Homer Hickam Speaks Out For Fission Rockets 424
jonerik writes: "Former NASA engineer Homer Hickam (perhaps best known for his 1998 memoir "Rocket Boys," which was turned into the 1999 motion picture "October Sky") has this article in Technology Review in which he advocates that the U.S. revive its nuclear rocket program of the '50s and '60s, arguing that nuclear-powered rockets are the only realistic way of opening up the rest of the solar system - particularly Mars - to human exploration."
Good Idea, just won't happen anytime soon (Score:5, Interesting)
Unfortunately, people are so freaked out about anything with the word "nuclear" or "reaction" attached to it the only way they would ever put a dime in it is if it was called "The Wonder Drive" or "Warp Drive". The really sad part about that is nuclear powered rockets really wouldn't be that dangerous. The most dangerous part about them would be getting the fuel off planet, which is not as dangerous as it sounds.
Dirty Words (Score:3, Interesting)
Well, bring'em up dammit! (Score:2, Interesting)
Fission? He's GOT to be kidding! (Score:4, Interesting)
The reactor shielding required for a manned spacecraft is pretty large. There isn't any particular mass savings through using a nuclear power source... most of the mass for a deep space mission is reaction mass, and the specific impulse developed by a nuclear rocket is only about 2 times that of a chemical rocket... reaction mass savings ends up being on the order of 75%, but this is offset by the increased payload/structural mass.
Now, if someone could finally get fusion rockets to work, I think we could finally go someplace. But I am skeptical about using fission for manned missions.
Re:Dirty Words (Score:5, Interesting)
This didn't stop nuclear submarines.
If I remember correctly, the first group of nuclear submarines to actually enter the fleet put to sea in the early 60s, four decades ago, when our friend Mr. Atom was going to make the whole world a better place. Frankly, I still think that Mr. Atom and the power he provides are great things.
[...]only PR would be necessary to gain back the confidence of the people[...]
Except that for every "Nuclear-powered space vehicles are safe and effective" commercial NASA would produce, the Sierra Club, Greenpeace, the World Wildlife Federation, and the Judean People's Front would be producing five commercials that say, "These rockets are going to contaminate the whole world!" Unfortunately, some times I think that people want to be scared by fanatical claims of imminent {ecological|financial|terrorist-caused} disaster. By and large, humans seem to be more willing to listen to the Chicken Littles than to voices of reason.
Don't get me wrong; I would love to see us go back to the old plans for nuclear reactor-powered spacecraft. I just think that there will be gigantic and wide-spread resistance to the idea.
Anagrams (slightly OT) (Score:4, Interesting)
Incidently, "October Sky" is an anagram for "Rocket Boys".
I kinda agree, and kinda don't. (Score:3, Interesting)
Putting the supposed issues of launching nuclear rockets to one side, all of the issues we know of will be solved by using the existing resources of space, rather than trying to launch every little thing from the earth. Right now we are doing the space equivalent of driving from East to West coast America, whilst carrying all our gas with us for the whole trip. Ever heard of gas stations?
NEOs and the moon have plenty of fuel for us to use, and if you refuel in space, the maximum distances we can go are enormous.
The other issues also become non issues. Radiation? A few tonnes of shielding isn't a problem if you have enough fuel. Gravity? Spin your spacecraft on a tether, and simulated gravity is plenty good enough [the only reason that this isn't proposed right now is mass constraints, also they want zero-g in the ISS for example]. Again, use non terrestial sources for materials, and most issues are gone.
Nuclear is an entirely safe and reasonable approach. But it's not a necessary one. And politically there are huge issues; for what are mostly dumb reasons. But we have to deal with dumb reasons, held by misguided people in life.
I don't wanna go to Mars! (Score:2, Interesting)
I think the idea of going to Mars is wrong headed. I don't think an exploration of Mars will lead to great new developments for humanity. I don't think the idea of colonizing Mars is practical, and if it was, it certainly won't help humans on the Earth. I realize Apollo R&D helped lead the push towards creation of ICs, but I think any R&D budget would be better spent elsewhere...
Specifically, I hear about the idea of terraforming, which even with the most advanced technologies would take a ridiculous amount of time, even if it's possible to replicate the complex necessities of Earth conditions on a planet wide scale. Or the idea of releaving overpopulation through colonization, which is so silly it can be freely ignored.
Mr. Hickam seems to assume everybody shares the dream of having people live in a big plastic bubble far away...and the enormous cost, as well as the very real threat of putting nuclear reactors in ships that tend to blow up in the atmosphere, are insignificant. It's an odd viewpoint that he doesn't bother to justify. Will it make people's lives better? Should it just be done because it can? Manifest Destiny in space is so sci-fi.
