Slashdot Mirror
Nuclear Rockets Moving Along
AKAImBatman writes "Bruce Behrhorst of NuclearSpace.com recently stumbled across a new engine from everyone's favorite Jet Engine maker, Pratt & Whitney. Unlike P&W's previous engines, however, this engine is not a jet, and is powered by Nuclear Fission.
It seems that P&W has responded to the need for Mars transportation by inventing the first commercially viable nuclear thermal rocket. They have heavily improved upon the NERVA NRX design from the 60's, and have even solved the graphite ablation problem! With this new engine, it seems that an inexpensive trip to Mars is now firmly within our grasp. Will we rise to the challenge?"
This technology is not already doomed because of politics...
I'd rather be sailing...
"They have heavily improved upon the NERVA NRX design from the 60's, and have even solved the graphite ablation problem!"
Really? I always found that the ablation problems were rarely touched on by my professor. We spent several weeks in the library and online researching this before coming to the conclusion that the vortex efflunziation was inherent with the NRX designs, especially seeing how the rocket designs went from paper to production in 5 months.
This isn't meant as a panicky "omg! nucular!" question. But we have seen a few space craft blow up spectacularly. Now, I assume the designers are bright enough that these engines could not actually produce a nuclear explosion, but wouldn't a conventional explosion at high altitude run a high risk of scattering nuclear material all over the place? Is there a good reason I shouldn't be worried about that?
What's wrong with Project Orion? ;-)
I mean, if we're going to go to Mars, we might as well do it properly - even if it does end up filling the atmosphere with radioactive fallout...
Tedious Bloggy Stuff - hooray?
Could someone briefly exlain this 'problem'. Apaprently students of architecutre aren't taught about such things. Who'd a thought?
Rad Adam
"So Lonestar, now you see that evil will always triumph, because good is dumb."
Was not NERVA somehow proscribed by the NTB? Wouldn't this be a deal-killer? Is it reasonable to believe the rest of the world will rescope the NTB to allow us to run nuclear rockets in space (i.e., why should the world trust the US?).
I'm serious about this.
aside:
I used to work with a cryogenics engineer who designed the Fermilab Tevatron LHe system, who had earlier worked on NERVA. He told some pretty interesting stories about bundle dissasembly during criticality tests. They used a tank with arms to pick up the pieces...
Or more precisely - what is the acceptable value of (rate of failure * consequences of failure)?
I think the easy solution to this is to get working on using the ISS as a space dock. Lift the engine into orbit using convential (i.e. chemical) methods and build the mars ship in orbit.
Yes Francis, the world has gone crazy.
Why should I not fear radioactive material in the atmosphere? Given the track record of shuttles, launchers and what have we - there's obviously a non-negligible chance of accidents happening. In case of such an accident, radioactive debris will fall down, radioactive rain could happen?
So, why should I not be worried? Please enlighten me.
Unable to read configuration file '/bigassraid/htdig//conf/14229.conf'
Geocrawler error message.
Nuclear power generation is self-contained, and only problematic in case of catastrophic failure. The other two are problematic when functioning as designed. Associating the three is precisely what has prevented the use of nuclear power generation.
You of course scare-monger by mentioning nuclear power plant failures, but you'll notice that the world has (shock!) survived just fine. While the death toll from an event like Chernobyl is certainly tragic, there are risks associated with developing any technology. Beyond which, I have the sneaking suspicion that more people have died from the effects of air pollution caused by fossil-fuel power generation than have died due to nuclear reactor failure by orders of magnitude.
I also suspect (based on broad stereotyping, admittedly, so feel free to tell me I'm wrong) that you also buy into global warming as a result of mankind's CO2 production, in which case the death toll from fossil fuel plants will be yet more orders of magnitude higher than would be caused by the occasional nuclear plant failure.
Reality has a conservative bias: it conserves mass, energy, momentum...
I think that is probably the number one obstacle to ever putting this type of propulsion system to work. In the event of an explosion during liftoff, it would become the largest dirty bomb ever conceived. I suppose it may be possible to try to launch the engine components separately and assemble them in orbit. (Similar to what the crew of the B-29 which dropped the atomic bombs on Hiroshima did (because of similar concerns). But you'd still have the possibility of radioactive material raining down in the event of a problem during liftoff.
- dj
discovery wings is at the moment running a show on Project Pluto, the government's project to develop a nuclear-powered ramjet in the 50s/60s. the research got up to successfully running the full-scale Tory-IIC 500Mw prototype for 5 minutes at 35,000lbs thrust. i realize a ramjet design is different from a thermal rocket design, but does anybody know why 'they' can't use the basic design of the tory reactor, homogenous uranium/beryllium oxide fuel tubes, at the heart of the rocket engine? seems an ideal situation, theres no graphite to ablate and AFAIK the oxide ceramics stand up pretty well to hydrogen.
