U.S. tests nuclear power system to sustain astronauts on Mars(reuters.com)
reuters.com
U.S. tests nuclear power system to sustain astronauts on Mars
https://www.reuters.com/article/us-space-nuclear/u-s-tests-nuclear-power-system-to-sustain-astronauts-on-mars-idUSKBN1F72T8
137 comments
From 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_ge...
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_ge...
In 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
2. https://en.m.wikipedia.org/wiki/Alpha_decay
1. https://en.m.wikipedia.org/wiki/Nuclear_fission
2. https://en.m.wikipedia.org/wiki/Alpha_decay
I don't think "thermonuclear" is the right term for the batteries in probes. Wikipedia says "thermoelectric"[1], as the electricity is generated directly by thermocouples.
"Thermonuclear" usually refers to the sorts of fusion reactions found in stars and modern nuclear warheads.
[1]: https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
"Thermonuclear" usually refers to the sorts of fusion reactions found in stars and modern nuclear warheads.
[1]: https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
Thanks for correction. Unfortunately I'm not able to edit it anymore.
Sorry I wasn't using the strict term of fission[1].
This reactor says it uses U-235 which would be full fission similar to the US SNAP-10A[2] or Russian BES-5 RTG[3]
So yes the fission part is more complicated than a P-238 alpha decay RTG. Perhaps I mischaracterized the R&D complexity on the reactor portion, although it has been done before.
1. https://physics.stackexchange.com/questions/35303/alpha-deca...
2. https://en.wikipedia.org/wiki/SNAP-10A
3. https://en.wikipedia.org/wiki/BES-5
This reactor says it uses U-235 which would be full fission similar to the US SNAP-10A[2] or Russian BES-5 RTG[3]
So yes the fission part is more complicated than a P-238 alpha decay RTG. Perhaps I mischaracterized the R&D complexity on the reactor portion, although it has been done before.
1. https://physics.stackexchange.com/questions/35303/alpha-deca...
2. https://en.wikipedia.org/wiki/SNAP-10A
3. https://en.wikipedia.org/wiki/BES-5
I didn't know about those reactors. Interesting.
When writing the answer, I didn't even consider, that those reactors need to be fast reactors. In retrospect it is obvious, but makes controlling the power even harder.
When writing the answer, I didn't even consider, that those reactors need to be fast reactors. In retrospect it is obvious, but makes controlling the power even harder.
There are fundamental physical limits of quantum nature to Seebeck effect based thermocouple efficiency.
The maximum what you can get can't be higher than the hypothetical ideal quantum diode made from a material pair.
There are much more down to earth alternatives that beat both stirlings and thermocouples on reliability and specific power density: thermionic converters, thermoaccoustic generators, AMTEC converters, radiophotovoltaic (works only in 0g)
The maximum what you can get can't be higher than the hypothetical ideal quantum diode made from a material pair.
There are much more down to earth alternatives that beat both stirlings and thermocouples on reliability and specific power density: thermionic converters, thermoaccoustic generators, AMTEC converters, radiophotovoltaic (works only in 0g)
Can you point me to the physical limit?
"Thermoelectric efficiency depends on the figure of merit, ZT. There is no theoretical upper limit to ZT, and as ZT approaches infinity, the thermoelectric efficiency approaches the Carnot limit. However, no known thermoelectrics have a ZT>3."[1]
There seem to be some in promising materials with a ZT of 2.2[2] which is around 20% similar to a solar cell. It seems again if more R&D where applied we might be able to make that cheap and practical.
1. https://en.wikipedia.org/wiki/Thermoelectric_materials#Devic...
2. https://newatlas.com/most-efficient-thermoelectric-material/...
"Thermoelectric efficiency depends on the figure of merit, ZT. There is no theoretical upper limit to ZT, and as ZT approaches infinity, the thermoelectric efficiency approaches the Carnot limit. However, no known thermoelectrics have a ZT>3."[1]
There seem to be some in promising materials with a ZT of 2.2[2] which is around 20% similar to a solar cell. It seems again if more R&D where applied we might be able to make that cheap and practical.
1. https://en.wikipedia.org/wiki/Thermoelectric_materials#Devic...
2. https://newatlas.com/most-efficient-thermoelectric-material/...
