease your true velocity. You are no longer really on the orbit around the first body. Instead, you are orbiting the second body.
Now, if you were to extend this to a third body, and a fourth and so on, you'd see how the gravity assists can be staged throughout the solar system. When the next planet flings you away from it, you usually have more than enough escape velocity for that planet. You can think of gravity assists as changing the focii of the ellipse that your orbital path takes.
Granted, overlapping conic sections (ellipses, parabolas, hyperbolas, points, and circles) is the best way to think of how orbits are put together, they are a bit more complicated than that. The complication comes from the fact that there is a lot of "junk" out there that introduces noise into your system, and there is the fact that no body is a perfect sphere (which would produce a perfectly spherical gravitational field).
Isn't orac2's point that the management still decided to fly, even though they had evidence in both cases that would have made them shout "No go!"?
Isn't the fact that the management over there always takes the attitude that they're right part of the problem in both cases (I have a co-worker that used to work at Dryden).
Isn't it a fact that the safety manager for the Columbia mission gave a stamp of approval, despite her engineers' concerns that the impact was worse than thought? Also, isn't it a fact that this same person DECLINED to request or even consider DoD satellite imagery that would have confirmed the extent of the damage?
Isn't it also true that the safety process broke down for Challenger because managers decided to NOT listen to their engineers?
Now, isn't it true that in both cases, MANAGEMENT didn't heed their engineers' warnings? Isn't it also true that they neglected (or conveniently forgot) about mission critical information that, had they had it in front of them, would have stated that there was a huge problem that should be investigated?
It is true as I see it that both accidents were caused by poor management decisions. NOT a faulty part (say a part that got through QA when it should have been screened out).
I think you're mistaking the technical differences between the accidents with the managerial differences. In both cases, management pushed ahead, even when some information was stuffed away somewhere that would have stopped the go ahead decision. NASA's problem, as orac2 is trying to state, is that they don't remember their mistakes... they're not propagating the information about their mistakes properly.
I'm an engineer myself (actually a true rocket scientist by training and trade), and I can understand the occasional calculation error, or the occasional bad call about assumptions. But when it comes to a manager, who should know something about management, who decides that he/she should press on with the mission without giving pause for previous failures, then that manager should be removed or retrained until they get it right. (It's kind of like president Bush's "we will stay the course" crap, when what's happening now clearly isn't doing the job in Iraq.)
How about:
autopilots, mars missions, ground penetrating radar, TDRS ( a deep space communications network), X43 (the world's only vehicle capable of Mach 7, and possibly Mach 10), the worlds first computerized inertial guidance system (apollo), Kalman filters (used in a LOT of electronics), not to mention thousands of improvements and inventions related to aviation safety (gust alleviation systems, flutter analysis methods, investigation into forward swept wings, supercritical airfoils, exploration into quieting turboprops, turbojets, and turbofans). And that doesn't even touch on the hundreds of thousands of earth sciences experiments, astronomy/cosmology experiments, planetary sciences experiments, and a whole host of other experiments.
Without NASA, we wouldn't have reliable weather forecasting (even three or five days is better than none at all), we wouldn't have had such a huge development of consumer electronics (which stemmed from both NASA and DoD interest in electronics), a plethora of medical knowledge that directly resulted from studying human reactions to low-gravity environments and animal and plant studies done to see what development of organisms is like with low gravity, and information about the earth's ozone layer and ionosphere (did you know that you could hear radio transmissions around the world because they bounce off the ionosphere, and that the stations you recieve depend on the time of day because the ionosphere expands when hit with daylight?). NASA also does quite a bit of work with NOAA for modeling and simulation of weather systems.
There are plenty of ways that NASA's work has influenced all of us.
15 km/s is more reasonable because the delta-v needed to go from earth to saturn is on the order of that much. 57 km/s sounds more like Neptune.
As for how they got it going that fast, you have to remember that the velocity that you came up with is an average. Actual orbital velocities vary greatly. The other thing is that the vehicle had some fun with gravity assists (angular momentum transfers), and other planets. The initial velocity when it left earth orbit couldn't have been much more than 12 to 15 km/s.
At Circuit City, BestBuy, CompUSA, RadioShack, Computer STOP, Fred Meyer, Allstar Auto, and a smog check station near where I live where I had to get my car tested before getting it registered in CA.
