True, except that the heat loads on a vehicle at this speed, at atmospheric pressure, are enormous, as is the drag. That's why they fly at altitude. I guess a simpler way of thinking about it is: if you can only shed your nose cone at 25km altitude (to prevent excessive heat load on the engine), how fast would the rail gun have to launch you at sea level to be going Mach 7 at 25km altitude?
I haven't done the Maths on it, but I suspect that a rocket launcher would actually be cheaper.
When you're on a shoe-string budget, it's hard to figure out if that really happened. It'll take a much more expensive project to figure this out for sure, hence, NASA's much more expensive project.
Not really, a pressure distribution along the combustion chamber was measured. You need to check two things. Is the gas supersonic, and was combustion achieved. Supersonic can be checked by comparing the pressure in the combustion chamber with that predicted due to wedge compression.
Combustion is shown by comparing the signal in one chamber with no fuel, with the signal in the second chamber with fuel.
In addition, supersonic combustion in a parallel combustion chamber gives a pressure profile which rises along the chamber, whereas subsonic combustion gives a pressure profile which drops along the combustion chamber.
The real trick is to check that nothing else could simulate these signals.
Scientific programming is a different branch of the business. Often it focusses on simply automating a task. That's why you'll find a lot of programmers use Matlab. Fortran (in the later versions, 90, 95) does everything Matlab does, only faster and cheaper, so long as you don't want fancy graphics.
It is a good tool for the job at hand. Scientists who do large codes (pretty much anything CFD oriented) use c, like the rest of the world.
Simply being able to program doesn't mean you could do a better job (read more accurate, or quicker code writing), than someone with experience in the field. Especially, as is often the case, if the code to be written is about 90% scientific algorithm and 10% IO.
Let me put it another way then. If I found a piece of stone that looked like it had been sharpened into an axe head, would you say that that, _by_itself_ , is a sufficient proof that a stone age civilisation existed. Would you, for instance, argue that it could be a natural phenomenon? The believers might well argue that it is too rare to be a natural phenomenon.
But that's kind of the point, really, isn't it. If it was a common natural phenomenon we would've found it long ago. Maybe it's not natural here on earth, at this current temperature and pressure, under this magnetic field, this UV concentration. There are plenty of natural phenomena which don't appear on earth, but do appear in other places. Try Mazers for one.
There can be a lot of other indications of life. Try microfossils like stromatolites, interesting chemicals, wear patterns, oxidation, and a lot of others. I think that drawing the assumption of life from these crystals, is like drawing the assumption of civilisation from an axehead, which is to say, that they may be right, but the evidence is a bit sparse.
I went to a talk some time ago, about 6 months after the "discovery of life in a martian rock" found in Antarctica. It was a half hour talk, at the AIAA confernce in Reno in mid-January 2000.
To summarise his arguments: They found some interesting crystals in a rock. They'd never seen anything like it. They looked for other places these crystals occurred. They looked and looked (He was quite adamant on this point), and couldn't find them anywhere except in some bacteria. Therefore these crystals can only be made by bacteria. Therefore these crystals are evidence of life.
You'll have to excuse my scepticism that this in any way constitutes proof. I'm quite willing to believe that there is bacteria on mars, just not that this is proof of it.
Firstly, it is not really useful for passenger aircraft. The high G to get up to speed is not really sellable.
The main use is as a secondary engine for rocket propulsion. Since atmospheric air is used, the scramjet theoretically can lift more payload for a given engine weight, and it is hoped that this will translate into launch cost savings for light payloads (I've seen one estimate that put the saving at a factor of 10 for a 1-10 tonne payload), however nothing really beats rockets for very large payloads.
The biggest advantage, in a launch to orbit is that, since the engine will be going sideways to pick up speed, the cost difference between a polar and equatorial orbit is negligible.
Depends that you mean by high fuel consumption. They go fast, and this creates drag, thus fuel must be expended. It you mean low efficiency, then you are half right: No scramjet achieves good fuel efficiency at the moment. However, since there are not really any working scramjets that should come as no particular surprise. Generally, Scramjets should work in the range Mach 6 to 20. I've never seen an upper limit on pulse detonation engine operation, but I can't remember ever seeing one that worked over Mach 8, even in theory.
There was a joint flight experiment between NASA and CIAM (Central Institute of Aviation Motors, Moscow), in 1998. There were three tests. they were launched on modified Russian SA5 missiles. One failed outright. One tested the engine in subsonic mode, and the third did not achieve supersonic combustion in the engine.
