Protectionist tarriffs rarely have the intended effect. Usually people just go elsewhere to obtain their goods. The U.S. has been guilty of this many times, and it's almost always backfired. If "helping" EU company sales is their goal, why the hell don't they reduce the tax burden of those companies so they can sell their products cheaper?
I think you are glossing over the fact that this country has run a deficit every year since WWII, under both Republican and Democratic presidents, and it hasn't harmed us a whit. I'd also like to point out that if your savior Bill Clinton really was serious about deficit destruction then he wouldn't have signed so many Democratic spending bills, but that would just be petty of me, wouldn't it? You seem to have a rather large axe to grind against the Republican's here, with Bush in particular. Sour grapes over the election?
"just widening existing taxation"...and you just sit there and defend it. They are taking YOUR money, to spend it on God knows what, which will most likely never bring any tangible benefit to YOU, but will certainly benefit the political career of someone else...with YOUR money.
How long before they have to "widen" things again? Pretty soon the vast majority of your disposable income will be going just to pay the taxes, not to buy things!
A recession is defined as two consecutive quarters of negative growth. My mistake, I should've said TWO quarters, not one.
Either way, that's 6 months, not 8. That mini-recession DID included a few quarters before and after of slow or stagnant growth (all recessions do) which made the apparent effects longer. You can review all these numbers at omb.gov.
I'm at a loss to understand how some idiotic tax (in an area that is already well known for outrageous VAT taxes) is supposed to help sales. Basic economics will indicate that if an item becomes more expensive, fewer items will be sold. Since the tax goes to the gov't instead of whoever is actually producing, selling, distributing the item, that money is for all intents and purposes LOST.
Very, very shortsighted. Historical evidence unequivocally shows that for the last 100 years, every time taxes have been lowered and economic boom came to fruition within 2-4 years (economic inertia). This boom has ALWAYS offset the short-term lowered tax revenues caused by lowering taxes in the first place. Pity that most politicians only think 2-4 years ahead, and thus do not realize (or don't want to realize) this obvious truth. If you don't believe me just go to www.omb.gov (Office of Management and Budget) for the lowdown on the economic figures for the U.S.
You'll note that Reagan lowered taxes and increased spending, resulting in a deficit. He was widely criticized for it, but the 80's were huge boom years. Apart from a very short (only 1 economic quarter) recession in 1990, the economy STAYED in high gear until the tech crash of 2000-2001. During the longest economic expansion in U.S. history (which started under Reagan, not Bush #1, and certainly not Clinton), tax revenues INCREASED to the point where we were whacking away at the deficit in huge chunks. During that same time period government spending INCREASED as well, something that should've caused more deficits, but didn't due to the greatly increased tax revenues.
Under Clinton taxes were radically increased. You'll note that about 4 years later the economy abruptly reversed. I'm not blaming Clinton for the recession (overenthusiastic investors are largely to blame), but it can be said that he did little to thwart it. Now Bush #2 is in the center seat, and he's cutting taxes. I have every reason to believe that we'll deficit spend for 1-2 years, but in the long run it will pay us to have done things this way.
The EU has never gotten this idea, and the absurd VAT tax is just another example. Governments and politicians don't EARN or PRODUCE wealth, they TAKE it and SPEND it without regard to who they took it from. There is no way in hell MORE taxes will lead to a BETTER economy. History does not lie.
And since you're so interested in sources, quotes, and figures, try this one on for size, taken from SPACE.COM:
"Funds are minuscule. They are extremely meager," adds John Cole, NASA's manager of the space transportation research project office at Marshall Space Flight Center.
"Beamed energy is one of the avenues we've got if we're ever going to get the cost of access to space down," Cole said.
Cole sees a 21st century where passenger-carrying space vehicles might be powered upward on laser light. That laser would churn out 100 gigawatts of power, he admits.
"That's 10,000 times bigger than any laser that's been built. But, hey, I'll take whatever works," Cole said.
Keep in mind that's 100 Gigawatts of power, AND that lasers are not 100% efficient. I've done some cursory web surfing and I've seen efficiency figures in the 30%-50% range for semi-lasers (these could be out of date, but I found about 20 references to figures in this range from a variety of sources). So, to be optimistic, we'd need at least 200GW input to the laser(s). Then we'd have to take into account that whatever's transmitting the power to the laser system has resistive losses, not to mention any step-up or step-down transformer inefficiencies, and then there's the actual efficiency of whatever's actually generating all these gigawatts. I would feel comfortable, even magnanimous, giving a 500GW figure. Per launch. For ease of comparison, let's call that 500,000,000 kilowatts, and assume that it takes 1 hour to completely loft our hypothetical vehicle, from warming things up all the way until turning them off post launch. That's half a billion kilowatt hours.
Annual electrical production of every nuclear power plant in the United States is around 700 billion KW/hrs for the entire year according to the DoE. That means daily production is about 1.9 billion KW/hrs per day.
Your proposed laser propulsion system would consume the electrical output of every nuclear reactor in the United States operating at full power for 6 hours.
For comparison, note (from Boeing's website) that the five F-1 engines equaled 160,000,000 horsepower, about double the amount of potential hydroelectric power that would be available at any given moment if all the moving waters of North America were channeled through turbines. Granted they were lifting an awful lot of fuel with that horsepower (although a lightship would require fuel to manuver in space), but it's a staggering display of the power required to get into orbit. And that was just the first stage of the rocket.
NOW is it starting to dawn on you how far off the mark you are/were?
Really? No. That's what you need if you want one big laser beam. We don't want that. In fact the atmospheric effects would be very detrimental- the beam would scatter horribly.
As I pointed out, this can be corrected with adaptive optics the same way that you can collimate the beam of a few billion laser pointers. The only thing is it's easier to do with fewer lasers (to a point) than billions of them.
This concept is thousands of semiconductors all pointing in parallel through a single telescope at the vehicle; and then having, say a thousand of these telescopes. (You can play with the numbers, but that's the concept).
If you do the maths, its gonna come comfortably under a billion.
So you're just going to mint a couple of billion souped up laser pointers and expect it to propel a spacecraft? Funny how none of the existing researchers are pursuing this. Perhaps it's because it's not feasible. First off, there's the difficulting of collimating a beam created in such a manner, but that can be somewhat compensated for by adaptive optics. Still, you haven't overcome the fact that you'd need obscene numbers of these to generate a beam working in parallel. I would point out the obvious cooling and control difficulties, but I'm sure you've given that LOTS of thought, eh?
Your idea, while technically possible, is impractical when you can take larger lasers to begin with. While the cost per laser is higher than semiconductor lasers the engineering difficulties are lower. You could shine a few quadrillion flashlights at the bottom of a spacecraft and get some propulsive effect, but again it's not worth it.
The figure I have seen quoted is about 1MW/kg, but it depends a bit on the system you're looking at. Do you have a source for your figure?
LLNL has a nice section, and Space.com has a bit on it as well. 150KW propells something that weighs the same as an empty coke can to the edge of the atmosphere, but that's straight up. Anything that intends to stay in orbit for long will have to achieve orbital velocity, which means slant range, which means the laser will be plowing through 4-5 times the amount of atmosphere as a straight shot. You claim to know lasers and optics, so why don't you save me the trouble of debunking this and do the math and see how that would affect beam power. You're going to quintuple your range AND you've got to achieve about 18,000mph while taking atmospheric friction into account (you DID consider all this, right? Nope, doesn't apear so) Huge, isn't it? How many "laser pointers" were you planning to glue together? Keep in mind that your average semi-laser is rated in milliwatts.
100Mw for 15 minutes. That's 400,000 kwh. 1 Kwh costs $0.01-0.05. That makes: $4000-$20,000 of electricity for ~100kg
100kg? First off, it seems that you're only counting boosting a payload. Last I heard, satellites don't just fly themselves through the atmosphere, they need a launch vehicle, one sturdy enough to withstand atmospheric flight on the way to orbital velocity. Your total launch weight is going to be much, much higher. And don't forget that USEFUL stuff being lofted is often weighed in tons, not kilos. You wanna loft a cocker spaniel wrapped in aluminum foil, be my guest. Most folks want to loft satellites and space stations. Again, please think about the total solution before jumping to a conclusion.
