Fusion Rocket Could Take Us To Mars 171
New submitter imikem writes "University of Washington researchers and scientists at a Redmond-based space-propulsion company are building components of a fusion-powered rocket aimed to clear many of the hurdles that block deep space travel, including long times in transit, exorbitant costs and health risks. 'Using existing rocket fuels, it's nearly impossible for humans to explore much beyond Earth,' said lead researcher John Slough, a UW research associate professor of aeronautics and astronautics. 'We are hoping to give us a much more powerful source of energy in space that could eventually lead to making interplanetary travel commonplace.' 'The research team has developed a type of plasma that is encased in its own magnetic field. Nuclear fusion occurs when this plasma is compressed to high pressure with a magnetic field. The team has successfully tested this technique in the lab. Only a small amount of fusion is needed to power a rocket – a small grain of sand of this material has the same energy content as 1 gallon of rocket fuel.'"
Required electricity (Score:3)
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Their stated cycle time is 1 minute. Article says they fire for a "fraction of a second" to compress the metal rings, so the peak power generation needed would be 2-3 orders of magnitude lower than the instantaenous power usage. Small scale fission reactor like the sort on a nuclear submarine would do the trick. Or a radioisotope thermal generator: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator
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You plan to send a submarine to Mars?
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Why not? They're not that different from space ships in many ways.
Both must keep high pressure and low pressure areas seperate and protected from one another. Both must supply the crew with life support functions and the ability to communicate. Sure keeping the ocean out vs keeping the atmosphere in is different, but thats a structual question, functionally it's pretty similar.
By far the largest difference is a sub doesn't have a weight limit anywhere near as strict as a space ship, but that's more of a t
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It worked for the Yamamoto!
ON STAR...BLAZERS
http://en.wikipedia.org/wiki/Star_Blazers
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You put a big paddle wheel off the back and run generators with it.
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I desperately hope that they use this solution-- it sounds both reasonable and exceedingly amusing to watch.
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Also, once they get a few miles out, they can open up the slot machines.
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You could probably run it off solar power, but I believe NASA has been looking to get approval to launch nuclear reactors into space again. NERVA-type engines still have inferior Isp compared to most of the fusion concepts out there - and whatever else it may be, using a fusion-based combustion chamber is going to be easier to make safe then a nuclear lightbulb type design. No need to shotgun blast a bunch of uranium into space/orbit/the atmosphere.
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You could run it off anything if you limit the reaction rate accordingly. The problem is that the generated energy has to be stored in a roomful of capacitors, which won't fit on a rocket.
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Depends how heavy that room is. And I suppose, how heavy the fuel is - you could justify launching a large, one-off ship that you then only have to send up fuel for. A 90 or 30 day trip to Mars would mean you'd be able to run regular missions shuttling between the two.
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Bingo. For a space mission they would optimize on capacitor energy density. For lab work they would use the cheapest capacitor available that does the job without regard to space/weight considerations.
They article specifies a million Amps for a short duration (but fails to specify the duration or voltage needed). Here's a 2000A, 5 KG ultracapacitor. 1 million amps at 16V is achieveable in 2500 KG with a 1 second long burst. http://www.maxwell.com/products/ultracapacitors/docs/datasheet_16v_series_10093
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They have a infographics [msnwllc.com] that gives a lot of nice details.
Mars Mission
Power Source: 180 kW solar array
Spacecraft Mass: 16 MT
Payload Mass: 61 MT
Propellent Mass: 57 MT
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The unit "metric ton" is written just 't' and not 'MT'.
I don't see how. (Score:2)
Wait, you are talking about Gillett, aren't you?
I thought I'd never see good things from Redmond. (Score:2)
But apparently there can be good things from Redmond, like nuclear fusion-powered spaceships :-).
linux fipth (Score:2)
a small grain of sand... (Score:2)
As Silicon Dioxide (silica, a component of sand) is not noted for its fusing properties, I was guessing that the fusion would be from more typical materials: hydrogen, or perhaps helium.
And while liquid hydrogen technology is well developed, liquid helium is a bit more difficult, and metallic hydrogen even more so. A "grain" of (metallic) hydrogen seems a bit beyond expectation. A grain-sized amount of hydrogen, I'd believe. But a tank of granulated metallic hydrogen?