In general, I've stopped going to stores for info. I have gotten to the point where I've researched what I want to buy to the extent that I know exactly what I'm looking for and I just need to find the best price to get it. On top of that, when a sales rep comes over and makes a comment like, "SuSe doesn't do as well as Windows, because...", or "32 bit processors, like Intels, are better than 64 bit processors, like AMDs, because the processor doesn't have to work with big numbers all the time. 64 decimal places is much bigger than 32 decimal places, and that's where the problem is."
Better yet was a mechanic trying to tell me that my Audi A4 didn't need its transmission fluid changed because "German cars are so well built that they don't need to have the transmission fluid changed." This was even after I pointed out the Audi Service Bulletin that described the mileage between changes and what transmission fluid to use!
In each case, I found that it was irritating, but kind of fun to call them on their lies. One guy even tried selling some RAMBUS RAM to me saying that they use genetically engineered silicon. I was like, WTF!? (I was looking for PC2100 RAM at the time.)
It was also especially fun if I made quite a bit of noise in the store about the salesperson lying.
What if the entire flash was encrypted with a small partition on it with a decryption routine that also pointed where to start?
It'd make it slower (probably a lot slower if you're operating in the USB stick only), but adding an encryption scheme would at least slow down someone that wanted to image your USB stick.
LLNL does nuclear research (basically simulating nuclear weapon detonations). We spend $400 Billion on defense per year, what is $200 - $300 million for the latest and greatest super-computer?
Also, since the US agreed to stop testing nuclear weapons, they've moved on to totally simulating them. Most often the research is done under the guise of astrophysics because the physical processes are almost identical. The US has to stay on top of things, and simulation is the only option to do so.
True. But wouldn't the thing that was luminescing get extra attention? Wouldn't that be a good thing?
And since explosives are so reactive, there is outgassing which produces a small chemical trail (how dogs can sniff explosives), which means that you can't hide the smell of the bomb by sealing it up.
I'm reminded of the slashdot poster who, on the day the sample return capsule crashed without deploying a parachute, turned on the TV with the sound off and the saw what appeared to be a flying saucer half buried in the desert with the words 'BREAKING NEWS' flashing across the bottom.
ROFL! That comment made me spit my drink all over my desk. Great!
If it were, then how do you think an apartment complex gets its water and sewer if it says to its tenants that the apartments will cover sewer, water, and garbage? The water, sewer, and garbage companies sure don't need it then.
At least in Washington state and California this is the case. And I'm fairly certain that there are only four organizations that can use your SSN in that manner: government agencies, employers, banks, and landlords. Anyone else can't legally deny you services based on your refusal to give your SSN. (I know that's a fact because when I became employed with the federal government, that's what they specifically told us. There are problems with federal employees and identity theft because people don't realize what the law is.)
It's illegal for anyone but the government, employers, banks, and landlords from requiring your SSN. Banks and landlords have very limited definitions on what they can do with your SSN.
Anyone else that requests your SSN can be told, by you, to fsck off. They can't withold services from you if you refuse to give it either.
At least that's the information I got from my employer when I was hired (government). They specifically warned about identity theft and listed the organizations that can legally use your SSN, the laws that apply to the use of SSNs, and they instructed us to get nasty with anyone that refuses service to us if we're asked to give up our SSN. It's private info.
The problem is that people are pretty easy to give up that kind of info. And when Joe Blow gets it and doesn't know how to secure his computer, bad things happen.
By law, the only places that can receive your SSN are government offices, employers, banks and landlords. Anyone else can't deny you any of their services based on you not giving them your SSN. I think banks and landlords are the ones that are most limited in what they can use the number for. Government and employers use the number for taxes and for government to turn you into a number (for medical benefits, social security payments, and so on). No one else has the right to ask for it.
Oh people will bitch and moan about not getting it from you. But who the hell at CompUSA needs your SSN?
And if a non-government or non-employer needs to verify that you are who you say you are, they can ask for your driver's license number. But the SSN is off limits to everyone else.
At least this is what my employer told me when I got hired (us government). They instructed me to safeguard my SSN as best I can, which includes not giving it to people that legally don't have a right to it. As they put it, 99% of the identity theft issues are from people giving their SSNs to folks or organizations that don't actually need it. And then those organizations don't know what a secure system is. To be honest, I'd rather have my SSN and other personal info stored on a DoD, DoJ, or whatever agency system, than on the computers at Joe Blow's Car Sales.
Re:The potential problem with these things...