Do you think so? Oh dear. How sad; still atleast I don't come across sounding all negative.
No, you come across as someone who is hopelessly optimistic or ridiculously idealistic. Either way, that's good for dreaming, but we're talking about practical application here and now. It may be possible, but it isn't practical. I'm not being negative here, I'm simply pointing out the flaws in your argument.
p.s. come back when you've investigated the cost per watt of semiconductor lasers power. ($10-50/W- dropping at ~30% per year).
Again, the cost of the semi-laser is not the issue. Big lasers cost big money but don't need all the fancy adaptive optics that a multi-billion laser array would need. Then there's power, which you've woefully underestimated by (a) not taking a realistic flight path mission profile into account and (b) not considering a worthwhile payload mass in conjunction with launch vehicle mass. Right now they're using 150KW to launch something that weighs ounces straight up. We need to launch tons, at an angle, at orbital velocities. Your math simply isn't in the same league as this.
p.p.s. I work with semiconductor lasers as part of my day job; I understand optics.
From your bent I'd have to guess that you work with semi-lasers on CD-ROM/DVD or some other consumer/professional electronic product. Those are just fine for small scale, short range applications, but massively parallel is an engineering challenge that no one has demonstrated an ability to cost effectively develop. And while you say you understand optics, you have consistently neglected to factor in a variety of optical phenomena that would affect such a laser propulsion system. Either you know a lot but aren't using your knowledge, or you know a little and are stretching beyond your means. If it's the former then you need to apply yourself, not blather. If it's the latter then I'm wasting my time anyway.
p.p.p.s. this wasn't my idea (I wish), it came from a professional rocket scientist... you know, somebody who actually designs them for a living, for money, for the US government. It is entirely possible there's some flaw; but if so I don't think you've spotted it.
The flaws are pointed out in stark detail above. Feel free to debunk them, but please take some time and put some thought into it. Shooting down poorly made arguments is easy but time consuming. I'd prefer to spend my time debating with someone who thinks something through before posting it.
Oh, the humanity. Please, please PLEASE do a little research before embarking on a debate about a subject which you don't seem all that informed about. Semiconductor lasers are not in the same class of power production as what would be needed for a laser-based propulsion system. A semiconductor laser might be great for a laser pointer or a DVD-ROM reader, but pushing megawatts or gigawatts of power is NOT what they do well. You need something more akin to a chemical reaction laser to generate this kind of power. Do a lookup on the EXCIMER laser to see what you'd need in order to make this project a reality.
And while we're on the subject, your little "so, just add more power" neatly sidesteps any logic or economic common sense. Power costs MONEY, and with the type of power you'd need, it may well outrun the cost of the hardware. This cost would be repeated FOR EVERY LAUNCH. And somehow I get the feeling that you are simply ignorant of just how much power would be needed here (hint: 100MW is off by at least an order of magnitude). Your comparison to shuttle costs ignores the fact that even though a shuttle costs $1bn, upkeep of the shuttle costs more than that.
Take some time, cool down, and try to research a subject before jumping to conclusions and making outrageous, silly statements. You're coming across as someone who's doing a lot of talking and very little thinking.
Most torpedos used on naval combat, agains a sub especialy or a carrier fleet are: nuked torpedos.
Sorry, I disagree. No navy currently fields sub-launched nuclear torpedos. Nuclear mines, nuclear depth charges perhaps, but not nuclear torpedos. Semantics, yes, but we wish to be accurate here.
You little sub does no longer exist after a full hit and its flattend like a piece of paper if its in a 10km range of the torpedos ignition. (yes I know this is an unfair point, but you said: *nothing* can break it)
Granted, I should've said no conventional weapon can destroy it, but I was expecting a little rationality and reality from you on this point, not quibbling. Of course a nuclear weapon would rupture it. Bravo! You've proven that absurd extremes make almost anything true or false. The point was this: nothing that is likely to happen is going to pierce a nuclear reactor pressure vessel, and a nuclear rocket designed to the same specs will be, for all practical purposes, just as indestructible.
I realy doubt that a navy sub reactor containment can stand a rocket torpedo like that one which sunk the Kursk.
Yes, it could, precisely because the rocket torpedos don't NEED that much power to destroy a submarine. Gross overkill is just that -- gross. All a torpedo (or mine, or depth charge for that matter) has to do is open the hull somehow. That will most likely sink the sub, accomplishing the mission of the weapon. Going the extra mile and trying to destroy the pressure vessel would be silly, useless, and result in a weapon that is too large, too expensive, and too dangerous to use near other friendly forces. Nuclear weapons used underwater are used for area destruction via the water hammer effect. The end result is the steel (or titanium in some cases) hull is collapsed by the pressure wave. In all simulations where the submarine was outside the fireball of the nuclear weapon, the pressure vessel remained intact even though the hull was effectively pancaked.
I doubt it can stand a simple ice berg. After all it is only metal isn't it? Supose you slice your side on an ice berg, I could imagine it just cuts through the containment.
Ah! Now your total ignorance of underwater nuclear propulsion comes to the fore! Sure did take you long enough. No, it is NOT merely metal. Pressure vessels are complex layers of many different metals, composites, and other solids (in some cases, even concrete). Ramming into an iceberg would pose no threat to the reactor (especially since a sub would have to ram one SIDEWAYS to even get a berg NEAR the reactor compartment). Ramming into another ship would not breach it. Sinking to the bottom of the deepest ocean trench would not crush it. You must remember that the vessel is designed to contain a nuclear reaction, no small feat. They are designed to be strong to begin with, and militarizing them only makes them stronger.
I also doubt that a standard anti carrier torpedo, which could be used against a sub if it is not diving, will leave anything intact.
I hate to break it to you but you're wrong. Go look up Janes Fighting Ships and you'll see.
Such a torp would lift a sub aproximately 50 meters into the air through its blast. Its just a question where it hits and your reactor is open.
50 meters? My, what a precise figure. You came to that conclusion after carefully considering the warhead yield, the depth of our hypothetical sub, the weight of the sub, it's speed and course, and about a thousand other variables that would influence such a statement...right? Oh, you didn't, did you? If you had, you'd have realized that your statement is not only wrong, it's stupid. Lifting a submarine 50 meters "into the air" as you say is not practical or possible with conventional antisub munitions. Nor is it necessary, due to the overkill described above.
Finaly: in the north atlantic is a sunken navy sub. Its regulary visited by Norway scientists. That sub leakes plutonium. So much to your claim.
So much for your argument, logic, or even sense. The sub is NOT leaking plutonium as you state, it is leaking radiation, something totally different. Plutonium is phyrophoric. Since you're obviously mentally deficient, I'll explain that pyrophoric means the substance spontaneously ignites outside of a containment vessel. If it were leaking plutonium it would be exploding. That would kind of make your Norwegian scientists a bit short lived, wouldn't you think? Oh, I forget, you aren't into that whole "thinking" thing.
No, it is leaking radiation. Reactors are complex devices and many, many parts of them contain radiation -- the cooling loops, for example. Extreme damage to the reactor compartment would no doubt shred all interconnects and penetrations of the reactor vessel (but NOT the vessel itself) allowing "hot" coolant to seep out. If the reactor had been subject to a meltdown then PERHAPS radioactive debris could be flushed from the vessel, but the vessel itself would STILL be intact.
It's been mildly entertaining to educate you out of your self-imposed ignorance, but poking idiots with a stick can only hold my attention for so long. Do both of us a favor and don't bother replying until you've actually done a little reading on the engineering of nuclear reactor pressure vessels. You'll come of sounding less like some illiterate child and it'll be actually mentally engaging for me, for a change.
