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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.
Put the research into increasing our population, then you can get a 10 parsec drive and get just as far in as many turns.
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
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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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?
that's about the feeling I got with their "300 watts" nonsense, an amount of boron will give an amount of energy. Han Solo type bragging with nonsense units. Power would only be known after knowing at time interval.
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.
They allow RTGs into space.
Play Command HQ online
Would you like to check my assembly for the monitor unit of the inverse klystron tube transmitter?
Masters of Orion?
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.
...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.
That's easy. All you have to do is beat them with it to show that they are better armored than a main battle tank, and won't be harmed by something so trivial as the detonation of several million pounds of rocket fuel.
The output is three alpha particles; not exactly the same as three helium atoms...
Truth isn't Truth - Guliani
Put the research into increasing our population,
I'm happy to help with that research!
Man who leaps off cliff jumps to conclusion.
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
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?
I think that scaling isn't as simple as that and also that maintaining a hard vacuum is probably a lot easier in space.
If God forks the Universe every time you roll a die, he'd better have a damned good memory.
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).
.
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.
We spend the equivalent of a huge forest of money trees on USELESS aggression; bring those troops and ships home, destroy deployed equipment in place, sell it to the locals, or bring it home if practical, leave the military brought home employed for a strong standing defense, and (a) we'd be acting morally for the first time in decades and (b) the money spent on the standing army, now home, would go right back into our OWN economy, and (c) we'd have huge overall spending reductions we could apply to the debt and perhaps once again, someday, have money to spend for our actual benefit.
Our budget problems are 100% solvable. All you need to do is get the cowards out of congress. Somehow.
I've fallen off your lawn, and I can't get up.
True. It is time to roll back all those expense that the neo-cons saddle us with. They are destroying America.
I prefer the "u" in honour as it seems to be missing these days.
Fusion thrusters means we will be ready when we meet the Kzinti for the first time
Climate Progress - Hell and High Water
software is just a hobby, my background is an engineering physicist.
power is energy (work) per time interval http://en.wikipedia.org/wiki/Power_(physics)
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.
--
make install -not war
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]
I wonder why the option of just cutting the budget of the military by 90% is never examined? I mean the US has one of the most powerful nuclear arsenals on earth, nobody is going to invade. Ever.
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
Jingoism aside, large standing armies (comprised mostly of testosterone-fueled young men) with zero threat and bored out of their skulls tend become rather restive, with less and less regard for the mere civilians they swore to protect. Citation: Iron Man, Black Sabbath
Since neither allows superluminal travel, each turn must be at most 20 years, and more likely somewhat closer to 100 years. That's a lot of patience...
I am TheRaven on Soylent News
The point the article seems to be making is that the power output is a function of the mass involved in the reaction, similar to the phenomenon of critical mass in a fission reaction. More mass means more chance of a proton hitting a nucleus means more average energy released per proton means more energy per time means more power.
You've obviously lost your edge as a physicist, because this is coming from an undergrad Physics student...and software is also my hobby.
nuclear weapons arent a defense against invasion, what are you gonna do, nuke manhattan the moment $ENEMY_POWER starts landing troops there?
Still, i agree the US military could probably do with losing a few pounds, all that foreign meddling seems a bit unnecessary at times
People, what a bunch of bastards
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
nuclear weapons arent a defense against invasion, what are you gonna do, nuke manhattan the moment $ENEMY_POWER starts landing troops there?
Nope, nuke $ENEMY_POWER the moment they start landing in Manhattan. Or preferably considerably beforehand.
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.