1. Work function - how much energy is needed to let an electron move from one material to another.
2. Quantum tunneling - electrons will tunnel back to lower charge density region, and preventing them from doing so is effectively impractical with modern day tech.
If they were any actual thermocouples with 20% efficiency, they would've nuked piston engines long time ago.
2. Quantum tunneling - electrons will tunnel back to lower charge density region, and preventing them from doing so is effectively impractical with modern day tech.
If they were any actual thermocouples with 20% efficiency, they would've nuked piston engines long time ago.
The thermoelectric generators with Pu238 don't use fission. The energy is released through alpha-decay.
Fission isn't necessarily easy. One problem is that the reactor behavior changes when you add the generators to the reactor. These components can reflect neutrons back to the reactor, which changes how much power the reactor produces. That being said, 'easy' or 'hard' are really not the best way to think about flight ready hardware. Actually making hardware and guaranteeing that it works involves so much more than just understanding nuclear fission. We can come up with a design on paper, but without testing we don't have assurance that it works.
Simply putting the reactor together and testing it are more complicated than they seem. This is because of three things matter can reflect neutrons back, humans are harmed by radiation, and humans are the ones assembling/transporting/testing the reactor. We have to be careful putting the reactor together so that it doesn't spew neutrons and harm the humans assembling it. We need to develop ways to transport the reactor so that it doesn't spew neutrons. When we test the reactor, we have to set up our test so that humans won't have to get anywhere close to the reactor for a couple of months. There's also other issues like training people to do these things and NASA cooperating with the DOE to do the testing. These are 'simple' things, but they still need to be done.
Simply putting the reactor together and testing it are more complicated than they seem. This is because of three things matter can reflect neutrons back, humans are harmed by radiation, and humans are the ones assembling/transporting/testing the reactor. We have to be careful putting the reactor together so that it doesn't spew neutrons and harm the humans assembling it. We need to develop ways to transport the reactor so that it doesn't spew neutrons. When we test the reactor, we have to set up our test so that humans won't have to get anywhere close to the reactor for a couple of months. There's also other issues like training people to do these things and NASA cooperating with the DOE to do the testing. These are 'simple' things, but they still need to be done.
>fission heat
Those probes are absolutely not using fission. Radioactive decay is not the same thing.
Those probes are absolutely not using fission. Radioactive decay is not the same thing.
They already completed the equivalent thermal power tests last year[0], and you most certainly don't need to do electrical tests at the Nevada Nuclear Test Site. How much progress they've actually made at this point is not clear from the article, but slides from a presentation they posted yesterday detail what they plan to test[1]/maybe already tested. They need to test the individual reactor components to measure reactivity, then they need to put the power generator on and see what happens when it's just critical, but not producing any heat, then they bring thermal power up to 4 kilowatts, then they do a full power test.
All of these tests involve fissile materials, so to quote Red Alert, "Gentlemen, it's a nuclear device."
[0]https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700... [1]https://www.nasa.gov/sites/default/files/atoms/files/kilopow...
All of these tests involve fissile materials, so to quote Red Alert, "Gentlemen, it's a nuclear device."
[0]https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700... [1]https://www.nasa.gov/sites/default/files/atoms/files/kilopow...
Thanks for the correction and a link to [1] which gives actual information on the tests. This is great news.
I 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.
There is a veritable orgy in nuclear tech for space here:
https://beyondnerva.wordpress.com/
See also
https://github.com/briligg/moonwards/wiki/Nuclear-Reactors--...
https://beyondnerva.wordpress.com/
See also
https://github.com/briligg/moonwards/wiki/Nuclear-Reactors--...
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[deleted]
What 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?
The 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.
It 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.
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.
A 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.
It'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.
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.
I 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.
In 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.
I 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)
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)
Gen-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.
I am not sure about the readings of the first two kanji (atomic) so I used generic ones heehe.
Thanks in advance.
Yes you are right.
原子 genshi means atom. 力 means power (strength). Stick them together and it means using the power of the atom.
原子 genshi means atom. 力 means power (strength). Stick them together and it means using the power of the atom.
> 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
Japan has completely shut down all operations of Nuclear Plants since 2011. https://en.wikipedia.org/wiki/Nuclear_power_in_Japan
And 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".
Consider 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.
That 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
Plutonium isn't toxic, not any more than any other heavy metal.
It is radiotoxic
Nope, 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.
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.
