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NASA Revives Plan to Put Nuclear Reactors on Mars

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Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#51

Post by iplaw »

davedx wrote: post #39

I looked into some numbers on this, comparing theoretical costs of nuclear power with a solar PV solution on Mars. Kilopower (NASA's research project for a Martian nuclear fission reactor, from the article): 7,200 kg for 40 kW. [1] ISS solar arrays: 14,515 kg for ~100 kW in Earth orbit. [2] If we assume 40-50% Earth solar insolation on Martian surface, the ISS PV array probably isn't far off 40 kW output on Mars Conc…

Thanks for this concise comparison. As others have noted, you also need to account for batteries, and battery churn. When the batteries need to be replaced, you have quite a bit of additional payload that needs to be delivered. I am sure that nuclear fuel rods (or pellets, or whatever fuel type they are using) will be dramatically lighter and easier to transport.

Dust will need to be cleaned off of the panels daily, which adds further expense associated with dedicated external missions to the array of panels.

Most of the ancillary considerations weigh in favor of the nuclear option.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#52

Post by DiThi »

mikejb wrote: post #48
danpalmer wrote: post #11

Earlier quoted context omitted.

I disagree. Nuclear reactors have been very safe for a long time now, but between high profile incidents with old reactors, the link with nuclear weapons, and misinformation, the public perception is that they are unsafe.

"very safe" might be true (your interpretation of 'very' might vary), but it is a low chance/high price kind of thing. I live in Bavaria, and hunters here still need to take precautions due to Chernobyl, some 31 years later.

It's very safe if you don't disable safety systems put in place (like it was explicitly done in Chernobyl to do dangerous experiments, even though they labeled it as "routine tests"). And if you don't ignore many warnings given in the industry (like TEPCO ignoring many recommendations of raising their tsunami protection walls many years before the catastrophe, like other plants closer to the epicenter that were unaffected).

So the chance is much lower than people think, if plans have measures to avoid such corruptions. And that's not counting the many safer designs we have nowadays. Many plants today don't even need backup electricity to automatically shut down by themselves.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#53

Post by knz »

batushka wrote: post #49
davedx wrote: post #39

I looked into some numbers on this, comparing theoretical costs of nuclear power with a solar PV solution on Mars. Kilopower (NASA's research project for a Martian nuclear fission reactor, from the article): 7,200 kg for 40 kW. [1] ISS solar arrays: 14,515 kg for ~100 kW in Earth orbit. [2] If we assume 40-50% Earth solar insolation on Martian surface, the ISS PV array probably isn't far off 40 kW output on Mars Conc…

Better windmills :D This green energy hoax barely sustains communities on earth, why would sane someone risk on Mars? Mission needs reliability - we have nuclear power sources reliably working for decades, powering bigger things than calculator.

Can you explain what you mean by "green energy hoax [that] barely sustains communities on earth"?

Renewables are part of having a diverse power grid and because of the investment needed they are situated in areas with consistent/reliable wind/solar radiation.

I drive past the massive wind farms of Minnesota and he Dakota's regularly - they are almost always generating electricity. My understanding is that the US has significant potential renewable energy reserves.

Edit. Wikipedia suggests that about 14% of the US grid is currently renewables (https://en.m.wikipedia.org/wiki/Renewable_energy_in_the_Unit...) - that seems far from "barely sustaining".

The map of potential for wind alone suggests great potential - https://en.m.wikipedia.org/wiki/File:Wind_power_potential_ma...

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#54

Post by tehwalrus »

simias wrote: post #10
sp0ck wrote: post #2

It's about time. Engineering decisions shouldn't be made based of irrational fears of general population. If nuclear power plant is best option for space mission we should use it.

I agree with your sentiment but let's face it, sending humans to Mars is as much PR as it is scientific research (maybe even more). Look how we ended up on the moon in the first place. If NASA wants to get the funding it has to make it as marketable as possible. If there's a big push back from the general population it will be hard to convince the politicians to invest billions in an unpopular project with no short-t…

I would say, given the state of politics and the general attitude to the climate and natural resources, our first priority should be colonising another planet. Putting some scientists on Mars for a few years is step 1 in that very important insurance scheme!

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#55

Post by dredmorbius »

avar wrote: post #46
xorfish wrote: post #41

Earlier quoted context omitted.