While I have no great love for government management, they do have one advantage that no private company could ever have: gov't agencies never have to show a profit. If safety costs are ridiculous, there are no stockholders to answer to, no bankers, no anything. They just sign the check. It's horrifically wasteful, and it's my damn tax dollars, but I'd rather SAFETY money be spent by an organization that has few reasons to pinch pennies.
Of course, there are ethical and honorable corps. out there that would not be inclined to scrimp on something like, oh, say, O-rings, but they never seem to get the big contracts.
Easy! Because corporate I.T. departments think nothing of shelling out huge coin for SCSI arrays. Let's face it, SCSI at home is nearly an impossibility in the face of gargantuan IDE drives for under a dollar a gigabyte. $400 will buy you about 18GB of SCSI storage if you include a controller. You can get about 180GB of IDE storage for the same price. Sure you can't hook up a SCSI scanner or SCSI CDROM to it, but why would you want to? Good USB scanners are everywhere, and IDE CDROMs lack nothing compared to their SCSI bretheren except an inflated cost.
So it has to be the corporations that are footing the SCSI bill and allowing the prices to remain inflated. The drive mechanisms and fabrication plants are IDENTICAL between IDE and SCSI. There is no special razzle-dazzle clean room with neato-keen testing equipment just for SCSI disk platters. It's the same! The only difference is in the electronics, and while SCSI chips cost more than IDE, we're talking the difference between a $10 IDE disk logic board and a $25 SCSI disk logic board, certainly not enough to account for the ridiculous pricing differences of SCSI vs. IDE.
Some have said that IDE is worse off because you can't get it in 10K and 15K RPM variants. To that I say "if you ask for it, they will build it". Your average consumer neither wants nor needs a banshee-screaming, egg-frying 10K or 15K drive. And as we've already seen, about the only thing RPM gets you is reduced rotational latency. It does NOT scale the transfer rate (i.e. a 15K drive's transfer rate is not double that of a 7200RPM drive) with RPM. Do we really care if the drive has a 0.5ms faster seek rate? On a database server, yes. On a desktop, or even a good workstation? No.
but a nuclear rocket engine would have to take this into consideration.
Well, as I pointed out in a) to f), it CAN'T.
Regards,
angel'o'sphere
Which points out little other than your ignorance of the subject. As I described in a post elsewhere on this subject, there are alternative means of using nuclear energy to propell a spacecraft other than the open chamber you suggest.
If you'd bother to do a little research you'd discover that ideas have surfaced about encasing the fission elements in ceramic to keep any radioactive debris in the reaction chamber. There is also the possibility of using a heat exchange loop to transfer heat from the fission core into an inert propellant that can be used for thrust. In both cases the radioactivity is contained within the system, not expelled And these are just two examples -- there are more, and all take environmental contamination into acount. Yes, they sacrifice a great deal of efficiency and weight advantage, but it's a necessity if it's ever to be used in the atmosphere.
And you're wrong about the sub reactors, by the way. You're talking to someone who's actually spent time in the military around these things, so I doubt your viewpoint is as clear as mine on this. The pressure vessel is designed to withstand the complete and total destruction of the submarine by any known or projected weapon system, and THEN they add a margin onto that. Short of an internal meltdown, there's nothing out there likely to rupture the pressure vessel.
So, to coin your little phrase, "You get it now?". Try being a little less condescending when you obviously don't know as much about the subject as you claim.
Who said anything about using NERVA-style rockets for atmospheric flight? I certainly didn't.
Obviously a NERVA-style rocket would be totally implausible for the reasons you describe. There are other ways, of course. One example had the fuel grains encased in a ceramic materials that was very heat efficient but constrained any radioactive debris from escaping the reaction chamber. There's also the possibility of using some sort of gas or liquid sodium heat exchange system to heat an inert propellant to use as thrust. There are a lot of possibilities beyond what has already been suggested, which is why I brought the point up in the first place. Scientists need to be thinking about this type of propulsion, not sidestepping it because of some absurd nuclear stigma.
Yeah. So? The cost per kg is 1/10 of the Space Shuttle. Cost per kg is a pretty reasonable metric. So you go there and back 10x and assemble on orbit.
Yeah. So? The S-V cost per kg was 1/10 that of the shuttle to begin with! The shuttle is NOT cheaper than the 60's era moon rockets -- not by a LONG shot. All that throwaway booster work was actually easier to deal with than the constant launch-inspect-refit-launch cycle that the shuttle goes through. Go look up NASA's data on the subject. It's all there.
>Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation.
Interesting. Is this caused by the lasers or just natural artifacts of the atmosphere? Incidentally power is the cheap bit in the equation, and you need less of it delivered at altitude due to g-limiting anyway; so it may not matter.
It's a natural effect of firing a laser through something other than a vacuum. The air molecules, water molecules, and even airborne dust all absorb and/or scatter the beam. Add to that the fact that a spacecraft isn't going to go straight up into orbit, it's going to follow a slanting path that could have a laser firing through 100-200 miles of atmosphere before it even touches the spacecraft, and THEN it actually has to still have enough energy to propell the craft. This is a HUGE problem that simply cannot be gotten around by anything other than brute forcing the laser output. Even adaptive optics will only get you so far. The power requirements would be orders of magnitude beyond anything even on the drawing board today, and the cost would be appropriately astronomical.
And let's not forget that if you had a ground based laser that powerful, it'd make a nifty weapon for zapping LEO satellites and space stations. I'm sure there's some hyper-concerned pacifists out there that would have an absolute conniption fit over such a thing.
Rational concerns of nuclear safety can be addressed by rational safety measures. Where the irrational come into play is those that will not be placated by any safety measure, no matter how comprehensive or effective. Those are the people I was referring to. There aren't that many of them, but those few are incredibly vocal.
Yes, the engines would be quite different from the nuclear thermoelectric devices we've already orbitted, but the safety measures would not be. The casks containing the hot material are subjected to absolutely insane tests (burned, blown up, impacted, submerged, simulated re-entry) to prove that they won't spill material, and to date none of them have despite a wide range of circumstances.
I believe that it is possible to design an engine such that all possible rational safety measures are taken. I just think that the knee-jerk crowd will NEVER be satisfied as long as the word "nuclear" is mentioned. People have been too conditioned to be afraid of that word. More's the pity.
It can be a knee-jerk response when you consider it's possible to design a nuclear engine that is (a) extremely safe to operate and (b) very damage resistant. Take a look at the types of containers they use to ship spent fuel rods from nuke plants to storage areas. They burn them, soak them, hit them with trains and planes, and even detonate explosives next to them. They survive.
Ever been on a nuclear submarine? The pressure vessel is incredibly strong. Torpedo hits, mines, implosion, seawater corrosion...the pressure vessel is designed to withstand all that. Sure, that makes it heavier and more expensive, but a nuclear rocket engine would have to take this into consideration. The specific impluse of such an engine would be of so much greater power and efficiency than any chemical rocket that the weight gains would be made negligible.
>performance rocket engine they had to use, couple >with the experimental composite cryogenic fuel >tanks.
No. This isn't the case; I was talking to some engineers that worked on the Roton just last weekend. They indicated that they knew of no problem that would have precluded the design from working. The composite cryogenic fuel tank THEY used (as opposed to the X33 debacle) - it worked fine in all testing; including something like 50 pressure cycles IRC.
It's good to hear that someone's worked on the problem a bit. Still, I'm sure it's quite expensive.
>you need a bigger rocket, which means more fuel, >then a bigger rocket...you get the idea.
No, the simulations converge- SSTO is definitely possible. I've seen atleast 2 hard and fast designs for SSTO vehicles- the Roton and Mockingbird. The Roton would have carried 3 tonnes to LEO; the Mockingbird design didn't have a payload of any note, but was really tiny (1.5 tonnes), and cheap. I've studied both concepts extensively; they both appear workable.