"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
Renaming things with bad public images is a popular trick.
Windscale > Sellafield
Blackwater > Xe Services > Academi
Philip Morris > Altria
The Blackwater one always mystified me. It’s like they set out to be villains.
It'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.
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.
> the reactor can just be jettisoned before re-entering Earth‘s gravity well
I think if there’s one thing to be learned from previous missions, it’s that nothing will „just work“. If the ejection mechanism is damaged, or the spacecraft is hit by some object and rendered useless shortly before ejection, then the radioactive payload will make it to Earth. I think a roundtrip would be dangerous, and the core should be left at Mars.
I think if there’s one thing to be learned from previous missions, it’s that nothing will „just work“. If the ejection mechanism is damaged, or the spacecraft is hit by some object and rendered useless shortly before ejection, then the radioactive payload will make it to Earth. I think a roundtrip would be dangerous, and the core should be left at Mars.
The political fallout will probably be more dangerous than adding another kilowatt-class nuclear reactor to decaying megawatt-class ones on sunken submarines.
This actually happened in the past. A Russian radar satellite failed to eject its nuclear reactor to a safe parking orbit and fell in Canada instead.
https://en.wikipedia.org/wiki/Kosmos_954
https://en.wikipedia.org/wiki/Kosmos_954
Never heard about this before, thanks for above link. Good link on Kosmos 954 recovery operation here: http://nationalinterest.org/feature/operation-morning-light-...
in that case you could still divert the vehicle itself, assuming it's unmanned.
My point is: yes, leaving it on mars is a pretty safe solution, but it's not the only one.
Triple redundancy usually works really well. Fail safes are great too.
"Hal, perform the earth orbit insertion burn"
"I'm sorry Dave, I can't let you do that"
"Hal, come on, not this shit again?"
"Dave, the reactor core cannot be ejected, and cannot be allowed to enter orbit"
"Hal, WTF?"
"Crew ejection will occur in 3, 2, 1...Goodbye Dave"
things are more and more likely to work now we can simulate things with computers first.
Ah, ok. Thanks for the explanation.
> 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?
Polluting the new homeland from the start, eh?
Just 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.
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.
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.
Or Runit Island: https://en.wikipedia.org/wiki/Runit_Island
Yep, Hanford Site was/is an epic disaster.
The correct response is reprocessing. Most of the "waste" generated by power reactors is actually still usable as fuel. It also eliminates the really long-lived stuff, so that the small amount of leftover waste only has to be kept stored for a much more manageable 500-1000 years.
The correct response is reprocessing. Most of the "waste" generated by power reactors is actually still usable as fuel. It also eliminates the really long-lived stuff, so that the small amount of leftover waste only has to be kept stored for a much more manageable 500-1000 years.
Fun 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.
That's so when the Martian Congressional Republic eventually decides to declare war on Earth, they'll be weakened from the get-go. It's called playing the long game...
How does pollution work exactly in an environment that's already hostile to life as we know it?
Thats 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?
It 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-...
https://listverse.com/2012/01/20/top-10-space-age-radiation-...
Not sure if applicable here; but where I come from they say "the fearful won't have kids"
If 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.
You will never be allowed to own one because you cannot be trusted to dispose of it correctly.
Ah yes, the Ford Nucleon
https://www.damninteresting.com/the-atomic-automobile/
https://www.damninteresting.com/the-atomic-automobile/
This oddly reminds me of the story of Fallout.
https://en.wikipedia.org/wiki/Fallout_(series)#Setting
https://en.wikipedia.org/wiki/Fallout_(series)#Setting
I 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.
Unfortunately for these miniaturized Uranium reactors, the Uranium must be highly enriched - in other words, weapons-grade.
I 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
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
The entire subject of what you're talking about, is a non-issue. Five years ago it was barely a legitimate concern. It has no legitimacy at this point. The problem, isn't a problem, it's solved.
See: Boeing and SpaceX. Add 8 to 12 months. Done.
And just like that, NASA has access to superior human launch capabilities versus Russia and China. And that's before Blue Origin builds out its New Glenn monster. Russia will fall very far behind over the next five years, only China will be able to afford to keep up over time.
SpaceX already passed Russia in launches this year. That's going to get a lot worse.
See: Boeing and SpaceX. Add 8 to 12 months. Done.