The cost wouldn't be trivial for powering a mars colony. I'm sure the demand for a colony would scale pretty fast to 100kW or more. Now we are talking about Billions. So I think that your original point that cost for Pu-238 is not an issue for a colony is wrong. Small reactors are a much better option as a single ton of fuel could supply a colony with a few MW for decades. You just have to make sure that the largest…

My original point was that dredmorbius's comment that Pu-238 is in low supply wasn't referencing some law of nature, but a political decision that could be changed. I said they were a "bad idea for general power generation", so I'm not suggesting that they be used to power a Mars colony, but rather that the reasons not to do so don't include Pu-238 being in low supply. We also have a low supply of rockets & other inf…

There are laws of nature involved. But also of men, nations, and war.

Pu-238 isn't found in nature, but has to be synthesized. The precursor material, U-238 is the most abundant form of Uranium, which is convenient. It's also produce via neptunium-237.

The real complication is that the nuclear synthesis processes are also those used for nuclear weapons production, which makes for some serious complications.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#56

Post by [deleted] »

knz wrote: post #53
batushka wrote: post #49

Earlier quoted context omitted.

Better windmills :D This green energy hoax barely sustains communities on earth, why would sane someone risk on Mars? Mission needs reliability - we have nuclear power sources reliably working for decades, powering bigger things than calculator.

Can you explain what you mean by "green energy hoax [that] barely sustains communities on earth"? Renewables are part of having a diverse power grid and because of the investment needed they are situated in areas with consistent/reliable wind/solar radiation. I drive past the massive wind farms of Minnesota and he Dakota's regularly - they are almost always generating electricity. My understanding is that the US has…

[deleted]

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#57

Post by aphextron »

davedx wrote: post #39

I looked into some numbers on this, comparing theoretical costs of nuclear power with a solar PV solution on Mars. Kilopower (NASA's research project for a Martian nuclear fission reactor, from the article): 7,200 kg for 40 kW. [1] ISS solar arrays: 14,515 kg for ~100 kW in Earth orbit. [2] If we assume 40-50% Earth solar insolation on Martian surface, the ISS PV array probably isn't far off 40 kW output on Mars Conc…

>The build cost of the ISS arrays was around $300 million (space PV is way more expensive than terrestrial).

That was 20 years ago, on a government contract, for panels that must survive the rigors of actual space.

Panel manufacturing costs have dropped almost 10x since then, and the environment (assumed under the protection of martian atmosphere) which they will operate will be far less extreme than Earth orbit, necessitating less expensive materials. I'm not so sure your numbers account for this.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#58

Post by mikejb »

DiThi wrote: post #52
mikejb wrote: post #48

Earlier quoted context omitted.

"very safe" might be true (your interpretation of 'very' might vary), but it is a low chance/high price kind of thing. I live in Bavaria, and hunters here still need to take precautions due to Chernobyl, some 31 years later.

It's very safe if you don't disable safety systems put in place (like it was explicitly done in Chernobyl to do dangerous experiments, even though they labeled it as "routine tests"). And if you don't ignore many warnings given in the industry (like TEPCO ignoring many recommendations of raising their tsunami protection walls many years before the catastrophe, like other plants closer to the epicenter that were unaff…

I fully agree that newer designs are safer, but ignoring the human factor in the equation is IMO not very reasonable. Without the human factor, driving a car is very safe. That argument is valid, but it doesn't reflect reality.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#59

Post by pbhjpbhj »

nradov wrote: post #5
foota wrote: post #3

Are there fissionable materials on Mars?

Sure there is uranium on Mars. But extracting and refining it won't be easy.

How predictably can we locate Uranium ore using surface topography? Like can we choose a site with a high probability of ore being find near by?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#60

Post by davedx »

aphextron wrote: post #57
davedx wrote: post #39

I looked into some numbers on this, comparing theoretical costs of nuclear power with a solar PV solution on Mars. Kilopower (NASA's research project for a Martian nuclear fission reactor, from the article): 7,200 kg for 40 kW. [1] ISS solar arrays: 14,515 kg for ~100 kW in Earth orbit. [2] If we assume 40-50% Earth solar insolation on Martian surface, the ISS PV array probably isn't far off 40 kW output on Mars Conc…

>The build cost of the ISS arrays was around $300 million (space PV is way more expensive than terrestrial). That was 20 years ago, on a government contract, for panels that must survive the rigors of actual space. Panel manufacturing costs have dropped almost 10x since then, and the environment (assumed under the protection of martian atmosphere) which they will operate will be far less extreme than Earth orbit, nec…

Good points. They do need to be tough enough to withstand Martian dust storms, but apparently they aren't as bad as they look due to the low atmospheric pressure. I read the biggest problem is cleaning the dust off them.
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