I will point out that the payload capacity you're speaking of is about a tenth of what one Saturn V can hurl into LEO. It's like comparing an old big-block V8 with a 4 barrel carb versus a high-winding multicam, turbocharged, intercooled 4 cylinder engine. Both will make gobs of horsepower, but the latter is going to be much more expensive than the former AND generally more prone to failure. The Shuttle main engines are a case in point with their trouble-prone turbopumps. The J5 engines on the Saturn only had to work once, thus were much cheaper AND more reliable.
>What we need is a way to extract more energy from >whatever fuel we use.
Another thing I saw on the weekend- I was at a presentation by a guy talking about a laser powered launch system. The idea is you take a large bank of lasers and point it at a hydrogen powered launch vehicle, which has a heat exchanger it uses to heat the hydrogen. The ISP is about 600 seconds, which is plenty for reaching orbit. The laser bank was priced at about $1 billion but its dropping at about 30% a year currently- only cheap semiconductor lasers are needed, and they're getting cheaper and cheaper.
I've seen this concept demonstrated with computer simulations, but I'm still skeptical of it. Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation. By the time you're 50 miles up, that's got to be a tremendous power loss, meaning you'd have to have incredibly powerful lasers chewing up gobs of power. You'd need a nuclear power plant on site just to power the darn thing most likely.
Unfortunately given our current level of rocket propulsion technology a single-stage-to-orbit (SSTO) isn't terribly practical. They made some prototypes and actually flew a scaled down prototype in the desert, but ultimately they had tremendous problems with the extremely high performance rocket engine they had to use, couple with the experimental composite cryogenic fuel tanks.
I honestly don't think we'll ever get SSTO going with conventional chemical propellants. You simple have to carry too much weight in fuel, which means you need a bigger rocket, which means more fuel, then a bigger rocket...you get the idea. What we need is a way to extract more energy from whatever fuel we use. One way to do that is to go nuclear.
Nuclear rockets have been proposed in the past and always shot down by the enviro-Nazi, anti-nuke crowd. Seems you can't split an atom these days without attracting a lot of attention from this fringe crowd that cringes at the very word "neutron". Yes, nuclear technology CAN be dangerous. So can a lot of other things. NASA has an enviably safety record given the hazardous work they do, and I have no doubt that if the nuclear engine project were ever to become reality it would be a paragon of safety.
Of course, there could always be something flying out of left field here like some sort of teleportation technology or anti-gravity, but I doubt it in my lifetime.
And if we ever get REALLY serious about getting off this planet, the ONLY way to fly would be a space elevator. A monumental engineering task to be sure, but once in place it'd be the cheapest ride into low Earth orbit that we could come up with.
How 'bout this one? Georgia Tech campus newspapers were stolen and burned because an editorial against racial quotas was in it. Nobody did anything, nobody said anything -- except that the paper later printed an apology for running the editorial and stated its urgent desire not to "offend" anyone.
This is just one example. There are others that can be produced with more digging. I can go find them, or if you're really interested in this topic you can google for them yourselves.
It's pretty interesting to see how many people will jump up and down and scream bloody murder when someone attempts to censor a left-wing website, but those same people are strangely silent when it comes to attempts to censor conservative or right-wing sites, college newspapers, or books.
Trees emit ozone in addition to other gases besides breathable oxygen. Further, a square acre of trees will not give the same CO2 processing capability of a square acre of the above-mentioned processing plant. And processing plants aren't subject to drought, disease, bugs, and forest fires.
Re:Space Defense Initiative (SDI)
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Space Wars
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· Score: 2
You've proven that any assertion, taken to absurd abstraction, breaks down. Bravo. It means little. My disagreement is much more fundamental and simple.
Max says that luck rules all. I disagree. Luck can account for much, but so can hard work. Where Max and I part company is that he believes if you've "made it", it's because of luck, not ambition, hard work, or anything else. You've "won the lottery", so to speak. This demeans anyone who's ever worked their way out of the ghetto by sheer force of will, despite a huge array of societal barriers to the contrary. Lesser people would give up, resign themselves to their "caste", and stay at whatever level they're at waiting for lady luck to give them a better lottery ticket.
Balderdash, I say. While hard work does not assure success, neither does luck. You can be born into riches and lose it all, the same way you can be born into poverty and end up rich. Working hard and having ambition improves your chances of elevating yourself in society regardless of any other external factors, luck included. Since hard work is a constant, ever-present improver of chances, but luck is totally random, it would follow that anyone who has any desire to be more than they are should work hard and have ambition to succeed, otherwise they have denied themselves an essential advantage. Unfortunately, it is much easier for many to simply give up, rot in mediocrity, and hate those who have worked their way upwards.
Here's a good example. Go find a bum somewhere with a "will work for food" sign. Give him a task to do in return for food -- yard work, for example. If he does a good job, task him with something else and reward (i.e. pay) him, increasing responsibility and pay as he completes more tasks. Eventually this conduct will allow him to rise out of his loitering state and become a productive member of society. Regardless that he may still be making minimum wage and live in relative poverty, he is better off than standing by the road with a "work for food" sign.
Of course, if you have any common sense about you, you'll know that if you were to try the above example you'd find that the individual would rarely be inclined to actually work for food. Instead, he or she would expect a handout for nothing, tell you a sob story about how they've been wronged by life, and then spend any funds you gave them as recklessly as they had in their bygone days, thus ensuring a continual existence as a bum. THIS is Social Darwinism -- those that refuse to elevate themselves when opportunties exist will eventually be made economically and socially "extinct". While they may still be alive, they will have little or no impact on the human race other than to present a constant drag on resources. Their chances of reproduction will be lessened (although this is not always the case -- just check the projects). It parallels traditional Darwinism fairly well.
You could, of course, believe like Max does, that anyone who has "made it" is there because of sheer luck. This has the side affect of allowing you to believe that the person doesn't "deserve" their "good fortune", thus perpetuating a hatred of successful people. This, in turn, leads to a rejection of the success ambition as a means to advance in society, and results in a largely unmotivated, unambitious, unimproving population. See various examples such as the former Soviet Union, where the idea of a classless society virtually abolished the desire to excel -- those who did poorly were rewarded just as well as those who did well. Thus, why try harder? It would gain you nothing. This is not a good thing for the human race. Granted we might be a kindler, gentler, more touchy-feely race, but we'd be a more stagnant race as a whole. It might take centuries to produce the same amount of progress that a more ambitious (but less feeling) society might've produced in mere generations.
Max, however, did not want to debate this point. He calls anyone who disagrees with him a megalomaniac, while at the same time barking his moral and philisophical superiority to all within earshot. It is a mark of weak minds that they will not debate with logic, but instead resort to emotional attacks and arguments. Max has distinguished himself well as just that, and it is a pity for this is a subject that I would love to debate with someone who had an opinion instead of an agenda.
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You go right on thinking that, then. I hear delusions such as yours have great healing properties for weak minds.
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I'm not going to dignify you attacks by answering them, I'm only going to express my disappointment at wasting my time trying to enter into a useful debate with someone so obviously childish as yourself. Perhaps when you grow up you'll be able to hold a meaningful discussion with your betters without devolving into inane ranting.
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It's a pity you resort to namecalling and profanity to further what looked to be an interesting debate. It makes you look rather unprofessional for someone wanting to debate the subject.
I would like to point out to you that there are plenty of people who started out with nothing, in the lowest social circles, and worked their way into power and wealth. There are plenty of people who started with a lot and have squandered it, social starting point be damned. Your argument that success is luck-derived is specious at best and demeans those who strive and toil, dealing with failure after failure, never giving up. Those are the people who ultimately succeed. True, being in the right place at the right time helps, but it (a) does not guarantee success and (b) is not required to achieve success.
Your references to megalomania and other barbed comments leads me to believe you're someone who has a burning envy of those who have succeeded in life, or perhaps an inferiority complex driven by some lack of success in your life. Get over it. Quit being envious of those who have more than you, and strive to succeed on your own merits. Do not wait for luck to find you, go and make it happen yourself. If you don't believe it's possible, then I pity you.