And just like that, NASA has access to superior human launch capabilities versus Russia and China. And that's before Blue Origin builds out its New Glenn monster. Russia will fall very far behind over the next five years, only China will be able to afford to keep up over time.
SpaceX already passed Russia in launches this year. That's going to get a lot worse.
I think outsourcing is precisely what we're doing; we're good at that.
Spaceflight is easy, creating a nuclear battery might be easy too, maybe even something we can outsource, but it's the one thing we definitely do not want other countries working on.
Spaceflight is easy, creating a nuclear battery might be easy too, maybe even something we can outsource, but it's the one thing we definitely do not want other countries working on.
What’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?
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?
> 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
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
If 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.
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.
I 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_inf...
https://www.boringcompany.com/faq/
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_inf...
https://www.boringcompany.com/faq/
I agree that Elon's companies do have suspiciously many things to do with Mars habitats.
However, the reliability of the tech we have is severely lacking. To get off Mars, you are going to need a rocket. So then you need to land a rocket on Mars.
Fully fueled.
You also need a backup. We simply do not have that kind of reliability yet, and I don't think we're even close.
Fine, we'll fuel it on Mars. That means a remote robotic mining-facility and rocket-fuel-plant, in nearly no atmosphere, in cold temps, up to 16 light-minutes away (at worst, true). So it's gotta be totally autonomous. And not explode while people are in transit. And it's likely going be on a pole, so that you have easy access to fuelstuffs. Which is boring as all heck compared to Valles Marianas (not a big deal, admittedly)
If we have that tech on Mars, then the economy of Earth is going to look a LOT different. Self-driving cars aren't the half of it.
Mars, in a nutshell, is VERY Hard.
However, the reliability of the tech we have is severely lacking. To get off Mars, you are going to need a rocket. So then you need to land a rocket on Mars.
Fully fueled.
You also need a backup. We simply do not have that kind of reliability yet, and I don't think we're even close.
Fine, we'll fuel it on Mars. That means a remote robotic mining-facility and rocket-fuel-plant, in nearly no atmosphere, in cold temps, up to 16 light-minutes away (at worst, true). So it's gotta be totally autonomous. And not explode while people are in transit. And it's likely going be on a pole, so that you have easy access to fuelstuffs. Which is boring as all heck compared to Valles Marianas (not a big deal, admittedly)
If we have that tech on Mars, then the economy of Earth is going to look a LOT different. Self-driving cars aren't the half of it.
Mars, in a nutshell, is VERY Hard.
Commercial crew tests (SpaceX/Boeing taking astronauts to the ISS) begin this year with plans for the first crewed flight in June. [1]
[1] - https://en.wikipedia.org/wiki/Commercial_Crew_Development#Fl...
[1] - https://en.wikipedia.org/wiki/Commercial_Crew_Development#Fl...
Except NASA was never really making the rockets in the first place. The US military and NASA work through contracts. The only thing that has really changed is that there are more competitors in the market now.
Unanswered 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?
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?
>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/201700... [1]https://www.nasa.gov/sites/default/files/atoms/files/kilopow... [2]https://www.daftlogic.com/information-appliance-power-consum...
>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/201700... [1]https://www.nasa.gov/sites/default/files/atoms/files/kilopow... [2]https://www.daftlogic.com/information-appliance-power-consum...
And 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?
Enriched uranium is one of the few supplies for which it's probably economically sustainable to provide continuously from Earth.
Considering the half-life, I'd assume the housing and device would fail long before the U235 decays enough for significant loss in heat production.
Part of Nasa's Game Changing Development program:
https://www.nasa.gov/directorates/spacetech/game_changing_de...
https://www.nasa.gov/directorates/spacetech/game_changing_de...
"Testing on components of the system, dubbed KRUSTY..."
Named after Krusty the Clown?
Named after Krusty the Clown?
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I'm curious, where does one get the nuclear fuel on Mars? Does it have to be flown all the way from the Earth?
Definitely. 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.
I 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.
What pertinent "special circumstances" do you mean?
Tectonic activety I suspect.
Tharsis region?
When was anything there last active?
Does it matter? It's not as if the deposits migrate.
I want one!
[deleted]
This 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.
I 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.
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.
What 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.
If 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.
There 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.
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.
> It's a human issue.
