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Clean Nuclear Launches?
AKAImBatman writes "When it comes to launching millions of pounds of material into space, nearly everyone knows about the Orion Project. Blow up a series of nuclear bombs under your dairy-aire and ride the explosion on up. Unfortunately, the Orion spewed out so much radiation that it just wasn't a feasible launch option. If we want commuter trips to space, we're going to have to find another way. Well, it turns out that NASA's been doing quite a bit of research on Gas Core Nuclear Rockets, an ultra-powerful nuclear rocket that puts out almost no radiation. This research has spurred a fascinating new generation of ideas on reaching the cosmos. Could inexpensive cruises to the moon happen within our lifetimes?"
Space Elevator. Everything else is too dangerous and expensive.
We should still build a secret Orion and keep it handy in case of alien invasion.
It's the landings that have always seemed a little too "dirty" for my taste.
I'm not tense. I'm just terribly, terribly, alert.
Now, I'm no rocket scientist, but I think you get the idea..
If you can read this sig - the bitch fell off.
Is derriere REALLY that f'ing difficult to spell? If you can't even come CLOSE to spelling the word properly, DON'T USE IT.
Jesus christ, use m-w.com or something if you're not sure.
I still think the Space Elevator will be the ticket for inexpensive space launches.
Pardon your french... It's "derriere", french for "behind".
..."almost no radiation"...
Call me back when there is none.
One of the biggest problems with anything Nulcear, be it power, subs, or rockets, there is a very negative public perception. You can tell people that it is safe all you want but there will always be that paranoia. It doesn't help that people don't neccesarily trust the government.
I'm not worried about the clean launches. What I'm worried about is the very dirty explosions (UF4 all over the place). I agree with the previous poster on spending money on the space elevator. Lets skip the flying dirty bombs.
-Sean
"Serious concerns surrounded the safety of carrying hundreds of atomic bombs through Earth's atmosphere."
I think it's great that the we are still seeing innovation in regards to propulsion for space-bound vehicles. I'm especially excited about the new concepts used in the Vostok booster-like series that the Russian space agency is evaluating.
We're definately a long way from the V2 when some simple hydrogen would be ignited, and then Bob would be your uncle.
Radiation can be beneficial and should not be feared. Of course there will be some potential for accidents and some minor radiactive pollution, but it's all worth it in the case of scientific progress. We don't have clean water or clean air, and you don't city inhabitants rioting, or do you?
Although i agree with you I can't recall ever seeing a post containing the words "butt munch" getting a 5: Informative.
What Seinfeld episode is this supposedly from? I've never seen it. Googled, too- no results.
Craimer??! Is that a new character?
Well since the link is dead we can only speculate about what it would consist of. But basically my theories is that such applications could easily be applied to almost any form of transportation. Clean (renewable?) source of energy that would cuase us to be less dependant on Oil. Of course this is all well and good except for the first time one of these things crashes and spills radioactive waste everywhere.
Just because it a clean propulsion method, the second the rocket goes off course and they decide to abort dump the payload or even selfdestruct the rocket, you have a nice 3 Mile Island.
30% Troll, 50% Underrated, 10% Interesting
Score:5, Troll
A project to explore the feasibility of building a nuclear-pulse rocket powered by nuclear fission. It was carried out by physicist Theodore Taylor and others over a seven-year period, beginning in 1958, with United States Air Force support. The propulsion system advocated for the Orion spacecraft was based on an idea first put forward by Stansilaw Ulam and Cornelius Everett in a classified paper in 1955. Ulam and Everett suggested releasing atomic bombs behind a spacecraft, followed by disks made of solid propellant. The bombs would explode, vaporizing the material of the disks and converting it into hot plasma. As this plasma rushed out in all directions, some of it would catch up with the spacecraft, impinge upon a pusher plate, and so drive the vehicle forward.
Project Orion originated at General Atomics in San Diego, a company (later a subsidiary of General Dynamics) founded by Frederick de Hoffman to develop commercial nuclear reactors. It was de Hoffman who persuaded Freeman Dyson to join Taylor in San Diego to work on Orion during the 1958-59 academic year.
Ulam and Everett's idea was modified so that instead of propellant disks, the propellant and bomb were combined into a single pulse unit. Plastic was chosen as the propellant material, not only because of its effectiveness in absorbing the neutrons emitted by an atomic explosion but also because it breaks down into lightweight atoms such as those of hydrogen and carbon which move at high speed when hot. This approach, in tandem with the pusher plate concept, offered a unique propulsion system that could simultaneously produce high thrust with high exhaust velocity. The effective specific impulse could theoretically be as high as 10,000 to one million seconds. A series of abrupt jolts would be experienced by the pusher plate, so powerful that, if these forces were not spread out in time, they would result in acceleration surges that were intolerable for a manned vehicle. Consequently, a shock absorbing system was devised so that the impulse energy delivered to the plate could be stored and then gradually released to the vehicle as a whole.
Various mission profiles were considered, including an ambitious interstellar version. This called for a 40-million-ton spacecraft to be powered by the sequential release of ten million bombs, each designed to explode roughly 60 m to the vehicle's rear. In the more immediate future, Orion was envisaged as a means of transporting large expeditions to the Moon, Mars, and Saturn.
Taylor and Dyson were convinced that chemical rockets, with their limited payloads and high cost, represented the wrong approach to space travel. Orion, they argued, was simple, capacious, and above all affordable. Taylor originally proposed that the vehicle be launched from the ground, probably from the nuclear test site at Jackass Flats, Nevada. Sixteen stories high, shaped like the tip of a bullet, and with a pusher plate 41 m in diameter, the spacecraft would have utilized a launch pad composed of eight towers, each 76 m high. Remarkably, most of the takeoff mass of about 10,000 tons would have gone into orbit. The bomb units ejected on takeoff at a rate of one per second would have yielded 0.1 kiloton; then, as the vehicle accelerated, the ejection rate would have slowed and the yield increased, until 20-kiloton bombs would have been exploding every 10 seconds.
It was a startling and revolutionary idea. At a time when the United States was struggling to put a single astronaut into orbit using a modified ballistic missile, Taylor and Dyson were hatching plans to send scores of people and enormous payloads on voyages of exploration throughout the solar system. The original Orion design called for 2,000 pulse units, far more than the number needed to reach Earth escape velocity. In scale, Orion more closely resembled the giant spaceships of science fiction than the cramped capsules of Gagarin and Glenn. One hundred and fifty people could have lived aboard in relative comfort in a vehicle built without the need f
on Gas Core Nuclear Rockets
those have been around for years, and i have been fortunate enough to work with them for much of my life. they are called bean burritos. there is more explosive energy in one of those bad boys than most realize, especially when the chemistry behind the force is just right...granted, the fallout is pretty terrible too...
xao
http://TheHillforum.hopto.org
A few years back, I remember there being some amazingly loud protests from some anti-nuclear power folks about the dangers of a deep space probe going up with a nuclear power source. Those folks were worried about the danger if the rocket blew up on the pad or the 1 in 100,000 or so chance the probe would hit the earth on one of its acceleration orbits.
Just imagine how happy these folks will be with a nuclear powered rocket, even if the scientific community claims that they are safe. After all, it's nuclear related, so it's gotta be bad!! (tongue firmly in cheek)
Could inexpensive cruises to the moon happen within our lifetimes?
I highly doubt it. As the last twenty years have shown, it's not the level of technology that determines how easily we get into space, it's the cost. And concepts such as these, while interesting to think about and develop, are ultimately going to take that many more decades to become proven.
Add to all this that the public would need a near-100% safety record in order to buy into a space tourism industry, and we're looking at more decades added onto the R&D and testing.
However, this kind of engine if developed properly COULD lower costs for putting satellites in orbit. So what's our benefit in the end? Lower satellite TV, telephone, and internet costs perhaps... But that's being optomistic.
But the design itself? Neat.
How many years are we talking about? The lease on my land on the moon is running out, and I need to know how soon I should renew.
(article text, minus pictures)
Opening the Next Frontier
by Anthony Tate
Part 1: The Frontier Spirit
America loves its legends. George Washington in Valley Forge. The Wild West. World War II. The Man on the Moon.
But lately, it seems the legends have stopped.
Sure, we have the Internet to play with now, and computers are changing the world in ways we can scarcely grasp as of yet. The Soviet Union is no more, and despite our current travails with terrorism, a certain comfortable familiarity has us in its grip.
Where is the next legend? Where is the next frontier? Or are we just going to go comfortably off into retirement?
If the 'entertainments' of the kids these days are any indication, no way.
Extreme sports, fun little things like 'base jumping' and other diversions indicate that the next generation of Americans are harkening back to their roots in a big way. America is ready for the next challenge, refreshed, revitalized, and shaking off old fears and inhibitions.
But what could have caused our recent doldrums?
Why have we not gone back to deep space, that logical 'Final Frontier,' for so many years after Apollo? I believe it was a confluence of several factors, most of which have now passed, that caused us to huddle close to the bosom of Mother Earth for these past decades.
Part 2: What went wrong.
To be blunt, it was the 70's.
After the turbulent change of the 60's, the 70's were just a hard time for America. The Cold War dragged on and on, no end in sight. Vietnam was a horrible, bloody mess, deeply misunderstood to this day, and bitterly divisive even in the aftermath. Watergate destroyed the faith of millions in their own government. The Oil Embargo shocked the economy as well, causing the nightmarish condition of 'stagflation.' Cultural upheaval became the norm as gains in civil rights were cemented into place.
With that litany of bad news, there is little wonder that the public lost interest in space. When you are scared for your job, your children, and whether or not your paycheck next year will still cover the rent, idealism and exploration goes out the window.
Also, lets be honest, landing on the Moon in the 1960's was an incredible feat. That entire rocket, the whole plan, was designed, built, and flown using less computing power than you have in your PC. Genius level effort was used to make that program possible, and the chance of disaster was perilously high, even by the comparatively relaxed standards of the day. In other words, Saturn was ahead of its time, by many years.
If it wasn't for the Cold War imperative to beat the Soviets, we'd probably be looking to go to the Moon right about now, all things considered.
Add in the fact that science itself was throwing up massive roadblocks, and there is little surprise to be had from the seeming 'retreat from space.' The rocket fuel used in the Saturn V moon rocket at launch was BETTER than the rocket fuel used to launch the Space Shuttle today. Why is that? Well, it's simple: The chemical fuels used in the Saturn V are among the best fuels that chemistry allows. Science is remarkably inflexible: unlike in the movies we can't just 'whip up' better rocket fuels. Chemistry is pretty stubborn that way.
So, exploring further in space was not important to the country while we had other problems to deal with, and making rockets better than the SaturnV was pretty much impossible.
So, NASA went sideways for a while. The Space Shuttle is a remarkable system, but it is at its core a compromise. So while it is good at many things, it is great at nothing. But nonetheless, the Space Shuttle kept America in space, and slowly we were building momentum to move forward once again away from the Earth.
Then Challenger blew up (and now we've lost Columbia and her crew as well).
Now, to the doughty folks who made Apollo fly, that disaster would have been a learning experience, and development would have continue
My understanding is that the clean nuclear propulsion systems presently under serious consideration don't provide a high enough thrust/weight ratio to actually lift a spacecraft off the surface of the Earth. Rather, their primary use would be for entirely space-born craft, which would be assembled in orbit and zip around the solar system without actually ever touching down anywhere.
This space unintentionally left unblank.
This is solving the wrong problem. It's like turning to petroleum to make the automobile's internal combustion engine work instead of hemp, as was Henry Ford's original intent.
That said, anything that increases the pace of our exploration of space is a good thing, particularly if said exploration makes settlement a priority.
We'll just need to watch and make sure the ultra-rich and other assorted-powers-that-be don't look upon the program as some sort of life raft that gives them license to fuck up the planet even more than it already is.
Is this truly the only Earth I can live on?
These nuclear-blast fueled ships are generally not designed for launch into orbit (or into space); rather, they are designed for propulsion once the vehicle has already left earth orbit (or at least earth itself).
From dictionary.com:
2 entries found for derriere.
derriere also derriere ( P ) Pronunciation Key (dr-ar)
n.
The buttocks; the rear.
Also:
No entry found for dairy-aire.
It's like the difference between a segway and a segue. One is a normal word used in English, the other is an amalgam coined for some other purpose.
What is music when you despise all sound?
Red sand between my toes,
Summer vacation in outer space.
--Robin Williams, "Reality, What a Concept"
A feeling of having made the same mistake before: Deja Foobar
The environmental whackos go nuts (and let slip the lawyers of war) when you launch a totally sealed reactor, can you imagine what they would do if you wanted to launch something that *gasp* released radioactive gasses into the atmosphere?
