Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Jeryko on April 11, 2013, 01:20:57 am
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NASA-backed fusion engine could cut Mars trip down to 30 days (http://www.theregister.co.uk/2013/04/10/nasa_fusion_engine_fast_mars_trip/)
Pretty damn cool, and NASA backing to boot.
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whats the specific impulse?
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Over 3000 seconds.
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I am getting a slightly Orion-y vibe from this....
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Torchships anyone? Funny thing, I recently drafted an SF story (in Polish, I'm afraid it'll be a while before I get around to translating it) which also used a fusion engine (though a bit different one) for a fast trip to Mars. It'd be funny to see my vision of 2150s come true around 2050s. :)
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Over 3000 seconds.
thats almost as good as vasimir. i take it the key advantage is thrust over efficiency then. though i wouldn't underestimate the power of mpd thrusters with a adequately rated nuclear reactor.
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I am getting a slightly Orion-y vibe from this....
When I first read that, I thought it said 'Onion-y' vibe and was about to post that I didn't think the Register did fake articles...
Should have gone to Specsavers... :/
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thats almost as good as vasimir. i take it the key advantage is thrust over efficiency then. though i wouldn't underestimate the power of mpd thrusters with a adequately rated nuclear reactor.
Supposedly there are a few strong features for this engine, such as that it can be easily powered (moderately-sized solar panels), and suffers less wear (fusion triggered by magnetic compression).
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I see two problems with this, as much as I hope it pans out.
1. "The proposed fusion driven rocket (FDR) is a 150-ton system"
A block II SLS is slated for 130 metric I believe, I'm assuming the 150 is too, but even if it's imperial it would just barely make a block II, and I doubt the block II SLS is ever going to launch the way things are going. It's going to take a pretty big rocket from SpaceX or someone else to get it up there, and those rockets seem to be just concepts.
2. "A working fusion reactor is always 30 years away."
Has been since the 60s it seems. Though they appear to have made progress, I'm still skeptical whenever I hear someone mention fusion.
That being said, this sounds awesome, and I hope it does pan out. With travel time down to 30 days I could see colonization rapidly becoming viable, not just short trips. Nothing mentioned about launch windows, thought the "30 to 90" day travel time could reflect that. But if it's really ready by 2020 and it works, I'd bet on a permanent presence on Mars and several NEAs by the end of the century.
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There's no fusion reactor involved here. The great problem with fusion reactors is getting them to break even, but this system doesn't have to do that - it just uses inertial confinement fusion to convert reaction mass and energy into propulsion.
This could be the great white hope for the solar system!
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i suppose if you want to be picky about what a fusion reactor is. think of it as the convertible of the reactor world. a fusion reaction does occur inside it and energy is produced in the form of heat. just cause it has a hole to let the boom out doesn't mean its not a reactor.
that said im still not impressed with the design. unless its an engine which can operate at all phases of flight so you only need one (i doubt it). you still need to use solar panels, lots of them, and their support structures. then you are somewhat limited to the inner solar system where those solar panels are most effective, but if all we are doing is going to mars i suppose thats ok. it still needs fuel/propellant/whatever (seems you need some kind of plasma, and then whatever metal youre using). these are likely not as easy to extract from mars has hydrogen or oxygen, so you need to carry your entire fuel supply on one ship. a ship weighed down by a lot of engine and structural mass.
better yet send up that vasimir prototype (the one slated for testing on the iss in a couple years), hab module and lander. grab one of those leftover soviet nuclear reactors orbiting around up there (assuming they still work). put em together and you got a mars ship. im still kinda questioning if its worth it to go to mars for a quick visit, something amounting to a publicity stunt, do be done once and then leaving everyone hanging on for another 50 years till the next manned mission to somewhere humans haven't been. no i think we should instead look into a lunar settlement and manufacturing complex, sort of a fuel depot and shipyard. a gateway to space. put mars on hold until we can launch the mission from the moon.
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i suppose if you want to be picky about what a fusion reactor is. think of it as the convertible of the reactor world. a fusion reaction does occur inside it and energy is produced in the form of heat. just cause it has a hole to let the boom out doesn't mean its not a reactor.
Yes, but Sharkfinn's criticism was on fusion reactors not yet being able to produce electrical energy on a large scale without net loss. This is completely different from using fusion reactors to produce thrust.
you still need to use solar panels, lots of them,
Not really. It only needs 200KW -- about the same power produced by the ISS solar panels.
seems you need some kind of plasma
...? It uses deuterium-tritium pellets.
these are likely not as easy to extract from mars has hydrogen or oxygen, so you need to carry your entire fuel supply on one ship. a ship weighed down by a lot of engine and structural mass
The required fuel mass fraction is significantly smaller than for conventional propulsion methods.