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"Honey can you pass the Lithium deuteride?"
"You know you shouldn't eat that stuff so much hon, it's bad for your heart. Remember what the doctor said..."
"Yeah yeah, I know it gives me bad hydrogen gas, but it tastes so good!"
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I was, rather, pointing out that "small as a grain of sand" has little meaning when referring to gasses, where the amount of material depends on the pressure involved; it has rather more meaning when describing liquids and solids, which are much less compressable.
This type of fusion was worked on 35 years ago (Score:5, Interesting)
The Trisops [wikipedia.org] machine at the University of Miami.
Disclosure: I am one of the authors of the cited paper in the article and the author of the above Wikipedia article
What powers the fusion drive? (Score:2)
What's not clear in the article is how they plan to power the drive... I seriously doubt solar will be sufficient (mostly due to the low insolation at Mars), which means nuclear. Which means *heavy*.
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The real question is could you do an Earth launch with this? Because the "heavy" equation changes a lot if we could actually use something like this to get into space in the first place.
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OK, think about those ridiculously high watt lasers. Recall how those are pulsed?
So is this, with a period of a minute or so. (large amount of energy in a tiny period of time, with a long 'idle' phase between). A traditional fission reactor or RTG could be used to charge the capacitor system for this, as well as the other ship systems.
The downplay of current tech (Score:3)
âoeUsing existing rocket fuels, itâ(TM)s nearly impossible for humans to explore much beyond Earth,â said lead researcher John Slough, a UW research associate professor of aeronautics and astronautics. âoeWe are hoping to give us a much more powerful source of energy in space that could eventually lead to making interplanetary travel commonplace.â
[...]
NASA estimates a round-trip human expedition to Mars would take more than four years using current technology. The sheer amount of chemical rocket fuel needed in space would be extremely expensive â" the launch costs alone would be more than $12 billion.
That's not true at all. Chemical rockets work as well. And with the Falcon Heavy in the near future, there's no reason to pay $12 billion in launch costs for a Mars mission, even if you use chemical rockets.
Note also the phrase "take more than four years". That makes it sound like it takes two years to come and go from Mars. It really only takes six months with chemical rockets (plus some time for attaining Mars orbit, there's probably not going to be a direct landing on Mars due to the high risks of aerocapture) The reason it would take that long is because humans would be staying on the surface of Mars for at least two years. I doubt even instantaneous travel would cut off more than a year and a half.
The more reasonable 90 day passage to Mars would takes six months off the travel time plus reduce the time needed to get into Mars orbit. It would also enable trips at any time rather than just during the most optimal trajectories. This really is the key constraint of chemical rockets.
At this point, it is worth noting that there are other viable near future propulsion technologies as well. A key one is electric propulsion which can be solar or nuclear powered. It has a good mass fraction and travel times. Solar sails could be used to ferry radiation-immune loads over very slowly.
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It's all about how much mass you can move though. More mass means more people, resources, landers arriving at Mars per trip, or more fuel which you can then blow on shorter trip times.
We obviously can technically do it - but being cost-efficient and speedy are not solved challenges.
Fart power... (Score:2)
"could" take us to Mars as well.
Unfortunately, harnessing fart power has proven much more elusive than fusion power.
Terrible ride quality (Score:2)
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I've wondered about this before, maybe someone more enlightened on the physics can clear it up.
If you add shock absorbers (I'm hypothetically imagining a giant spring mechanism to keep it simple). As the fusion reaction provides forward force, the spring will compress absorbing the impact and lessening the discomfort for the crew module. Then it un-compresses releasing the energy.
But half that energy is going back in the direction of the fusion reaction (assuming it's a short-lived pop). Aren't you losing h
Either bullshit, or too important for NASA (Score:2)
These guys are claiming to have controlled thermonuclear fusion above breakeven. That's huge. No one has ever done that. If it works, we have a new major power source. They write: "Now, the key will be combining each isolated test into a final experiment that produces fusion using this technology". That's a Nobel prize if they succeed.
This is too important to let NASA fuck up.