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Protectionist tarriffs rarely have the intended effect. Usually people just go elsewhere to obtain their goods. The U.S. has been guilty of this many times, and it's almost always backfired. If "helping" EU company sales is their goal, why the hell don't they reduce the tax burden of those companies so they can sell their products cheaper?
I think you are glossing over the fact that this country has run a deficit every year since WWII, under both Republican and Democratic presidents, and it hasn't harmed us a whit. I'd also like to point out that if your savior Bill Clinton really was serious about deficit destruction then he wouldn't have signed so many Democratic spending bills, but that would just be petty of me, wouldn't it? You seem to have a rather large axe to grind against the Republican's here, with Bush in particular. Sour grapes over the election?
"just widening existing taxation"...and you just sit there and defend it. They are taking YOUR money, to spend it on God knows what, which will most likely never bring any tangible benefit to YOU, but will certainly benefit the political career of someone else...with YOUR money.
How long before they have to "widen" things again? Pretty soon the vast majority of your disposable income will be going just to pay the taxes, not to buy things!
Apathy must be fun.
A recession is defined as two consecutive quarters of negative growth. My mistake, I should've said TWO quarters, not one.
Either way, that's 6 months, not 8. That mini-recession DID included a few quarters before and after of slow or stagnant growth (all recessions do) which made the apparent effects longer. You can review all these numbers at omb.gov.
I'm at a loss to understand how some idiotic tax (in an area that is already well known for outrageous VAT taxes) is supposed to help sales. Basic economics will indicate that if an item becomes more expensive, fewer items will be sold. Since the tax goes to the gov't instead of whoever is actually producing, selling, distributing the item, that money is for all intents and purposes LOST.
Very, very shortsighted. Historical evidence unequivocally shows that for the last 100 years, every time taxes have been lowered and economic boom came to fruition within 2-4 years (economic inertia). This boom has ALWAYS offset the short-term lowered tax revenues caused by lowering taxes in the first place. Pity that most politicians only think 2-4 years ahead, and thus do not realize (or don't want to realize) this obvious truth. If you don't believe me just go to www.omb.gov (Office of Management and Budget) for the lowdown on the economic figures for the U.S.
You'll note that Reagan lowered taxes and increased spending, resulting in a deficit. He was widely criticized for it, but the 80's were huge boom years. Apart from a very short (only 1 economic quarter) recession in 1990, the economy STAYED in high gear until the tech crash of 2000-2001. During the longest economic expansion in U.S. history (which started under Reagan, not Bush #1, and certainly not Clinton), tax revenues INCREASED to the point where we were whacking away at the deficit in huge chunks. During that same time period government spending INCREASED as well, something that should've caused more deficits, but didn't due to the greatly increased tax revenues.
Under Clinton taxes were radically increased. You'll note that about 4 years later the economy abruptly reversed. I'm not blaming Clinton for the recession (overenthusiastic investors are largely to blame), but it can be said that he did little to thwart it. Now Bush #2 is in the center seat, and he's cutting taxes. I have every reason to believe that we'll deficit spend for 1-2 years, but in the long run it will pay us to have done things this way.
The EU has never gotten this idea, and the absurd VAT tax is just another example. Governments and politicians don't EARN or PRODUCE wealth, they TAKE it and SPEND it without regard to who they took it from. There is no way in hell MORE taxes will lead to a BETTER economy. History does not lie.
And since you're so interested in sources, quotes, and figures, try this one on for size, taken from SPACE.COM:
"Funds are minuscule. They are extremely meager," adds John Cole, NASA's manager of the space transportation research project office at Marshall Space Flight Center.
"Beamed energy is one of the avenues we've got if we're ever going to get the cost of access to space down," Cole said.
Cole sees a 21st century where passenger-carrying space vehicles might be powered upward on laser light. That laser would churn out 100 gigawatts of power, he admits.
"That's 10,000 times bigger than any laser that's been built. But, hey, I'll take whatever works," Cole said.
Keep in mind that's 100 Gigawatts of power, AND that lasers are not 100% efficient. I've done some cursory web surfing and I've seen efficiency figures in the 30%-50% range for semi-lasers (these could be out of date, but I found about 20 references to figures in this range from a variety of sources). So, to be optimistic, we'd need at least 200GW input to the laser(s). Then we'd have to take into account that whatever's transmitting the power to the laser system has resistive losses, not to mention any step-up or step-down transformer inefficiencies, and then there's the actual efficiency of whatever's actually generating all these gigawatts. I would feel comfortable, even magnanimous, giving a 500GW figure. Per launch. For ease of comparison, let's call that 500,000,000 kilowatts, and assume that it takes 1 hour to completely loft our hypothetical vehicle, from warming things up all the way until turning them off post launch. That's half a billion kilowatt hours.
Annual electrical production of every nuclear power plant in the United States is around 700 billion KW/hrs for the entire year according to the DoE. That means daily production is about 1.9 billion KW/hrs per day.
Your proposed laser propulsion system would consume the electrical output of every nuclear reactor in the United States operating at full power for 6 hours.
For comparison, note (from Boeing's website) that the five F-1 engines equaled 160,000,000 horsepower, about double the amount of potential hydroelectric power that would be available at any given moment if all the moving waters of North America were channeled through turbines. Granted they were lifting an awful lot of fuel with that horsepower (although a lightship would require fuel to manuver in space), but it's a staggering display of the power required to get into orbit. And that was just the first stage of the rocket.
NOW is it starting to dawn on you how far off the mark you are/were?
(sigh) this is getting tiring.
Really? No. That's what you need if you want one big laser beam. We don't want that. In fact the atmospheric effects would be very detrimental- the beam would scatter horribly.
As I pointed out, this can be corrected with adaptive optics the same way that you can collimate the beam of a few billion laser pointers. The only thing is it's easier to do with fewer lasers (to a point) than billions of them.
This concept is thousands of semiconductors all pointing in parallel through a single telescope at the vehicle; and then having, say a thousand of these telescopes. (You can play with the numbers, but that's the concept).
If you do the maths, its gonna come comfortably under a billion.
So you're just going to mint a couple of billion souped up laser pointers and expect it to propel a spacecraft? Funny how none of the existing researchers are pursuing this. Perhaps it's because it's not feasible. First off, there's the difficulting of collimating a beam created in such a manner, but that can be somewhat compensated for by adaptive optics. Still, you haven't overcome the fact that you'd need obscene numbers of these to generate a beam working in parallel. I would point out the obvious cooling and control difficulties, but I'm sure you've given that LOTS of thought, eh?
Your idea, while technically possible, is impractical when you can take larger lasers to begin with. While the cost per laser is higher than semiconductor lasers the engineering difficulties are lower. You could shine a few quadrillion flashlights at the bottom of a spacecraft and get some propulsive effect, but again it's not worth it.
The figure I have seen quoted is about 1MW/kg, but it depends a bit on the system you're looking at. Do you have a source for your figure?
LLNL has a nice section, and Space.com has a bit on it as well. 150KW propells something that weighs the same as an empty coke can to the edge of the atmosphere, but that's straight up. Anything that intends to stay in orbit for long will have to achieve orbital velocity, which means slant range, which means the laser will be plowing through 4-5 times the amount of atmosphere as a straight shot. You claim to know lasers and optics, so why don't you save me the trouble of debunking this and do the math and see how that would affect beam power. You're going to quintuple your range AND you've got to achieve about 18,000mph while taking atmospheric friction into account (you DID consider all this, right? Nope, doesn't apear so) Huge, isn't it? How many "laser pointers" were you planning to glue together? Keep in mind that your average semi-laser is rated in milliwatts.
100Mw for 15 minutes. That's 400,000 kwh. 1 Kwh costs $0.01-0.05. That makes: $4000-$20,000 of electricity for ~100kg
100kg? First off, it seems that you're only counting boosting a payload. Last I heard, satellites don't just fly themselves through the atmosphere, they need a launch vehicle, one sturdy enough to withstand atmospheric flight on the way to orbital velocity. Your total launch weight is going to be much, much higher. And don't forget that USEFUL stuff being lofted is often weighed in tons, not kilos. You wanna loft a cocker spaniel wrapped in aluminum foil, be my guest. Most folks want to loft satellites and space stations. Again, please think about the total solution before jumping to a conclusion.