Why is it that the proponents of "one nation under God" are so eager to get rid of "liberty and justice for all"?
Google Cache to the rescue!
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Javascript + Nintendo DSi = DSiCade
At the least, give Kramer's "i" to Elaine.
You are being bombared with deadly radiation right now! Coming from the ground, objects in your home, and worst, from mankind's eternal nemesis, the Sun itself. Please flee your home screaming and head for your nearest all-lead fallout shelter!
We'll call you out when it's safe.
The enemies of Democracy are
I'd like to see a return of that word, along with poppycock, dipstick, and shunt.
they are called bean burritos
This is what people in the USofA, call "humour", is it not? I do find it very amusing, sir. May we have another?
Correct me if I'm wrong, but I thought that the Orion proposal was for travel in space. I don't remember reading anything about it being used as a launcher from the ground. Excuse me while I RTFA and see if I was mistaken....
Drill baby drill - on Mars
"I'm Kramer!"
"No, I'm Craimer!"
Do you even know what a clit IS? I mean, since you're first-posting on Slashdot, I know you've never actually SEEN one.
Me very stupid - can someone explain how exactly this works please?
Posting Anon. as I don't want you guys to know exactly how thick I really am.
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Javascript + Nintendo DSi = DSiCade
One the lucrative space waste management contracts that will be available in the coming years? Millions of pounds of material sounds like $$ in the bank to me when it needs to be hauled to the landfill on the Moon. Hopefully (fingers crossed) we can avoid unions
If you can read this sig - the bitch fell off.
To prevent any sealed radio active capsule from possibly breaking on impact with the ground a malfunctioning rocket will have a 50Meg hydrogen bomb on it to destroy all the pieces in the air
Just like Footfall! What a great book. I don't think anybody's read it though.
--
RumorsDaily
Haven't you seen that guy Michael Jackson on TV yet??!!
The Project Orion guys believed they could make
the explosions clean and as small as they wanted.
This scared the shit out of them. They
puposefully did not pursue that line of
development for fear of weapons applications.
Easy. Here are several: Check it!
..."almost no radiation"...
Drat, it seems to be getting harder and harder to realize my life long ambition of being exposed to massive quantities of harmful radition that will be the key to unlocking my secret mutant powers.
MHD Disk is the latest in video encoding for Media requiring a High-Definition format. It is superior to the other formats that are being fought over right now, including certain DVD initiatives that were discussed here recently. MHD is the only high-definition encoding that supports VCR, as the article judiciously illustrates.
The initial prototype comes with a dual-tray system that allows you to load two MHD disks at the same time, and makes a smart use of different color cables to facilitate connections with your Audio/Video receiver.
And it runs BeOS, too.
WTF is "dairy-aire"? Cow farts?
Could this be the DOD's "justification" for research into Stimulated Gamma Decay Weapons?
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Magnetoplasmadynamic was actually a word? And why didn't Piccard ever use it?
VASIMR (Variable Specific Impulse magnetoplasmadynamic Rocket)- And I though telecom had too many acrynoms.
A gas core nuclear reactor has a high ISP (meaning it's very efficient), but it does not have a particularly high thrust. That means it's great for cruising and orbital work, but it's not a launch engine like Orion could be.
and bananas (damn that radioactive potassium!). What they should do is classify the amount of radiation that they mean. For example, the Navy guidelines for radiation exposure are 3millirems per calander quarter, not to exceed 5 millirems per calandar year. Only half the population will experience the mildest forms of radiation poisening at 25-50 rems (not millirems).
My point is this, a little bit of radiation ain't that bad. Just how much is a little bit is what we need to know.
(I read one of the articles but the other one is /.ed at the moment) I didnt find any hard numbers on performance... did anyone see any? Like isp and T/W-ratio and so on. IIRC the old NERVA-style nuclear rockets only managed to get isps of around 1000, so it didnt really seem worth the risk. Are these babies any better?
You want nuke powered spaceships? Find the material in asteroids, mine it and proceess it on the Moon, or somewhere even further away from the Earth. Here's an idea, imagine a 9-11 type terrorist sabatoge of some radioactive rocket blasting off from Florida....aa Afterall the 9-11 terrorists didn't BUILD the airplanes, they just took over them and used them to destroy.
-------- In Soviet Russia, "Soviet Russia" sigs hate Slashdot.
Define "almost".
Could inexpensive cruises to the moon happen within our lifetimes?"
No.
See, here's the problem:
Nothing is permitted any more without a "business case" being made for it. No document, no invention, no idea, no presentation is countenanced unless it has 20% annual growth and the accountants and the management committee sign off on it.
Since it is impossible to get a bureaucracy to sign off on anything, nothing is permitted at all.
Small businesses and entrepreneurs are starved for capital. Large businesses and management committees have substantial capital, but refuse to invest it. Therefore, there is no capital; or, if there is, it is usually totally inadequate.
Middle management has a perfect series of questions for ideas like this. There is nothing in the world easier than criticizing an idea. Questions like "what do we need that for?" and "yeah, but how do you know it will work?" or "how can you be sure that will sell?" These questions are asked as if an answer is expected. The questions are followed by the comments: "It'll never work," and "sounds expensive" and "why can't we just use $OTHER_IDEA?"
But no answer is expected. The people asking the questions simply want to see how well the "idea person" can ad lib and how many bullshit one-liners and jokes they can reply with. After the middle managers have been entertained, a cocktail party laugh will circle the room, and the idea person will be escorted out of the building and into obscurity as the five-foot-wide-asses return to their bean salads.
As long as this continues, the rate of invention and "innovation" will be reduced to unmeasurably small levels. No vision, idea or invention can surmount well-funded cynicism. Brilliant, well-educated people's minds are being wasted because they report to lying, cheat fuck, greed-driven managers.
Middle management routinely turns its back on paying customers and competition-less markets. How the fuck are they ever going to accept a new "unproven" idea?
They won't.
Business isn't willing to pay for products, innovation and careers, so we get brands, mortgage commercials and layoffs.
Get your thoughts in line with the Slashbot hive, my friend. Criticize the editors or story submissions and you get slapped as offtopic or overrated. Why? Many of those with mod points (provided through karma provided by similar minded folk) will tolerate only cliched, overdone M$ or SCO humor, or posts that are intended to make you stroke your chin while sipping your chai. See?
Conform or your posts will only be seen by the non-uptight types.
Excuse me while I RTFA and see if I was mistaken...
We'll wait. Can you post your findings in this thread.
Thank you.
Sweet baby Jesus on a stick, they're toast!
Why you should not host a website that might be featured on /. on an IIS server:
The page cannot be displayed
There are too many people accessing the Web site at this time.
Please try the following:
* Click the Refresh button, or try again later.
* Open the www.nuclearspace.com home page, and then look for links to the information you want.
HTTP 403.9 - Access Forbidden: Too many users are connected
Internet Information Services
Technical Information (for support personnel)
* Background:
This error can occur if the Web server is busy and cannot process your request due to heavy traffic.
* More information:
Microsoft Support
Assorted stuff I do sometimes: Lemuria.org
Are you referring to a specific project crossing a specific river next to a specific materials lab building?
The above post should be Humorous, not Interesting. The Vostok was built back in the 1960s, and the V2 was fueled by LOX and Alcohol, not liquid hydrogen as is implied. ...but Bob is still definately your uncle.
The truth is brutally silenced in modern-day USA.
It's time for a revolution!
Blowups Happen.
My Photography - http://ian-x.com
The Deathlings (comic) - http://thedeathlings.com
Not-so-obligatory paraphrased Mr. Show quote:
We have the technology! The time is now! Children are our future! We will blow up the Sun!
When I MM, and if I get this, the parent's moderation will be marked - UNFAIR!
I hate to say it but where did you get your Rocket Science degree ? The V2 used KEROSENSE and O2
NOT hydrogen
--- DIRTY BOMB!!!!!!!
--- DIRTY BOMB!!!!!!!
The funniest show I ever saw was the Daily Show the day the DIRTY BOMB!!!!! 'news' hit the corporate media circuit (2 weeks after they detained the guy).
Forget get Emmys that damn show deserves a Pulitzer!
-------- In Soviet Russia, "Soviet Russia" sigs hate Slashdot.
Chris Burke: ... and worst, from mankind's eternal nemesis, the Sun itself.
[from snpp]
Burns: Since the beginning of time man has yearned to destroy the sun.
Don't forget to put on your Technology-Interference-Negation-Field Operational Insulating Layers before you leave!
Besides, nobody's going to be sending a nuclear rocket into orbit anywhere near me, so I don't mind. Let the Floridians suck it up! They're already addled from all that solar radiation beating down on their pates and overheating their brains - a bit more won't make much difference...
You must think in Russian.
Seems all those Star Trek ships explode when the warp core can't be ejected. So...
all-lead fallout shelter
and when you're in there, please don't lick the walls!
I'm guessing that telling some of the more extreme environmentalist elements that your launch puts out "almost no radiation" isn't going to hack it as far as they're concerned. 1 microrad/hr above background will be reason enough to predict apocalyptic nightmares of mass cancers, food contamination, mutations, dropsy, genital warts, and flatulence. They're essentially anti-technology and will use any excuse to oppose it. Frankly, I'm surprised I can still buy a radium-dial wristwatch.
Try breaking the cable high enough above the planet that the counterweight exits Earth orbit. Now, imagine TIMING such an event so that the counterweight ends up headed right for a lunar base.
Earth may not have much to worry about, but I wouldn't want to be a lunar scientist listening to an Earth broadcast about an attack on the elevator. Perhaps that's a worry for another day, though... let's build the elevator and found a moon base first.
"Could inexpensive cruises to the moon happen within our lifetimes?"
My hope is that advances in medicine will extend my life to 150+ years so I can see more of these things come to pass.
Sorry to disappont the Kim Stanley Robinson fans, but this simply isn't the case.
Even if the SE breaks at halfway, we're not going to get a catastrophic shockwave. You have to consider the material to know how it's going to behave. First, this thing is VERY light weight. It's also VERY thin. Not much displacement means not much shockwave. Not much weight means it will be easily dampened by the atmostphere.
After a break, yes, the end near the break will start off at a pretty high velocity because of the tension that it was under. But -- and this is part of the design -- carbon is combustible and will BURN UP in the atmosphere if it's travelling too fast.
There is NO WAY that a falling CNT ribbon will be catastrophic, even to those right underneath it.
You'd be better advised to worry about payloads that might fall off it. But even these would be engineered to have re-entry systems for just such an eventuality.
--
LiftWatch.org - Space Elevator News
and it'sa verrry nice-ah
it's called "Cruithne".
So why be rich when Democrats all want to increase your taxes to pay for social programs? Funk dat! Let the weasels starve, its called "Law of the Land" and "only the strongest survive."
If the Dems do get into office, I will refuse any pay increases. What's the bother of making more when they'll just take more?
This is a test. This is a test of the emergency sig system. This has been only a test.
HAHAHAHAAHAHAHAHAHAHAHAH!
smart foreigners
*wipes tears from eyes*
That's a good one. Let me know when any country can produce nearly 1/20 of the television programs the United States can.
The space elevator needs equal pull on both sides of the point where it would be at the same distance from Earth as objects in geosynchronous orbit. You can either do that using a counterwieght such as a large asteroid, or by making the elevator exceedingly long, about the same length on either side of that geosync orbit position.
Admittedly, the basic ground-to-counterweight-above-sync-orbit design has great potential. But there are other designs with less cost, extreme materials, and risk.
For instance: A section of cable in low orbit, spinning end-over-end so that each end periodically dips into the stratosphere at approximately the average local wind speed. Fly up to it, hook on as it goes by, and get lifted into orbit. Balance the momentum by bringing back a payload of space-mined material on the other end.
Build it so that if the orbit decays it will break up on reentry rather than crashing, keeping its own mass low enough that it won't create another Cretaceous event by spreading tons of red-hot debris throught the upper atmosphere if it comes in. (But if you get your spin right you can design it so that it tends to be pushed UP if the active guidance fails.)
Use a near-circular orbit if you want to lift a lot of payloads to near orbit (where you can use slower engines - like ion or light-sail - to achieve high orbit or escape), or an eliptical orbit for fewer payloads to a higher initial launch.
Lots of ways to do the active guidance:
- Control the spin with currents through the cable to electron guns and collectors at the ends working against the earth's mag field.
- Small attached light sails - For orbital elements, spin, attitude, AND killing vibrations.
- Ion thrusters ditto - and you can collect reaction mass each time an end dips into the atmosphere.