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Actually, they're not. What they're creating is more akin to uncontrolled thermonuclear fusion.
Pretty much mini-bombs without the fission primary. Still pretty much bombs though. Usable for a rocket, not usable for electrical generation.
Also, even if it doesn't achieve breakeven, it may still be able to achieve very good Isp - e.g. lots of thrust per gram of propellant mass.
We could call it Project Pluto! (Score:2)
Seems like an appropriate name for a very fast nuclear powered vehicle where we don't have to worry about disposing of the exhaust left in its wake right?
Are they using 'fusion' as a noun? (Score:2)
Only a small amount of fusion is needed to power a rocket – a small grain of sand of this material has the same energy content as 1 gallon of rocket fuel.
Fusion is a process, not a material.
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We already had this ability in the 1960's (Score:5, Interesting)
It was the NERVA rocket. it wasn't fusion, but it was a nuclear-powered rocket, and it would have easily made Mars our bitch.
It was canceled to, fucking get this, no seriously, wait for it. It was canceled TO SAVE THE BUDGET because the politicos at the time were afraid a successful Mars rocket would "drag" the US into this huge "space program" where we'd explore the solar system and stuff. And that would cost a lot of money.
Instead, we killed the NERVA rocket and saved our budget for Vietnam, which was a roaring success that paid incredible dividends . . . . oh, fuck.
Anyway, this is nice to hear, but I'm not going to hold my fucking breath. Our national priorities are far too ass-backwards for something forward-looking like a Mars mission. I suspect the first people to land on Mars will likely be an international team, and America will be riding along in the back begging for a look out the front window from time to time.
Re:We already had this ability in the 1960's (Score:4, Insightful)
I went online looking to debunk this, but frankly its essentially true.
Some further sad facts: In all of history there have been 12 human beings to set foot on another planet [wikipedia.org]. The youngest of them is now 77. Most of them are still alive (probably thanks to the extreme physical fitness required of astronauts), but the day is not too far off when they start dying, and we will be left with no living people who have visited another planet. Most US citizens were not born yet when this was going on.
Space exploration is not something we are actively doing, but part of our history, joining its place alongside the Civil War and Lewis and Clark as "things to bore kids with in US History". If we tried doing it again, we've lost so much capability that it would probably take longer to accomplish, and cost more. We might as well post the poem Ozymandias next to our old Apollo artifacts in the museums:
I met a traveller from an antique land Who said: Two vast and trunkless legs of stone Stand in the desart. Near them, on the sand, Half sunk, a shattered visage lies, whose frown, And wrinkled lip, and sneer of cold command, Tell that its sculptor well those passions read Which yet survive, stamped on these lifeless things, The hand that mocked them and the heart that fed: And on the pedestal these words appear: "My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!" Nothing beside remains. Round the decay Of that colossal wreck, boundless and bare The lone and level sands stretch far away
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That's no planet...
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It was cancelled because costs were spiraling, performance decreasing, and a practical engine getting further away every day.
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Also, in part, due to the increasing resistance of the nukaler nutters who protested against just about anything having to do with nuke stuff. Except of course for X-ray machines when they needed them. It was around this time that "Nuclear Magnetic Resonance" was re-named "Magnetic Resonance Imaging" so that hospitals could continue to have a useful diagnostic apparatus, and there began sweeping cutbacks in commercial power nukes due to greatly-increased costs for environmental and safety studies, and fin
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Plus, god forbid we leak radiation into space. Keep space black!!
Sounds like they have a BS degree (Score:2)
Let me guess - in 20 years? (Score:2)
We are talking about fusion here so of course it perpetually will be available in 20 years.
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It's a real toss-up which will come first:
1. Fusion power
2. Artificial intelligence
3. The Year of the Linux Desktop.
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you're not factoring-in relativity. Fusion will be available in 20 years, unless you approach the speed of light, using a fusion drive, in which case, time slows down, and fusion will be available at some point further in the future.
Interesting thing about a fusion rocket... (Score:3)
Acceleration? Braking? (Score:2)
And how not to kill all involved? No mention of that in the article from my quick read.
ho hum (Score:2)
Re:nuclear fusion? (Score:5, Insightful)
And if the fuels take more energy to prepare than they yield when reacted(tritium is one such fuel), then they're not very useful for energy production, but very useful for energy storage.
