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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

#141

Post by Retric »

gorkonsine wrote: post #134
Retric wrote: post #110

Earlier quoted context omitted.

Mining asteroids has a ton of issues even beyond the obvious cost and R&D problems. They are generally far from the sun so solar power is significantly less useful. You need to move a lot of bulk material which means heavy Delta V problems. Micro gravity means you can't have humans in the area for long without giant structures. Finally, economically resources are just not that scarce. The delta V issues are more reas…

>They are generally far from the sun so solar power is significantly less useful. No, they aren't. There's tons of asteroids in Earth-crossing orbits. And Mars-crossing orbits too. It'll be a long time before we use those up. >You need to move a lot of bulk material which means heavy Delta V problems. No, you don't. You process the ores near the asteroids; you don't have to ship it all to the point-of-use. >Micro gra…

Basically, if you can mine it on earth you can do the same on mars excluding organic compounds.

Anyway, back to your argument. Processing ore is not light weight. Total mass of asteroids inside earths orbit is actually surprisingly low relative to planetary manufacturing needs. Sure the asteroid belt is ~4% of the moons mass, but inner planets have mostly cleared their orbits.

Yea, there are KM sized objects, which might be rich in stuff we want. But consider, Bingham Canyon Mine for example is 0.6 miles deep and 2.5 miles wide and that's just for copper. And even if you processed it all you still need Delta V on 19 million tonnes of copper.

Look at a periodic table. Mines can only really provide you with that stuff. Now exclude the useless elements and the stuff and what's abundant and there really is not a huge niche for asteroid mining. Futher ateriods regularly impacted mars after it had a solid surface so all the same elements are there much like they are on earth.

So, you really need asteroid mining to stand on it's own independent of colonizing Mars.

PS: Artificial gravity only gets you part of the way to dealing with micro gravity You need life support, food, water etc. Spin all that stuff and you need an even stronger tether with a larger counter weight.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#142

Post by [deleted] »

TomK32 wrote: post #88
SCAQTony wrote: post #79

Wouldn't the moon would be a better choice? Asteroids could be processed there, it could be a de facto source of microwave power for asteroid mining ops and a weigh station to bring metals back safely.

The moon is boring, Mars once had water and very likely life on it. Moon has a month-long day/night cycle and less gravity, two thing humans aren't well adapted.

[deleted]

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#143

Post by [deleted] »

TomK32 wrote: post #88
SCAQTony wrote: post #79

Wouldn't the moon would be a better choice? Asteroids could be processed there, it could be a de facto source of microwave power for asteroid mining ops and a weigh station to bring metals back safely.

The moon is boring, Mars once had water and very likely life on it. Moon has a month-long day/night cycle and less gravity, two thing humans aren't well adapted.

[deleted]

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#144

Post by SCAQTony »

TomK32 wrote: post #88
SCAQTony wrote: post #79

Wouldn't the moon would be a better choice? Asteroids could be processed there, it could be a de facto source of microwave power for asteroid mining ops and a weigh station to bring metals back safely.

The moon is boring, Mars once had water and very likely life on it. Moon has a month-long day/night cycle and less gravity, two thing humans aren't well adapted.

I am astonished by your comment. In no way would Mars assist the earth whatsoever economically or as a safe haven. The purpose of spending billions upon billions on an off world reservation where you could never go outside or produce anything productive for the earth is not worth it.

IMHO the moon is not boring it would be vital if we take mining for metals off world and perhaps discover new ways clean up out carbon issues and economic disparity.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#145

Post by mrep »

Symmetry wrote: post #111
DennisP wrote: post #97

Earlier quoted context omitted.

NASA's Kilopower design uses enriched uranium fuel, and with such a small reactor it won't be much uranium.

I'd expect that part of the reason they use uranium instead of plutonium is exactly to make sure the reactor is safe in the event of a rocket failure.

I expect it to be because there isn't much plutonium left [1].

[1]: http://www.popsci.com/plutonium-238-is-produced-in-america-f...

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#146

Post by valuearb »

vkou wrote: post #117
monocasa wrote: post #109

Earlier quoted context omitted.

> on the surface of mars Why? Wouldn't it be easier to bootstrap by mining asteroids, and manufacturing in micro gravity, then dropping nearly finished goods onto the planet? That'd also allow you to use the same bootstrapping infrastructure for several surface sites.

Why would you want to manufacture in microgravity? What are the practical advantages of this? I can't think of any, but I can think of a lot of disadvantages of this. Also, a Mars colony would require millions of tonnes of raw materials. You can only get that in-situ.

It's far cheaper to send people to asteroids than Mars. Even those in the belt. And they have trillions of tons of easily accessible raw materials.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#147

Post by louithethrid »

yellowapple wrote: post #139
menzoic wrote: post #78

Earlier quoted context omitted.

If we could terraform a planet as barren as Mars, wouldn't fixing earth be significantly easier?

Yes, which is exactly why we should terraform Mars: as a test run of a severe-case rebuilding scenario. If we can handle Mars even at its best (let alone its worst), then we can handle Earth in all but the most catastrophic events. I personally feel that having a "fallback" in case something literally Earth shattering happens is compelling enough a reason to colonize other bodies in our solar system, Mars included.

I just dont get it why we have to go down another gravity well.. why is it such a unpopular idea, to put some tents up inside a asteroid?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#149

Post by davedx »

Robotbeat wrote: post #112
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…

ISS solar arrays produce more power than that, plus they're literally from the 1980s. We have far more efficient and lower mass designs. You should use Ultraflex or similar as a standard. Instead of the ~7W/kg you used for ISS arrays at Earth orbit, you'll get ~150W/kg at Earth orbit: https://www.orbitalatk.com/space-systems/space-components/so... We have commercial satellites that also use much cheaper arrays with m…

Wow, nice, thanks for the information. I find this stuff fascinating! Do you have any further reading?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#150

Post by danpalmer »

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.

Sure, but that was a) 31 years ago, b) a reactor built without the safety standards we have now, and c) a reactor operated without the safety standards we have now.

As far as I understand, making a reactor built in the last 25 years go 'wrong' in any way like that is very difficult, and would take much more than negligence or incompetence.

Fukushima is an example of this – the reactor that had issues was over 50 years old, but all the modern ones were fine.

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