- Control, solar power plant, etc. at the center, which never enters the atmosphere. (Elevator/cable-crawler to get there from the ends.)
Lots of other systems are possible, too.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
you launch a totally sealed reactor, can you imagine what they would do if you wanted to launch something that *gasp* released radioactive gasses into the atmosphere?
Well, first, what happens when something goes wrong, say after launch? Like, say it explodes? Second, how is it a good idea to launch a plume of radioactive gasses into the atmosphere?
You can't talk seriously about space travel (or just about any other technology) without including *failure* and if the benifits after the risks still are acceptable, go for it. But theres a simple old saying: if something can go wrong, it will. Launching a reactor into space via our precious atmosphere makes my ears prick up a little. So explain it to me tough guy.
Quack, quack.
Unless they plan on catching everything they launch again, then we will slowly be slowing the earth down. (Things traveling up and down only have a net zero momentum balance; the issue is launching spacecraft) This will, over time, have way more adverse effects on the planet's climate than all the gasoline-powered cars, forest burning, and nuclear engines combined. I could care less about stuff falling, but I do care about longer days totally wacking out the distribution of temperatures across the planet!
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
We're not talking thousands of tons to launch a space elevator.
We're talking 100-200 tons. And it could be divided into several payloads.
I'm not trying to argue against the idea of nuclear powered rockets here... but they would not be REQUIRED in order to raise a space elevator because the amounts of mass we're talking about are really not 'insane'.
--
LiftWatch.org - Space Elevator News
I agree. We urgently need a Swiss equivalent of the Jerry Springer Show to let the world know how smart we are.
It's truy amazing that you actually took an 'Introduction to Marxism' course (I assume you got a 'C' grade) just to troll slashdot.
Cruithne, 1998 UP1 and 2000 PH5.
This argument always reminds me of Huff's analysis of the Martingale betting system. The advocates say it is a safe bet for a progressive win. The pessimists note that there could be a catastrophic loss at the end.
We can't use the words nuclear, fission or fusion. We need a nice slang word that people will like and be willing to spend money on...
We could call it a nano-energy source, pico-energy source, or an atto-energy source. Stop laughing. With the general disreguard for science education in this country, it could actually work. If foreigners actually try to tell the environmentalists, the truth, they'll just be labeled terrorists or worse French.
I haven't seen anyone mention Aurora yet...
TZ
It's NIMBY time!
What about the children who live downwind of the rockets?
Shouldn't we be spending money on feeding the homeless instead of plotting our nuclear doom?
If it's bad for Arabs to have nuclear bombs, why should americans have nuclear rockets?
Visualize world peace!
Conformity is the jailer of freedom and enemy of growth. -JFK
Okay, mom.
I hate to rain on people's parades but this has nothing to do with launching rockets from the surface of Earth. If you review the website that is linked to it only talks about Nuclear power for NEP (Nuclear Electric Propulsion) via Hall Thrusters. These thrusters generate very minimal levels (less than 1 N) of thrust and are only appropriate for in space travel.
There is a lot more that went into going to the moon than just propulsion. Thats the most obvious thing that you need to go to the moon, but what about all of the other things you would need, like a safe place to dock, and cheap spacesuits? Those things are just as important as getting off the ground if you want to survive the trip.
I just wanted to be the first to explicitly invoke him. Seriously though, they really need to come up with a new, more marketable name for nuclear technologies, i.e. -- "The Other Green Power".
Strange things are afoot at the Circle-K.
The first spelling option has a ` accent on the middle e, for some reason accented characters won't post (even as HTML code) here. This is the more accurate spelling as the word is taken directly from French.
-- *~()____) This message will self-destruct in 5 seconds...
...quoting J Frank Parnell here on slashdot.
Although i agree with you I can't recall ever seeing a post containing the words "butt munch" getting a 5: Informative.
Quick people here is your chance to make it happen!
The parent is Offtopic at the moment, but with alittle more help he can get that Informative. Then he won't believe his eye's when the words "butt munch" have been modded to +5 and isn't funny.
You don't know how good you have it. Here in Northern Europe people on minimum wage pay 40% income tax, so quit your whining.
We have a geiger counter in the physics department here. We used to scare the new students by bringing it near them, or near their bananas (high in Potassium), and listen to the counter go ape-shit. Scared them a little bit :-)
dominionrd.blogspot.com - Restaurants on
"so nasty we have no idea how to deal with it safely"
Bullshit, pure and simple.
Bake it into glass, stack it someplace dry where kids won't play in it. It's that easy.
The more radioactive something is, the less time it stays radioactive. This is indeed a problem that disappears on its own if you leave it long enough. The nasty shit is short-lived, the rest is no more dangerous than arsenic, lead, mercury, or other common long-lived poisons.
The problem is that the politicians and public don't understand it and "environmentalists" lie to them plausibly enough to keep the waters muddy. Add in the fact that switching to nuclear power would be disruptive and painful to some very powerful industries and some very rich people, and the current situation is not really surprising.
Oh, give me a goddamn break. If you expect that level of safety out of anything, then I look forward to your explaining why you dare cross the street. After all, there's a greater than zero chance of your getting hit by a car, or at least tripping on the curb. There's such a thing as taking the precautionary principle to the point of lunacy.
Nothing like cowardice - cowardice based on ignorance and, even worse, an active refusal to know anything about risk, or think in terms of the real world - to help keep people stagnating until it's too late to do anything productive about it.
"All that is necessary for evil to succeed is for good men to do nothing." - Edmund Burke
LiftWatch.org - regular news updates, links directory, etc. All about space elevators and related techs.
Although the space elevator is a great idea (frankly I love it), the problem I've never found an aswer to (and if you have an answer please let me know) is how do we attach the ribbon?
Seriously, the counterweight on Earth is no issue, neither is the opposing end in LEO; but how do we get the ribbon from "A" to "B"? Near as I can tell, nobody's ever covered that.
Obviously you've not read up on the subject.
Right.... I make over 100k and I pay nowhere near that. Republicans always spend all the money plus some and create deficts that need to be paid for with, you guessed it, taxes. You see any tax break from bush? Not much if you make less than $300k. Look at you tax statement, look at the deficit and the budget, look who *got* the tax breaks under this administration and wake the hell up.
The Republicans aren't on your side.
Because there's no such thing like complete induction in technology, dumbass, and because a crashing spacecraft with nuclear material will very likely not hit the originating country (which would be okay if it did).
open (SIG, "</dev/zero"); $sig = <SIG>; close SIG;
Shame those projects got dropped....
Tho' I must admit, given the chance to work on something like that it would be hard to resist... :-)
since the sucessful creation of the jet engine.
Also looks like the ONLY way we're going to get
Commercial space flight going economically.
Look up FUD on jet engines when they first came out.
Hilarious stuff
Have you ever seen a plane crash in person? Actually watch one hit the ground?
What about a tornado? Ever seen 1 house left standing in the middle of rubble that used to be a neighborhood? It happens.
Ever visited a debris field?
What's the difference between 30#s of open cell foam vs 30#s of a Lego contruction falling to the ground from 30,000? Does this explain the passport? Can I make you believe it? You can't have it both ways.
Oh, and according to 10/2000 IRS data Average taxable income was $43,172. The top %50 of wage earners pay %84.01% of all income taxes. Sounds like the "financially advantageous" aren't the ruling class. Soon, the majority of voters will pay no income tax, just watch.
The same people who vote yes for "Raise taxes on everyone but me" will prefer to have tax "refunds" for money they never paid, then to have space exploration, or scientific advances. Maybe I can agree with Trolling4Dollars that people can be made to believe almost anything.
Democracy alone is a group of 5 wolves and sheep discussing what's for dinner. It needs to be tempered with equal treatment, equal freedoms for all by Law.
www.facebook.com/DareDefendOurRights
www.fairtax.org
I am not against nuk-u-lar engines on spacecraft. Just don't use them in the atmosphere. If you use them, use them in space where they belong.
In other words, "I don't care about actual risks, costs, and benefits! "Nuk-u-lar" is a scary, scary word!"
You don't need nuk-u-lar rockets to get into orbit.
You don't need com-bus-chun engines to get across the country! Horses were good enough for my grandpappy's grandpappy, and they're good enough for me!
Oh, please. Chemical rockets are not safe or reliable. It's just barely possible to make them powerful enough to get up there and sturdy enough to survive. Fortunes are spent to avoid serious disasters with them every time they're launched.
A more powerful engine with much lighter fuel would mean incomparable safety and cost.
Osama is chomping at the bit for newer more powerful things to hijack.
Table-ized A.I.
Another gimmick. Those people got the tax breaks because they PAY Federal Income Tax. The top 5% pay 85% of the federal income tax. I am NOT in favor of giving money to people who didn't pay into the system. This is NOT a socialist America.
This is a test. This is a test of the emergency sig system. This has been only a test.
True, but very misleading. We will be slowing the Earth down by a NEGLIGIBLE amount.
You know, when you drive a heavy truck East, you are actually slowing the Earth's rotation by a small amount due to the same law of conservation of (angular) momentum.
The Earth is VERY heavy, however. 6.6x10^21 tons. So you would have to move many billions of tons of mass in order to have a measurable effect on the Earth's rotation.
Not to worry.
--
LiftWatch.org - Space Elevator News
Orion was never meant to be a launch engine. It's an interstellar system, and that's it.
You don't ride nuclear blasts out of the atmosphere. It wouldn't have any of the important stability and control characteristics.
Or even better, Norway or was its Sweden, anyway some "nordiac" country, workers pay 70% tax on their wages. And to think America has one of the lowest tax systems in the World and they still whine.
This is a test. This is a test of the emergency sig system. This has been only a test.
The last three Republican presidents have run about $4 trillion plus onto a $7 trillion debt (Reagan $2.9T / Bush Sr. $1.1T / Bush Jr. ? (probably >$1T)). No social programs there, just lots of money they didn't have and never created spent as if it did. It seems like the Republicans rather than the Democrats are responsible for your shrinking paycheck - after where exactly does that money come from? If it isn't paid back, it raises the cost of your home, car, and other loan payments - so you essentially pay an unseen tax on those items to the gov't. If it is paid back, the gov't has to get the money from somewhere, either less services (which means you pay for them from your paycheck) or higher taxes. Since Republicans spent the money while saying they were "fiscally responsible" (but unwilling to actually act to back it up) and then wouldn't (until Bush Sr.) raise taxes to cover their debt, I think your arrow of responsibility is a little mixed up.
It doesn't help to get tax cuts (that primarily go to the rich, as the last round did, despite claims to the contrary) when the gov't spends more (or even if it just doesn't spend less), in which case the tax cuts are essentially high interest loans to the gov't, and you lose more than you got in the first place (because the money is paid for later, with interest). If tax cuts by Republicans resulted in smaller total gov't (not just moving gov't from the Feds to the local and state levels), your position might hold merit. Since that have been nowhere near the case, I'd say it holds less water than GWB's coke^H^H^H^Hsilver spoon.
I'd rather give money to the Democrats - at least they actually intend to cover what they spend, unlike Reagan/Bush Jr. who seem to have the policy of spend, go to sleep, and hope the debt they run will simply go away.
can someone explain to me how this is Offtopic? Looks pretty dead on to me...
uh, thats not nessisarily a good thing, Television is an Excuse for Lazyness, so what your saying is that the US is the most Lazy Country on the planet...
nope, your definately not getting back to the moon
/. is overrun by bed-wetting elitist nerds
let it be known, for anything other than servers, a *nix OS sucks
Just thought I'd throw more fun into the discussion...
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
You want us to risk lead poisoning?
You need to read about more recent deployment plans for the space elevator. Start here.
Things you got wrong:
--
LiftWatch.org - Space Elevator News
Could all that radioactive waste that people don't want stored near their house be used as fuel in this kind of vehicle? As we know, space exploration is limited by funding but *IF* we could find an economical way of converting this to fuel, couldn't we clean up the neighborhood down here too? Probably naive dreaming :)
I had a great sig.. then I lost my penmanship.
By the time you get to 75 grand a year, you'll be paying half that in taxes every year, roughly 43% of your total income.
BULLSHIT
For 75K you are at the bottom end of the 30% tax bracket, you get taxed at 30% for each dollar over $63550 at 30%, your federal income tax (the largest hitter in most peoples taxes) will come to $17144 or almost 23%, even before Bushes tax cut it would have only been $17931, or just under 24%. That is before any deductions at all, even the standard deduction. Medicare and Social Security combined are only about 8% and you can live in one of the states that doesn't have income tax, like Alaska, Florida, Nevada, South Dakota, Texas, Washington, or Wyoming.