Which could be applied to any challenge that humanity face. This basic human weaknesses is always what holds us back in any endeavour. It is dangerous to just dismiss it as "arbitary". You have to deal with these issues if you want to make big projects achieve their objectives.
Which could be applied to any challenge that humanity face. This basic human weaknesses is always what holds us back in any endeavour. It is dangerous to just dismiss it as "arbitary". You have to deal with these issues if you want to make big projects achieve their objectives.
It's fine to put yourself to a danger willingly. It's not fine to put your neighbors to a danger without their consent.
The problem with many pieces of large-scale tech is potential harmful side effects on unrelated people who did not ask for that.
The problem with many pieces of large-scale tech is potential harmful side effects on unrelated people who did not ask for that.
Yes, I agree. People are often nonchalant about those low probability dangers. But a single death from Cancer is just as bad as the death of an astronaut, perhaps worse as they have not consented to the risk or understand it. We should care about that, especially as space exploration is such an optional undertaking which people don't have to support. That is why there is a range safety system and why anything radioactive needs to be treated with caution.
Hi, just to point out a hole in your reasoning, if these reactors are so safe then why even a small portion of the radioactivity escaping the containment shell can cause such a big disaster like Fukushima or Chernobyl?
Now, I understand there are differences in size and the level of radioactivity used (they won't be driven as close to prompt criticality as the power reactors) and they may be designed to be less reliant on active protection (pushing a lot of water as required means to prevent disaster).
But still, this is radioactive material in Earth orbit where stuff tends to fall back after some time and we don't always control when and where it reaches us.
Now, I understand there are differences in size and the level of radioactivity used (they won't be driven as close to prompt criticality as the power reactors) and they may be designed to be less reliant on active protection (pushing a lot of water as required means to prevent disaster).
But still, this is radioactive material in Earth orbit where stuff tends to fall back after some time and we don't always control when and where it reaches us.
> small portion of the radioactivity escaping the containment shell
The Chernobyl reactor was very unsafe by modern standards, it did not have a containment vessel and tens of tons of reactor material was blown into the air, not a small amount.
The Chernobyl reactor was very unsafe by modern standards, it did not have a containment vessel and tens of tons of reactor material was blown into the air, not a small amount.
To actually blow the Chernobyl reactor, the personnel explicitly disabled quite a few safety systems that otherwise would not allow for a runaway reaction which led to a mighty (thermal and chemical) explosion.
Yeah, that's what happens. Tons of reactor material gets released. Not by humans, but by physical processes.
And your comment conveniently ignores Fukushima.
And your comment conveniently ignores Fukushima.
Modern nuclear power plants are relatively safe. However, there is not enough data to determine how safe nuclear power is in general, because you have to take into account the whole production cycle including all long-term storage of nuclear waste.
Half life time of nuclear waste ranges from 30 years to 24,000 years, so it's possible that hundreds of people die in 30,000 years from now by being exposed to nuclear waste from our time.
Half life time of nuclear waste ranges from 30 years to 24,000 years, so it's possible that hundreds of people die in 30,000 years from now by being exposed to nuclear waste from our time.
If you're taking that kind of thing into account you need to take the same time range into account in other power sources.
How many hundreds of billions of people will die over the next 30000 years from coal effects? How does that compare to your 'hundreds'?
How many hundreds of billions of people will die over the next 30000 years from coal effects? How does that compare to your 'hundreds'?
I completely agree and don't think coal is better than nuclear power at all. Reduction of energy waste, renewable energy sources and nuclear fushion are the obvious way to go, but it may make sense to temporarily accompany them with nuclear power.
Sure, I didn't mean to imply that. I just meant that whatever long term damages are done need to be put on a timescale that actually helps us compare alternatives.
If hundreds of billions of lives are saved in the time it takes for nuclear to do real damage, maybe that's just worth it.
If hundreds of billions of lives are saved in the time it takes for nuclear to do real damage, maybe that's just worth it.
It is also worth to estimate how quickly nuclear production can scale up and deplace coal. I personally think wind and solar can scale up much faster economically and socially and more easily deplace coal and gas than nuclear could in the best case.
I'm not sure I am convinced by this argument. You say it "only adds to the cost of the mission" as if that wasn't an issue, but unfortunately our resources are finite. If we increase the cost of any given mission that means we cannot do other missions. There is always a trade-off here, and I am not sure if the advantages of solar would be worth the cost of holding back research that much.