Do you think so? Oh dear. How sad; still atleast I don't come across sounding all negative.
No, you come across as someone who is hopelessly optimistic or ridiculously idealistic. Either way, that's good for dreaming, but we're talking about practical application here and now. It may be possible, but it isn't practical. I'm not being negative here, I'm simply pointing out the flaws in your argument.
p.s. come back when you've investigated the cost per watt of semiconductor lasers power. ($10-50/W- dropping at ~30% per year).
Again, the cost of the semi-laser is not the issue. Big lasers cost big money but don't need all the fancy adaptive optics that a multi-billion laser array would need. Then there's power, which you've woefully underestimated by (a) not taking a realistic flight path mission profile into account and (b) not considering a worthwhile payload mass in conjunction with launch vehicle mass. Right now they're using 150KW to launch something that weighs ounces straight up. We need to launch tons, at an angle, at orbital velocities. Your math simply isn't in the same league as this.
p.p.s. I work with semiconductor lasers as part of my day job; I understand optics.
From your bent I'd have to guess that you work with semi-lasers on CD-ROM/DVD or some other consumer/professional electronic product. Those are just fine for small scale, short range applications, but massively parallel is an engineering challenge that no one has demonstrated an ability to cost effectively develop. And while you say you understand optics, you have consistently neglected to factor in a variety of optical phenomena that would affect such a laser propulsion system. Either you know a lot but aren't using your knowledge, or you know a little and are stretching beyond your means. If it's the former then you need to apply yourself, not blather. If it's the latter then I'm wasting my time anyway.
p.p.p.s. this wasn't my idea (I wish), it came from a professional rocket scientist... you know, somebody who actually designs them for a living, for money, for the US government. It is entirely possible there's some flaw; but if so I don't think you've spotted it.
The flaws are pointed out in stark detail above. Feel free to debunk them, but please take some time and put some thought into it. Shooting down poorly made arguments is easy but time consuming. I'd prefer to spend my time debating with someone who thinks something through before posting it.
Oh, the humanity. Please, please PLEASE do a little research before embarking on a debate about a subject which you don't seem all that informed about. Semiconductor lasers are not in the same class of power production as what would be needed for a laser-based propulsion system. A semiconductor laser might be great for a laser pointer or a DVD-ROM reader, but pushing megawatts or gigawatts of power is NOT what they do well. You need something more akin to a chemical reaction laser to generate this kind of power. Do a lookup on the EXCIMER laser to see what you'd need in order to make this project a reality.
And while we're on the subject, your little "so, just add more power" neatly sidesteps any logic or economic common sense. Power costs MONEY, and with the type of power you'd need, it may well outrun the cost of the hardware. This cost would be repeated FOR EVERY LAUNCH. And somehow I get the feeling that you are simply ignorant of just how much power would be needed here (hint: 100MW is off by at least an order of magnitude). Your comparison to shuttle costs ignores the fact that even though a shuttle costs $1bn, upkeep of the shuttle costs more than that.
Take some time, cool down, and try to research a subject before jumping to conclusions and making outrageous, silly statements. You're coming across as someone who's doing a lot of talking and very little thinking.
Sorry. I dissagree.
Most torpedos used on naval combat, agains a sub especialy or a carrier fleet are: nuked torpedos.
Sorry, I disagree. No navy currently fields sub-launched nuclear torpedos. Nuclear mines, nuclear depth charges perhaps, but not nuclear torpedos. Semantics, yes, but we wish to be accurate here.
You little sub does no longer exist after a full hit and its flattend like a piece of paper if its in a 10km range of the torpedos ignition. (yes I know this is an unfair point, but you said: *nothing* can break it)
Granted, I should've said no conventional weapon can destroy it, but I was expecting a little rationality and reality from you on this point, not quibbling. Of course a nuclear weapon would rupture it. Bravo! You've proven that absurd extremes make almost anything true or false. The point was this: nothing that is likely to happen is going to pierce a nuclear reactor pressure vessel, and a nuclear rocket designed to the same specs will be, for all practical purposes, just as indestructible.
I realy doubt that a navy sub reactor containment can stand a rocket torpedo like that one which sunk the Kursk.
Yes, it could, precisely because the rocket torpedos don't NEED that much power to destroy a submarine. Gross overkill is just that -- gross. All a torpedo (or mine, or depth charge for that matter) has to do is open the hull somehow. That will most likely sink the sub, accomplishing the mission of the weapon. Going the extra mile and trying to destroy the pressure vessel would be silly, useless, and result in a weapon that is too large, too expensive, and too dangerous to use near other friendly forces. Nuclear weapons used underwater are used for area destruction via the water hammer effect. The end result is the steel (or titanium in some cases) hull is collapsed by the pressure wave. In all simulations where the submarine was outside the fireball of the nuclear weapon, the pressure vessel remained intact even though the hull was effectively pancaked.
I doubt it can stand a simple ice berg. After all it is only metal isn't it? Supose you slice your side on an ice berg, I could imagine it just cuts through the containment.
Ah! Now your total ignorance of underwater nuclear propulsion comes to the fore! Sure did take you long enough. No, it is NOT merely metal. Pressure vessels are complex layers of many different metals, composites, and other solids (in some cases, even concrete). Ramming into an iceberg would pose no threat to the reactor (especially since a sub would have to ram one SIDEWAYS to even get a berg NEAR the reactor compartment). Ramming into another ship would not breach it. Sinking to the bottom of the deepest ocean trench would not crush it. You must remember that the vessel is designed to contain a nuclear reaction, no small feat. They are designed to be strong to begin with, and militarizing them only makes them stronger.
I also doubt that a standard anti carrier torpedo, which could be used against a sub if it is not diving, will leave anything intact.
I hate to break it to you but you're wrong. Go look up Janes Fighting Ships and you'll see.
Such a torp would lift a sub aproximately 50 meters into the air through its blast. Its just a question where it hits and your reactor is open.
50 meters? My, what a precise figure. You came to that conclusion after carefully considering the warhead yield, the depth of our hypothetical sub, the weight of the sub, it's speed and course, and about a thousand other variables that would influence such a statement...right? Oh, you didn't, did you? If you had, you'd have realized that your statement is not only wrong, it's stupid. Lifting a submarine 50 meters "into the air" as you say is not practical or possible with conventional antisub munitions. Nor is it necessary, due to the overkill described above.
Finaly: in the north atlantic is a sunken navy sub. Its regulary visited by Norway scientists. That sub leakes plutonium. So much to your claim.
So much for your argument, logic, or even sense. The sub is NOT leaking plutonium as you state, it is leaking radiation, something totally different. Plutonium is phyrophoric. Since you're obviously mentally deficient, I'll explain that pyrophoric means the substance spontaneously ignites outside of a containment vessel. If it were leaking plutonium it would be exploding. That would kind of make your Norwegian scientists a bit short lived, wouldn't you think? Oh, I forget, you aren't into that whole "thinking" thing.
No, it is leaking radiation. Reactors are complex devices and many, many parts of them contain radiation -- the cooling loops, for example. Extreme damage to the reactor compartment would no doubt shred all interconnects and penetrations of the reactor vessel (but NOT the vessel itself) allowing "hot" coolant to seep out. If the reactor had been subject to a meltdown then PERHAPS radioactive debris could be flushed from the vessel, but the vessel itself would STILL be intact.
It's been mildly entertaining to educate you out of your self-imposed ignorance, but poking idiots with a stick can only hold my attention for so long. Do both of us a favor and don't bother replying until you've actually done a little reading on the engineering of nuclear reactor pressure vessels. You'll come of sounding less like some illiterate child and it'll be actually mentally engaging for me, for a change.