You shouldn't even be paying 43% marginal until you are making well into the 6 figure range.
If you want low taxes that is fine, argue your point and try to get like minded politicians elected, but don't lie to make people think it is worse than it is... It doesn't help your case.
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
can someone explain to me how this is Offtopic? Looks pretty dead on to me...
It wasn't. Some people don't like their tin gods criticized and react by modding the offending post down.
Many of the posts so far have the attitude that there is an irrational fear of nuclear power and that the public is simply ignorant. There are a few points to counter that:
1)Many governments around the world, including the US government, put humans in unsafe radiation environments, which they knew to be unsafe, either to test the effect on the humans or because they didn't care. A significant number of people in the US military died because of this. There was a show on Nova about the Bikini Atoll nuclear tests, where the sailors watched the explosions from the decks of their ships. Many of those died.
You might say that this is all in the past, but look at how the Gulf War Syndrome patients have been treated by the US and UK governments. The symptoms are there, but nobody knows what causes them and so they just deny the effect and keep exposing more and more soldiers to whatever it is that causes the illness.
Look at how the US and UK governments deny the harmful effects of depleted uranium. DU munitions are not very radioactive, but the dust that is released when they burn finds its way into the human body very easily. Once inside, it can not only irradiate the body but also have other toxic effects associated with heavy metal. The military's OWN practice is aggressive decontamination of anything that is exposed to DU ash, but this is denied in official reports.
So in the absence of reliable independent reports, it is very difficult to accept these assertions of safety.
2)If only we had a way to quantify the danger posed by radiation we might not have this problem. However quantify it we cannot. Because of the random nature of radiation damage, it is very difficult to study. We know the effects of large doses fairly accurately but small doses require large population samples, and it is difficult to expose large populations to controlled doses of radiation.
The greatest danger posed by small radiation doses is genetic damage that can lead to cancer. We don't know how cancer works or how the human body normally prevents it. We don't know what enables humans to survive the genetic damage caused by the natural radiation environment. We can't even measure genetic damage. We know that USUALLY, small doses of radiation have no effect but don't know why SOMETIMES they do or what is a safe dose.
At its root, the fear of low level radiation is similar to the fear of other carcinogens. There is no way to quantify or track exposure because just ONE unlucky mutation could lead to a deadly cancer, but we have no idea which mutations these are or how to find them.
So what I would say is that those people who want to talk about irrational fears of the population should rationally counter some of these points. Most people who are pro-nuclear cannot counter them. They don't know anything about how radiation exposure is measured (except that it's in REMs), what the natural background radiation is in REMs, how many Curies are contained in coal ash, etc. etc. etc.
I know that people were laughing at NASA's small anti-gravity experiments, but something like that is probably the only thing that will make space affordable in our life-time. Nuclear has too much political risk and perhaps actual risks. We need a revolution, not evolution. It just takes too damned much energy to get into space. If we can find an anti-gravitron and harvest it, then we could just float up to space like a helium balloon does in air. (It might not be gravitrons, but something equally breakthru-ish.)
Table-ized A.I.
Incidentally, the earth has an angular momentum of about 9e33 kg-m^2/s (I might be off by a factor of two), for all those interested. For comparison, a 6000 pound (about 3000 kg) truck moving 30 m/s (about 70 mph) only has an angular momentum about the earth center of about 6e11 kg-m^2/s. A 10000kg spacecraft moving at 3000 m/s at 30000 km altitude, though, has 1e15 kg-m^2/s. Launching one spacecraft - just ONE - at this rate will take off about 4e-12 seconds of earth rotation per year. So, yeah, I guess that's small, but it's real!
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
Orion could have moved a lot of mass into and around space quickly.
Would the Martians, for one, have welcomed their new human overlords?
Who said anything about Marxism stupid mother fucker?! I certainly didn't. Class warefare and Marxism are not inextricably associated. I could be a middle of the road conservative who hasn't benefited from the system at the moment and my money grubbing could be leading to such assertions. You never know. So watch your misplaced statements you idiot bastard. (Ad Hominem attacks are ALWAYS called for when it comes to politics)
...radiation is this green ooze stuff that they store in barrels. Really. Its this gunk, and you can pick it up and carry it around. Yeah, that was sarcasm. I wish people understood, oh, I dunno, the electromagnetic spectrum.
"ribbon so light and with such a surface area that it would fall to the earth like a peice of paper" even so, wouldn't 36,000 km of paper be quite heavy :)
I'm old.
If you RTFA and all the pdf's on the site you see that they mostly talk about UF4, uranium quadra flouride. If you took a good chemistry course you'll remember that flourine does not like letting go, and the Uranium in this case has it's VESPR locked up by flourine. If one of these power core wafers cracked and got loose, the uranium would not leech into surfaces, as happend in the cities around cheyrnoble. There the uranium chemically attached to all sorts of stuff leaveing hotspots. If there is a nukee reading this, where did the radioactive iodine come from in chern and 3 mile isle.
Bacardi + slashdot = negative karma.
I'm convinced that StarFleet actually never implemented core ejection, it's there in the technical manuals, and the engineers think they can do it, but when the moment finally comes it never works.
Or did Geordi actually sever the exploding bolts on the core to raise the stakes? We'll never know.
"Sometimes, I think Trent just needs a cup of hot chocolate and a blankie." -Tori Amos on Nine Inch Nails
So the technology we'd need to leave a heavily-polluted Planet Earth would be the very technology that would be causing the pollution that we'd have to leave behind?
If we don't whine, then they could jack it up to 70% without much resistance.
We pay low amounts now and there's still tons of government inefficiencies that can be cut. Theoretically, we could be paying a lot less, so why to try achieve that goal?
Cassini, if I recall right, was to go inward to Venus for a gravitational assist, then fly by Earth again for another boost before leaving for the outer solar system. Because the trajectory was only marginally possible to begin with, they had to come rather deep in the gravitational well -- only 200 or 300 miles above the top of the Earth's atmosphere.
During that flyby, Cassini was traveling well above Earth's escape velocity of 10 km/sec. I never saw anyone seriously claim that the plutonium would have remained contained in case of impact.
NASA's response to that point was, essentially, "We don't hit planets by mistake". That was good enough to avoid the various court orders and injunctions that were being cooked up, but it might not suffice today. A few months after the Cassini flyby, NASA (or JPL or Lockheed, depending on whom you ask) did hit a planet by mistake, when the mars probe impacted instead of aerobraking.
On the other hand, the protestors' argument that there was enough plutonium on board to kill half of the Earth's population, if properly distributed, is sheer alarmism. Almost every Slashdot reader generates weekly enough of a certain other substance to, if properly distributed, impregnate half of the Earth's population. Yet only a tiny fraction of children are descended from slashdotters.
Umm... actually, wouldn't an all-lead fallout shelter big enough to contain a human being's sleeping quarters and necessary survival tools, food, etc. be a large enough quantity of lead to pose a significantly dangerous threat from radiation? IIRC, lead in large quantities is a fairly dangerous radioactive substance to hang around.
Alito: A vote for Alito is a punch in the eye to put that bitch back in her place!
Because let's face it, if you *have* to eat nuclear lunches, you want them to be clean. Coworkers might not be so understanding about your expelling radioactive gas.
How about Inverse Fusile Energy Extraction? :p Or Exothermic Matter Decomposition... or Half-Life Accellotron?
Don't use radiation or a space elevator, use a giant cannon with phlogistonite.
(Ultima: Worlds of Adventure II: Martian Dreams)
Just make sure you've got plenty of phlogistonite canisters, and that nobody steals them.
Try breaking the cable high enough above the planet that the counterweight exits Earth orbit. Now, imagine TIMING such an event so that the counterweight ends up headed right for a lunar base.
You assume it would have enough momentum to get much higher in orbit.
Yeah, if the ribbon breaks while your on it, your in a bad spot. But pods with people could always have horizontal ejections mechanism without parachutes.
Finally, the current plans is to position the ribbon base in the pacific ocean like a moveable oil rig. The likelyhood of the ribbon hitting anything on the way down is pretty remote.
The construction of the ribbon would make severing it pretty difficult in the first place. Yeah, it could be struck by an asteroid. But I would be the odds of that happening are a LOT lower than a shuttle bursting into flames (which has happened twice).
Hopefully, NASA is giving grant money to Carbon Nano-tube researchers. Unlike most NASA crap, they actually have far reaching applications in military and civilian use.
Bush really fucked up with his whole Moon and Mars bit. The space elevator concept will make orbiting stuff cheap. It will make going to the Moon and Mars reasonable. In fact, I don't think NASA should even consider new manned interplanetary missions until a space elevator is in place.
-------- -------- Support Wesley Clark for president!!!
"This engine produces 1,200,000 pounds of thrust, with an exhaust velocity of 30,000 meters per second, from a thermal output of approximately 80 gigawatts....Since we are using the Saturn V as our template, we will make the new machine about the same weight, or six million pounds launch weight. With our engines giving 1.2 million pounds of thrust, we need at least five to get off the ground. But, since we have the power of nuclear on our side, we will use seven engines instead of five."
Let them publish a study and when we get concensus go for it. What happens if it pops at the launch pad?
Quack, quack.
nope, your definately not getting back to the moon
Why do we need to go back to the moon? We already sent men there 34 years ago using the technology of the day - a feat no other country has been able to accomplish to this day. China? No. Russia? No.
And do you know the real reason the United States was able to send men to the moon decades ago? Because we had the money to spend on it. We had the credit to run up a bill of billions of dollars. That's the real reason Russia couldn't pull it off and why China still hasn't pulled it off. It's because they have no money and a crappy credit rating. They are the international equivalent of a Mexican.
I say let the robots do everything from now on.
...is that it's called "NUKE YULER".
... use a bean stalk.
4) ???
5) Profit!
Shhhh! I'm having fun watching the idiots chant "space elevator, space elevator, space elevator"! Oh, wait. They do that for every single fucking space story that comes along these days dont they... I'll catch 'em again on the next round.
"Per booster" is meaningless in this context.
The specific impulse (measured in seconds) remains the same no matter how many boosters there are.
You could gang together several motors to increase the delivered thrust, but the exhaust velocity would remain the same.
I couldn't find a figure for Isp on the research site linked to. The second article suggests an Isp of 3,000 seconds for his "lightbulb" motor, but that sounds awfully high for a fission rocket.
Stefan
What is a "dairy aire"? An air of superiority put on by dairy owners? Are they using methane from cows farting?
Or perhaps you meant the French word for posterior? You know--derriere.
is that George Bush would still pronounce it as NUCULAR.
-S
Does that mean that once there is a space elevator, it'll be surrounded by a protective swarm of American military jets, missile batteriers, etc every time the alignment is right to target the moon?
It's a joke now, but if the thing ever gets built it will be a serious consideration - and the cost of protecting the ribbon needs to be accounted for in any cost analysis.
Reactor use delayed neutrons to be controlled critical. Reactors can be very well controlled in this range. It is when a reactor/bomb/tank etc becomes critical with prompt neutrons that things become problematic.
That said the gas fuel reactor is an excellent design that should be put into operation when a few more issues are worked out.
Voyager ejected their core at least once. They had to go back and get it with a tractor beam, as it didn't actually explode like they thought it would. In the meantime they were even more screwed than usual being 70,000 light years from home without even FTL.
There are several problems with this... You can't predict breakthroughs. The odds are loooooong. Until the breakthrough (that may never come), you are stuck where you are if all you do is wait.
then why aren't we using it on the ground?
Forgive me for having RTFA, but if the 'Nuclear Lightbulb' style of engine is so efficient and so safe, then why isn't it being used to heat water into steam that drives a big turbine at the end of my power company's high tension lines?
Environmentalists are suing power companies because a windmill kills a bird every other year. here Imagine their flaming at a bit of nuclear power.
Every time the subject of space exploration comes up on Slashdot, I just have to take a few minutes to point out the obvious:
There is nothing in space.
There is no reason to spend billions of dollars to go there.
Abvocating the expenditure of billions of dollars to go to a place where there is nothing and no reason to go there makes you look like idiots to all of the rest of the people who have more important ways that these billions of dollars could be spent to benefit humanity instead of indulging the fantasies of NASA twits with StarTrek fetishes.
In other words, you'all make us techies look bad to all the other civilized people in the world.
I'm not against space exploration. I simply believe that it needs to be put into a realistic priority schedule.
Let's set a goal of putting the first human on Mars to match the 1000th anniversary of the unveiling of Botticelli's Birth of Venus painting (you know, the babe on clam shell from the software box). It was unveiled in 1484, that would put the Mars landing goal at 2484.
