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Fusion Thrusters For Space Travel
kgeiger writes "John J. Chapman, a physicist and electronics engineer at NASA's Langley Research Center, envisions a laser-pumped fusion drive. Chapman estimates the drive can produce thrust 40 times more efficiently than existing ion engines such as those on the Dawn mission now exploring the asteroid belt."
Alrighty so I haven't RTFA but this is the kind of stuff NASA should be doing more. Hire ambitious smart people with grand ideas, give them resources and turn 'em loose! Probably much of what they do will amount to nothing but you just never know (a great concept may become reality).
mfwright@batnet.com
*LASER*-pumped *FUSION* drive... Say that out loud...
Are we living in the future yet?
Fusion drives allow travel at 4 parsecs per turn and ion drives at 6. Physicist and engineer? Pah!
Yummy AND efficient!
I RTFA. The guy has an interesting idea to be sure. However, as he acknowledges, that level of technology is at least a decade away from a flying prototype (I'd wager more like two decades). Furthermore, the whole article was a bit scant on other details. Specifically, I would like to know the power requirements for a piece of equipment like this. If its reaction can sustain the apparatus's own power draw, that would be a huge point in its favor. However, something tells me this particular thruster would require a lot of electricity.
Furthermore, I'd like to see some thermal numbers for the thing. How hot/cold does it need to be to oeprate? Also, how much waste heat does it produce. If it requires a ten square meter black body radiator attached to it to function, it may not prove to be the miracle thruster that it claims to be. All in all it is an interesting concept. I would be surprised to see a prototype developed before 2030 or so though.
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Someone smarter than me will obviously fill in the details but it's not that simple. There is an international ban on nuclear anything or another in space iirc.
I've always thought that we'd have viable fusion rockets long before we have practical fusion power generation. The reasoning being, power could come from another source (fission reactor) to trigger the fusion, the resulting high-velocity particles would be a source of thrust alone. This seems to be exactly what TFA describes. Proton-boron fusion spits out high-energy alpha particles that are easily deflected into thrust... clever.
... and "The specific power of the proton-triggered boron fuel would be so great that a mere mole of it (11 grams) would yield roughly 300 megawatts of power. " (!) the efficiency sounds awesome.
With todays tech something like electrostatic inertial confinement fusion (like an Ion drive, but can reach energy levels for some fusion) could gain a bit of extra thrust from fusion, even if it was a long way off being able to generate useful power. But using a laser is novel
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
How will the shark tanks work in space with zero Gs?
love is just extroverted narcissism
We haven't gotten fusion to be a net energy gain here on Earth yet (outside tritium-boosted or thermonuclear atomic bombs). While I'm sure it will eventually happen, what makes it so that it's easier to make fusion work in space, compared to Earth?
The reaction is
1H + 11B -> 12C -> 4He + 8Be -> 4He + 4He + 4He
so there are more output nuclei than input.
However, I suppose it is true that all of the energy is coming from fusion, as 12C -> 4He + 4He + 4He is exothermic. (The reverse reaction is an energy source for stars under some circumstances.)
12C is normally stable, so for this reaction to go as stated the nucleus must be created in some suitable excited state.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Would you like to check my assembly for the monitor unit of the inverse klystron tube transmitter?
10^18 Watts/cm^2 with a 20cm disk for 1 picosec == 87.2 KWH ?
2.9 MeV per alpha particle * 100,000 ~= 0.00000047 joules
I'm not into engine building, but that seems like a tiny amount of force for 87.2 KWH.
A Fission-fragment rocket. Saw it on a program called Beyond 2000.
My question here is why only use it in space? Over 300MW of generated power is quite a bit. How small is the device? How often do the boron fuel plate and other metal plate need to be replaced? Are the components dangerous for the average person to be around once they have been used up? These devices could be scaled down to power electric vehicles such as cars, trucks, trains, and aircraft as well as our homes without the need for fossil fuels. What do you think?
...between power and energy.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
When I think about how much more the US could do if we didn't squander our money on bullshit
On Earth, we want to use fusion to power homes, ground vehicles, etc. However, the amount of work and energy we put into fusion gives us much less gain when compared to the amount of energy we can extract with fission, wind, solar, waves, geothermal, oil and coal. We attempt this with deuterium and tritium to produce neutrons. As the article puts it; [To make use of neutrons, "you need an absorbing wall that converts the kinetic energy of the particles to thermal energy," he says. "In effect, all you’ve got is a fancy heat engine, with all its resultant losses and limitations."]