While I have no great love for government management, they do have one advantage that no private company could ever have: gov't agencies never have to show a profit. If safety costs are ridiculous, there are no stockholders to answer to, no bankers, no anything. They just sign the check. It's horrifically wasteful, and it's my damn tax dollars, but I'd rather SAFETY money be spent by an organization that has few reasons to pinch pennies.
Of course, there are ethical and honorable corps. out there that would not be inclined to scrimp on something like, oh, say, O-rings, but they never seem to get the big contracts.
Easy! Because corporate I.T. departments think nothing of shelling out huge coin for SCSI arrays. Let's face it, SCSI at home is nearly an impossibility in the face of gargantuan IDE drives for under a dollar a gigabyte. $400 will buy you about 18GB of SCSI storage if you include a controller. You can get about 180GB of IDE storage for the same price. Sure you can't hook up a SCSI scanner or SCSI CDROM to it, but why would you want to? Good USB scanners are everywhere, and IDE CDROMs lack nothing compared to their SCSI bretheren except an inflated cost.
So it has to be the corporations that are footing the SCSI bill and allowing the prices to remain inflated. The drive mechanisms and fabrication plants are IDENTICAL between IDE and SCSI. There is no special razzle-dazzle clean room with neato-keen testing equipment just for SCSI disk platters. It's the same! The only difference is in the electronics, and while SCSI chips cost more than IDE, we're talking the difference between a $10 IDE disk logic board and a $25 SCSI disk logic board, certainly not enough to account for the ridiculous pricing differences of SCSI vs. IDE.
Some have said that IDE is worse off because you can't get it in 10K and 15K RPM variants. To that I say "if you ask for it, they will build it". Your average consumer neither wants nor needs a banshee-screaming, egg-frying 10K or 15K drive. And as we've already seen, about the only thing RPM gets you is reduced rotational latency. It does NOT scale the transfer rate (i.e. a 15K drive's transfer rate is not double that of a 7200RPM drive) with RPM. Do we really care if the drive has a 0.5ms faster seek rate? On a database server, yes. On a desktop, or even a good workstation? No.
but a nuclear rocket engine would have to take this into consideration.
Well, as I pointed out in a) to f), it CAN'T.
Regards,
angel'o'sphere
Which points out little other than your ignorance of the subject. As I described in a post elsewhere on this subject, there are alternative means of using nuclear energy to propell a spacecraft other than the open chamber you suggest.
If you'd bother to do a little research you'd discover that ideas have surfaced about encasing the fission elements in ceramic to keep any radioactive debris in the reaction chamber. There is also the possibility of using a heat exchange loop to transfer heat from the fission core into an inert propellant that can be used for thrust. In both cases the radioactivity is contained within the system, not expelled And these are just two examples -- there are more, and all take environmental contamination into acount. Yes, they sacrifice a great deal of efficiency and weight advantage, but it's a necessity if it's ever to be used in the atmosphere.
And you're wrong about the sub reactors, by the way. You're talking to someone who's actually spent time in the military around these things, so I doubt your viewpoint is as clear as mine on this. The pressure vessel is designed to withstand the complete and total destruction of the submarine by any known or projected weapon system, and THEN they add a margin onto that. Short of an internal meltdown, there's nothing out there likely to rupture the pressure vessel.
So, to coin your little phrase, "You get it now?". Try being a little less condescending when you obviously don't know as much about the subject as you claim.
Who said anything about using NERVA-style rockets for atmospheric flight? I certainly didn't.
Obviously a NERVA-style rocket would be totally implausible for the reasons you describe. There are other ways, of course. One example had the fuel grains encased in a ceramic materials that was very heat efficient but constrained any radioactive debris from escaping the reaction chamber. There's also the possibility of using some sort of gas or liquid sodium heat exchange system to heat an inert propellant to use as thrust. There are a lot of possibilities beyond what has already been suggested, which is why I brought the point up in the first place. Scientists need to be thinking about this type of propulsion, not sidestepping it because of some absurd nuclear stigma.
Yeah. So? The cost per kg is 1/10 of the Space Shuttle. Cost per kg is a pretty reasonable metric. So you go there and back 10x and assemble on orbit.
Yeah. So? The S-V cost per kg was 1/10 that of the shuttle to begin with! The shuttle is NOT cheaper than the 60's era moon rockets -- not by a LONG shot. All that throwaway booster work was actually easier to deal with than the constant launch-inspect-refit-launch cycle that the shuttle goes through. Go look up NASA's data on the subject. It's all there.
>Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation.
Interesting. Is this caused by the lasers or just natural artifacts of the atmosphere? Incidentally power is the cheap bit in the equation, and you need less of it delivered at altitude due to g-limiting anyway; so it may not matter.
It's a natural effect of firing a laser through something other than a vacuum. The air molecules, water molecules, and even airborne dust all absorb and/or scatter the beam. Add to that the fact that a spacecraft isn't going to go straight up into orbit, it's going to follow a slanting path that could have a laser firing through 100-200 miles of atmosphere before it even touches the spacecraft, and THEN it actually has to still have enough energy to propell the craft. This is a HUGE problem that simply cannot be gotten around by anything other than brute forcing the laser output. Even adaptive optics will only get you so far. The power requirements would be orders of magnitude beyond anything even on the drawing board today, and the cost would be appropriately astronomical.
And let's not forget that if you had a ground based laser that powerful, it'd make a nifty weapon for zapping LEO satellites and space stations. I'm sure there's some hyper-concerned pacifists out there that would have an absolute conniption fit over such a thing.
Rational concerns of nuclear safety can be addressed by rational safety measures. Where the irrational come into play is those that will not be placated by any safety measure, no matter how comprehensive or effective. Those are the people I was referring to. There aren't that many of them, but those few are incredibly vocal.
Yes, the engines would be quite different from the nuclear thermoelectric devices we've already orbitted, but the safety measures would not be. The casks containing the hot material are subjected to absolutely insane tests (burned, blown up, impacted, submerged, simulated re-entry) to prove that they won't spill material, and to date none of them have despite a wide range of circumstances.
I believe that it is possible to design an engine such that all possible rational safety measures are taken. I just think that the knee-jerk crowd will NEVER be satisfied as long as the word "nuclear" is mentioned. People have been too conditioned to be afraid of that word. More's the pity.
It can be a knee-jerk response when you consider it's possible to design a nuclear engine that is (a) extremely safe to operate and (b) very damage resistant. Take a look at the types of containers they use to ship spent fuel rods from nuke plants to storage areas. They burn them, soak them, hit them with trains and planes, and even detonate explosives next to them. They survive.
Ever been on a nuclear submarine? The pressure vessel is incredibly strong. Torpedo hits, mines, implosion, seawater corrosion...the pressure vessel is designed to withstand all that. Sure, that makes it heavier and more expensive, but a nuclear rocket engine would have to take this into consideration. The specific impluse of such an engine would be of so much greater power and efficiency than any chemical rocket that the weight gains would be made negligible.
>performance rocket engine they had to use, couple
>with the experimental composite cryogenic fuel
>tanks.
No. This isn't the case; I was talking to some engineers that worked on the Roton just last weekend. They indicated that they knew of no problem that would have precluded the design from working. The composite cryogenic fuel tank THEY used (as opposed to the X33 debacle) - it worked fine in all testing; including something like 50 pressure cycles IRC.
It's good to hear that someone's worked on the problem a bit. Still, I'm sure it's quite expensive.
>you need a bigger rocket, which means more fuel,
>then a bigger rocket...you get the idea.
No, the simulations converge- SSTO is definitely possible. I've seen atleast 2 hard and fast designs for SSTO vehicles- the Roton and Mockingbird. The Roton would have carried 3 tonnes to LEO; the Mockingbird design didn't have a payload of any note, but was really tiny (1.5 tonnes), and cheap. I've studied both concepts extensively; they both appear workable.