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Jet Engine on a Chip
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· Score: 1
You could conceivably scale that kind of axial flow turbine down to very small levels. You wouldn't necessarily need to extremely high rotation speed for a bladed turbojet. The only problem again is viscosity... There is just too much friction between the plate and the working fluid and the working fluid and the wall.
Now, if there was a way to directly extract the energy from the flow, rather than having the flow do some work on some mechanical device, than the efficiency of the process would be improved. I'm thinking of using a material that just so happens to get excited in such a way that it lases; then you collect photons at the exhaust. Conversely, you could use some material that gets excited when you irradiate it with something (radio, light, IR, whatever), and chemically react it with something (say as in combustion), and the reaction also just so happens to produce material that is excited and spontaneously emits radiation.
The irradiation, chemical change, and spontaneous emission processes would mirror the processes in an engine: compression, combustion, expansion. The problem is, I don't think any materials have been discovered that could satisfy the requirements for the process I outlined. I also don't think people have looked at that kind of thing too much, considering I couldn't find anything during a quick (20 minute) literature search. It could be a PhD in the making??
You are definitely on the right track with using a Tesla pump, over a bladed system. That kind of device better exploits the physics at such small scales. You'd want to stack the plates though, and you'd either want the wall very close to the plates (to minimize frictional losses), or you make the plates have holes of an appropriate size in them to minimize how much mass has to move.
Another thing to note is that at small enough scales, Coulomb effects could be exploited to have say, bearingless devices.
Also, if you get small enough, and rotate your plates fast enough, you might start running into problems with synchroton radiation. That's just a result of whipping the electrons of the atoms in your plate around the axis of rotation. At slower speeds, you get the rare emmission, but as you increase speed, the chances of an emission goes up.
The potential problem with these things...
on
Jet Engine on a Chip
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· Score: 3, Informative
is that many of the physicists working on the problem don't understand fluid mechanics at such a small scale. The viscous forces are huge compared to the inertial forces, and you have a completely different set of physics.
That's why you don't see very many working concepts of small aircraft (the kind that fit in the palm of your hand) with what most people recognize as wings. They're usually equipped with small flat-plate type wings, or a ribbon-like system like on a cuttlefish.
And the reason that many folks that do happen to understand the physics don't try and do things at such small scales is that the problem is difficult. Not impossible, but difficult.
As a person with a background in fluid mechanics, I don't see how the approach in the article will ever work well or efficiently. It might work, but it's not using the kind of principles that you need. (The whole point of my post is that you can't scale a device down without adjusting or remaking how it does what it does. The physics change.)
It's great in theory. But you forget that the Treasury is only authorized to do things for a fiscal year. They can't suddenly print up a buttload of money on a whim. They have to get Congress to approve what they do.
That's why the Federal Reserve is tasked with controlling and monitoring things on a much shorter term than an entire fiscal year. If this was not done, then we would end up with a dollar that doesn't change value throughout a year, but everything else would change value in relation to that dollar.
After all of that, you still didn't realize that I answered your question: "Where did THAT money come from is the question now."
You know... the one that you posted in the parent to my post above. The money today comes from peoples' confidence in our economy. The actual paper money itself is printed in the treasury. The actual amount printed is calculated based on what is needed, and on what the value of the dollar is.
It doesn't come from thin air. Yes, the basis for that money is not a tangible item. But it is based on a measurable quantity.
Slashdot Mirror
Which is management's fault. They should have had those documents at the forefront of their minds (if they related to safety issues).
I understand that the shuttle is one of the most complicated things ever built. But the safety process can't stop because something is complex.
But we can say whether vibrational loads will ever cause a problem. Vibrational testing is one of the hot "test items" that is performed for launch vehicles. Many, if not all, launch vehicles are modeled, simulated, tested, and characterized before they ever get fueled and launched.
The vibrational problem is well understood. To give an example, active force-feedback flight control sticks are used in the Apache. One of their tests is a vibration test. As part of that vibration testing, all conceivable vibration inputs are considered. The big ones are: engine noise, sustained impacts from enemy munitions, and firing of the apache's weapons with the emphasis on the machine gun under the cockpit. A vibration on the pilot's seat caused by the pilot farting isn't really considered because it's understood that such a vibrational input has very little impact on the Apache's flight controls (unless it tickles, I guess). But it's understood that the fart won't do much because the system is almost fully characterized (testing will help to fully characterize it).
