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Antimatter Propulsion
er333 writes "A group at Penn State is building prototypes of antimatter storage for space applications, and makes a good case that with the amount of antimatter that will be produced in a few years, "omniplanetary" missions will become practical, including manned missions to Jupiter.
They have some images describing possible missions and a concept craft design called the ICAN II."
Looking back to the past from the present, we tend to forget the psychology of the day, instead seeing events through a filter of modern opinion and judgement.
:/
The Japanese (at least their military) were fanatical. Their country had never been successfully invaded by a foreign nation. They had the samurai mindset of death before dishonor. Even the Mongols who terrorized Eurasia couldnt do it: They sent the largest force of soldiers over water in the history of the world (unbeaten until WWI) and what happened? The Japanese gods intervened, sending a "Kamikaze" or "divine wind" that wrecked the Mongol ships after the first few battles. (And since the Mongols made the error of sleeping on their ships rather than making camps on the shores, they were all killed.)
Thats why in the end of the war they had suicide pilots (named after the supernatural forces they believed defended them). They were training civilians, women, to fight the Americans when they came. Running out of metal, they resorted to building balloons out of cloth and wood with incendiary payloads, and tried to float them over to North America to start massive forest fires. In short, they were doing absolutely everything they could to win. The Emperor knew things were lost, but go read what he said he was dealing with in the end: A pack of generals who were still adamant that they would WIN the war, not just successfully defend Japan.
But by dropping the atomic bomb, a weapon of unforseen destructive power, their mindset was broken: They realized that if they persisted in fighting, it wouldnt matter how hard they fought, they and their land and everything they were would be obliterated for all time in an atomic blast. Like a slap in the face to wake someone up from a delusion. So whenever you weep for those slain by the bomb (and you should), dont forget that it likely saved a lot more human life on both sides of the conflict, by bringing a swifter end to the war. (I admit though that I dont know why the second bomb was dropped.)
Sorry for the offtopic post.
Yes, many have noted that, including myself who is not an American and not as prone to many of their delusions. (Sorry guys.) Youll find the argument for the dropping of the bomb not only made by American historians, but by British and others if you look.
While you cant ignore the subjectivity introduced by the background of the person making an argument (or that of the sources they use), but also do not throw aside a persons argument in the hasty thought that they are not intelligent enough to make an effort at objectivity themselves.
It's funny how when this trait is present in our armies, we call it "courage" or "tenacity" isn't it?
Except that the level of fanaticism, or "courage" or "tenacity" or whatever else you wish to call it, wasnt there in, say, the European theatre. Theres a difference between fighting courageously and fighting a completely hopeless cause.
See the contradiction? If they were training all of these suicide pilots, what were they going to suicide in?
Planes that were already built, and modified to be packed with explosives perhaps? Those modified planes were extremely good bang for the buck: If one got through, you scored one sunken ship. All it took was one hit. Simple economics when youre in dire straits.
Ah, they were suicide balloonists, trained to float through the skys like a deadly horde of jellyfish, waiting for the chance to swoop down on helpless American fighters and explode.
Well, more details just to be serious: The balloon idea depended on the time of year: summer. During that time, prevailing winds blew from west to east, and also, the American west coast was experiencing a drier than normal summer, so their forests were like a tinderbox. The balloons were given enough helium to make it to North America, where they would run out and descend. When they got below a certain altitude, the charge would go off and an incendiary burst would result. No really expensive components, no fancy guidance systems. Did they work? No. :) Some balloons DID make it to the states, but most failed to detonate. I think one DID detonate, but it landed in the middle of a ploughed field and caused no major damage. At the time, the farmer and authorities had NO IDEA wtf was going on. :)
Along with a fair old chunk of the civilian population.
Regrettable, but as I said, perhaps that loss of life prevented even greater losses. Just something to consider.
Oh, further: Although some American generals really did just want to "blow stuff up" Im sure, they WERE considering it as a psychological weapon and not just a physical one. They were planning to blow up Kyoto (Japans former capital, and a spritiual center, it wouldve been like dropping the bomb on the Vatican) to really send a message to Japan but recalled that idea, fortunately for us all.
I wont deny that Hiroshima was a test. (It was selected since it hadnt been bombed much until then and would reveal best the results.) But I wont accept that it was only a test. The drop had a purpose, and that was to end the war. That was by far the primary reason for its use.
It's fairly clear why the second bomb was dropped, although these reasons don't stand up brilliantly in hindsight.
The Japanese civilian leadership wanted to surrender after the first bomb was dropped, but the more powerful military leadership refused. One of the reasons for this was that news didn't get from Hiroshima to Tokyo for at least a day after the first bomb was dropped, something that the american leadership failed to predict. The americans were therefore surprised that the Japanese didn't sue for peace immediately.
Another reason for dropping the second bomb was that Stalin declared war on Japan just after the Hiroshima bombing, and immediately attacked Japanese positions on mainland Asia. The Americans didn't want Stalin to win too much against Japan (the mindset of the cold war had already started at this point), so it was deemed necessary to get the Japanese to surrender immediately.