I will point out that the payload capacity you're speaking of is about a tenth of what one Saturn V can hurl into LEO. It's like comparing an old big-block V8 with a 4 barrel carb versus a high-winding multicam, turbocharged, intercooled 4 cylinder engine. Both will make gobs of horsepower, but the latter is going to be much more expensive than the former AND generally more prone to failure. The Shuttle main engines are a case in point with their trouble-prone turbopumps. The J5 engines on the Saturn only had to work once, thus were much cheaper AND more reliable.
>What we need is a way to extract more energy from
>whatever fuel we use.
Another thing I saw on the weekend- I was at a presentation by a guy talking about a laser powered launch system. The idea is you take a large bank of lasers and point it at a hydrogen powered launch vehicle, which has a heat exchanger it uses to heat the hydrogen. The ISP is about 600 seconds, which is plenty for reaching orbit. The laser bank was priced at about $1 billion but its dropping at about 30% a year currently- only cheap semiconductor lasers are needed, and they're getting cheaper and cheaper.
I've seen this concept demonstrated with computer simulations, but I'm still skeptical of it. Ground based lasers will always be subject to thermal blooming due to atmospheric attenuation. By the time you're 50 miles up, that's got to be a tremendous power loss, meaning you'd have to have incredibly powerful lasers chewing up gobs of power. You'd need a nuclear power plant on site just to power the darn thing most likely.
Unfortunately given our current level of rocket propulsion technology a single-stage-to-orbit (SSTO) isn't terribly practical. They made some prototypes and actually flew a scaled down prototype in the desert, but ultimately they had tremendous problems with the extremely high performance rocket engine they had to use, couple with the experimental composite cryogenic fuel tanks.
I honestly don't think we'll ever get SSTO going with conventional chemical propellants. You simple have to carry too much weight in fuel, which means you need a bigger rocket, which means more fuel, then a bigger rocket...you get the idea. What we need is a way to extract more energy from whatever fuel we use. One way to do that is to go nuclear.
Nuclear rockets have been proposed in the past and always shot down by the enviro-Nazi, anti-nuke crowd. Seems you can't split an atom these days without attracting a lot of attention from this fringe crowd that cringes at the very word "neutron". Yes, nuclear technology CAN be dangerous. So can a lot of other things. NASA has an enviably safety record given the hazardous work they do, and I have no doubt that if the nuclear engine project were ever to become reality it would be a paragon of safety.
Of course, there could always be something flying out of left field here like some sort of teleportation technology or anti-gravity, but I doubt it in my lifetime.
And if we ever get REALLY serious about getting off this planet, the ONLY way to fly would be a space elevator. A monumental engineering task to be sure, but once in place it'd be the cheapest ride into low Earth orbit that we could come up with.
How 'bout this one? Georgia Tech campus newspapers were stolen and burned because an editorial against racial quotas was in it. Nobody did anything, nobody said anything -- except that the paper later printed an apology for running the editorial and stated its urgent desire not to "offend" anyone.
This is just one example. There are others that can be produced with more digging. I can go find them, or if you're really interested in this topic you can google for them yourselves.
This is not a flame, just an observation.
It's pretty interesting to see how many people will jump up and down and scream bloody murder when someone attempts to censor a left-wing website, but those same people are strangely silent when it comes to attempts to censor conservative or right-wing sites, college newspapers, or books.
Trees emit ozone in addition to other gases besides breathable oxygen. Further, a square acre of trees will not give the same CO2 processing capability of a square acre of the above-mentioned processing plant. And processing plants aren't subject to drought, disease, bugs, and forest fires.
You've proven that any assertion, taken to absurd abstraction, breaks down. Bravo. It means little. My disagreement is much more fundamental and simple.
Max says that luck rules all. I disagree. Luck can account for much, but so can hard work. Where Max and I part company is that he believes if you've "made it", it's because of luck, not ambition, hard work, or anything else. You've "won the lottery", so to speak. This demeans anyone who's ever worked their way out of the ghetto by sheer force of will, despite a huge array of societal barriers to the contrary. Lesser people would give up, resign themselves to their "caste", and stay at whatever level they're at waiting for lady luck to give them a better lottery ticket.
Balderdash, I say. While hard work does not assure success, neither does luck. You can be born into riches and lose it all, the same way you can be born into poverty and end up rich. Working hard and having ambition improves your chances of elevating yourself in society regardless of any other external factors, luck included. Since hard work is a constant, ever-present improver of chances, but luck is totally random, it would follow that anyone who has any desire to be more than they are should work hard and have ambition to succeed, otherwise they have denied themselves an essential advantage. Unfortunately, it is much easier for many to simply give up, rot in mediocrity, and hate those who have worked their way upwards.
Here's a good example. Go find a bum somewhere with a "will work for food" sign. Give him a task to do in return for food -- yard work, for example. If he does a good job, task him with something else and reward (i.e. pay) him, increasing responsibility and pay as he completes more tasks. Eventually this conduct will allow him to rise out of his loitering state and become a productive member of society. Regardless that he may still be making minimum wage and live in relative poverty, he is better off than standing by the road with a "work for food" sign.
Of course, if you have any common sense about you, you'll know that if you were to try the above example you'd find that the individual would rarely be inclined to actually work for food. Instead, he or she would expect a handout for nothing, tell you a sob story about how they've been wronged by life, and then spend any funds you gave them as recklessly as they had in their bygone days, thus ensuring a continual existence as a bum. THIS is Social Darwinism -- those that refuse to elevate themselves when opportunties exist will eventually be made economically and socially "extinct". While they may still be alive, they will have little or no impact on the human race other than to present a constant drag on resources. Their chances of reproduction will be lessened (although this is not always the case -- just check the projects). It parallels traditional Darwinism fairly well.
You could, of course, believe like Max does, that anyone who has "made it" is there because of sheer luck. This has the side affect of allowing you to believe that the person doesn't "deserve" their "good fortune", thus perpetuating a hatred of successful people. This, in turn, leads to a rejection of the success ambition as a means to advance in society, and results in a largely unmotivated, unambitious, unimproving population. See various examples such as the former Soviet Union, where the idea of a classless society virtually abolished the desire to excel -- those who did poorly were rewarded just as well as those who did well. Thus, why try harder? It would gain you nothing. This is not a good thing for the human race. Granted we might be a kindler, gentler, more touchy-feely race, but we'd be a more stagnant race as a whole. It might take centuries to produce the same amount of progress that a more ambitious (but less feeling) society might've produced in mere generations.
Max, however, did not want to debate this point. He calls anyone who disagrees with him a megalomaniac, while at the same time barking his moral and philisophical superiority to all within earshot. It is a mark of weak minds that they will not debate with logic, but instead resort to emotional attacks and arguments. Max has distinguished himself well as just that, and it is a pity for this is a subject that I would love to debate with someone who had an opinion instead of an agenda.
You go right on thinking that, then. I hear delusions such as yours have great healing properties for weak minds.
I'm not going to dignify you attacks by answering them, I'm only going to express my disappointment at wasting my time trying to enter into a useful debate with someone so obviously childish as yourself. Perhaps when you grow up you'll be able to hold a meaningful discussion with your betters without devolving into inane ranting.
It's a pity you resort to namecalling and profanity to further what looked to be an interesting debate. It makes you look rather unprofessional for someone wanting to debate the subject.
I would like to point out to you that there are plenty of people who started out with nothing, in the lowest social circles, and worked their way into power and wealth. There are plenty of people who started with a lot and have squandered it, social starting point be damned. Your argument that success is luck-derived is specious at best and demeans those who strive and toil, dealing with failure after failure, never giving up. Those are the people who ultimately succeed. True, being in the right place at the right time helps, but it (a) does not guarantee success and (b) is not required to achieve success.
Your references to megalomania and other barbed comments leads me to believe you're someone who has a burning envy of those who have succeeded in life, or perhaps an inferiority complex driven by some lack of success in your life. Get over it. Quit being envious of those who have more than you, and strive to succeed on your own merits. Do not wait for luck to find you, go and make it happen yourself. If you don't believe it's possible, then I pity you.