Seriously, nuke, did you even read the article? All of the points you've raised were addressed in it. Your first question on specific impulse could have been answered just by skimming it.
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i suppose if you want to be picky about what a fusion reactor is. think of it as the convertible of the reactor world. a fusion reaction does occur inside it and energy is produced in the form of heat. just cause it has a hole to let the boom out doesn't mean its not a reactor.
Yes, but Sharkfinn's criticism was on fusion reactors not yet being able to produce electrical energy on a large scale without net loss. This is completely different from using fusion reactors to produce thrust.
look up reactor in the dictionary pls. for an apparatus to be called a reactor, there is no specific requirement that it be enclosed, nor does it specifically require the output to be electricity. its still a reactor. (hint that was irt to what battuta said, not sharkfin)
you still need to use solar panels, lots of them,
Not really. It only needs 200KW -- about the same power produced by the ISS solar panels.
those panels are huge. there are a lot of them. and the structures that support them are heavy. the iss wasnt exactly a single launch affair either.
seems you need some kind of plasma
...? It uses deuterium-tritium pellets.
where do you think you get the plasma? out of the aether? im actually much more concerned over the metal "liners" i believe is what the article called them. if the metal has a low enough meltim point you might stick those in tankage, of course you would need some kind of process for shaping them to the required geometry.
these are likely not as easy to extract from mars has hydrogen or oxygen, so you need to carry your entire fuel supply on one ship. a ship weighed down by a lot of engine and structural mass
The required fuel mass fraction is significantly smaller than for conventional propulsion methods.
Seriously, nuke, did you even read the article? All of the points you've raised were addressed in it. Your first question on specific impulse could have been answered just by skimming it.
yes i read the article, and was rather unimpressed. i read about every kind of propulsion technology and power systems. i also look at their technological readiness level. fdr hasn't even seen a vacuum chamber test. countless engines with better isp have, and they work. only problem is they are rather hungry beats. vasimir can pull off a higher isp, and is ready to fly, and uses plain old hydrogen. we know we can make nuclear (fission) reactors that work in space (there are some up there btw thanks to soviet russia). so looking at other technologies, id say were better off using those.
that does not mean screw fdr, that means we have engines closer to flying that could pull off a mars mission. fdr might be the revolutionary engine that they say it is, or it can end up in the queue with the other engines waiting for their trl to rise.
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look up reactor in the dictionary pls. for an apparatus to be called a reactor, there is no specific requirement that it be enclosed, nor does it specifically require the output to be electricity. its still a reactor. (hint that was irt to what battuta said, not sharkfin)
I know perfectly well what a reactor is. Try reading what you quoted again and work on your reading comprehension skills.
those panels are huge. there are a lot of them. and the structures that support them are heavy. the iss wasnt exactly a single launch affair either.
And it shows that we are not only capable of building such a thing, but we have already done so. It is not so massive that we can't build it, nor is it so massive that we can't move it.
where do you think you get the plasma? out of the aether?
I was specifying what the propellant was for you, since saying "some kind of plasma" made it sound like you didn't have a clue.
yes i read the article, and was rather unimpressed. [etc]
It's a very new development; of course it hasn't been completely tested yet. But given that NASA is funding its development, they must think it has some potential. I'm not saying this thing is going to be the holy grail of interplanetary space flight, but I think it does looks promising.
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There's nothing wrong with trying different approaches. Even if something doesn't work we can still learn from it.
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nothing wrong with this engine. but its still on paper. i dont mean to say that the technology should not be developed (every engine that looks good on paper seems to get tested at some point). but that we have engines that are further along that could do the job just as well (if not better). seems it would be easy to ground test it though.
but every time a new engine design comes up the articles seem to think its the keystone of a mars mission. the main issue for getting to mars is political will and funding. not technology. we could build a nuclear-electric ship that can get to mars, with tech that is either proven in space or slated to be tested in space (which means it passed its ground tests).
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wasn't the nerva adequate for a mars mission in the 60s
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wasn't the nerva adequate for a mars mission in the 60s
Yes the NERVA owned
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I mean the nuclear saltwater rocket owns everything else and its mother but the NERVA's nearly as cool.