According to the article, he's suggesting using Aneutronic fusion using Boron-11 as a fuel source to produce alpha particles (Helium-4 and Beryllium) via a laser which will yield 60% - 70% efficiency and 100,000 particles with each pulse. Boron will yield 300 MW of power per 11 mg, whereas Helium-3 isotopes as a fuel source would yield 493 MW in equal quantities. However, Helium-3 is scarce whereas Boron is not so it makes more sense to go with Boron instead. He claims it would be 40% more efficient than current deep space ion engines.
Keep in mind, that these engines have to run for long periods of time over great distances. They have all the time in the world to increase their acceleration to their mass potential. It's Hare vs the Tortoise, on Earth we need our power *right now* in large quantities and quickly. Whereas, in space you have patience because the distances are already so vast, you don't have much room to store fuel, and there is little or no friction so you can take your time building up speed.
Hope that helped you make heads or tails of this.
Starfleet ships only use those during docking procedures.
So if the other engines had an efficiency of 2%, this could get 80%? And if they operated at more than 2.5% efficiency, it would be fusion with a net energy gain - a real reactor? It might easily not take diversion of much of the thrust to produce the energy necessary to sustain the reaction.
So what if getting a sustainable fusion reaction requires a thruster design - that's easy to engineer around.
Look, you do know that money doesn't grow on trees, right? If everybody with a powerpoint presentation got billions of dollars, then there'd be nothing left to spend.
The output is three alpha particles; not exactly the same as three helium atoms...
Truth isn't Truth - Guliani
We can't do fusion with net energy gain on earth.
So why would we be able to do this in space?
First build a working fusion reactor that generates energy on the ground.
And only then take it to the skies and stars.
http://www.stolk.org/tlctc
Sanger proposed this way back in the early 1950's.
And Spencer wrote about it later:
Spencer, Dwain F. "Fusion Propulsion for Interstellar Missions". Annals NY Academy of Sciences 140, 407-418 (1966).
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Robert Forward documented all the above in a book I have on my shelf, but for the life of me can't remember the title. Heck, I was doing solar sail research/simulations on an x86 back in the 80's and we were proposing fusion drives as a power source for sails when the vehicle was in interstellar space.
It's great for today's visionaries to talk about their theories, but we all need to remember our ideas are based on the shoulders of those before us, whether they are giants or not.
While this isn't a full-blown warp core, fusion drive is what is used to go slow between planets. "Full Impulse" is the usual term, but its good enough to go extra-terrestrial. If you want to go inter-galactic, you need that warp core. Right now physics says 'no'. 110 years ago, physics and flying were equations on paper and nothing more. There was nothing feasible. 50 years ago, it was hot stuff (crappy engines and glorified kites of the first decade of flight --still miracles at the time-- had been replaced by better engines and wing surfaces in the second decade, faster engines pressurized cabins, high altitude bombing and millions of flight hours per year after the third decade, jets and faster commercial flight after the next decade, space flight after the next and on it went. Ships started off as boats. Boats started off as logs that people floated across the river with. A bit of work and the log went better if it was pointy at both ends. You didn't get wet if it was hollowed out inside and you were in it. You didn't have to get wet hands if you had a flat stick to push the water. Later, steel hulls and turbine shafts made going across the ocean more routine. Right now we are at the 'logs' end of space flight. For going across the ocean, logs to turbines was more than 3000 years. When I was 4 years old, people were all jumping up and down because some guy was the first guy to step foot on the moon *ever* and he came back to talk about it! We will get there. Likely not in my lifetime, but we *will* get there.
Fusion thrusters means we will be ready when we meet the Kzinti for the first time
Climate Progress - Hell and High Water
So raising the debt ceiling will cause economic collapse, but instantly shutting down the US credit won't? Because the US will be able to borrow enough to spend - that will destroy the country.
I see. Income taxes that corporations and their richest currently pay while amassing the largest stack of profit of all time must be reduced, because they make manufacturing unprofitable. The US manufacturing industry, the largest in the world and in history, is run for the fun of it but not the profits.
You Republicans are stupid.
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make install -not war
We should have these power collectors/transmitters in orbit around the Sun, pointed down at the Earth to collectors floating on the seas. Where they could electrolyze water, or any of a number of other ways to get the energy back to the land where it can be consumed. Emissions free, vastly more power than we can use for the foreseeable future.