You could easily make the opposite argument - solar power is an easy way out of making nuclear power safe enough to go up into space. Having to use nuclear power for missions might do a lot of good in terms of researching and perfecting safe nuclear power.
You could easily make the opposite argument - solar power is an easy way out of making nuclear power safe enough to go up into space. Having to use nuclear power for missions might do a lot of good in terms of researching and perfecting safe nuclear power.
Nuclear reactors that have some service time on them are very, very, very radioactive. Just look what happens when a very small portion of that radioactivity finds itself into the atmosphere or water (Chernobyl, Fukushima, etc.)
It is maybe not as big a problem if we never plan it to return to Earth or Mars orbit (reactor is not as radioactive until it actually is started), but if we are using it to supply energy to the crew for the duration of the mission in deep space, the reactor will inevitably be radiactive and brought at least to Mars orbit or even back to Earth orbit.
Now, if that piece of junk falls to Earth, we have a big problem. Not the same kind of problem as falling solar array.
It is maybe not as big a problem if we never plan it to return to Earth or Mars orbit (reactor is not as radioactive until it actually is started), but if we are using it to supply energy to the crew for the duration of the mission in deep space, the reactor will inevitably be radiactive and brought at least to Mars orbit or even back to Earth orbit.
Now, if that piece of junk falls to Earth, we have a big problem. Not the same kind of problem as falling solar array.
Exactly what do you think "happens" ?
Not even Chernobyl, that had an atmospheric nuclear fire, the worst case scenario imaginable, had a economic, environmental or human live cost comparable to the impact of a single coal power plant.
It really concerns me when people on this forum, that has no excuse to not know better, parrots this anti-nuclear FUD.
Not even Chernobyl, that had an atmospheric nuclear fire, the worst case scenario imaginable, had a economic, environmental or human live cost comparable to the impact of a single coal power plant.
It really concerns me when people on this forum, that has no excuse to not know better, parrots this anti-nuclear FUD.
Chernobyl had far worse consequences than you are indicating, even taking into account a coals plant's lifetime impact from mining to air pollution.
Aside from the headline numbers of 31 dead and 237 with acute radiation poisoning other costs include:
- Encasing the site in a sarcophagus that will need to be maintained essentially forever. Immediate disaster response was estimated at $18B in today's dollars.
- A 30km exclusion zone from which 135,000 people were evacuated. Costs from this include costs of resettlement, loss of essentially all capital, cropland, and infrastructure in the zone
- Outside the zone millions of tons of contaminated earth were trucked for containment. Remediation is ongoing to this day and will continue indefinitely. Certain agricultural production is limited by type and practice to reduce probability of contamination from deeper in the soil.
- Health monitoring response across Europe in the aftermath, plus increased monitoring forever in the neighboring countries
- An unknown number of additional cancers and birth defects
There are additional costs, mostly more evacuees than were likely strictly necessary and compensation to others affected. Its unclear how much of this are legitimate costs or not, but its worth noting that uncertainty and lack of transparency themselves have costs.
https://en.wikipedia.org/wiki/Chernobyl_disaster
https://en.wikipedia.org/wiki/Effects_of_the_Chernobyl_disas...
Aside from the headline numbers of 31 dead and 237 with acute radiation poisoning other costs include:
- Encasing the site in a sarcophagus that will need to be maintained essentially forever. Immediate disaster response was estimated at $18B in today's dollars.
- A 30km exclusion zone from which 135,000 people were evacuated. Costs from this include costs of resettlement, loss of essentially all capital, cropland, and infrastructure in the zone
- Outside the zone millions of tons of contaminated earth were trucked for containment. Remediation is ongoing to this day and will continue indefinitely. Certain agricultural production is limited by type and practice to reduce probability of contamination from deeper in the soil.
- Health monitoring response across Europe in the aftermath, plus increased monitoring forever in the neighboring countries
- An unknown number of additional cancers and birth defects
There are additional costs, mostly more evacuees than were likely strictly necessary and compensation to others affected. Its unclear how much of this are legitimate costs or not, but its worth noting that uncertainty and lack of transparency themselves have costs.
https://en.wikipedia.org/wiki/Chernobyl_disaster
https://en.wikipedia.org/wiki/Effects_of_the_Chernobyl_disas...