I think that the outcome from these experiments could be summarised as that no working scramjet was flown. As a note though, the main objective was to prove the Hypersonic flying laboratory, "Kholod", which is a package with fuel and telemetry to attach to a rocket so that any experiment can be easily flown on a rocket. This package was successfully tested (ie fuel, power and telemetry were provided to the model)
Yes it was controlled, and yes it did crash land (Why should the two be exclusive?) The rocket has a ballistic trajectory, and the experiment is performed on the way back into the atmosphere (between 32km and 22km altitude), for about 4 seconds, you can work out the speed yourself. It then has about 10 seconds before it hits earth. When the payload of the last attempt was found, the nosecone was buried about 1 meter below ground, and it only flew upward for about 10 seconds. The current experiment goes upward for 5 minutes.
Suffice to say, that this is an unmanned experiment.
Mainly because last time, the rocket veered off course and crashed into the ground before the test could be conducted. This time, the rocked stayed on path, they received telemetry from the package, and nothing spectacular went wrong. It is still very possible for something non-spectacular to go wrong, and clearly they're avoiding talking before thinking (an increasingly rare occurrence).
Unfortunately, the diagram is not totally correct. It's possible to have scramjets with duct convergences, and ramjets without duct convergences. The difference lies in the fact that in a ramjet the air becomes subsonic, and in a scramjet the air does not become subsonic. Making the air subsonic provides a great deal of control over the combustion process, thus the problem with scramjets.
Depends, in the Hyshot test last year, from the same launchpad last year, A fin came off the second stage, also wiping out a fin on the first stage, as the rocket came off the pad. This test still made it to 60-odd km altitude, and this rocket was spin-stabilised.
I doubt (though I don't know) that this rocket was spin stabilised, simply because the payload was non-symmetric, and spin-stabilisation would have greatly added to their problems. My guess would be either some mechanical failure (the rocket broke in half), or the gyros failled in some fashion, under the high force of ignition or takeoff. Failure of the gyros is far more likely.
I always find it amazing just how high the failure rate is for what should, after 50 years, be routine rocketry.
Actually the claim of oldest form of government is pretty debateable. The Isle of Man, for instance claims a continuous parliament of over 1000 years, Certainally there are others who could make a similar claim, for instance the English westminster system has been pretty solid since 1678. Still, it's pretty academic, since government is fundamentally a changing process.
As for the rest, the opinion of the rest of the world seems pretty much to be that if the US wants to take sides and beat the crap out of one side in some piss-poor third world conflict then nobody is going to stop them, but it still doesn't make the action moral. Politically convenient and domestically popular, for sure, but morality's a tricky thing when you're slaughtering natives by the mass-grave load.
Practically speaking, is there a lot of differences between a crack and reverse engineering the hardware? If someone writes a key generator and patches it into the OS, it still does the same job. Still, good point about having to move the software.
I wonder if this could be the straw which breaks the camels back, and finally gets some legislation in place to regulate the rights of software licencees. For example, I would think that getting a free (or for the cost of the media), replacement of all programs, when my HDD dies would not be an unreasonable thing to have written into law. I'm sure there must be plenty of others.
No big drama except for the person who's account is compromised. You now have the expense of replacing your MOBO, and I'm not thinking that MS is footing the bill for that as the bank does with your credit card. In addition it's not like you get a credit card bill for every program your CPU ran, or was run by other CPUs on your sayso, or every website accessed, do detecting a break in security yould be more difficult than with a credit card. Potentially you may never know, or months may pass before youre sure you have to fork out another (Insert price here) for new hardware. In addittion you'll have to buy all new software, since your old stuff will think it's been pirated and shut down after calling the MS police.
Sure, I agree that this makes it harder to break _all_ identifiers, but the point of the system is that you don't have to break all of them, just one, and then you have free reign through every system which trusts that person. It's like credit card fraud: fairly rare in actual fact, but devastating when it does happen, with the difference in this system, that replacing your MOBO is considerably more inconvenient than replacing your credit card
Re:If I were an MS employee
on
Analyzing Palladium
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· Score: 3, Interesting
It's like the security scheme for credit cards though. If one person compromises Palladium on your computer, you need to change all your identifiers. Otherwise you have the problem of identifying falsely authourised code amongst the legitimately authorised code already there. Then you're exactly back to where we are now, running virus scanners and firewalls, except the user has forked out money for a security scheme which doesn't work.