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Re:nuclear fusion? (Score:5, Insightful)
This. It's all about specific impulse in space travel - which is a very separate concept to net energy production. There's no problem spending a lot of energy making rocket fuels on Earth, when the big cost multiplier is launch mass.
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The purpose of this engine is to generate a very high speed ionized spray of lithium in a specific direction. How would that be converted into electrical energy? Generating kinetic energy (especially in space where waste byproducts just kinda go away) is extremely easy compared to generating electrical power.
Re:nuclear fusion? (Score:5, Informative)
High-speed ions would actually be easier and more efficient to use for generating electricity than conventional thermal energy. You set up an opposing electric field with a voltage that corresponds to the ions' energy in MeV, and capture them once they've slowed down. This creates a direct electric current at that high voltage, without the need for Carnot cycles, steam equipment, heat exchangers, etc.
One of the attractions of aneutronic fusion is that most of the energy is released in the form of charged ions that can be harnessed in this way.
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High-speed ions would actually be easier and more efficient to use for generating electricity than conventional thermal energy. You set up an opposing electric field with a voltage that corresponds to the ions' energy in MeV, and capture them once they've slowed down. This creates a direct electric current at that high voltage, without the need for Carnot cycles, steam equipment, heat exchangers, etc.
One of the attractions of aneutronic fusion is that most of the energy is released in the form of charged ions that can be harnessed in this way.
Still depends on achieving efficient fusion. This doesn't have to be efficient - it's just a way of boosting the specific impulse you get from rocket fuel, using some other energy source (probably a fission reactor in a spacecraft) while also having a large enough impulse that it can get you around quickly. Ion engines are efficient - but you get up to speed slowly.
Re:nuclear fusion? (Score:5, Insightful)
We've had nuclear fusion working for over sixty years now. [wikipedia.org] The trick has been containing it in a reactor for power generation. A fusion rocket might be easier to pull off--that's essentially just a semi-contained and directed H-bomb.
Re:nuclear fusion? (Score:5, Interesting)
Worth noting, is that this concept is essentially the Orion engine without the heavy radioactives - the idea is essentially what we do in the hydrogen bomb.
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Creating a fusion reaction and containing the very-hot-indeed reaction inside a box, so you can draw off the heat to run a turbine, as multiple generations of despondent physicists will tell you, that's something else.
.
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erm... if they've got nuclear fusion working, couldn't they just forget about Mars and work on making it available as a power source to replace conventional powerplants to solve the world's energy needs?
I'm told we're fifty years away from that.
Re:Yuh huh (Score:5, Informative)
I don't think practical fusion technologies are as far away as you're acting like they are. If you've been following fusion news, there are several projects that are getting pretty close to scientific net+(my favorite is the Focus Fusion experiment).
Re:Yuh huh (Score:5, Insightful)
Lets not forget that the objective of the rocket is to move you, not generate usable energy. You don't necessarily have to have a net+ for this to be useful.
Think of it as a super high density fuel that just takes a lot of energy on the ground to process.
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The Ford Focus Fusion is designed to move you.
Whoosh!
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Might as well use fission based energy then.
Re:Yuh huh (Score:4, Informative)
Think of it as a super high density fuel that just takes a lot of energy on the ground to process.
It doesn't even have to be exothermic (net energy gain) on the spacecraft, without considering any ground processing. In other words, it's perfectly fine if, for each kWh of electric energy you supply into the engine, you only get e.g. 0.4 kWh of kinetic energy of exhaust gases (plasma) coming out of the engine's nozzle. What's much more important is that the engine puts that 0.4 kWh into a very tiny amount of plasma, so that the plasma's velocity is very high (for a given amount of kinetic energy, the velocity is proportional to the reciprocal of the square root of the mass). That velocity is the "specific impulse" of the engine, and it determines how much fuel mass you need to achieve a given delta-v of the vehicle.
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Oh yeah, and what do you use for powering the magnetic field to contain the plasma?
The design proposed here uses inertial confinement and pulsed (rather than continuous) operation.