Please provide a citation for this claim.
Chernobyl still is a massive cost factor for plenty of countries ( all that are helping out financially with building the new mantle ).
Also look at the large effects of Fukushima.
Every time nuclear power comes up here on HN, there are some fierce defenders.
No matter how 'safe' newer generation plants are and how much it was the oprators fault, the potential for disaster is there. And that's not even mentioning the high lifetime cost when you consider safely storing the material, which often falls to the public.
Chernobyl still is a massive cost factor for plenty of countries ( all that are helping out financially with building the new mantle ).
Also look at the large effects of Fukushima.
Every time nuclear power comes up here on HN, there are some fierce defenders.
No matter how 'safe' newer generation plants are and how much it was the oprators fault, the potential for disaster is there. And that's not even mentioning the high lifetime cost when you consider safely storing the material, which often falls to the public.
http://www.unscear.org/docs/reports/2008/11-80076_Report_200...
Now please provide citations for your claims. Specifically 'Massive Costs' and 'large effects'.
Nuclear power does not need to be safe, only saver than the alternatives, this includes long term pollution from solar panel waste.
Every ounce of nuclear waste is entirely contained, every other power source's waste is dumped into the environment.
Now please provide citations for your claims. Specifically 'Massive Costs' and 'large effects'.
Nuclear power does not need to be safe, only saver than the alternatives, this includes long term pollution from solar panel waste.
Every ounce of nuclear waste is entirely contained, every other power source's waste is dumped into the environment.
> Every ounce of nuclear waste is entirely contained, every other power source's waste is dumped into the environment.
That's a little disingenuous, though, isn't it? It's only contained because no one will allow it to be dumped ("stored") near them. Actually, the fact that we have to take special precautions with nuclear waste due to its toxicity is a disadvantage of nuclear power vs. fossil fuels (for example).
Obviously, there is a much different calculus when thinking about Mars though.
That's a little disingenuous, though, isn't it? It's only contained because no one will allow it to be dumped ("stored") near them. Actually, the fact that we have to take special precautions with nuclear waste due to its toxicity is a disadvantage of nuclear power vs. fossil fuels (for example).
Obviously, there is a much different calculus when thinking about Mars though.
Your reference has absolutely nothing to do with economic effects.
Chernobyl costs for new "sarcophagus": 1.5bn (https://en.wikipedia.org/wiki/Chernobyl_New_Safe_Confinement, sources on bottom)
Fukushima cost: 188bn + (https://www.reuters.com/article/us-tepco-fukushima-costs/jap...)
Costs for decomissioning a nuclear power plant in the US: up to 500mil (https://www.nrc.gov/reading-rm/basic-ref/students/decommissi...) (which needs total cost and revenue to put it in perspective, but it gives a sense of the scale and difficulty of decommissioning and storage.
Chernobyl costs for new "sarcophagus": 1.5bn (https://en.wikipedia.org/wiki/Chernobyl_New_Safe_Confinement, sources on bottom)
Fukushima cost: 188bn + (https://www.reuters.com/article/us-tepco-fukushima-costs/jap...)
Costs for decomissioning a nuclear power plant in the US: up to 500mil (https://www.nrc.gov/reading-rm/basic-ref/students/decommissi...) (which needs total cost and revenue to put it in perspective, but it gives a sense of the scale and difficulty of decommissioning and storage.
It has everything to do with the economic costs. There is no other reason other than perceived threat to human life that drives that cost. How is that not obvious ?
That paper, and others like it, demonstrates that radiation is much more benign than generally believed, and that level of resources spent on threads that don't exists, especially in comparison with others, like drink a can of soda a day, or living in a city, is not justifiable.
That paper, and others like it, demonstrates that radiation is much more benign than generally believed, and that level of resources spent on threads that don't exists, especially in comparison with others, like drink a can of soda a day, or living in a city, is not justifiable.
The use of nuclear power should be encouraged and popularised whenever we can. Years of nuclear FUD needs to be unwound and humanity re-educated on the benefits of nuclear power. So much of our current climate change predicament could have been avoided. Its a crying shame.
https://www.youtube.com/watch?v=ciStnd9Y2ak
https://www.youtube.com/watch?v=ciStnd9Y2ak
This isn't a fission test. It's a mechanical engineering test. Still cool.