Anyone notice the inherent similarities
on
Analyzing Palladium
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· Score: 5, Insightful
between this and biometric security methods. Very strong security. When the single layer is cracked, there is no backup mechanism, and resecuring and reverification of user are almost impossible.
Although, I guess if I had to choose between getting a new MOBO and new eyeball I'd pick the MOBO. Maybe this is Microsoft's attempt to be least-worst.
Lots of problems ahead for MS
on
Analyzing Palladium
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· Score: 5, Insightful
Look, lets not get our knickers in a knot. It may happen, but it's never going to be the only, or even a high-level verification method. Obviously not, it's embedded in hardware.
I would think that an identification code embedded in hardware is going to be cracked, and in short order. What happens to Charlie consumer when he finds that his version of Word no longer works because some cracker has a hold of his unique identifier? And that he can't change that identifier without a new MOBO? Or that Microsoft is giving away his credit card number to anyone who can spoof his identity?
It's a common failing of software manufacurers to think that new hardware can solve problems that software cannot (CF pretty much every dongle ever made) Just let MS run with the ball until they realise that the same thing can be done in software at a fraction of the cost.
In addition, I think it would die in Anitrust. Just wait until those computers start being returned, because they won't play nice with my operating system of choice, and watch Intel turn on a dime.
Look, lets not get our knickers in a knot. It may happen, but it's never going to be the only, or even a high-level verification method. Obviously not, it's embedded in hardware.
Anyone with half a brain can tell you that an identification code embedded in hardware is going to be cracked, and in short order. What happens to Charlie consumer when he finds that his version of Word no longer works because some cracker has a hold of his unique identifier? Or that his personal information is subject to manipulation by a cracker, or that microsoft is giving away his credit card number to anyone who can spoof his identity?
It's a common failing of software manufacurers to think that new hardware can solve problems that software cannot (CF pretty much every dongle ever made) Just let MS run with the ball until they realise that the same thing can be done in software at a fraction of the cost.
In addition, I think it would die in Anitrust. Imagine buying a car, that could only be refuelled at with BP petrol, but not being told about it at point of sale. Just wait until those computers start being returned, because they won't play nice with my operating system of choice, and watch Intel turn on a dime.
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True, except that the heat loads on a vehicle at this speed, at atmospheric pressure, are enormous, as is the drag. That's why they fly at altitude. I guess a simpler way of thinking about it is: if you can only shed your nose cone at 25km altitude (to prevent excessive heat load on the engine), how fast would the rail gun have to launch you at sea level to be going Mach 7 at 25km altitude?
I haven't done the Maths on it, but I suspect that a rocket launcher would actually be cheaper.
When you're on a shoe-string budget, it's hard to figure out if that really happened. It'll take a much more expensive project to figure this out for sure, hence, NASA's much more expensive project.
Not really, a pressure distribution along the combustion chamber was measured. You need to check two things. Is the gas supersonic, and was combustion achieved. Supersonic can be checked by comparing the pressure in the combustion chamber with that predicted due to wedge compression.
Combustion is shown by comparing the signal in one chamber with no fuel, with the signal in the second chamber with fuel.
In addition, supersonic combustion in a parallel combustion chamber gives a pressure profile which rises along the chamber, whereas subsonic combustion gives a pressure profile which drops along the combustion chamber.
The real trick is to check that nothing else could simulate these signals.
Scientific programming is a different branch of the business. Often it focusses on simply automating a task. That's why you'll find a lot of programmers use Matlab. Fortran (in the later versions, 90, 95) does everything Matlab does, only faster and cheaper, so long as you don't want fancy graphics.
It is a good tool for the job at hand. Scientists who do large codes (pretty much anything CFD oriented) use c, like the rest of the world.
Simply being able to program doesn't mean you could do a better job (read more accurate, or quicker code writing), than someone with experience in the field. Especially, as is often the case, if the code to be written is about 90% scientific algorithm and 10% IO.
Let me put it another way then. If I found a piece of stone that looked like it had been sharpened into an axe head, would you say that that, _by_itself_ , is a sufficient proof that a stone age civilisation existed. Would you, for instance, argue that it could be a natural phenomenon? The believers might well argue that it is too rare to be a natural phenomenon.
But that's kind of the point, really, isn't it. If it was a common natural phenomenon we would've found it long ago. Maybe it's not natural here on earth, at this current temperature and pressure, under this magnetic field, this UV concentration. There are plenty of natural phenomena which don't appear on earth, but do appear in other places. Try Mazers for one.