All rockets shouldn't be grounded. I'm a bit biased on that, since I'm a rocket scientist. But it seems clearly reasonable to make sure that the rocket is understood as much as possible so suprise situations don't arise often.
As for the falling foam being understood by NASA, ANY person with a background in fluid mechanics would have pointed out the impulse that such an impact could impart to the wing would be much greater than anticipated. That's a management issue too: not putting the right people in place, or not consulting with the right people to get the answers.
No offense to any mechanical engineers, but I believe that the first thoughts concerning the foam were put forth by mechanical engineers with NO experience with aerodynamics. If I recall correctly, the prevailing thought was, "foam is soft, it'll just bounce off".
orca2 stated well the issue with not acknowledging the 10th engineer in his reply to your post.
The main thing that NASA's management forgot about the shuttle is that it was a EXPERIMENTAL vehicle. Even though it had a proven track record, it was still experimental. I now work in an environment that involves experimental stuff. And I'll tell you what... we make damn sure that all of the safety issues are addressed. We even have people unrelated to the program, but still proficient in areas related to the program, come in and examine how we go about test safety. Even though a lot of the stuff that we do has never been done before, we still make sure as much as we can that nothing will happen. We'd rather have our test personnel come back, and lose the experiment or lose data, than see our test personnel come back in a body bag.
That's part of the issue here... NASA didn't want to scrub the mission for fear of losing money and face, so they lost money and life.
As for the Italian company's work, NASA signs NDAs all the time. And JPL was where mission control was for Cassini, they had a powerful voice in the mission (and still do).
As for NDAs... At least at my former employer, we did TONS of NASA contracts and each time NASA had no problem signing an NDA. They are a bit different when the government is involved, but the government CAN'T take your company's technology/idea and go to another company and develop it cheaper, or publish your data (it's proprietary). There are strong laws against that.
In all seriousness, NASA has a way of pulling through. They'll figure out how to implement proper safety procedures and checks. And they'll figure out how to do those safety items without stalling their programs. I'm actually very suprised that NASA would forego the lives of its astronauts by NOT implementing good safety measures, even on experimental vehicles.
I did the same thing as NASA... minus the vector math.
The patched conic method is how you visualize the vector math, and those two together are only an approximation. The vector math is kind of the mortar between the patched conic approach. Patched conics offer visualization, but to figure out the actual direction and magnitude of the velocities, you need to do vector math. =)
Hill's equations are solved if you want a more precise orbit calculation.
Exactly!
In both cases, the managers became complacent. It's the same idea as, "the sun rose yesterday, and today, it's GOING to rise tomorrow!" There is no evidence that says the sun WILL rise tomorrow; only evidence that says that it has, and that it's very likely that it will again.
But the common thread to both of your paragraphs is that NASA had some info tucked away somewhere and didn't have it out.
Though I do agree with the fact that NASA didn't really explore the foam impact until after Columbia.
It's still true that NASA declined DoD imagery which would have easily spotted the shuttle's damage. Then at least they would have known. Though there was no way for the shuttle's crew to do anything about it, really... the next shuttle wasn't ready, and the next resupply vehicle was a month away. But they would have had better information about the problem, which is what NASA's management problem is.
NASA managers seem to put too much faith in their QA process. NASA managers also have the whole attitude of "I've been here XX years, I know what's going on!" or "I have 9 engineers telling me 'GO' and one saying 'NOGO!'; 9 in favor... it's a GO!"
Those attitudes pervade EVERY program over at NASA. Just look at the swedish engineer that found the doppler shift problem with the Hyugens probe. JPL just accepter the italian contractor's work without question. That's something that a good manager would NEVER do.
NASA also has the whole backstabbing, take your work and call it my own, ALWAYS put a good face on me attitudes amongst most of their managerial staff. That kind of thing is counter-productive especially when they are doing primarily R&D or T&E work.
What gravity assists do can be thought of in this way:
Think of ALL orbits as ellipses (this will avoid confusion).
Realize that the ellipse pictured in your head is the path that you will travel as you orbit something, with one focii of the ellipse at the center of mass of the object you are orbiting.
The result of one of the ellipse's focii being the object you are orbiting is that you will have a maximum and minimum altitude relative to that planet. (A result of this thought experiment, rather.)
You will swing really fast around the planet you are orbiting when you are closest to it. Then you will be sent on your way away from the planet, only to fall back down.