Facts do not cease to exist because they are ignored. - Aldous Huxley
Okay, so what *should* we do with the products of fission? Recycling is not allowed, since this yields a bit of plutonium which automatically causes all nations to start building bombs. You don't want to store it. "Use it" or "throw it away" seem to be the only options. Should we wave a magic wand and make it disappear?
Rename it, like they did with nuclear magnetic resonance, which is now a household word as MRI.
Actually, part of the neat thing about this rocket is that it can indeed provide thrust from the beginning. With LOX injection, around 1/3rd of the thrust comes from the nuclear engine and 2/3rd from chemical reactions. However, when the reactor is really new, it consists mostly of uranium, and uranium just isn't all that radioactive (U-235 has a half-life of 700 million years, and U-238 is at 4.5 billion years). It is not a catastrophy if a bunch of uranium is spread around. Much more was thrown around in Yugoslavia and Iraq, anyway.
Finally! A year of moderation! Ready for 2019?
I'm not a rocket scientist, or I'd have something more informative to say.
I did skim over the Wikipedia article, though, and I was curious -- the impression given is that these sorts of rocket engines can't escape Earth gravity and would have to be put together in orbit (again -- going strictly by Wikipedia article on subject).
I have 2 questions. First, if you build it in space, and you make it to Mars, would you have enough thrust in the lower gravity of Mars to lift off again with a full payload, say, of people and Mars rocks? Would a Mars lander be required with conventional rockets to get back to a control vehicle?
My second question is -- how the hell would they put this together at a reasonable cost in space? The Russians blew the hell out of their Mir space station at least a few times. And I seem to remember that the new ISS crew nearly rammed the hell out of the space station when they hooked up with the station last week. Feel free to pile on with other minor news stories about lost tools, broken this and that, etc. with the ISS.
And you want politicians with money from taxpayers to approve funding for NASA to build something "nuclear" in orbit with this kind of scary news history? I have full faith that NASA or an international consortium could make it work, but what about Joe Public, the environmentally-motivated voter, who fears a mushroom cloud screwing up astronomy night for his kids?
Finally, and this is most important -- with this nuclear rocket engine, would the guy from Sliders and Gary Sinise be able to save Tim Robbins before he burned up in the Mars atmosphere?
IronChefMorimoto
Burning coal puts 25 tons of bomb grade Uranium into the air every year and I forget the exact amount of U238. The U238 gets hit by high energy neutrons from cosmic ray impacts and changes into
Launching a little dab of Uranium under highly controlled conditions doesn't seem like such a big deal when you know this fact.
I am very easy to get along with, but I don't have time to waste being nice to people who are being stupid. -Theo
The fear is ridiculous because nuclear plants have an excellent track records, because modern designs are inherently safe, because nuclear waste is compact and relatively easy to store.
It isn't ridiculous. As this recent near catastrophy illustrates.
A buddy of mine has a masters in nuclear engineering. He tells me of testing steel alloys for various reactor applications and finding siginficant issues. But because the goal of the study was elsewhere, he was told to ignore it by the professor.
You should hear him talk about how F'd up the Yucca mountain waste storage project is. The government and US industry consider the project solved to the point where they won't even fund further research. He says Europe is much further along in how they encapsulate and handle the waste problem.
Note that the engineering term "intrinsically safe" has a substantially different meaning than "inherently safe". Although the terms are used interchangably by some, those who live by the "law of milspecs" never confuse the two.
In any case, it'd be wise for P&W to rename it something other than a nuclear engineer. That's dumb marketing. Hell, they don't call the Army's M1 tank the "nuclear tank", despite its use of depleted uranium.
And anyhow, many jet engine parts use radioactive materials for hardness and during the manufacturing process. This is not news.
Unfortunately, they ignored the fact that coal burning power plants put more radioactive material into the air every minute than was in the Cassini probe, and that the plutonium wouldn't atomize. It would sink like a rock into the muck at the bottom of the ocean, just like the dozen or so nuclear subs that have been lost. And it would pose no threat to life on Earth.
Nuclear and radiation are buzzwords that freak out people that don't understand. I'm radioactive right now. Should I be buried in a Nevada salt mine or shot into the sun?
You have two hands and one brain, so always code twice as much as you think!
I can't believe my president has 'twang.' And I can't believe Kerry isn't mopping the floor with him.
You have two hands and one brain, so always code twice as much as you think!
You encapsulate the burnt fuel in ceramic modules, and dump them into tectonic subduction zones. Fairly cheap, fairly simple, and very safe.