Throughout this you have to remember that six months earlier, the allies had won a war against Germany, with German divisions generally surrendering or retreating after 30% casualties. When the Americans invaded Guam and Saipan, the Japanese troops didn't surrender at all, and after ~90% losses, forced Japanese civilians on the islands to commit suicide rather than be captured, before committing suicide themselves. This event appeared in the American press, and the feeling was that if the Japanese defended a captured territory that strongly, then there was no chance of invading Japan.
A blockade on Japan would have hurt even more civilians, as food and fuel would have been cut off. Japan gets very cold in winter, and civilian deaths from a blockade would have been much higher than from the two atom bombs.
Most of this view is explained in "The Making of the Atom Bomb" by Richard Rhodes, which I admit takes an American viewpoint for most of the book, but I would say is fair at explaining the reasons the Americans had for dropping the two bombs.
Antiprotons are currently created by slamming a proton beam into a fixed target (Beryllium, IIRC), which creates a shower of hadronic junk. A very small fraction of that is antiprotons. The junk is filtered to keep the antiprotons, and dump the rest. It's an extremely inefficent and expensive process.
--Bob
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
The problem comes down to having to stop and the propellant used in combination with Relativity.
.5c relativity predicts your inertial mass will have increased to %150 your mass at rest. So you'll have to %50 more work to accelerate.
.5c. If you throw in a passanger, a craft, engines, parts, etc and make the equation slightly more realistic, you get to around .1c.
Bummer #1: You have to stop, so half of your fuel and propelant must be saved in order to stop the craft.
Bummer #2: You still need to carry propellant (what you are going to push away from) in addition to your fuel. The more propellant you carry the more energy it takes to accelerate the craft. Ultimately, you reach a point at which carrying more propellant will just slow you down more.
Bummer #3: At
Add these up into a nasty equation, and you get to roughly
Someone you trust is one of us.
Penning trap + diagram
Ok, first off, a number of people seem to be missing the point on this article (largely because most of them read little more than the introduction, if they made it through that), so I figured I'd cover some of the details better.
:) ). In a chaotic sea of reactions such as the sun, yes, you'll get a little antimatter, and it'll go away just as quickly. Of course, you could harness solar energy to produce antimatter by having a manufacturing station near the sun, but you could harness that energy for a lot of other things too, and we get to the economic feasability issue discussed in the last paragraph.
:) I don't see economic viability in bringing it into space at this point.
Misconception 1: Antimatter is a poor choice for a propellant because its manufacture is inefficient.
Indeed, its manufacture is highly inefficient. In fact, its maximum possible manufacturing efficiency is a mere 50% yield, and such a yeild is beyond the wildest expectations of most scientists. But, there is a much greater inefficiency involved here (actually two of them): acceleration energy and relativistic effects. Picture a system where you have 10% of the mass as propellant. Then, you're wasting 10% of your energy merely accelerating the propellant (roughly - the propellant, naturally, will decrease in volume). Now, picture a system where 99% of the mass is propellant. That's a 99% energy loss. Well, even at those weight levels, the best chemical propellants can't get you very fast. To make matters worse, we have relativistic effects which, the faster you go, the larger portion of energy it takes to accelerate you. At 1/2c, energy requirements are doubled. So, mass is an incredibly critical thing. In addition, the speed exhaust particles are propelled is, if anything, more critical, because it sets a maximum theoretical speed for the craft - and for chemical rockets, it is incredibly slow. And to get close to that speed requires massive waste.
Misconception 2: Antimatter is a great concept for a weapon.
In actuality, no. Due to the huge manufacturing difficulties mentioned before, it is a poor weapons concept. Even with the proposed efficiency increases, manufacture is expected to cost several billion per gram (a gram of antimatter has roughly the energy potential of 27 of the space shuttle's solid booster rockets). This level of explosive power doesn't really compare at all to a boosted thermonuclear weapon, which isn't that incredibly expensive to build (U235, for boosting, is incredibly cheap, and the rest is a standard hydrogen bomb core). It isn't even that good of an idea for a small stealth weapon, given our current scientific knowledge. Containment for an amount of antimatter that would be enough to take out merely a building hasn't been developed; the smallest containment systems we have for antiprotons are roughly 2m by 1m by 1m. You'd be better off with conventional explosives.
Misconception 3: Antimatter storage is dangerous
Not with the amount we're dealing with. The mars mission proposals were planning to use 100 micrograms of antimatter, to start fission/fusion in tiny spheres. If it were to detonate, it'd be a smaller explosion than the challenger had, to say the least. The real worry would be the fissionable material causing a chernobyl-like effect apon a small area (this has happened in the past when we've had nuclear weapons accidentally "detonate" - not a nuclear explosion, of course, but a conventional explosion which scatters the radioactive material around). There'd be no need to do anything like "hiding it behind the moon". We don't worry about space shuttles and satelites blowing up many miles above us. We need to worry even less about this.
Silly Misconception Someone Made: Antimatter should be manufactured in space so we don't have to ship it up.