There can be a lot of other indications of life. Try microfossils like stromatolites, interesting chemicals, wear patterns, oxidation, and a lot of others. I think that drawing the assumption of life from these crystals, is like drawing the assumption of civilisation from an axehead, which is to say, that they may be right, but the evidence is a bit sparse.
I went to a talk some time ago, about 6 months after the "discovery of life in a martian rock" found in Antarctica. It was a half hour talk, at the AIAA confernce in Reno in mid-January 2000.
To summarise his arguments: They found some interesting crystals in a rock. They'd never seen anything like it. They looked for other places these crystals occurred. They looked and looked (He was quite adamant on this point), and couldn't find them anywhere except in some bacteria. Therefore these crystals can only be made by bacteria. Therefore these crystals are evidence of life.
You'll have to excuse my scepticism that this in any way constitutes proof. I'm quite willing to believe that there is bacteria on mars, just not that this is proof of it.
Sorry, not a german, though Resident.
My deepest sympathies to someone who can be the butt of both Irish and American jokes.
Firstly, it is not really useful for passenger aircraft. The high G to get up to speed is not really sellable.
The main use is as a secondary engine for rocket propulsion. Since atmospheric air is used, the scramjet theoretically can lift more payload for a given engine weight, and it is hoped that this will translate into launch cost savings for light payloads (I've seen one estimate that put the saving at a factor of 10 for a 1-10 tonne payload), however nothing really beats rockets for very large payloads.
The biggest advantage, in a launch to orbit is that, since the engine will be going sideways to pick up speed, the cost difference between a polar and equatorial orbit is negligible.
Depends that you mean by high fuel consumption. They go fast, and this creates drag, thus fuel must be expended. It you mean low efficiency, then you are half right: No scramjet achieves good fuel efficiency at the moment. However, since there are not really any working scramjets that should come as no particular surprise.
Generally, Scramjets should work in the range Mach 6 to 20. I've never seen an upper limit on pulse detonation engine operation, but I can't remember ever seeing one that worked over Mach 8, even in theory.
Exactly, a siren was sounded so that the kangarooy were not takes unawares this time.
There was a joint flight experiment between NASA and CIAM (Central Institute of Aviation Motors, Moscow), in 1998. There were three tests. they were launched on modified Russian SA5 missiles. One failed outright. One tested the engine in subsonic mode, and the third did not achieve supersonic combustion in the engine.
I think that the outcome from these experiments could be summarised as that no working scramjet was flown. As a note though, the main objective was to prove the Hypersonic flying laboratory, "Kholod", which is a package with fuel and telemetry to attach to a rocket so that any experiment can be easily flown on a rocket. This package was successfully tested (ie fuel, power and telemetry were provided to the model)
Yes it was controlled, and yes it did crash land (Why should the two be exclusive?) The rocket has a ballistic trajectory, and the experiment is performed on the way back into the atmosphere (between 32km and 22km altitude), for about 4 seconds, you can work out the speed yourself. It then has about 10 seconds before it hits earth. When the payload of the last attempt was found, the nosecone was buried about 1 meter below ground, and it only flew upward for about 10 seconds. The current experiment goes upward for 5 minutes.
Suffice to say, that this is an unmanned experiment.
Mainly because last time, the rocket veered off course and crashed into the ground before the test could be conducted. This time, the rocked stayed on path, they received telemetry from the package, and nothing spectacular went wrong. It is still very possible for something non-spectacular to go wrong, and clearly they're avoiding talking before thinking (an increasingly rare occurrence).
Unfortunately, the diagram is not totally correct. It's possible to have scramjets with duct convergences, and ramjets without duct convergences. The difference lies in the fact that in a ramjet the air becomes subsonic, and in a scramjet the air does not become subsonic.
Making the air subsonic provides a great deal of control over the combustion process, thus the problem with scramjets.
Being an Irish university:
Was the problem that they couldn't find a 100 Ohm superconductor?
Not exactly, it actually broadcasts at 2.4GHz
Depends, in the Hyshot test last year, from the same launchpad last year, A fin came off the second stage, also wiping out a fin on the first stage, as the rocket came off the pad. This test still made it to 60-odd km altitude, and this rocket was spin-stabilised.
I doubt (though I don't know) that this rocket was spin stabilised, simply because the payload was non-symmetric, and spin-stabilisation would have greatly added to their problems. My guess would be either some mechanical failure (the rocket broke in half), or the gyros failled in some fashion, under the high force of ignition or takeoff. Failure of the gyros is far more likely.
