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U.S. tests nuclear power system to sustain astronauts on Mars
- baron816 9y agoWhat happens if the launch rocket fails? That’s been the main concern of sending nuclear reactors into space thus far, right? Has this been addressed here?
- njarboe 9y agoIt is too bad that most people are so afraid of anything nuclear. I hate to say it, but maybe people working on nuclear power need to change the name. Isotopic power would have pretty bland associations. Uranium 235 is a very low level radioactive metal. Even if the rocket blew up, the isotopic fuel would remain intact (that is, not vaporized into breathable particles). The radioactivity from a Uranium 235 isotopic reactor comes after the reactor has been running for some period of time (from byproducts of the nuclear reaction), not the original fuel itself.
- tbihl 9y agoIn Japan they just call them 'thermal plants' or 'thermal generators' or something like that. Still, in Japan you have people who follow around US aircraft carriers and submarines to sample their wake for any signs of radioactive discharge.
- ekianjo 9y ago> In Japan they just call them 'thermal plants' Japan has completely shut down all operations of Nuclear Plants since 2011. https://en.wikipedia.org/wiki/Nuclear_power_in_Japan https://en.wikipedia.org/wiki/Nuclear_power_in_Japan
- ptaipale 9y agoAnd as that page also explains, has restarted some of them, and the long-term policy calls nuclear power "the country's most important power source".
- rangibaby 9y agoI haven't heard that before. 原子力(atomic, using atoms)+発電所(power plant) is the common term eg 福島(Fukushima)第一(No. 1)原子力(nuclear)発電所(power plant)
- fb03 9y agoGen-shi-ryoku Hatsu-den-sho? Let's see if I got it right, my Japanese is a bit rusty. I am not sure about the readings of the first two kanji (atomic) so I used generic ones heehe. Thanks in advance.
- rangibaby 9y agoYes you are right. 原子 genshi means atom. 力 means power (strength). Stick them together and it means using the power of the atom.
- stevedonovan 9y agoConsider the thermal Plutonium power sources that have been sent on outer Solar System missions. One of those crashing is a much more serious problem than a new U-235 reactor, since Plutonium is very toxic.
- garmaine 9y agoPlutonium isn't toxic, not any more than any other heavy metal.
- ttul 9y agoIt is radiotoxic
- garmaine 9y agoNope, it is not. Not anymore than the straight radiation you would get from it. When you talk of radiatoxicity what is usually meant is the hot particle theory which says that a bit of radioactive material lodged in one place is more likely to cause cancer, because the radiation given off repeatedly hits the same tissue. It turns out that in cohort studies done this is not true. Specifically people who have inhaled plutonium, an inadvisable thing to do, actually have lower rates of lung cancer. Pu-238 has some radioactivity, although not as much as many fission products. Radioactivity is bad. But the fear over plutonium toxicity is actually overblown beyond the baseline radioactive dose it provides.
- black_puppydog 9y agoThat already happened. Not something we'd want to happen regularly, but not as dramatic as one (me) would have thought. https://en.wikipedia.org/wiki/Kosmos_954#Aftermath https://en.wikipedia.org/wiki/Kosmos_954#Aftermath
- sjcsjc 9y ago"maybe people working on nuclear power need to change the name" Renaming things with bad public images is a popular trick. Windscale > Sellafield Blackwater > Xe Services > Academi Philip Morris > Altria
- lostlogin 9y agoThe Blackwater one always mystified me. It’s like they set out to be villains.
- godelski 9y agoA good way to remember energy levels is "longer life, lower energy." Things with a long half life are not decaying very fast. Short half lives, well clearly they don't want to be there, so neither should you.
- Balgair 9y agoI mean, there is a bit of precedence for the fear. It's not that we can't deal with the fission, it's that we can't have really really smart people on deck at all times. The consequences of big failures are pretty bad and pretty newsworthy.
- debt 9y agoIt's an extremely toxic, dangerous material overall. The fear is well-founded in a geopolitically chaotic, variable world. Not to mention, in this case specifically, they're going to strap it to a rocket and send it to Mars. Gonna be hard to sell people on the safety of the mission if we're potentially spewing nuclear material over thousands of square miles in the worst case scenario.