This would give us enough time and money to address real issues like global overpopulation, ecological deterioation, climate change, and omicide technology (technologies that can destroy all human life on earth if released. Stuff like genetically engineered smallpox or the near-syncronous detonation of thousands of thermonuclear warheads from an all-out nuclear war, and other stuff that I shouldn't mention in a public forum).
A five-hundred year deadline for going to Mars would give us some time to deal with real problems without exposing us to the charge that we 'abandoned' the space program and its supposed long term benefits.
Thank you,
Hello, Melt Down. its a "Gaseous Core Reactor"
it can't melt its already gas.
Just to educate the willing...
There are two primary types of nuclear fission propulsion being researched
NEP - Nuclear Electric Propulsion
The use of a nuclear reactor to provide electricity to ion thrusters, instead of Solar arrays like Deep-Space 1. This is the kind of propulsion being planned for JIMO. Low thrust, very high effiency (exhaust velocity)
NTP - Nuclear Thermal Propulsion
Take a nuclear reactor, pump hydrogen through it with a turbopump, hydrogen expands, and produces thrust when forced through a nozzle.
This kind of propulsion has much higher thrust than NEP, but it less efficient (still about twice as efficient as LOX/LH2 chemical propulsion though. This can produce enough thrust for launch.
IAARS, FWIW
"Open the pod by doors, Hal" > "I'm afraid I can't do that, Dave" sudo "Open the pod bay doors, Hal" > alright
I haven't heard of this reactor type before, and it is really exciting me right now.
The author of this piece is almost certainly dumbing it down big time, but he makes sense. I don't see any logical inconsistencies or wishful thinking here.
The thing I do understand is the following statement:
" I believe there is a huge pent-up demand for resources in space, and if we could put huge payloads into orbit, uses for those payloads would appear quickly."
Exactly! If weight isn't so all fired important you can build it simpler, faster and cheaper, which lets you build more, which allows economies of scale, which allows research into how to make it better, lighter, stronger, for cheaper... and so on and so forth. Not all feedback loops are bad.
My post doesn't add a whole lot, I know, but this is beyond cool. It may even be possible. Thanks.
Why do I have this? I don't smoke.
Specific impulse is a clunky way of stating exhaust velocity.
It has nothing to do with a thrust to weight ratio.
In fact, ion motors, and proposed fusion motors (google for "inertial confinement fusion" and "magnetic confinement fusion") have a very high Isp (3000 seconds for ion motors, up in the mid 100,000 seconds for fusion motors) but generate very low thrust.
The stream of particles these motors produce move very quickly, but there aren't a lot of them.
Why is a high specific impulse a Good Thing?
Recall Newton's Third Law of Motion: Every reaction produces an equal an opposite reaction. Simply put: In a rocket, the momentum of the stuff the motor accellerates out the back ("reaction mass") translates into forward momentum. The faster the stuff you toss out the back, the more bang the buck you get out of that mass.
A higher exhaust velocity means you need less reaction mass, in terms of the percentage of your starting total mass, to achieve the same changes in velocity.
Here's the rocket equation:
M(f)+M(0)
--------- = e ^ (Vd/Vex)
M(0)
M(f) = mass of fuel
M(0) = mass of space ship w/o fuel
e = natural log number, about 2.718 is fine for these purposes
Vd = desired velocity change
Vex = exhaust velocity
The "velocity change budget" for a fast trip to Mars is about 20 kps. The exhaust velocity of a good chemical motor is about 5 kps. If you plug these numbers into the above, you find you need a mass ratio of 54:1 for your Mars trip. That is, 53 tons of fuel for every ton delivered to Mars orbit. With a nuclear fission rocket motor with a exhaust velocity of 10 kps, the mass ratio is more like 7:1.
Stefan " I'm not a rocket scientist but I play one on TV" Jones
Unless and until it can be proven that this thing will fly with zero chance of a CATO (catastrophic failure; "prang" for the more Britishy types), it'll never get off the ground, Orville.
It doesn't matter if the reaction mass is completely inert. As long as the fuel itself is a harmful substance, (in this design, uranium tetraflouride), it shouldn't be used where people who don't want to take the risk are not put at risk.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Arthur C. Clarke wrote about such engines in 1947 in his first novel "Prelude to Space."
I can't debate your first point, as you didn't provide me with any sources. The fact that Gulf War Syndrome is defined as "Gulf War Syndrome" obviously means that the effects aren't deniable, indeed they are observable. We don't name things that have no observable effects. We can't. We wouldn't know they existed. The fact that the soldiers are sent into the Gulf in the first place is akin to sending fire-fighters to put out a fire. We know flames are dangerous. Yet we continue to send fire-fighters to put them out. There are always going to be bad people in positions of power that do bad things. If you don't want to be placed "in harms way" do not sign up to be a soldier. It is your job, necessarily, to die to protect those that cannot or do not fight. I would find it hard to believe that the scientific body of knowledge dealing with radiation's effect on physiology was anything larger than "slim" during the time period of the Bikini Atoll, Manhatten Project, and "Fat Man" and "Little boy" projects.
As to your second point, we can quantify the amount of damage to a biological system. We can use either rem (roentgen-man-equivalents) or Sieverts. One Sievert is the equivalent to 100 rem ( 1 Sv = 100 rem). A Sievert is the amount of energy delivered per unit mass ( measured in Grays ) multiplied by relative biological effectiveness ( RBE or some quality factor ). A gray is a measure of Joule/Kg. The quality factor you use depends upon the type of radiation you are exposed to (i.e. Gamma, Beta, Alpha, etc...). Different types of radiation are more "reactive", or more energetic than others. Cancer is typically a broad term that describes a malfunctioning of cells during cellular reproduction. The affected cells reproduce themselves at a rate that is too fast for the bodies natural mechanisms (cell "suicide switch") to keep up with (or when the natural mechanism fails altogether.). Radiation causes the genetic mutations within the cell that eventually lead to the generation of cancer. We do not know that it takes "ONE unlucky mutation" to lead to cancer. It may take several to overwhelm the bodies defenses. Please visit this website for more information. I would counter that it is the public that is ill informed with regards to nuclear power, nuclear safety, and nuclear regulation. The pro-nuclear lobby, the ones that truly "have a dog in the fight" are well versed in radiation and its affects. They have to be, it is their jobs.
To know is to have knowledge....to understand is to be enlightened.
...you'd see that this design is a booster the size of Saturn V, but with a two million pound cargo capacity. It's not the same kind of nuke rocket you're thinking of.
I have a real problem with any plan which involves hiding a problem away and hoping that a future generation will figure out how to deal with it.
Obviously, what we can do with the waste is shoot it into space. Problem solved.
It's rare that you're presented with a knob whose only two positions are Make History and Flee Your Glorious Destiny.
Metal Gear? Strap ourselves onto the rockets and let it's rail gun shoot us into space!!
The Snake Hole: a Metal Gear Solid encyclopedia + Mirror
hate titty pee colon slash slash
I see a fairly large amount of comments about the rational usefulness of space travel, the cost/profit issue etc. But most of you guys forgot that the nr.1 reason for even thinking about space travel is its never-ending fascination. that's the main reason why there still are sci-fi movies and series. offer people a not-so-expensive space craft capable of flying them to the moon, or even to mars, in a reasonable time period (say, 1 week up to 1-2 months, in case of the moon lets calculate with 3 days). security wouldn't be 100%, however - and you tell them. i bet there would be a _hell of a lot_ of volunteers, even with the security issue. i can tell you, if i was given the choice whether to continue life as usual on earth, or to spend all money i have in order to enable myself the possibility to travel to the inner planets of the solar system, i'd be writing a cheque right now. i wonder if the time is right. i think it is. i see people becoming tired of the same everyday stuff. nothing to believe in, nothing worth even an effort. i guess this explains the huge interest in the recent mars missions. o.k., a diehard businessman would frag me for this posting, but i don't expect these kind of people to be the first ones exploring a new, unknown area.
This sig does not contain any SCO code.
Vaporware!
Nuclear Vaporware, actually
Vacuum cleaners suck. Kings rule.
No entry found for dairy-aire.
Apparantly, you've never been to Wisconson.
MHD is Magnetohydrodynamic. It's like a coilgun, but with water as the projectile. Let water pass through the middle of a large electromagnet, put current through it, and it will want to move.
Unfortunately the effect of this is rather weak compared to the power required, which is why the people who are working on it are using superconductors and such. Here's a good overview.
Also it requires an ionic solution such as salt water to work. Submarines are often used to stealthily swim up rivers and into freshwater ports - this may not be possible with MHD propulsion, although maybe the average river is polluted enough to allow it to work.
yes..... situations today are probably much
better than they were in the early days of
nuclear power adoption, still you can't say
it hasn't killed anyone solely because they
died of (usually many different kinds) cancer
15 years after they retired and not on-the-job.
Now who's Naive?
Replace "nuclear" with High-temp
Magnetic Plasma device.
The moronic public doesn't need to know what
REALLY makes it work..... they're a bunch of biased ingrates anyway.
What about the new practice of pumping greenhouse gases (i.e. CO2) underground to stay under emissions caps. Ever read those reports of a stagnant lake turning over and releasing a cloud of gas that kills a bunch of people? Just think what will happen when a geologic change cracks just the right place to spew your good old-fashion byproducts out in large amounts. Granted, it's still not as long lasting (at scales I can imagine) as nuclear waste, but they are starting to bury the chemical waste problem too.
Although it is utterly ridiculous that the the word "nuclear" is feared in most every context by the public, this should not be a surprise. The nuclear bomb is the most powerful weapon devised by mankind so far, and even a nuclear power plant evokes a twinge of that fear, that image of a mushroom cloud. It's irrational, of course, but I think that the people we have to blame for this are those who associated nuclear power with death and destruction: the generals and bureaucrats who perpetuated the nuclear arms race for decades.
Imagine that Einstein had sent a letter to President Roosevelt denying the feasibility of an atomic bomb, but citing its potential as a power source. We would have fought Japan a little longer in WWII, but the bomb would never have been dropped, let alone developed (perhaps?). In that eventuality, the rest of the century would have been spent growing to respect the deadly potential of nuclear materials, but remembering that they provide prodigious amounts of inexpensive power and propulsion. There would be as much fear of "nuclear" as there is of coal power plants and airplane engines.
Given a few more decades, I think the tangible fear of atomics will subside a little. Hopefully humanity has survived the test of the late 20th century without destroying itself with atomics, and is ready to put the to use in better ways. Hopefully.
A lot of people claim that the reason why the US doesn't use nuclear power everywhere is because of environmentalist whackos. This is not true. The reason is economics.
Back in the 50's when nuclear power was first proposed, people talked about having electricity too cheap to meter. The thing they did not consider is that a nuclear power plant costs much more to build than a coal/oil/natural gas plant. I want to make sure everyone understands why.
First of all, the radiation given off by fission destroys inorganic materials just as happily as it destroys human tissue. Very high quality metal must be used in all parts of the reactor to prevent degradation and to prevent it from becoming highly radioactive. This is even more of a problem in fusion reactors which have a much higher flow of neutrons, and in those, the only solution will be to replace the pieces every so often.
Second, the plant must be extremely highly reliable. One reason for this is draconian public safety regulations. However you have to keep in mind that even an accident that is contained within the plant and poses no risk to the public (a la Three Mile Island) can still destroy the reactor and put the plant out of commission.
This is true because of a property of the nuclear chain reaction. Dropping all of the control rods (scramming) does not instantly shut down the reaction in the way that dousing a coal fire would extinguish it. The reactor will continue to produce heat for around an hour after it is shut down. This means that it must be cooled for that hour, otherwise it will melt and flood the building with radioactive chemicals. The Chernobyl accident was caused by an attempt to test what happens if the cooling system is disabled.
So the system has to be very highly redundant, in part to protect the public, but mostly to protect the plant.
The last problem is that if the coolant is radioactive, you can't just call in a plumber to fix the leak as you might in a coal plant. See the movie K-19 Widowmaker for the effects of radioactive coolant on humans. You better make damn sure that system doesn't leak in the first place.
So the plants are expensive. This means you want economy of scale and build one large plant instead of many small ones. This means you don't want to build these plants in the Midwest where that much power just isn't useful. You want to build them near population centers. That explains why there is no nuclear power in sparsely populated places.
The other thing is that even though uranium is much cheaper than coal per joule (because you need so much less of it), the cost of the nuclear plant makes the whole process expensive enough that it has to compete with coal for the market. This means that in places where coal is cheap (as in the United States) building nuclear plants is only sensible up to a point. As the nuclear plants drive down demand for coal, the coal gets cheaper, so there is a natural feedback mechanism.