Part of Kennedy's Dream (Score:2, Interesting)
The nuclear rocket is probably the best choice in large distance exploration that we have right now. Solar power becomes useless pretty much past the Earth and no other power source can pack the mass to power ratio that nuclear power can. If we want to go big, we have no choice but to use a nuclear rocket or take a long, long time. The weight issue in rockets is a big deal, so alternate propellants are out since they will take up to much weight for the same power.
For close distance exploration (i.e. the moon) I don't really see a nuclear rocket taking any part. While obviously it could achieve its goal, its a little overkill for the purpose (and considering the fact that if it were a direct exhuast type it would have a plume of activated radioactive materials, assuming it uses water as a propellant, it probably wouldn't be that popular).
I hope this happens, and I've been hoping for a long time. Its our only real chance to get off the earth permanently at the present time.
A clean energy source? (Score:4, Interesting)
As a uranium producing country, Australia has seen a number of 'mishaps' in relation to uranium mines. Admittedly, most of them have been relatively minor, but they demonstrate that no human activity is 100% failsafe, and the potential for massive disaster is huge when compared to other forms of energy production, fossil fuels included. Of course, this does not diminish the need to find alternatives to fossil fuel sources, they are dirty and finite (ie. unsustainable). Nuclear energy is not an appropriate response, though.
Also, beyond the production and disposal of nuclear material, what happens when something goes wrong with the rocket itself? Could you imagine a nuclear version of the Challenger disaster?
I'm as much of a technocratic utopian as any other /. reader, but even I realise that the use of technology, and its impact on society, is more important than any geek factor.
Re:Maybe... (Score:3, Interesting)
Check your terms (Score:2, Interesting)
So what's the difference between drifting and moving at a constant velocity? Spaceflight analysis really shouldn't be done by people who fail to distinguish between velocity and acceleration.
Fission Rockets: why it didn't work before nor now (Score:1, Interesting)
Been there, done that (Score:2, Interesting)
NASA is already sending out hydrogen ion stream rockets, using the magnetic ionizer you're describing. It is a complete success, and many times more efficient than traditional rockets.
As for a scramjet launcher... that is silly. You don't save a lot of money. The major expense in a launch is not the fuel, it's the craft. A reusable craft does not always result in a cheaper launch, because that requires a fancier craft. For example, Shuttle launches are more expensive than disposible rocket launches.
Saturn in a year claim is dubious. Ion propulsion gives slow, steady, efficient thrust, perfect for long cheap trips, but terrible at fast acceleration. Though a combo with chemical early stages, and ion later stages, might work well for a fast distance trip. The actual thrust in the Deep Space craft using ion propultion is about the weight of a sheet of paper... but that really adds up over a few months!
See also: ion faq [nasa.gov] at NASA
Re:Interstellar trips (Score:5, Interesting)
To reach
1. Fission fragment sail or reactor.
Uses thin films of highly fissionable Americium as fuel.
The fission fragments from the nuclear reaction escape at very high velocities, propelling the ship very fast. You can't use plutonium in this setup because it cannot fission when formed into thin films. You need thin films for fission fragment propulsion so the fragments can escape.
This setup can reach a specific impulse of 1,000,000,000. 2,000 times more efficient than chemical rockets. However, this gets too expensive when you scale it up beyond a small probe. Americium is fscking expensive, millions of dollars per ounce.
2. Fusion
Fusion's great. Once power fusion reactors come on line, the fuel will be cheap.
There are several different fusion concepts. The closest to being realized is the ant-matter catalyzed fusion type. It blows up little fusion pellets at it's rear. This uses fusionable pellets of Deuterium and Tritium that are surrounded by uranium. A very small quatity of antimatter is fired at it. This starts the fission which then starts the fusion and causes the whole thing to explode.
This could be built in 20 years. Everything is here except the antimatter. You only need a few micrograms of antimatter. We could be producing that pretty soon. It could theoretically reach 200,000 seconds.
There are other types of fusion rockets that could reach 1 million seconds. These use magnets to confine the fusion plasma. Some is leaked out the back for propulsion. However, it's hard to build a self-sustaining fusion reactor. Plus the magnet weight (1,000 tons) would have to be reduced dramatically to be practical at all. That's about 50 to 70 years away.
3. Antimatter-matter
Efficiencies of 10 million seconds
A helluva long ways away. We don't know how to begin producing enough anti-matter.
4. Beamed energy
In the distant future, the best thing for fast intersteller flight.