- gh02t 9y agoIt's not really a concern. U235 is basically radiologically inert, it doesn't become significantly radioactive until after the reactor has been running for a while. The concern with fission reactors in space is for stuff that might return to Earth after it's been in operation long enough to build up other isotopes that are radioactive and subsequently burning up in the atmosphere. For a vehicle that is on a one-way trip to Mars, and where the reactor will be brought online after it's out of Earth's orbit, this isn't a problem. Edit: even on a round trip it wouldn't be a big deal, the reactor can just be jettisoned before re-entering Earth's gravity well. You just can't have a fission reactor with spent fuel anywhere near Earth orbit. Space reactors in general are pretty interesting, because the design criteria are so different from terrestrial power reactors.
- baron816 9y agoAh, ok. Thanks for the explanation.
- pishpash 9y ago> For a vehicle that is on a one-way trip to Mars, and where the reactor will be brought online after it's out of Earth's orbit, this isn't a problem. Polluting the new homeland from the start, eh?
- Jesus_Jones 9y agoJust bury it out back, we'll clean it up later just like we did in Hanford. No problemo https://en.wikipedia.org/wiki/Hanford_Site https://en.wikipedia.org/wiki/Hanford_Site. More seriously, we can afford to have a small amount of nuclear waste there, but we need to plan for it better than we have previously. First, document where it is and what it contains. Second, I don't know.
- optimiz3 9y agoFun fact: right across from the Hanford Site is a massive Conagra plantation. Source: visited Hanford Site, looked up the company associated with the plantation across the road.
- nahumba 9y agoThats what is bothering you? Did you hear about fukushima? Where are the water to cool it and make steam for the turbine to turn? How much water is needed for a reactor to run safly? What other matterial are they going to heat to turn turbine to produce energy? What is the amount of lost metirial expected over time? And what happen when no cooler matirial is available? Boom?
- StreamBright 9y agoIt happened many times that a nuclear device exploded or by other means entered atmosphere. Lunch site explosions also happened. I think the on the ground accidents are less serious because you can contain them and it is less spread out than for example a satellite exploding in the higher atmosphere. https://listverse.com/2012/01/20/top-10-space-age-radiation-incidents/ https://listverse.com/2012/01/20/top-10-space-age-radiation-...
- nurettin 9y agoNot sure if applicable here; but where I come from they say "the fearful won't have kids"
- InclinedPlane 9y agoThe reactor will be launched in a "cold" state, it will also be in a robust structure (though not as strong as RTGs, though that's unnecessary). The absolute worst case scenario is that you get a release of U-235. That's not great but on the scale of radiological hazards it's comparatively very minor. The reactor doesn't start generating fission products (aka "fallout" isotopes) until it's in space and operating, presumably with no chance of returning to Earth.
- njarboe 9y agoI would love to have more details about this reactor. How much is the total mass? What is the expected power output over time? What kind of heat sink is necessary? But in any case this is really cool development.
- T-A 9y agoThere is a veritable orgy in nuclear tech for space here: https://beyondnerva.wordpress.com/ https://beyondnerva.wordpress.com/ See also https://github.com/briligg/moonwards/wiki/Nuclear-Reactors------Kilopower-(KRUSTY) https://github.com/briligg/moonwards/wiki/Nuclear-Reactors--...
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- yellowapple 9y agoIf each core really is the size of a paper towel roll, then this seems like a solid step toward me eventually owning a nuclear-powered car.
- wolf550e 9y agoYou will never be allowed to own one because you cannot be trusted to dispose of it correctly.
- hodl 9y agoA Tesla can be remote nuke powered.
- wcoenen 9y agoAh yes, the Ford Nucleon https://www.damninteresting.com/the-atomic-automobile/ https://www.damninteresting.com/the-atomic-automobile/
- feliix42 9y agoThis oddly reminds me of the story of Fallout. https://en.wikipedia.org/wiki/Fallout_(series)#Setting https://en.wikipedia.org/wiki/Fallout_(series)#Setting
- maushu 9y agoI love the story of Fallout. They decided to use nuclear reactors on cars because there as a lack of petroleum. It was too late though since the Great War started (and ended) a couple of years later.
- caf 9y agoUnfortunately for these miniaturized Uranium reactors, the Uranium must be highly enriched - in other words, weapons-grade.
- vadimberman 9y agoI'm curious, where does one get the nuclear fuel on Mars? Does it have to be flown all the way from the Earth?
- acidburnNSA 9y agoDefinitely. You can probably mine uranium on Mars but that would require a bunch of infrastructure and other power sources. These babys are way down-rated so they can run on a single loading of fuel for decades, like nuclear submarines. Good old E=MC^2.