In the United States, we are a little bit below the optimal balance. We could economically build more nuclear plants but not that many. This difference is in part accounted for by the public perception of nuclear power.
It is also accounted for by the fact that it takes ten years to build a nuclear power plant, so if you have an energy crisis NOW, building a nuclear power plant is no good. California had to go with building natural gas power plants after their energy crisis because they are cheap and fast to build. Natural gas is more expensive but that's life.
Now it should be clear why France and Japan, two countries that use nuclear power for most of their needs, are able to do so while the US cannot. It has nothing to do with progressive governments or the lack of environmentalists. It is simply that France and Japan are small, densely populated countries (compared to the US) that have expensive coal (compared to the US). So they have a lot of nuclear plants (compared to the US).
I hope that explains a few things. Now as
Hence he spells it phoentically.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
Arthur C. Clarke had it right (read 3001). Build a flexible elevator column up to a geosynchronous space station and haul stuff up that way. Build the spacecraft in space where it belongs. Cost of launch will plummet, safety will skyrocket, coolness will exponate. Mod parent up!
"It's a rock! It has no vulnerable spots!"
I saw BeO... anyone for some beryllium spheres?
SIGERR: laziness exceeds quota
1) Costs tons of money to lift the waste and containers
2) Lighter containers (to save money on 1) could spell instant disaster if you have launch trouble.
No, I'd rather have my taxes used to build breeder reactors and pay the armed forces more to guard the generated plutonium.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
Spewing radiation all over hell and gone is a predictable reaction from the government types of course.
They'll probably be able to string the younger naive techies along for a while -- but really -- who do they think they're fooling anymore when the Congress votes overwhelmingly to import H-1b employees during an unemployment crisis and against the will of 86% of the voting public? They hate their technologists due to the fear that they will discover who really has the real power over technological civilization. Yhey just don't have any good way to extracate themselves from their responsibility for what they have done to the pioneering technological culture that was The United States. It was embodied in the baby boomer generation raised to think they were going to be the vanguard of life migrating off the planet -- and relegated to doing nothing more than building the Internet so they could then be outsourced to Asia. Spew radiation all you want guys -- it won't save your asses from judgement day.
Seastead this.
mod down this fuckin karma whore.
Post AC, asswhipe.
My understanding is that the Orion folks originally anticipated that there would be fission free hydrogen bombs created. These devices use conventional explosives rather than a fission based nuclear bomb to invoke fusion. Officially no such devices exist-but the chemicals you might use to create one are _VERY_ tightly regulated. Part of the concern here as I understand it is that fission free fusion bombs downscale VERY nicely(i.e. they can be made VERY compact and can create any size explosion you might want).
Lego bricks, you idiot! Then we can just build in orbit anything we might need.
All employees must wash hands before seeking equitable relief.
Of course, the reason to go to space is just to fix the "real issues" of overpopulation, ecological deterioation, etc. Space exploration requires and stimulates the advancement of human science, and human science is the only way we're ever going to have the ability to overcome those serious issues.
Could inexpensive cruises to the moon happen within our lifetimes?
:)
That depends on speed of development of science. And curiously, less of rocket science but of genetics/medicine. With some luck we may live till day when aging is stopped... and then we can live till _any_ following day
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
The Germans had the right idea about how to build a rocket, and we used that to go to the moon, and to launch the Space Shuttles. Not going to improve much on that in our lifetime. Now we need to settle back and watch our little Mars machines do their work, started on their way to the surface of Mars with technology developed for the most part by the Germans under Dr. Wernher von Braun .
How many people protested the Iraq War? Did that even give Bush pause?
How about the Kyoto convention. Out the window it went despite a massive amount of outcry from the environmental movement.
Same with energy policy. Here were all these people having flowery visions of solar and wind farms in other people's back yards, and Bush and crew held some closed meetings, decided on coal and fuel cells, and that was that.
One of the first things Bush did as president was to restart research into nuclear propulsion. This happened long before Columbia, IIRC.
Bush doesn't care about the more extreme environmentalists because they are simply never going to be a part of his support base. Next year, he will win reelection, and things like nuclear propulsion will have four yeas to develop enough bureaucratic momentum to perpetuate themselves. IMHO, that's a GOOD THING.
Now if only the administration will start being straightforward with the American people and start thinking more about protecting our freedoms instead of needlessly curtailing them.
Thank you.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
mod down this fuckin karma whore.
Well pardon me for posting the story in the first place. I didn't realize how little the Nuclear Space servers could take and scrambled to post mirror links in a hurry. And I at +2 so the mirror would get seen. I'm hardly looking for Karma. I'm already capped and in no danger of dropping.
Javascript + Nintendo DSi = DSiCade
1) get 100 000 slaves to build a pyramid
2) buy a magnet, suspend from ceiling on a fishing line
3) profit!
Wait... what happened to step ?
Translation: almost no increase in mortality statistics!
Reminds me of the government's take on CJB in the state of washington...the threat to the US population is "virtually zero"!
What the hell, America invaded Iraq because the USA said it was a "virtual certainty" that Iraq had ongoing and active NBC weapons programs!
What a comforting trend!
Those who are interested in nuclear rocketry may want to check out NASA's Project Prometheus.
There's also an excellent write-up of present day and past efforts HERE.
Great opportunity to mend ties with the French. They're quite comfortable with nuclear power and if there's any opposition, they could always launch from some radioactive atoll in the South Pacific where they demonstrably don't give a f*ck. Only loss of life will be fish choking on the exhaust of the Rainbow Warrier as they protest about the environmental consequences. Unless of course the French sink them before they get there - again.
One of these days I'm moving to Theory - everything works there
1) The military was together for ten months before Afghanistan. GWB didn't have a whole lot of time to firm it up if Clinton screwed it so badly, but he had to go so I can understand why he went no matter what. There hasn't been a lot of evidence to indicate why GWB chose the timing of the invasion of Iraq for now. The ex-Tres. Sec. has claimed that GWB already intended to prosecute such a war when he entered office - if true, he either was planning with forethought (possible) or he thought the military was good enough to do it. If the military wasn't good enough to go to Iraq, then GWB had to improve it - what has the President done to improve it (other than cutting benefits while increasing time in service)? If, however, GWB did build up and improve the military, did the improvements have enough of an effect that in two years the military went from useless and underpowered to being able to prosecute two wars (one medium- or small-scale, the other a regional war). This doesn't seem likely - thus either the military was prepared to act as now (and thus wasn't as bad as you asserted) or GWB decided to go with a force than was less than he wanted, knowing it would be worse to wait for it to be ready.
If the military was bad but the war in Iraq had to be prosecuted, then there has to be some reason why GWB went when he did and not when he could be ready (or more so). It wasn't WMDs (the evidence was questionable - for firmer evidence of intent to develop them, he could have looked at Saddam's actions 12 years ago and the discovery of programs then), and the terrorism angle doesn't hold a lot of water (Saddam promised money to Palestinian suicide bombers but never paid; he did have a "retired" terrorist living in Baghdad, although I don't think that that level of support for terrorism is likely sufficient to go to war). In the lack of a good reason to go when he did, I would assume that GWB went to war because he thought the military was ready - this doesn't support the incompetence implied about the Clinton military. Maybe this is a flawed assumption on my part or there is a significant reason for GWB to have authorized war on Iraq when he did that I have missed (always possible). War in Iraq might have been the correct way to achieve a better Middle East, but it doesn't support the position of a Clinton-nuked military without a really good reason to go post-haste.
2) If (the federal) gov't should not be involved in social or other welfare programs, I can understand (but would disagree) with that opinion. If Republicans spend as much money but on things you prefer, that is a good reason to vote for them. For much of the time I have been interested in politics, the overt agenda of the Republican Party is to decrease the size of the federal gov't. The last three presidents have not only failed to do this, but have significantly expanded the federal government. Part of that may come from necessity; neither party wants to lose the money they need for their goals, so they give everybody what they want - this is not sustainable however, and inconsistent with the Republican Party's goals. As a bonus, cutting spending with a large debt will be ever harder to do. The RP's goals seem at odds with their means and have been so for some time - I can only conclude (with some bias) that they either cannot achieve what they want (in which case they need to change tactics or give up) or they do not want to decrease the size of the federal gov't (in which case they are either lying or very, very clueless). Smaller gov't might be a good goal, but if the politicians advocating it don't even seem to try to achieve it, I have reason to question what their actual goals are.
As for Franken, while he is sometimes a crank (he sometimes sounds like he forgot to take his schizophrenia medicine) and always biased, when he makes arguments with the (externally verifiable) evidence to back them up, he can be taken seriously. GWB said that his tax cut is going mainly to the poor and middle classes (don't have the exact quo
i don't care how "advanced" you think you are, your all too lazy because of TV, that was my point.
however, i suppose that point would be too much for your "primative" American Mind
Back in the '60s I read some stuff by Arthur C. Clarke on these nuclear powered rockets. So I wondered if my local state library (Library of NSW)knew anything. So went in and did a search. And amazingly came across detailed diagrams (as in draughting plans by NASA) etc for a nuclear rocket using gas pumped through the core as the exhaust. It was a geek's dream come true. However, it was quite obvious and known to the writers that this also posed a huge risk. It was soooo compelling ... go to Mars in a couple of weeks from Earth liftoff.. hmmm. Though the launch pad and environs might glow a bit in the dark if there was any ablation from the core.
Damn!
Bitter and proud of it.
You're arguing with a guy who thinks you FUSE uranium.
Don't waste your time.
Well, intellegent post and all, but "critical" isn't a bad word in Nuclear Speak. It is a word that media types use to sound flashy, but it't not surprising that it is used wrong. A reactor that "cannot go critical" is a reactor that "cannot produce power."
See "nuclear piles" are just that, "piles" of nuclear material. When you get enough of the fissionables together in sufficent density, you reach a point where enough "slow nutrons" are released spontaniously so that fission is caused in other nearby atoms. That fission, in turn, produces more "slow" and "fast" nutrons. Once this is happening at a sustainable rate your nuclear pile has gone "critical" and power ensues.
The control rods and other "moderators" do one thing that produces two consequences. The "moderators" absorb slow nutrons "harmlessly". Put in enough moderator material and you absorb enough slow nutrons to quench the pile and return to the sub-critical no-meaningful-power state. In short the "Control rods" (etc) (originally nense carbon in the form of packed graphite, but I don't know if that is current state-of-the-art) slide in-and-out of the pile to turn up or down (e.g. moderate) the ongoing reaction.
So bandying about the word "critical" is kind of like the math-geek character in Jurassic Park rambling on and on about "Catastrophy Points" in chaos math, when that phrase translates to "the point in some functions where you stop using one equation and start using another" as in "its linear until X == 5 then it is exponential. X == 5 is a "catastropy point".
Anyway, to make an atomic bomb you have to arrange enough fissionable material in sufficent concentrations for the pile to go "super critical" where almost all the fissionables get their slow nutrons all at once. This requires the focusing of huge forces that pack a "Very concentrated" mass into a "Very Small" space. It is "damn hard to do" and takes an incredible balancing of forces. If you saw the movie "piecemaker" they have the suitcase nuke and they "have to cut all the wires at once." That is bull. If it had been a real bomb and they had just shot the thing once with a handgun they would have deformed the outer conventional explosive enough to prevent the compression of the material to super critical densities. As it was, the true secret of the atom bomb is that you have to put a bunch of different materials of different densities between the conventional expolsives and the nuclear pile to make the various shock waves arrive in the pile at the same time.
One of the more fascinating parts of this is the "fast" and "slow" nutrons. It is odd-but-true that fast nutrons cannot cause fission. The things, if they hit, just blow through with no effect. Each uranium based fission produces two fast and one slow nutron. This means that it takes a lot of urnaium to make a simple pile.
Water, however, is excellent at "slowing down" fast nutrons. The colder the water the denser it is and the more likely it becomes that the water will way-lay and slow down a nutron. So we cool our nuclear plants with water. As the water heats up the chain reaction in the pile slows down. As the water cools, the reaction speeds up. "Steam, however, is "not our friend" in a pile as it is harmful and hard to control.
Water also cannot become radio active. (Consequently there is, in fact, *technically* no such thing as "radioactive steam". Unfortunately, water is never 100% pure so the "other stuff" in the water can become radioactive.)
So we put a pressurized a loop of water through the pile but we don't let it become steam because of the intense pressure. Then we use that water to heat "second stage" water which is then taken over to a boiler where it boils "third stage" water into steam that drives turbans and makes electricity. (millitary plants on ships are only two-stage, but I recall our civilian systems are "always" three-stage, but I could be wrong. 8-)
The "neat bit" is that the process of making that steam "cools" the
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
The problem as you described is probably because the 'new ideas' are outside the envelope of the company. You might think that middle management is useless, but the beancounters would get rid of them if they could -- so they're probably doing SOMEthing, even if it's just making sure that the company's capital isn't frittered away on frivolous experiments that may or may not work.