BUT! Let's say you added another planet at the OTHER focii. But let's make it simpler (in terms of the big picture) and say that the planet will be at the focii when you get near it. In other words, that other planet's orbital path puts it dead center on the focii of your orbit's ellipse just at the time that you happen to be close to that ellipse.
What will happen is that the gravity of this new, second planet will influence you more and more as you get closer to it. It gets to a point where your orbit will be changed so much by this new planet that you are travelling in a different direction.
If done properly, your gravity assist comes when you happen to swing around this second planet. Remember that as you get close to the body you are orbiting, you gain speed. And since as you get closer to the second planet, you are orbiting it more and more, this new speed you encounter can increase or decrease your true velocity. You are no longer really on the orbit around the first body. Instead, you are orbiting the second body.
Now, if you were to extend this to a third body, and a fourth and so on, you'd see how the gravity assists can be staged throughout the solar system. When the next planet flings you away from it, you usually have more than enough escape velocity for that planet. You can think of gravity assists as changing the focii of the ellipse that your orbital path takes.
Granted, overlapping conic sections (ellipses, parabolas, hyperbolas, points, and circles) is the best way to think of how orbits are put together, they are a bit more complicated than that. The complication comes from the fact that there is a lot of "junk" out there that introduces noise into your system, and there is the fact that no body is a perfect sphere (which would produce a perfectly spherical gravitational field).
A small band of players complaining in a forum - sometimes incoherently - isn't going to change the mind and behavior of the developer.
Tell that to the tribalwar forums and the development of Tribes 2.
Isn't orac2's point that the management still decided to fly, even though they had evidence in both cases that would have made them shout "No go!"?
Isn't the fact that the management over there always takes the attitude that they're right part of the problem in both cases (I have a co-worker that used to work at Dryden).
Isn't it a fact that the safety manager for the Columbia mission gave a stamp of approval, despite her engineers' concerns that the impact was worse than thought? Also, isn't it a fact that this same person DECLINED to request or even consider DoD satellite imagery that would have confirmed the extent of the damage?
Isn't it also true that the safety process broke down for Challenger because managers decided to NOT listen to their engineers?
Now, isn't it true that in both cases, MANAGEMENT didn't heed their engineers' warnings? Isn't it also true that they neglected (or conveniently forgot) about mission critical information that, had they had it in front of them, would have stated that there was a huge problem that should be investigated?
It is true as I see it that both accidents were caused by poor management decisions. NOT a faulty part (say a part that got through QA when it should have been screened out).
I think you're mistaking the technical differences between the accidents with the managerial differences. In both cases, management pushed ahead, even when some information was stuffed away somewhere that would have stopped the go ahead decision. NASA's problem, as orac2 is trying to state, is that they don't remember their mistakes... they're not propagating the information about their mistakes properly.
I'm an engineer myself (actually a true rocket scientist by training and trade), and I can understand the occasional calculation error, or the occasional bad call about assumptions. But when it comes to a manager, who should know something about management, who decides that he/she should press on with the mission without giving pause for previous failures, then that manager should be removed or retrained until they get it right. (It's kind of like president Bush's "we will stay the course" crap, when what's happening now clearly isn't doing the job in Iraq.)
Ground breaking stuff... like ...?
How about:
autopilots, mars missions, ground penetrating radar, TDRS ( a deep space communications network), X43 (the world's only vehicle capable of Mach 7, and possibly Mach 10), the worlds first computerized inertial guidance system (apollo), Kalman filters (used in a LOT of electronics), not to mention thousands of improvements and inventions related to aviation safety (gust alleviation systems, flutter analysis methods, investigation into forward swept wings, supercritical airfoils, exploration into quieting turboprops, turbojets, and turbofans). And that doesn't even touch on the hundreds of thousands of earth sciences experiments, astronomy/cosmology experiments, planetary sciences experiments, and a whole host of other experiments.
Without NASA, we wouldn't have reliable weather forecasting (even three or five days is better than none at all), we wouldn't have had such a huge development of consumer electronics (which stemmed from both NASA and DoD interest in electronics), a plethora of medical knowledge that directly resulted from studying human reactions to low-gravity environments and animal and plant studies done to see what development of organisms is like with low gravity, and information about the earth's ozone layer and ionosphere (did you know that you could hear radio transmissions around the world because they bounce off the ionosphere, and that the stations you recieve depend on the time of day because the ionosphere expands when hit with daylight?). NASA also does quite a bit of work with NOAA for modeling and simulation of weather systems.