- jacobush 9y agoI don't think there is any uranium to be had there. For such heavy elements to get deposited in ore near the surface takes special circumstances, such as those of Earth.
- superkuh 9y agoAs far as I understand it they are pumping the equivalent thermal energy as an actual operating core would produce into the reactor casing and assembly using a specially designed electrical insert that uses external power. This isn't a fission test. It's a mechanical engineering test. Still cool.
- SigmundA 9y agoFrom my understanding the fission part is "easy", the hard part is taking the heat and converting to electricity efficiently and reliably. The Mars Curiosity rover among other probes use a thermocouple based generators to create electricity from the fission heat[1]. Extremely robust , no moving parts, but extremely inefficient just a few percent converted to electricity the rest to heat. The heat is very useful on mars though due to the low temps, kinda like your combustion engine in your car, the waste heat can be used to provide useful heating, but still most needs to be rejected and it only puts out about 100 watts of electricity. This new one looks to be striling engine based which means its going to have much better efficiency since it is a more standard heat engine with moving parts, prob 20-40%. Hence the higher output. However that comes with much more complexity and things to go wrong over long term use. I still wonder if there is much more efficiency to be had from thermocouple's if the research effort was put into it, it would be similar to solar cell improvements over the last few decades. You just don't hear about thermocouple R&D and if it where improved to say a typical solar cell efficiency of 18-20% it would open all sorts of doors. 1. https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
- tarre 9y agoIn fact the fission[1] part in such small scale is hard. Curiosity and other probes using thermonuclear batteries harness alpha decay[2], which is relatively easy as it happens whether or not you want it to happen, but creates also much less power. In that case the hard part is to obtain material with appropriate half-life and other properties. Perhaps best material for this is Pu-238, which is far more expensive to create than weapons grade plutonium. 1. https://en.m.wikipedia.org/wiki/Nuclear_fission https://en.m.wikipedia.org/wiki/Nuclear_fission 2. https://en.m.wikipedia.org/wiki/Alpha_decay https://en.m.wikipedia.org/wiki/Alpha_decay
- lmilcin 9y agoI am not sure this is a good idea. Nuclear reactor is an easy way out of a problem that has alternative solutions. Restriction on using nuclear power for previous missions did a lot of good in terms of researching and perfecting the alternatives (solar arrays). Restricting the use of nuclear power does not prevent missions, it only adds to the cost of the mission, which is not really a technical problem. Maybe launching one, fresh, yet inert reactor, is not a big issue. The issue starts when we fly a lot of them and they start falling back to Earth after some service time. It is relatively easy to build safe reactors on Earth (if only everybody was interested in safety and not their own agenda). It is much more difficult when you are going to shoot the entire device into space and you can't have 1000:1 of shields and casings.
- schwarrrtz 9y agoWhat power source do you propose for a long-duration human mission to Mars, if not nuclear? Solar won’t work, given the loss of output during a dust storm.
- twothamendment 9y agoIf I were on my way to Mars I wouldn't go without nuclear power. It is too far away to have an Amazon drone drop off a fresh batch of batteries or solar panels.
- icelancer 9y agoThere is essentially no actual ecological or serious fear about these devices. The weapons ban was meant to help avoid nuclear exchange between nations; there's very little scientific data that shows there's added cost or risk of thousands of reactors falling to Earth and causing radiation poisoning. Nuclear is exceptionally safe and all the recent accidents (and ones in the past, really) are all due to human stupidity and bypassing several failsafes. You can argue that's an issue that will never go away, and that's true in the absolute sense, but it's not a nuclear problem. It's a human issue. We're holding ourselves back for scientific research because of arbitrary issues; and the weapons test ban didn't even solve nuclear proliferation anyway. Solar won't be held back because nuclear is finally an option. They serve two different purposes entirely.
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- cx_in_the_chat 9y agoCan't wait for Doom 3 to become reality. Amazing how quickly we're catching up with science fiction.
- mikaelgyth 9y agoI want one!
- davedx 9y agoHow will they cool it?
- InclinedPlane 9y agoIt's radiatively cooled, just as RTGs are.
- ourmandave 9y agoUnanswered in article: How long does the power unit lasts until you have to replace the paper-towel-roll-sized U-235 core? Where are they going to put the old ones? What's the plug interface? Can I charge my iPhone? What about my electric razor? Are they going to test burying one in red sand for 15+ years and see if it can be dug up to phone home in an emergency?