If the rate of innovation is really that stifled, then your brilliant ideas will get lapped up by a market starved for new and interesting solutions. The market has the final say, after all.
If you have a good idea, start a company. Attract investors, organise capital, supplies, and a place to work. Or you could just make your ideas more persuasive. You think you've got the managers figured out and you think you're smarter than they are... So go ahead and prove it. Or not, it's up to you.
But don't complain about the two-month stints you do. After all, it's your life, YOU get to choose what you do with it.
I am artificially intelligent.
Sorry, missed a point. The design of a lift vehicle that used the nuclear pile to generate the acutal lift would only need to be designed to "blow up" into several separate chunks. In short, you would only need to make it perferated into "break here" segments. As stated the pile "could not ever" explode spontaniously as an atomic bomb. The densities and placements for a sustained reaction are orthogonal to an atomic explosive.
So you would only have to worry about the life vehicle blowing up for "some other reason" (including but not limited to sabatoge). But it isn't carying all thait fuel so it isn't going to be even as likely to explode as an average sports car. (And contrary to what you see in the movies, it is also *damn hard* to make a car blow up.)
So the payload of fisionables isn't going to blow up because it is just a bunch of parts. The actual lift system isn't going to blow up because it isn't even flamable and it is designed to deliver sustained power so it can't go super critical. There is no "rocket fuel" to blow up.
It's just not going to happen.
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
Do you really think the US Government would give up such a promising propulsion technology, just because of a little radiation and the prohibition of international law, at the height of the Cold War?
I think not. I reckon the data was sent to Area 51 (along with the nuclear plane plans) and was developed into a more flexible and controlled verision capable of atmospheric and space flight, utilizing dramatically improved minature charges derived from conventional nuclear testing. Undoubtedly it was responsible for many UFO sightings and tangential information.
---If you can't trust a nerd, who can you trust?
Just as we thought - Wal-Mart the Discounter - is a danger to America! Just look at their initials "WMD"!
I believe radium coated dials on wristwatches are illegal in California if not the US. Current 'glow in the dark' coatings just use phosphorus compounds?
...Is when will people back on Earth learn to spell "its"?
Let's face it, hijacking aircraft and using them as giant bombs probably seemed pretty far-fetched too. There was a great book on the problems of using Nuclear power called The Atom and the Fault It covered the danger of building a plant near or on a fault, but now it's very interesting to look at the book in the light of terrorism. In the same way, the builders of the twin towers built the structure to withstand strong winds, and a small plane crashing into it, never in their dreams could they imagine someone crashing a plane full of gas into it.
The issue here is you can't have a government at one point crying chicken little about WMD's (chemical biological and nukes) while at the same time using nukes in Space craft, especially in light of the recent catastrophes.
That seems like a very bad combination to me - we have a scant budget, let's skimp on design, let's skimp on testing, and use nuclear - seems like a disaster in the making.
Anyway - the world changes, design must changed too. What once looked like a great idea is nothing of the sort. And I haven't even mentioned the problem of nuclear waste - shall we put that in your back yard? I think there was some vague idea of trucking it out to space - now there's an idea! (Maybe the entire world would achieve the exalted ranks of a Darwin Award, all in one big bang!)
You can still buy used/antique watches with radium dials.
If you're unsure how to spell a word, simply post it to /. and walla!, it will be answered in no time.
Just look at all the movies where there's nuclear reactors that have had problems. No one wants to be one of the victims of radiation poisoning. Most people know that cancer and radiation poisoning go hand in hand. When you try and just state that most of the public is uninformed and that coal/oil plants generate more polution, everyone already knows that.
Ha! ha! You're so smart that I'll bet you're an Anonymous Structural Engineer! In fact, it's obvious since you're so smart that you conveniently missed an entire sentence while your powerful brain parsed the contents of my post:
Ok, so maybe that didn't really happen.
The only question that remains, I suppose, is which one of us is the idiot being trolled by the other. I vote you for idiot since you can't even read a post the whole way through without spasmodically hitting Reply to share your incredible insight and intellect. Tell me, does Slashdot rot people's brains, or were you stupid BEFORE you posted here?
Moron.
Alito: A vote for Alito is a punch in the eye to put that bitch back in her place!
you could tie a couple stones to it and throw it up into the air hard enough so that it doesn't fall down.
or...
You could take the whole thing up in a shuttle and drop one end down very carefully.
or...
You could tie one end to a rocket and tie the other end to the ground and hope the rocket doesn't overextend the line on the way up.
Ben
Work Safe Porn
This truly sounds like a great idea. The one thing that puzzles me is the passing reference to the buffer gas that keeps the 25000-degree UF4 from melting the silica "light bulb". This gas would have to be extremely transparent to ultraviolet. I wonder which gas would be suitable. Also, would the energy from the hot UF4 be all ultraviolet, or wouldn't it also radiate a hell of a lot of plain old heat, which the buffer gas would have to dissipate somehow? Hopefully these are not fatal flaws glossed over.
...not because of whether it can work or if it's feasible - but as long as it is a nookleer wessel, the likes of Greenpeace or the 'Green' party will scare the public into being against it.
There was a problem with getting the technicians to speak the same language, and it got all messed up.
How would you prevent the UF4 mixing with the buffer gas, especially if the buffer gas is being swirled around?
The analogy of cooking a raw egg in a vortex of swirling water might be misleading. The egg is cohesive. But what would keep the UF4 gas similarly contained? I would think the buffer gas would have to be denser than UF4, or the UF4 would move outward because of centrifugal force. What buffer gas would work?
In any case I would expect the UF4 to contaminate the buffer gas to some extent, simply because gases are not solid. Is the contaminated buffer gas the waste that he talks about ejecting into the sun? Unless I missed it, he doesn't mention carrying a stock of buffer gas.
As exciting as this idea is, the more I think about it the more magical this buffer gas seems to be.
Not to mention the fact that your average coal burning plant simply doesn't have the potential to cause a catastrophe on the scale of Chernobyl, Three Mile Island, etc. Why does everyone insist on calling the accident at Three Mile Island a catastrophe? As I recall, the accident released Xenon 133 and Krypton 85, certainly bad gasses, but hardly anything to freak out about. Xenon 133 is a beta emitter, which means it launches electrons fast. (Cathode ray tubes anyone?) In addition, its half life is about 5.25 days, (in a month, less than 2 percent of the isotope is left at all). The end product? Caesium 133, non-radioactive. As for Krypton 88, it has a slightly more interesting decay pattern, it undergoes beta decay, like Kr133. First from Kr88 -> Rubidnium(sp) 88, with a half life of about 2.8 hours, so in the first week(about 60 half lives), it was all gone (to at least ten nines .0000000001% of its original mass)
Rb88 is radioactive, again with beta emmission to Strontium 88, only this time, its half life is a bit shorter at roughly 18 minutes (17.78 minutes). In the same week, there would have been 567 half-lives, so effectively, there is no Rb88 out there.
Strontium 88 is stable. So, within a month, the only radiation we have out of this is effectively that of the Krypton, and at less than 2% of its original level. All of the radiation is beta-emissions, the kind that all of you (LCD panels excluded) have aimed at your faces right now from your monitors.
Not one person died, not one person got sick. Containment CONTAINED, as it was supposed to. Effective contamination now? Zero. Where is the problem?
Isotope and half life information from This periodic table
Didn't I see a movie like this with Slim Pickins riding an A bomb out the bomb bay doors of a B-52, riding it like a cowboy and yelling yeeeehawwww as he held onto the bomb with one hand and waved his cowboy hat around with the other. I think the only difference here is that he is travelling down with the bomb, whereas NASA's plan is to have people going up with the bomb.
Everybody knows that the environmental folks would pitch a fit if we tried to launch a fission-based spacecraft. But they already hate President Bush as it is, so he could include a proposal for a new fission-based shuttle replacement tomorrow and it won't get them any more angry at him than they are now (I mean, is it possible?).
And President Bush could even help handle crowd control at the launch site as well! Let's say we're launching from Cape Canaveral. During that week, Bush flies off to... say... Amundsen-Scott, muttering phrases like "oil exploration," "WTO" and "nukuler." Maybe suggest he's going to do something that will kill off the ultra-rare Antarctic Dodo. Those myopic protesters that don't die of an instant embolism upon hearing of it will then take off after him, leaving the Cape nearly deserted for lift-off.
As far as I can see the glass is supposed to not absorb the 80GW of light, yet the hydrogen is. Is the author claiming that silca glass absorbs less photons than hydrogen? If it absorbed only 0.01% of the total photons it would still get 8MW of heat, which is going to be quite hard to keep cool. For comparison, the optics used in cameras absorb 0.1% of the incoming photons.
On the other hand, hydrogen doesn't strike me as particularly absorbent. I thought it was mostly transparent except for a few frequencies (the hydrogen bands). As the gas reactor is acting as a purely blackbody radiator it's going to emit in a classical SB distribution, which will mean that most photons are going to just bounce around until they get absorbed by the mirror or glass.
So the obvious problem to me (and let's face it, I'm not a rocket scientist..) is that you have an 'impedance mismatch' between your energy source and your energy sink.
'Almost no radiation' is synonymous to being half pregnant.
Radiation exposure is binary.
It would be better if that was '...no radiation.'
Could inexpensive cruises to the moon happen within our lifetimes?
Or maybe we could use the energy to help people instead of turning it into another jerk-off consumer product.
That's you all right. "Critical" in the nuclear sense is the state of being able to sustain a chain reaction. Every nuclear powerplant on earth is "critical" while it's running, and none of them have melted down in the last 20 years or so.
Just so you don't say anything else stupid, "critical point" means something completely different when you're talking about phase diagrams.
And I hope the nitwits who modded you up to 5 get meta-modded into oblivion. Moderators, a hint: If you don't know how to evaluate the truth of a claim, you cannot properly moderate it as "informative".
Time is Nature's way of keeping everything from happening at once... the bitch.
*sigh* First off, I'm not a nuclear physicist, so you have to cut me some slack. Second, I was referring to "critical" in the colloquial sense of the term. i.e. The melt-down reaches a point where an explosion happens. Not being a nuclear physicist, it's a bit difficult to know about things like "prompt critical".
Actually, I take that back. It probably came up in my private studies, but it's one of those things that tends to slip your mind when you have 20+ years of television crammed into your head. "You should run before the reactor reaches critical! Where can I run? There's no way to escape the blast!" Blech. I should have watched less TV growing up.
Javascript + Nintendo DSi = DSiCade
According to the graph on page 10 of the article, we should have material strong enough for the elevator before mid-2004.
This seems to conflict with the report being published march 2003, and the mention of 2 years in the article, though.
Does anyone know the CN state of current ribbons?
I'm a dreamer, the world is my playpen. But hey, I'm a serious person, I can't dream all the time.
Actually it was Alcohol, not Kerosene. IIRC they made it out of sugar beets. Perhaps it was due to the lack of fuel because of the war, dunno.
Rotating space tethers can be built today. They do not need anything stronger than Spectra-2000, which is used for fishing line. Even though we could really build these, space tethers don't get nearly the press that space elevators get. I think this is because the space elevator is simpler to understand.
A rotating space tether is long (like maybe 500 km long) with a weight at one end. It is rotating around its center of mass, which is close to the weighted end. The whole thing is in orbit around the Earth. It is spinning fast, like maybe 2.5 km/sec at the tip. The tip is going backwards relative to the orbital speed when it is down and forwards when it is up. So when it is down something can grab on even though it is not going at orbital speed.
Rotating space tethers can catch a payload from a reusable suborbital rocket and toss it into orbit. The reusable 1st stage of the SpaceX Falcon-1 could lift a payload high enough and fast enough for a practical tether to catch it. This could make for very cheap access to space.
Rotating tethers can recycle energy. If one tourist is coming down and another is going up there is no need to use an ion-drive or other thruster. This is a fantastic win. But even if you have to use a thruster it can be a high ISP thruster or you can even push on the Earth's magnetic field with an EDT.
Rotating space tethers can toss a payload every 100 minutes. A space elevator could easily take days to climb.
I have a Java applet that you can use to simulate space tethers at my site:
http://spacetethers.com/
With this you can see how they work. In my unbiased opinion, this is the best way to get into space with current materials.