There are plenty of ways that NASA's work has influenced all of us.
15 km/s is more reasonable because the delta-v needed to go from earth to saturn is on the order of that much. 57 km/s sounds more like Neptune.
As for how they got it going that fast, you have to remember that the velocity that you came up with is an average. Actual orbital velocities vary greatly. The other thing is that the vehicle had some fun with gravity assists (angular momentum transfers), and other planets. The initial velocity when it left earth orbit couldn't have been much more than 12 to 15 km/s.
Yep.
At Circuit City, BestBuy, CompUSA, RadioShack, Computer STOP, Fred Meyer, Allstar Auto, and a smog check station near where I live where I had to get my car tested before getting it registered in CA.
In general, I've stopped going to stores for info. I have gotten to the point where I've researched what I want to buy to the extent that I know exactly what I'm looking for and I just need to find the best price to get it. On top of that, when a sales rep comes over and makes a comment like, "SuSe doesn't do as well as Windows, because...", or "32 bit processors, like Intels, are better than 64 bit processors, like AMDs, because the processor doesn't have to work with big numbers all the time. 64 decimal places is much bigger than 32 decimal places, and that's where the problem is."
Better yet was a mechanic trying to tell me that my Audi A4 didn't need its transmission fluid changed because "German cars are so well built that they don't need to have the transmission fluid changed." This was even after I pointed out the Audi Service Bulletin that described the mileage between changes and what transmission fluid to use!
In each case, I found that it was irritating, but kind of fun to call them on their lies. One guy even tried selling some RAMBUS RAM to me saying that they use genetically engineered silicon. I was like, WTF!? (I was looking for PC2100 RAM at the time.)
It was also especially fun if I made quite a bit of noise in the store about the salesperson lying.
What if the entire flash was encrypted with a small partition on it with a decryption routine that also pointed where to start?
It'd make it slower (probably a lot slower if you're operating in the USB stick only), but adding an encryption scheme would at least slow down someone that wanted to image your USB stick.
A keylogger would still get stuff though. Hmm...
LLNL does nuclear research (basically simulating nuclear weapon detonations). We spend $400 Billion on defense per year, what is $200 - $300 million for the latest and greatest super-computer?
Also, since the US agreed to stop testing nuclear weapons, they've moved on to totally simulating them. Most often the research is done under the guise of astrophysics because the physical processes are almost identical. The US has to stay on top of things, and simulation is the only option to do so.
True. But wouldn't the thing that was luminescing get extra attention? Wouldn't that be a good thing?
And since explosives are so reactive, there is outgassing which produces a small chemical trail (how dogs can sniff explosives), which means that you can't hide the smell of the bomb by sealing it up.
If it's so useful, then why doesn't it make sense to reimburse and reward the person who discovered it?
You mean like... with a patent?
I'm reminded of the slashdot poster who, on the day the sample return capsule crashed without deploying a parachute, turned on the TV with the sound off and the saw what appeared to be a flying saucer half buried in the desert with the words 'BREAKING NEWS' flashing across the bottom.
ROFL! That comment made me spit my drink all over my desk. Great!
Yes, you can attach sound to powerpoint presentations. You can even embed movies, animated GIFs, and probably a whole host of other things.
That's not true.
If it were, then how do you think an apartment complex gets its water and sewer if it says to its tenants that the apartments will cover sewer, water, and garbage? The water, sewer, and garbage companies sure don't need it then.
At least in Washington state and California this is the case. And I'm fairly certain that there are only four organizations that can use your SSN in that manner: government agencies, employers, banks, and landlords. Anyone else can't legally deny you services based on your refusal to give your SSN. (I know that's a fact because when I became employed with the federal government, that's what they specifically told us. There are problems with federal employees and identity theft because people don't realize what the law is.)
It's illegal for anyone but the government, employers, banks, and landlords from requiring your SSN. Banks and landlords have very limited definitions on what they can do with your SSN.
Anyone else that requests your SSN can be told, by you, to fsck off. They can't withold services from you if you refuse to give it either.
At least that's the information I got from my employer when I was hired (government). They specifically warned about identity theft and listed the organizations that can legally use your SSN, the laws that apply to the use of SSNs, and they instructed us to get nasty with anyone that refuses service to us if we're asked to give up our SSN. It's private info.