Just a couple decades down the road, we could build Robert Forward's starwisp probe. It would be 6 kilometers wide and be made of a fine mesh. It would weigh 42 grams, if you can believe that. It would be easily propelled to
For manned flights, you need gigantic solar arrays around the sun. Here, I'll talk about a project for a Class 2 civilization. That means one able to harness the power of an entire sun. Say, 100 years down the road, we decide to have thin-film photovoltaics constructed around the sun. That would capture around 1 octillion watts. Anyway, autonomous self-constructing robots and nanobots would get the materails off a large asteroid and begin constructing this. Being very thin solar cells, you'd only need maybe 1,000 square miles of materials. After a few years, we would have a working Dyson sphere.
Some of the power, maybe a quintilion watts could be funneled into lasers and broadcasted to a giant gold-foil sail the size of texas or the US or even much larger. The laser would be able to propel it to
Anyway,
Re:Interstellar trips (Score:2, Interesting)
The idea is that since interstellar space is not empty, the craft will not have to carry all its own fuel, but can rather use huge magnetic coils (around 10^6 Tesla in strength) to gather its own fuel. It would have to carry enough on-board fuel to reach a certain threshold speed, at which point it begins moving quickly enough to pass through enough space in a given time to gather all the fuel it needs.
It would work by 'funneling' hydrogen, which is the most available (though by no means is it plentiful) gas in interstellar space, into a fusion reactor. Needless to say, this is a long way off, if it will happen at all, but it's a really nifty idea.
Some quick searching reveals a quick once-over here [woodmansee.com] and a more mathematical treatment here [dangermouse.net].
nuclear rockets were never meant for planetside (Score:1, Interesting)
1)power the ship
2)power the shields (use coils to deflect alpha, beta, (etc)particles)
3)provide thrust along the lines of the recently proven ion drive, or superheat H2 and expell it like a chemical rocket, and keep the o2 for the astronauts.
4)allow 100x more payload to be shipped around.
5)waste? ship it to the biggest nuclear reactor in the solar system => the sun.
I have yet to see a suggestion by nasa to use nuclear "rockets" to lift off from earth. Never have, never will.
Herpes (Score:3, Interesting)
Re:Unfortunately (Score:2, Interesting)
Roughly 95% of petroleum use in the US is for transportation, and roughly 98% of the transportation system is powered by petroleum. Switching to electric (really, fuel cells, since lead/acid batteries do not have the power to weight ratio to build the kind of vehicles we want/need to have) does eliminate (or nearly so) the need for petroleum, foreign or domestic. But it does create a need for massive increases in electricity production, as you point out. So we would need to add a lot of solar capacity.
Actually, I believe it is ethanol that is produced, and then denatured with a small amount of methanol.
While I have not seen any figures on the amount of land it would take to produce that much extra grain, it would clearly be substantial, and our grain surpluses together with the land in CRP (Crop Rotation Program) would likely not be enough to equal the 20 million barrels of petroleum the US consumes daily. I have also read that producing ethanol takes more energy than is present in the fuel produced, probably for distallation. That would make the ethanol a secondary fuel, not a primary one.
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Tidal/Solar/Wave power? Sure, they're neat science fair projects for the kiddies, but they're simply not capable of contributing substantially to our energy needs for the forseeble future.
You may be right with regards to tidal power.Wind power is already being added to the grid in many places (one plant in my state of Colorado, another is planned, lots of capacity being added in Texas). It is cost effective today. Adding large amounts of unbuffered wind power to the grid mix is not feasible because of fluctuations in the production. So, we need to buffer it! Crack water with the wind power, run the grid from fuel cells.
Solar works. Today. This post is being made with solar energy. There is exactly one problem: it is more expensive (by 10x or so) than we are used to paying for electricity.
Fission power works. But for how long? And at what cost?
If we were to switch the US to fission power completely (including powering the transportation system), and continue to use uranium fuel without reprocessing, we would be out of fuel before the plants were all built, let alone depreciated. Reprocessing the fuel would add another 40 or 50 years to the supply. Even if you consider breeder reactors, you get another 1000 years or so of energy. Then what?. Solar will be present for as long as Earth is a viable place to live.
Radioactive waste is produced by and for nuclear plants. It lasts for a long time. It cannot be disposed of. It must be stored until it decays. That takes, for the high level wastes, geologic time. I am sceptical that we can build storage facilities that are secure for 10 times the age of the pyramids. We simply do not have that sort of track record.
We just launched Cassini... (Score:2, Interesting)
Perhaps cooler heads DO prevail.
Here's some links.
http://www.bessereweltlinks.de/english/book44h.
Dirty and Expensive and Short Lived (Score:1, Interesting)
First off, everyone in the space industry that has their sights beyond our own orbital boundary really needs to get off the idea of building large ships and drives inside our gravity well. This work has to be done in a low or zero g envronment. That means we need to get our butts to the moon and build stations at la-grange that are not merely scientific outposts for waving the flag, but actually working space construction yards, factories, and living quarters for training and building.