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You'd get more energy out of a kilogram of this fuel than you would with a kilogram of, say, hydrazine and oxygen.
That means you can either:
1. Keep the total energy the same but launch with less mass (cheaper launch, better acceleration in orbit as you have less mass to move around)
2. Keep the same launch mass but bring along more energy (same or more expensive launch (increased volume?), more fuel to orbit so more endurance)
You'd need to do a much deeper analysis and have actual numbers to figure out what
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I hear we're about 40 years away from viable fusion technology.
Clearly (Score:2)
Clearly a Ford man.
Re:Yuh huh (Score:4, Informative)
All of the fusion projects that I'm aware of are not only heavy, they're also delicate, and require lots of skilled technical attention.
I'd say we're *at least* two decades from a fusion engine that's practical in a spaceship. Three or four wouldn't surprise me. And I also wouldn't be totally surprised if it is one of those things that can just never be made practical (though I'd be very disappoiinted).
For that matter, while several of the fusion projects appear to be near the technical "break even" point, I can't think of one of them that's even approaching the economic break even point. Even fission is a bit dubious about that, when you count in all if the expenses. (E.g., government providing "insurance" against massive problems [in the form of saying "you won't be held liable"], and what to do with spent reactors and fuel.) That said, one mussn't forget that coal also gets massive subsidies, if only in the form of permission to engage in environmental degradation and pollution.
Note that all mining is environmentally destructive, and it is rare for the costs of that destructuion to be included in the cost of the products of the mining. So it's quite difficult to come to a rational balance of which technology is more expensive. Fusion has the problem that it's less dependant on mining, so it doesn't get the benefit of free pollution of the environment. This makes it more difficult for it to compete with established technologies. But it's not even nearly ready yet anyway. None of the existing projects have passed the technological break even point, which is a lot easier than the economic break even point.
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All of the fusion projects that I'm aware of are not only heavy, they're also delicate, and require lots of skilled technical attention.
All of the ones I've worked on were quite robust and solid for the basic structure, as they basic plasma is created and managed with not much more than just a large vacuum vessel, magnets and some power supplies or capacitor banks. This is to the point no one would bother with ladders half the time, because the large bolts and plates on the vacuum vessel turned it into essentially a giant jungle gym that let you get to wherever you needed to on the machine. What tended to be really fragile on the other ha
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FWIW, perhaps a version of the original "Project Orion" which propelled the ship by exploding nuclear explosives behind it could be built, but that would be a lot easier to design with fusion explosives than with fusion explosives. Gramted that fusion explosives would probably be less polluting, and thus could be used closer to an inhabited planet (or space station?).
Even if ground based fusion reactors turn out to be cheap and simple in the near term, I have severe doubts about thier suitablitity for powe
Re:Yuh huh (Score:5, Insightful)
There are a few small details to deal with regarding both potential technologies.
Except we know how to create uncontrolled fusion, and a fusion rocket is closer to a hydrogen bomb than a fusion reactor. You're just trying to make fusion happen and throw the resulting plasma out the back, not keep the plasma in one place and generate power from it.
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What about radiation shielding?
If you're using a nuclear rocket, you have plenty enough payload to add any required shielding. Besides, you want as many fusion products as possible to go out the back of the rocket, not the front.
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Actually that is fairly well controlled. Its excursions (flares, CMEs) are tiny compared to its steady-state output.
Problem is we don't know how to make a controlled reactor that isn't significantly bigger than the entire planet and uses gravity for confinment yet.
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Actually that is fairly well controlled.
A stable system is not inherently a controlled system. There's a big different in control of the Sun between "I put my sunglasses on" (which just controls the little bit of solar power that falls on you) and "I use the Hand of Omega to increase solar output by 0.1%" (which is controlling the entire Sun).
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The obvious solution is to go so fast the radiation never catches up. I hear that electromagnetic energy has some sort of hard speed limit, perhaps they could just go a little faster than that?
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You can use astronaut poo for shielding.
And on a nuclear ship I'm sure there'd be plenty.