The problem is that people are pretty easy to give up that kind of info. And when Joe Blow gets it and doesn't know how to secure his computer, bad things happen.
By law, the only places that can receive your SSN are government offices, employers, banks and landlords. Anyone else can't deny you any of their services based on you not giving them your SSN. I think banks and landlords are the ones that are most limited in what they can use the number for. Government and employers use the number for taxes and for government to turn you into a number (for medical benefits, social security payments, and so on). No one else has the right to ask for it.
Oh people will bitch and moan about not getting it from you. But who the hell at CompUSA needs your SSN?
And if a non-government or non-employer needs to verify that you are who you say you are, they can ask for your driver's license number. But the SSN is off limits to everyone else.
At least this is what my employer told me when I got hired (us government). They instructed me to safeguard my SSN as best I can, which includes not giving it to people that legally don't have a right to it. As they put it, 99% of the identity theft issues are from people giving their SSNs to folks or organizations that don't actually need it. And then those organizations don't know what a secure system is. To be honest, I'd rather have my SSN and other personal info stored on a DoD, DoJ, or whatever agency system, than on the computers at Joe Blow's Car Sales.
You could conceivably scale that kind of axial flow turbine down to very small levels. You wouldn't necessarily need to extremely high rotation speed for a bladed turbojet. The only problem again is viscosity... There is just too much friction between the plate and the working fluid and the working fluid and the wall.
Now, if there was a way to directly extract the energy from the flow, rather than having the flow do some work on some mechanical device, than the efficiency of the process would be improved. I'm thinking of using a material that just so happens to get excited in such a way that it lases; then you collect photons at the exhaust. Conversely, you could use some material that gets excited when you irradiate it with something (radio, light, IR, whatever), and chemically react it with something (say as in combustion), and the reaction also just so happens to produce material that is excited and spontaneously emits radiation.
The irradiation, chemical change, and spontaneous emission processes would mirror the processes in an engine: compression, combustion, expansion. The problem is, I don't think any materials have been discovered that could satisfy the requirements for the process I outlined. I also don't think people have looked at that kind of thing too much, considering I couldn't find anything during a quick (20 minute) literature search. It could be a PhD in the making??
You are definitely on the right track with using a Tesla pump, over a bladed system. That kind of device better exploits the physics at such small scales. You'd want to stack the plates though, and you'd either want the wall very close to the plates (to minimize frictional losses), or you make the plates have holes of an appropriate size in them to minimize how much mass has to move.
Another thing to note is that at small enough scales, Coulomb effects could be exploited to have say, bearingless devices.
Also, if you get small enough, and rotate your plates fast enough, you might start running into problems with synchroton radiation. That's just a result of whipping the electrons of the atoms in your plate around the axis of rotation. At slower speeds, you get the rare emmission, but as you increase speed, the chances of an emission goes up.
is that many of the physicists working on the problem don't understand fluid mechanics at such a small scale. The viscous forces are huge compared to the inertial forces, and you have a completely different set of physics.
That's why you don't see very many working concepts of small aircraft (the kind that fit in the palm of your hand) with what most people recognize as wings. They're usually equipped with small flat-plate type wings, or a ribbon-like system like on a cuttlefish.
And the reason that many folks that do happen to understand the physics don't try and do things at such small scales is that the problem is difficult. Not impossible, but difficult.
As a person with a background in fluid mechanics, I don't see how the approach in the article will ever work well or efficiently. It might work, but it's not using the kind of principles that you need. (The whole point of my post is that you can't scale a device down without adjusting or remaking how it does what it does. The physics change.)
As for your idea...
It's great in theory. But you forget that the Treasury is only authorized to do things for a fiscal year. They can't suddenly print up a buttload of money on a whim. They have to get Congress to approve what they do.
That's why the Federal Reserve is tasked with controlling and monitoring things on a much shorter term than an entire fiscal year. If this was not done, then we would end up with a dollar that doesn't change value throughout a year, but everything else would change value in relation to that dollar.
After all of that, you still didn't realize that I answered your question: "Where did THAT money come from is the question now."
You know... the one that you posted in the parent to my post above. The money today comes from peoples' confidence in our economy. The actual paper money itself is printed in the treasury. The actual amount printed is calculated based on what is needed, and on what the value of the dollar is.
It doesn't come from thin air. Yes, the basis for that money is not a tangible item. But it is based on a measurable quantity.