The beams would have to be only a few times the intensity of sunlight, but shine all day/night (courtesy of geosync relay satellites) over a few dozen square kilometers on each station. No danger from a beam missing the target, though extra protection added by laser interlocks back from the surface to space that drop both up and down beams when the down beam goes off the target.
That system would require several $billion, perhaps several hundred $billion, investment. But at $0.01:KWh, and $100B is only 1KW:m^2 * 3intensity * 36Km^2 * 6stations * $0.01:KWh = 22.5 months payback time. That's better than 50% ROI, on hundreds of $billions. Plus the value of eliminating emissions, terrestrial fuel production and distribution, energy wars and corruption. And regaining the envy of the world.
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make install -not war
No, read it again... EITHER WAY, we're going to get a collapse. Its just whether we get it in about a month, or a couple years. The root cause is the income tax that has gutted US industry, chased jobs overseas, closed 42,400 factories since 2001, caused $10T - $14T US dollars to be sequestered overseas to hide from the income tax... we simply have to nuke the income tax. Its our last chance. Get rid of it, or we are toast.
I see you stopped to whine about corporate income taxes... that corporations don't pay. There is no such thing as "corporate money", that tax comes from three sources:
Corporate$$$ = Employee$$$ + Stockholder$$$ + Customer$$$
Raise a corporate income tax, and shoot the American public in the foot. Those taxes come out of employee pay that is not raised, and stockholder dividends that are reduced or eliminated, and product prices that are raised. Do the companies pay that tax? No, those 3 sections of society pay that tax, never the corporation. The corporation doesn't HAVE any money, it all comes from those 3 sources, employees, stockholders, and customers.
Can't figure out why CEO's and executives make billions, and employees are still making 19670 wages? Its because of the frappin' taxes and the frappin' envrronmental expenses and the frappin' safety expenses and the frappin' lawsuits. Every time the company has to pay these or taxes, it doesn't come out of the CEO's pay, nosirreebob! It cones out of everybody else's pay. Go ahead and rejoice about the multi-billion dollar smokestack scrubber that the "company" is having to buy, and remember that that money is coming out of the employees salaries and the stockholders dividends and the customers pockets. The CEO? He's going to get his scheduled raise, like usual.
The best thing we can do is get rid of the income taxes, and untax US industry. THAT will get those 42,400 closed factories re-opened, and new factories built, and millions of new jobs coming to the USA. Its the only thing that will work. Do it or die as a nation.
Hi there, bit off-topic but was wondering if you could find this link... see comments. Link [http://news.cnet.com/8301-17938_105-20074065-1/should-you-spend-$20-on-orbs-ps3-streaming-disc/?tag=mncol;title]
The whole idea of a rocket is so 1940's. Better to have emdrive electromagnetic devices. No more carrying loads of fuel up with us. Run the whole thing on fission based tech which we do have.
In this case NASA is obsoleted by Arthur Clarke who envisioned telecommunication satellites earlier. And the space race to the moon was started by Russia. It was their idea. Yet who does not credit NASA with rockets, spaceships and all space staff? /.ers have stated many times. Ideas (and non-hardware patents) are cheap. Implementations are difficult.
To repeat what
I see 2 problems with that : ... think HAARP on steroids
1) possible anihilation of anything flying/swimming/roaming in the beams' course, including rain-providing clouds
2) all kinds of weird things, doing with the ionosphere getting that much additional energy, ranging from beautiful Northern Lights up to appocalyptic crumbling of its protection from Gamma (and other) spacey particles
Btw, I remember Robert Becker's 1984 book (Body Electric), stating that storms & huricanes have been increasing in strength ever since ground-based electricity began resonating with above-mentionned ionosphere. Funny things would then happen when tremendously increased energy gets into it ...
But, well, do the math, and cross the fingers for someone else to foresee any consequences
All the energy released from the 1H + 11B stays at the 12C nucleus, since there is no particle carring it away. So, of course it is in an excited state, since that part of the reaction is exotermic.
It is quite common for the result of an 1H + X fusion to break into things with mass lower than X.
Rethinking email
OK, we're researching fusion drive. Now we need tritanium armour and battle pods.
The race is on to get at least phasers and class III shields before the Antarians show up.
-- What do you need?
-- Gnus. Lots of Gnus.