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Re:Yuh huh (Score:4, Interesting)
Ok, apologies if this is a joke that's wooshing over my head, but nuclear fusion produces very little radiation. A small fraction of the reaction energy is released in neutrons and some x-rays. Most of the energy is released as heat. I'm not a nuclear physicist, but hydrogen fusion is causing hydrogen atoms to smack into each other with enough energy that they fuse producing helium and a very large amount of energy. You're thinking perhaps of fission, which is when radioactive isotopes give off energy as they change into different radioactive isotopes. It's a completely different thing.
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Thanks for providing some clarity. What if we're not depending on the actual fusion reactor for motive force? Heinlein's torchships, as I recall, use the fusion energy to heat reaction mass (usually water) to something approaching plasma. The fusion reactor in this concept exists to provide heat, not motive force, which is provided instead by the reaction mass. This allows the reactor to have something closer to the configuration of a power plant rather than a rocket engine.
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You need plenty of neutron shielding for fusion. But the advantage of having a spacecraft over a power plant is that you can use distance, by putting it on the end of a long structure, and that you won't care what the neutrons will do to the shielding and equipment on timescales longer than the mission.
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Google Solve for X: Skunkworks Fusion (Score:5, Interesting)
Here is a video [youtube.com] of a scientist named Charles Chase who works for Lockheed Martin Skunkworks. The presentation is made at Google's "Solve for X". The video is 14 minutes long so I'll give an executive summary. Chase claims that his team has made a breakthrough in developing a small fusion reactor that will lead to a 100MW reactor the size of a truck trailer and of the complexity of a jet engine. The prototype they have built is a cylinder 1m in diameter by 2m long. In their experiment they put deuterium gas into a magnetically confined space and heat it up with radiofrequency energy. He infers that the confined plasma is reaching the conditions necessary for fusion to occur. The reactor is "high beta", with "beta" referring to the ratio of the magnetic field pressure to the pressure of the plasma pushing out. He says that the magnetic field strength in the reactor increases as you go out from the centre of the plasma, thus creating an extremely effective plasma confinement. He contrasts this with a Tokamak reactor, where the magnetic field is generated by the moving plasma itself, and thus decreases in strength out from the centre of the plasma. He says that this decreasing field strength is the main problem with Tokamak reactors and that it causes the confinement to be unstable. If the confinement becomes unstable, the magnetic field decreases, thus creating a negative feedback loop. This contrasts with his reactor design, that tends to create a far more stable plasma confinement.
I have a background in physics and what this man says in his video makes sense to me. It is of course short on details, but what would you expect for a short presentation. And you wouldn't expect a Skunkworks scientist to publish information in the same way as a university scientist. I have often puzzled in the past as to why we can't use an elegant method of magnetic confinement to achieve the conditions for fusion on a small scale. Tokamak seems an inelegant dead end. I think that if you can adequately confine the plasma, you have solved the energy balance problem that has plagued fusion reactors in the past.
Watch the video and see what you think.
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Actually, thinking about it for a minute, a hydrogen bomb is a bad comparison. What this idea is closer to is a Farnsworth Fusor [wikipedia.org]. For those of you who haven't heard of those, click the link. Short version: we can very easily make a device that causes fusion to happen, in a controlled non-explody way, provided we aren't too concerned about breaking even on energy. And fusors date from 1964, just to give you an idea of how long the tech has existed. There are even homemade ones in existence.
Achieving fus
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boom.
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In space no one can hear you boom.
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The devices we call 'hydrogen bombs' are not pure fusion explosives. They are more correctly known as 'hydrogen-boosted fission' devices. The hydrogen fusion is used to provide more neutrons to sustain the fission reaction, but in most cases the majority of the energy still comes from fission.
(At least, that's my understanding.)
Correct. Fission --> Fusion --> Lots More Fission --> Very Big Kaboom
Although the energy density of hydrogen fusion is greater than that of Uranium/Plutonium fission, the energy of individual fusion reactions are generally much less energetic than individual fission ones. H-bombs are crazy because fusion produces high-energy neutrons (and lots of 'em), which are sufficient to cause fission in normally non-fissile U238. So, they jacket the fusion part with cheap U238, which is useful as a tamper
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The Deep Space pack (and whatever that electrical pack is that goes with it) already have a nuclear reactor and ion engines.
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Highly recommended. The mods really help too. [youtube.com]