- SideburnsOfDoom 9y agoAnd in 15 years, do you need to import a new core from Earth or what - have a uranium mining and refining operation up and running by then?
- jessriedel 9y agoEnriched uranium is one of the few supplies for which it's probably economically sustainable to provide continuously from Earth.
- godelski 9y agoConsidering the half-life, I'd assume the housing and device would fail long before the U235 decays enough for significant loss in heat production.
- gene-h 9y ago>How long does the power unit lasts until you have to replace the paper-towel-roll-sized U-235 core? It's not a completed design, but based on their proposed design[0] 20 or more years. The old reactor core is going to remain in the spacecraft, which will probably be at the very least hundreds of thousands of kilometers from Earth. In short, you don't replace the core, you would replace the entire reactor, which is doable because the reactor isn't very big. >plug interface whatever you want it to be, it's not a complete design >Can I charge my iPhone? What about my electric razor? The current tests should enable reactors with electrical power outputs ranging from 500 watt to 10 kilowatts. An iphone probably has a power consumption of around 1 watt max, so you should probably be able to run between 500 and 10,000 iphones. Electric razors have a max power draw of 20 watts, so it should be possible to run between 25 and 500. >Are they going to test burying one in red sand for 15+ years and see if it can be dug up to phone home in an emergency? Any such tests would be purely ad-hoc. That being said, if you don't have enough power to phone home(<100 watts), you are already screwed. [0]https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170011067.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700... [1]https://www.nasa.gov/sites/default/files/atoms/files/kilopower-media-event-charts-final-011618.pdf https://www.nasa.gov/sites/default/files/atoms/files/kilopow... [2]https://www.daftlogic.com/information-appliance-power-consumption.htm https://www.daftlogic.com/information-appliance-power-consum...
- ifdefdebug 9y agoI find it frustrating NASA talking about putting people on Mars but if you look at reality, it can't even put astronauts in the orbit anymore. What about solving that problem first, and when it's done, then we can dream about Mars... Or are we going to outsource such mundane tasks like manned orbital space flight to the Russians and Chinese forever, while we are proudly preparing the colonization of Mars? /s
- fyfy18 9y agoWhat’s wrong with collaborating and using the collective knowledge of the human race to achieve this? It’s really no different than using private contractors to do the same thing. NASA can’t do everything themselves, so why not let Russia launch the rockets while the US and other countries focus on other parts of the mission?
- zach43 9y ago> it can’t even put astronauts in orbit anymore But this isn’t really a NASA problem, this is a US government funding problem right? I can’t imagine how anyone can put people in space without the budget for it
- ifdefdebug 9y agoIf there is no funding for orbital space flight, how are they supposed to go to Mars? Missing funds is a NASA problem, it's NASA's biggest problem today, and if it doesn't get fixed, nobody goes to Mars (at least nobody from NASA). IMO all that sandbox research they are doing now is useless, because they ain't gonna need it: they ain't gonna need it if they are not going, and they ain't gonna need it if and when they are really preparing to go because everything is gonna be different and nobody will give a shit about how such a power device might have looked like 10 years ago.
- imglorp 9y agoI find it encouraging the private sector is filling the gap. Musk's vision is clear if you assemble all the pieces his companies have built on Mars: solar and battery power, tunnel boring for both shelter, water, and air (which could imply return fuel he can do O2+H2). Solar might not be the most efficient for Mars, but he can bring tons of it without messing with nuclear politics and PR. Note also the Boring Company TBM diameter is less than the BFS. Don't be surprised if a TBM one of the first payloads. https://en.wikipedia.org/wiki/SpaceX_Mars_transportation_infrastructure#Passenger_spaceship https://en.wikipedia.org/wiki/SpaceX_Mars_transportation_inf... https://www.boringcompany.com/faq/ https://www.boringcompany.com/faq/
- MikeWazowski 9y ago"Testing on components of the system, dubbed KRUSTY..." Named after Krusty the Clown?
- aurelianito 9y agoQ
- alangibson 9y agoThis thread is a great example of why I love HN. I clicked on Comments expecting to see a bunch of "nuclear = devils energy" posts, but what I found was reasoned discussion weighing the real pros and cons of this particular use case.
- kristianp 9y agoPart of Nasa's Game Changing Development program: https://www.nasa.gov/directorates/spacetech/game_changing_development/index.html https://www.nasa.gov/directorates/spacetech/game_changing_de...