I always find it amazing just how high the failure rate is for what should, after 50 years, be routine rocketry.
Actually the claim of oldest form of government is pretty debateable. The Isle of Man, for instance claims a continuous parliament of over 1000 years, Certainally there are others who could make a similar claim, for instance the English westminster system has been pretty solid since 1678. Still, it's pretty academic, since government is fundamentally a changing process.
As for the rest, the opinion of the rest of the world seems pretty much to be that if the US wants to take sides and beat the crap out of one side in some piss-poor third world conflict then nobody is going to stop them, but it still doesn't make the action moral. Politically convenient and domestically popular, for sure, but morality's a tricky thing when you're slaughtering natives by the mass-grave load.
Practically speaking, is there a lot of differences between a crack and reverse engineering the hardware? If someone writes a key generator and patches it into the OS, it still does the same job. Still, good point about having to move the software.
I wonder if this could be the straw which breaks the camels back, and finally gets some legislation in place to regulate the rights of software licencees. For example, I would think that getting a free (or for the cost of the media), replacement of all programs, when my HDD dies would not be an unreasonable thing to have written into law. I'm sure there must be plenty of others.
No big drama except for the person who's account is compromised. You now have the expense of replacing your MOBO, and I'm not thinking that MS is footing the bill for that as the bank does with your credit card. In addition it's not like you get a credit card bill for every program your CPU ran, or was run by other CPUs on your sayso, or every website accessed, do detecting a break in security yould be more difficult than with a credit card. Potentially you may never know, or months may pass before youre sure you have to fork out another (Insert price here) for new hardware. In addittion you'll have to buy all new software, since your old stuff will think it's been pirated and shut down after calling the MS police.
Sure, I agree that this makes it harder to break _all_ identifiers, but the point of the system is that you don't have to break all of them, just one, and then you have free reign through every system which trusts that person. It's like credit card fraud: fairly rare in actual fact, but devastating when it does happen, with the difference in this system, that replacing your MOBO is considerably more inconvenient than replacing your credit card
It's like the security scheme for credit cards though. If one person compromises Palladium on your computer, you need to change all your identifiers. Otherwise you have the problem of identifying falsely authourised code amongst the legitimately authorised code already there. Then you're exactly back to where we are now, running virus scanners and firewalls, except the user has forked out money for a security scheme which doesn't work.
between this and biometric security methods. Very strong security. When the single layer is cracked, there is no backup mechanism, and resecuring and reverification of user are almost impossible.
Although, I guess if I had to choose between getting a new MOBO and new eyeball I'd pick the MOBO. Maybe this is Microsoft's attempt to be least-worst.
Look, lets not get our knickers in a knot. It may happen, but it's never going to be the only,
or even a high-level verification method. Obviously not, it's embedded in hardware.
I would think that an identification code embedded in hardware is going to be cracked, and in short order. What happens to Charlie consumer when he finds that his version of Word no longer works because some cracker has a hold of his unique
identifier? And that he can't change that identifier without a new MOBO? Or that Microsoft is giving away his credit card number to anyone who can spoof his identity?
It's a common failing of software manufacurers to think that new hardware can solve problems that software cannot (CF pretty much every dongle ever made) Just let MS run with the ball until they realise that the same thing can be done in software at a fraction of the cost.
In addition, I think it would die in Anitrust. Just wait until those computers start being returned, because they won't play nice with my operating system of choice, and watch Intel turn on a dime.
Look, lets not get our knickers in a knot. It may happen, but it's never going to be the only, or even a high-level verification method. Obviously not, it's embedded in hardware.
Anyone with half a brain can tell you that an identification code embedded in hardware is going to be cracked, and in short order. What happens to Charlie consumer when he finds that his version of Word no longer works because some cracker has a hold of his unique identifier? Or that his personal information is subject to manipulation by a cracker, or that microsoft is giving away his credit card number to anyone who can spoof his identity?
It's a common failing of software manufacurers to think that new hardware can solve problems that software cannot (CF pretty much every dongle ever made) Just let MS run with the ball until they realise that the same thing can be done in software at a fraction of the cost.
In addition, I think it would die in Anitrust. Imagine buying a car, that could only be refuelled at with BP petrol, but not being told about it at point of sale. Just wait until those computers start being returned, because they won't play nice with my operating system of choice, and watch Intel turn on a dime.
Laser tweezers
, of course, it begs the question as to whether the machine is minaturised is the power source is macroscopic.