-- Vince
Youre right, WE (the US tested em postwar with different fuel diffusers and kerosene)
Im more of a V-1 fan myself but hey
To make this stuff useful for space industrialization, people are going to have to be able to commute regularly to orbit. This means things like regular passenger flights, lots of crews, lots of ... sounds like the airline industry, doesn't it? And like the airline industry, we can NOT figure on no operator error, ever, and we can NOT figure on perfect maintenance procedures every single time.
How tolerant of fuckups are designs based on the technology discussed here going to be?
While plane crashes are unusual, they are also not unheard of. Safety standards that are good for very occasional research flights are not appropriate for when flights to orbit are an everyday thing and flights to/from other planets are regularly scheduled.
The supporters of nuclear space propulsion seem to be thinking of flights of frequency similar to that of the Shuttle. To open the door to the Solar System via direct launch, we're talking lots of flights per day, and to pay for this, we're going to have to industrialize space. Powersats are a good first step with a short-term return.
Personally, for hauling freignt to orbit, I prefer the Space Elevator with railgun technology as the backup possibility if we find that CNT can't be scaled up to mass production at the strength levels required to make the Elevator practical.
If nuclear-powered vehicles can be made safer than more conventional designs (I include scramjet-rocket hybrids in the "more conventional" category), then they're worth looking at.
Tech Public Policy stuff
A dairy aire is what you sing to a cow.
the article about nuclear powered space travel is bunkum. the author clearly knows very little about his topic as it is riddled with factual errors. He is talking about a land rush on mars - the idea that say half the earth's population would jump into their space ships and go to mars is nonsense! the sheer amount of energy required to do this just is not feasible.
Then he talks about "deltaV" by which he means that in space it costs energy to change your speed rather than maintain your speed. He completely neglects the fact that the biggest limit on acceleration is going to be how much "g force" the human body can tolerate for extended periods, rather than how much fuel or how powerful the rocket/engine is.
He also talks about bringing a large asteroid into earth's orbit for mining. maybe this is feasible, but this would a) alter the moon's relationship to the earth's orbit (question: are 3 body systems as stable as 2 body systems) and b) completely discounts the risk of the asteroid falling to earth, potentially destroying a swathe of the population!
Just like he completely neglects the risk of a large quantity of radioactive material being released into the earth's atmosphere in the case of an accident. He claims that although one of his engines would use the same amount of radioactive material as chinobyl, but 1% of the amount of material as the "ivy mike" nuclear test, then there would not be a problem with radioactive material being released into the atmosphere.
TO THIS DAY, radioactive materials from chernobyl can be detected in sheep which are farmed on hills in Wales. I don't see why this wouldn't be true about other parts of (northern) europe. He is incredibly myopic if he thinks that nuclear space disasters are an acceptable risk.
I could go on, but I shall leave it at this: the author is guilty of wishful thinking, he conveniently ignores major showstoppers, and I can only describe him as a complete buffoon.
God his stupidity makes me angry.
SURELY NOT!!!!!
As a qualified Reactor Physics Engineer with nearly 5 years experience in an operational nuclear power plant I must correct your ignorant trolling and scaremongering.
You have no clue what critical means. A critical reactor is one in which there is a steady, sustained chain reaction of constant power. In other words, the neutron flux is constant: neither increasing or decreasing. Reactors are in this state normally during operation.
sub-critical refers to a reactor in which the neutron flux is decreasing, i.e. power is being reduced.
super-critical is the opposite, i.e. when power is increasing. The neutron flux is increasing.
prompt-critical is what happened at Chernobyl. This is when the reactivity of the reactor becomes too great suchg that the effect of delayed neutrons in the chain reaction is no longer dominating, and the neutron flux (and hence power) increases exponentially on a time scale of miliseconds.
The term critical comes from Enrico Fermi's first public demonstration of his pile, the first man-made nuclear reactor. During his demonstration, when he got to a stage when there was a self-sustaining fission chain reaction with constant neutron flux he said, "Gentlement, we have reached a critical point."
That's all there is to it. There's nothing scary or dangerous about a critical reactor, contrary to what the mad "environmentalists" and ignorant journalists would have us believe.
Stick Men
(2) This is pretty much a lost cause, but are you *sure* that Orion is "too dirty"? Consider the sheer quantity of mass you can boost into orbit with an Orion launch, and compare it to the amount of damage resulting from the fall-out. Suppose someone proposed a scheme whereby a single Orion launch would put enough solar power satellites in orbit to completely replace coal burning. The number of deaths likely to result from the Orion fall-out would pale in significance compared to numbers you would save by dumping coal burning.
Reverse the problem. Nuclear powerplant feeding a high-power pulse laser for launch? No nuclear payload on the vehicle means a lighter vehicle (and less danger if the vehicle fails to fly).
0 /1 0/1219229&mode=thread&tid=134&tid=160
http://science.slashdot.org/article.pl?sid=03/1
..so it's possible that anything based on that in my argument doesn't work (although I don't need it for the whole argument, it doesn't help)
This thing (will) must have quite impressive normal modes
Working for necessity's mother.
The article wants to use a nuclear lightbulb to heat hydrogen gas to launch a rocket. Several posters said that nuclear lightbulbs are pretty efficient, but they don't heat much gas, so they can't give you sufficient thrust to counter gravity. I googled and found a reference that said you could get .37g from a nuclear lightbulb, less than the 1+g needed to launch, but the page said that number was probably tuned for maximum efficiency. Other posters pointed out that if you put in more gas, each atom wouldn't heat up as much, but you'd get more thrust.
So my question. Does anyone know for sure if a nuclear lightbulb approach can give you enough thrust to launch a rocket?
Dude, 2004 has only just begun. At least wait until November elections to crash and burn.
"Only one thing, is impossible for god: to find any sense in any copyright law on the planet." Mark Twain
Why? Are we to assume that you're better than any other idiot expounding on a subject of which he knows nothing?
A wise man once said, "'Tis better to be silent and be thought a fool, than to open one's mouth and remove all doubt." On Slashdot, if you are silent you are also invisible. Think about it. If you conclude that you ought to spend more time researching for the time you spend posting, it will have done some good.
A wise man once said, "'Tis better to be silent and be thought a fool, than to open one's mouth and remove all doubt."
... Then shalt thou understand the fear of the LORD, and find the knowledge of God."
Solomon, if I remember correctly. From Proverbs (one of my favorite books). In fact, Solomon also states, "Yea, if thou criest after knowledge, and liftest up thy voice for understanding;
I have done quite a bit of research into the subject of Nuclear Physics. Unfortunately, I'm only human and I *will* make mistakes. But I do my best to learn from those mistakes and gain new knowledge.
"It is as sport to a fool to do mischief: but a man of understanding hath wisdom."
Javascript + Nintendo DSi = DSiCade
> By the time you get to 75 grand a year,
> you'll be paying half that in taxes every year,
> roughly 43% of your total income.
BULLSHIT
For 75K you are at the bottom end of the 30% tax bracket, you get taxed at 30% for each dollar over $63550 at 30%, your federal income tax (the largest hitter in most peoples taxes) will come to $17144 or almost 23%, even before Bushes tax cut it would have only been $17931, or just under 24%. That is before any deductions at all, even the standard deduction. Medicare and Social Security combined are only about 8% and you can live in one of the states that doesn't have income tax, like Alaska, Florida, Nevada, South Dakota, Texas, Washington, or Wyoming.
You shouldn't even be paying 43% marginal until you are making well into the 6 figure range.
In UK we have VAT at 17.5% on virtually every single sales transaction you make. Is the US equivalent called Sales Tax or something?
Seeing as you spend virtually all your income on VAT taxable things, you would be foolish to discount it.
Also we have road tax, alcohol and tobacco tax and national insurance so a hell of a lot of our income goes on tax. A lot more than you think if you only pay attention to income tax, which is what they want you to do. In the UK we have a word for all these extra taxes that they won't charge upfront off your income - stealth taxes.
SURELY NOT!!!!!
mebbe if u read more abt nuclear physics then that mystic junk u wud be able 2 quote the right def 4 critical w/o looking like a jerk.
What's my point?
your total exposure to radiation is acculmative = natural sources + man made sources
Fissile material has extreemly long half life and once it is released in the environment it just doesn't go away. There is an ever increasing amount of it from Chernobil, atmosphere testing, power plant leaks, nuclear satellites crashing etc, etc.
The idea is to reduce it as much as possible, not to put your, so-called 100 REM limit to the test.
How do you know for sure that this limit is even accurate anyway? I don't think anyone can actually prove that you won't get cancer if you are exposed to less than this limit.
Wow. You're just freaked out about this stuff, aren't you? Let me put it this way: Plutonium is what we call an "Alpha Emitter". Alpha emitters emit, predictably, alpha radiation. Alpha radiation consists of slow moving protons. Now here's the kicker: Alpha radiation poses no external risk to human beings. The stuff is so powerless that it can be shielded against with a sheet of paper. The particles can't even penetrate the outer layer of dead skin cells.
Plutonium only puts out gamma radiation when it spontaneously fissions. Now when you look at the fact that spontaneous fission is rare, and each event only puts out a handful of particles, you'll find that having plutonium around is no worse than all the Uranium contained in your backyard. (Uranium is an extremely common material. Even more common than nickel or tin.)
Plutonium does pose a danger when inhaled however. If a small particle gets lodged in your soft tissues, the alpha particles will be able to penetrate enough to possibly cause cancer. Don't worry though. Ingestion will not lead to plutonium in your system, and inhalation of plutonium is very difficult. With an atomic number of 94, it doesn't break up very easily (read: it has to be machined) and it doesn't stay in the air very long when it is (too heavy).
There is an ever increasing amount of it from Chernobil, atmosphere testing, power plant leaks, nuclear satellites crashing etc, etc.
Correction, there's an ever DECREASING amount of it in our food and water supplies. First off, the chemicals came from the earth, so it's not like they're somehow foreign to the ecosystem.
Secondly, Chernobyl released fallout only in the immediate vicinity of the plant. Anyone who told you that all of Europe was contaminated, lied. In fact, the remaining three reactors continued to run for years afterwards.
Thirdly, atmospheric testing was banned forty years ago. The fallout from those tests has been declining ever since.
Fourthly, all the leaks from all the nuclear plants in the world don't add up to anywhere near the amount of uranium put out by a single coal-burning plant. Guess what? Most coal deposits are Uranium rich.
Fifth, "nuclear satellites" have not been a major contributor to nuclear waste. The US only burned up one (intentionally) before realizing the public's fear. After that, RTGs were encased in strong black box type devices. When a satellite crashes, they simply dive and recover the black box. In some instances, they even reuse the RTG. If you want to talk to someone who doesn't care if they send unshielded RTGs or reactors into space (the US has never sent a reactor), talk to the Russians. They've been exceedingly careless with nuclear technology. Still, not a single person has been killed by them burning up Plutonium in the atmosphere.
Do some research. Once you understand nuclear technology, you won't be so afraid of it. The media has tried to tell us that nuclear technology makes things glow in the dark, produces mutant monsters, and causes reactors to blow up like nuclear bombs. None of this is true! In fact, most of the chemicals in your kitchen cabinet pose more of a threat to your health than anything nuclear.
BTW, your total exposure is not accumulative. Your body is used to radiation (gets it every day) and repairs against it. The problem comes in when you are exposed to more radiation than your body can repair. About 100 REMs per year is considered safe for the average human. Some medical treatments exceed this by a large margin. Old style X-Ray used to give 10 REMs per X-Ray, but new digital machines only give about 100 milliREMs.
Javascript + Nintendo DSi = DSiCade
Well, if you want to believe that plutonium is harmless and coal is radioactive... go ahead, I obviuoysly can't win this arguement on logic.
You might find this link interesting. Just because you see the characters on Back to the Future in rad suits, doesn't mean that's how they actually handle plutonium.
Javascript + Nintendo DSi = DSiCade
Our sales tax (you had the right word...) is determined by the states, there are some that have very low sales tax, and many that have no sales tax on non-luxury items, like clothing under $50 and food...
So you are right, but I still would not say that taxes in the US are very high...
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
I, for one, welocme a longer day.
Litigious bastards
...or inhale.
Outhaling is ok though.
I think they hold alot of promis esp for deep space eninges. We really need rockets like this for mars missions as they could cut what would have been a dangerous 2.5 year mission to a 4 month round trip. Plus you would also have abort capibility,in that if something goes wrong halfway though you can turn back to earth. A chemical powered mission would have to at least go to mars and then use it gravity to help send it back to earth or even wait till mars and earth get back in to position. As for danger if it over heats it wouldn't be chernybole since the fuel is a gas and all reactions would stop if containment failed.
hm