Our greatest problem for orbital stations is intitial costs and a few minor technological elements we have not addressed yet, especially in medical science:
1) Costs are hugely high. This is because this is still a handbuilt, custom industry. It needs to be commercialized, just like PC's were in the 80's. The first PC's were hugely expensive because of their rarity and lack of overall demand... now they are as cheap as some more expensive PDAs.
You have got to put the technology we have developed and built to use on a large scale. There has to be a design revelation that dispenses with the expensive design qualities of very fine tolerances and puts in sturdiness and reliable redundancy in it's place. Christ, a single simple module on the ISS costs billions, but if you built it to work in our gravity well with off the shelf technologies and parts it would be 1/10 that.
Materials are present and exist, but are currently expensive to make due to the same lack of demand. These materials could be used to make the stations more 'bullet proof', while modern manufacturing could reduce costs overall. You just have to build the lines, ala AMD's effort to build their last FAB in germany...
In other words, reduce cost by building more.
To increase demand though you have to have some reason. They are zero-g crystal and chip manufacturing, bio-medical manufacturing, advanced research, entertainment (hotels... nothing like a zero-g night of bliss on your honemoon!), and mining (either going out to get easily retrieved exotics from asteroids or towing one back to orbit... both would pay handsomely over the initial investment in equipment, training, and technology).
2) You have got to get the physiological and psychological elements sorted out for low-g and zero-g environments and how they impact human physiology. There have been alot of studies, some announced counter drugs to bone loss and fluid loss, and research on how to keep healthy. There still needs to be some research on the psychology of space and how it effects people too. These have got to be a priority if humans are to exist in space until we devise some form of artificial gravity other than centrifical spinning of ship elements (which is a mechancial and energy nightmare, but one we must do at first until we find an alternative method of producing a gravitic field).
The other item to address is propulsion / energy. These two are very inter-related so you really can't say one without meaning the other in some way. Fision is just not viable. Shielding is very heavy, fuel is rather exotic and expensive, and the dangers of accidents and other technical glitches too hard to eliminate or discount.
Excited Ion is a method. Low fuel cost and weight, easily refueled from a broad range of gases available in space or around gas giants. Engines are not too technically expensive or difficult, but the power to weight ratio is relatively low. They are efficient and clean however, but certainly not enough to climb out of a gravity well like ours.
Fusion or Fusion Plasma is another. The creation of fusion power should be our 'short term goal' here on earth. The creation of these powersources, especially if their size can be minimalized brings us to the age of clean fuels and power, with the ratio of cost of fuel to output power (figuring in construction costs of the power source) to a point where it is 'cheap power. An excited plasma torch can then be coupled to this to create a relatively clean booster that can technically accelerate an object to very high speeds over a long run (upwards of
Anti-Gravity would be great. There is some research in the rather exotic field in physics centered on wave theories and graviton particles. This is probably a long way off, though quantum computers would certainly speed up the calculations end of this. I truely lean towards the existing theories that gravity is not only a nuclear force, but a wave/particle similar to light but in such a excited state we have yet to detect it or generate it knowingly. I expect that artifical gravity is possible, but at extreme power costs for generation and control.
Anti-matter would be the best. Well duh. We are making steps here, if only baby steps, in the past decade and especially in the past three years. We understand the principals and math, the physics of it all, and are pretty sure now that we can, at huge power expense, generate the particles we are interested in and contain them. I think that AM is tied in with fusion in alot of ways as it will take great amounts of cheap power to generate AM and store it for use as a reaction fuel... but boy what a fuel it would make.
In fact, if we were to discover a cheap way to generate, store, and use AM overnight, we couldn't use it right now for manned flights at it's full potential because our physiology just won't withstand the forces of acceleration it is capable of... it would be a crippled technology until we could somehow dampen inertia or control gravity.
But, you could theoretically build a ship that could get you to Saturn in back in less than a month in system, and give
Ultimately we need to look towards finding a shortcut around einstien and the theoretical limit barrier of 1c. This may come in the form of energy tranferance/transmission or dimensional control allowing us to move in a straight line through the dimmensional curve of space/time. Instead of 10-20 years to the nearest star, 10-20 minutes should be 'long term' goal of humanity.
We have got to get off this rock we call Earth. We are inquisitive by nature, divided amoung ourselves because we all seek our own perfect version of life and avoid our innate primal fear of the unknown in each other, and we are wasting away in on a single point of life that is one big target for mass extinction should some otherwordly or political fate befall us. With the driving force of exploration, commerce, and establishing new worlds humanity could work together and put behind some of the oddities that make us great and doom us at the same time.