The main concern with shipping things up to space is the mass requirement. The antimatter we're dealing with has almost no mass, relatively - only its containment units do, and they'd need to be brought up even if the antimatter was being produced in space - in addition to *an entire antimatter generation facility*, personell to run it and maintain it, power generation, etc... oy, what an economic nightmare! There are much better things to work on producing in space.
As for the issue of "converting solar energy to antimatter", well, that's a tricky question. The sun does not release antimatter; that'd be silly. Antimatter has this lovely habit of detonating virtually instant with regular matter (that's why we love it so!
Now, a real issue to be investigated from the sun is (and, please, all ye experts on particle accelerators and animatter production, step in and comment (probably badly, sure, but its an idea)) whether or not you could produce antimatter from solar rays, which travel at a good percentage of the speed of light (sorry, no numbers on me right now). Most high-energy particle emissions from the sun are light nucleii, such as hydrogen and helium, but the sun does eject some denser nucleii. It'd be a free source of high-energy collisions, and you might be able to filter anitmatter from that in a fairly simple, low-weight, free-power (the main reason), low maintinence method, if you could set up simple automation. It'd need to automatically stabilize its orbit and adjust its distance from the sun according to conditions, to eject containers from earth when its on the right trajectory, etc, but it is doable. But, in reality, I recommend sticking with antimatter production on earth for now
- Rei
Look at me, still talking while there's science to do.
Nope. I think you may have misunderstood what your professor was saying. Total annihilation of 1 kilogram of matter will produce about 8.9E16 Joules of energy (E=mc^2). There are about 4.2E12 Joules in a kiloton of TNT equivalent, so this is roughly equivalent to a 21000 kiloton, or 21 megaton nuclear bomb. A big bang, certainly, but not anywhere near enough to destroy a whole continent. Many nukes of that size (and larger.... 50 MT and up) have been detonated, and as far as I know all the major continents are still here. :-)
Of course, the kilo of antimatter will also wipe out a kilo of normal matter, doubling the yield, but that's still not enough to vaporize a continent.
... that currently, it's really hard to produce - as the article says there are less than 10 nanograms currently produced each year, and the projected yield from Fermilab's new equipment would be no more than 140ng or so. And this requires huge particle accelerators costing billions of dollars.
And even when you've got these going, the cost to run them is prohibitive. And then there's the problem of keeping them stored for long periods at a time and transporting them. Despite a 100% matter to energy conversion rate antimatter has got to be one of the most inefficient fuel sources out there when you look at the entire picture! We'd be conserving resources by making coal-powered spaceships...
So Bush is probably going to love this :)
And an increased capacity to produce antimatter, while way out of our reach at the moment, brings new problems with it. After all, matter-antimatter reactions are far more efficient than even fusion reactions at converting matter to energy, and the military uses for this are obvious, especially to anyone who has read the Night's Dawn trilogy. It wouldn't suprise me if this sort of thing is being investigated somewhere as a speculative new military tool.
Hopefully, I'm just being paranoid. But given the military's obsession with technological superiority, I doubt it...
Well, at least when Penn State implodes in on itself and dissapears, we'll have an idea about what happened.
-S
--- What parts of "shall make no law", "shall not be infringed", and "shall not be violated" don't you understand?
The original CAN was built by NASA in the fifties as the prototype crew module for all of the Apollo missions.
During the late 90s, with the cold war over and budgets dropping, NASA had to make space travel more appealing. As a result, they created the iCAN. Similar to the shuttle, the iCAN's engines, the crew module and all the rest are enclosed in a single module. While it makes upgrading the iCAN harder, it does allow the iCANs to be produced at a lower unit cost. Perhaps the most important advance for the iCAN was the addition of clip on heat shielding that came in a variety of attractive, transulcent shades.
While the iCAN saved NASA at the time, Russia has been coming up with more and more powerful rockets that, while harder to use, have outpaced the once popular iCAN. As a result, NASA have re-released the iCAN in its new iCAN II form. New features include patterned as well as coloured head shielding and the ability for astronauts to listen to and rip MP3s.
Note: You will probably see the iCAN II referred to as the ICAN II. Don't be confused by the capitalisation change, it's simply NASA trying to lose the dated late 90's i feel.
In Peter Hamilton's Night's Dawn trilogy, they make antimatter in small space stations located very close to the sun. Lots of energy there :)
Ok maybe "easy" is overstating it, but anyway..
A much more interesting part of those books is that antimatter is outlawed, due to its potential for mass destruction. I'm no expert on this, but isn't that essentially correct? If larger quantities than a few nanograms are produced, aren't we dealing with something extremely dangerous here?
-- If no truths are spoken then no lies can hide --
It blows my mind that we're actually discussing putting a man (or woman) on Mars using an anti-matter propelled craft that will be assembled and launched from an orbiting space station. The fact that we're capable of such a thing absolutely amazes me. It's even more amazing when you realize that space exploration is less than fifty years old.
To put things in perspective, my father remembers Sputnik. My grandfather got around town in a horse and buggy. I wonder what my kids will get to see...
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-- Imperial units must die --