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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

#151

Post by yellowapple »

louithethrid wrote: post #147
yellowapple wrote: post #139

Earlier quoted context omitted.

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?

I don't disagree. Ceres ain't that much further, and it's literally a giant ball of water and hydrocarbons.

That said, it's possible that even Mars' relatively low gravity is enough to stave off the health problems associated with prolonged microgravity/freefall, so that might be good motivation. If there's some lower bound on how high g needs to be in order for our bones to not become brittle, and Mars is above it while - say - the Moon is below it - then Mars is really the only option besides the moons of the gas/ice giants (and their respectively-giant gravity wells) or Venus (with its Earth-like gravity well and its hellscape of a surface).

So there's another scientific motivation: to measure the effects of low but existing gravity on human health.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#152

Post by mr_overalls »

simias wrote: post #63
tehwalrus wrote: post #54

Earlier quoted context omitted.

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!

I don't know if I agree. Creating a self-sustainable colony on Mars will take a very long time and even if we manage to do it can we really afford to "lose" the earth? Mars is an inhospitable hell for humans and practical terraforming technology is still in the realm of science fiction. Maybe if we manage to destroy earth completely out of selfishness and hate we don't really deserve to spread the virus throughout th…

The fear of self-destruction (or phrased as its complement, the drive for survival) is one of the most potent motivators that humans have.

The argument could be made that Martian humans would be supremely motivated to move the environmental parameters there toward a survivable state for lightly-outfitted humans.

Contrast this with Earth, where space exploration is a four-order or fifth-order concern for most people, and long-term environmental issues are treated as abstract exercises in reducing economic externalities. This is because Earthlings have (mostly) had it easy. We're biologically evolved and culturally adapted to survive here, and thus don't have a strong intrinsic motivation (yet) to maintain the long-term health of the biosphere.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#154

Post by gorkonsine »

Retric wrote: post #141
gorkonsine wrote: post #134

Earlier quoted context omitted.

>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 m…

Luckily for us, a bunch of wealthy and influential people disagree with you and know more about this stuff than you do, and have started companies like Planetary Resources. All that stuff we're mining from the Earth's crust came from asteroids, not from the formation of the planet, and it's far better concentrated in asteroids than it is in the crust, so no, there really is a huge niche for asteroid mining or else there wouldn't be a lot of money put into exploring this. No, asteroids impacting Mars are going to have the same problem that they do on Earth: it reduces the concentration too much so you have to process a lot of dirt to get to the valuable ores; this isn't the case with asteroids.

>You need life support, food, water etc.

We figured all that stuff out ages ago. We can already recycle air and water and have been doing so on space stations for decades. Food can be supplied by resupply missions, and also grown on-site; it's not that hard. You're completely overstating the problem. If you think that running a small space station is somehow far harder than running a habitat on Mars (where you cannot control the gravity at all), which seems to be what you're implying here, you have no idea what you're talking about, and I think you're being intellectually dishonest to boot.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#155

Post by Retric »

gorkonsine wrote: post #154
Retric wrote: post #141

Earlier quoted context omitted.

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 m…

Luckily for us, a bunch of wealthy and influential people disagree with you and know more about this stuff than you do, and have started companies like Planetary Resources. All that stuff we're mining from the Earth's crust came from asteroids, not from the formation of the planet, and it's far better concentrated in asteroids than it is in the crust, so no, there really is a huge niche for asteroid mining or else th…

'Planetary Resources' is a scam. They get good PR by talking about space mining while working on something completely different.

To put things in perspective if we knew about a 1,000 ton 100% gold asteroid at say 1.2 AU, getting that to earth right now would cost more than it was worth. Add on top of that the need to refine stuff in space or send back less valuable material and it's a pipe dream until we get a lot better at spaceflight.

PS: You can increase the gravity of living spaces on mars 'easily' by rotating the habitat. Though we don't expect that to be necessary.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#156

Post by gorkonsine »

Retric wrote: post #155
gorkonsine wrote: post #154

Earlier quoted context omitted.

Luckily for us, a bunch of wealthy and influential people disagree with you and know more about this stuff than you do, and have started companies like Planetary Resources. All that stuff we're mining from the Earth's crust came from asteroids, not from the formation of the planet, and it's far better concentrated in asteroids than it is in the crust, so no, there really is a huge niche for asteroid mining or else th…

'Planetary Resources' is a scam. They get good PR by talking about space mining while working on something completely different. To put things in perspective if we knew about a 1,000 ton 100% gold asteroid at say 1.2 AU, getting that to earth right now would cost more than it was worth. Add on top of that the need to refine stuff in space or send back less valuable material and it's a pipe dream until we get a lot be…

How would you rotate a habitat on Mars, without having a major engineering challenge due to the existing gravity? Citation needed. And how would it not be necessary? 1/3g gravity is surely not healthy for humans long-term. Citation needed.

How is Planetary Resources a scam? Citation needed.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#157

Post by Retric »

gorkonsine wrote: post #156
Retric wrote: post #155

Earlier quoted context omitted.

'Planetary Resources' is a scam. They get good PR by talking about space mining while working on something completely different. To put things in perspective if we knew about a 1,000 ton 100% gold asteroid at say 1.2 AU, getting that to earth right now would cost more than it was worth. Add on top of that the need to refine stuff in space or send back less valuable material and it's a pipe dream until we get a lot be…

How would you rotate a habitat on Mars, without having a major engineering challenge due to the existing gravity? Citation needed. And how would it not be necessary? 1/3g gravity is surely not healthy for humans long-term. Citation needed. How is Planetary Resources a scam? Citation needed.

Ahh, keep talking long enough and it's obvious you don't know what your talking about.

We can easily do 20g on earth: https://en.wikipedia.org/wiki/High-G_training

1g is much easier in mars gravity as you can simply tilt the chamber at an angle while spinning it. Training centrifuges generally have the chamber on a hinge so you automatically get the correct angle.

Now, sure you lose some energy to friction. But, not all that much further, we have a lot of experience dealing with very heavy rotating objects for decades. EX: Power plants.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#158

Post by vkou »

logfromblammo wrote: post #130
vkou wrote: post #117

Earlier quoted context omitted.

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.

I think the largest problem in orbital manufacturing is actually rejection of waste heat. Otherwise, being able to run robots in an oxygen-free environment and move around large masses without conveyors sounds pretty good.

It's also an environment full of cosmic rays, which requires hardening of all your electronics, an environment where fluids don't flow through pipes, an environment where dust and powders don't settle, an environment where conveyor belts don't work because things float off them...

Almost every single industrial process that we have relies on a constant, freely available, predictable, unidirectional acceleration of 9.8 m/s^2.

Imagine trying to build a twenty-tonne steel smelter that will function in orbit - I'm sure working with tonnes of molten steel that won't stay where you put it would be a breeze.

There's also the part where many of our industrial processes are extremely water-hungry. Any kind of space industries would require complete reclamation of all waste water, stream, etc - with a large cooling cycle, to boot. And heaven forbid if the process consumes nitrogen, oxygen, or hydrogen in any appreciable amounts - unlike on Earth, you can't synthesize them in space.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#159

Post by gorkonsine »

Retric wrote: post #157
gorkonsine wrote: post #156

Earlier quoted context omitted.

How would you rotate a habitat on Mars, without having a major engineering challenge due to the existing gravity? Citation needed. And how would it not be necessary? 1/3g gravity is surely not healthy for humans long-term. Citation needed. How is Planetary Resources a scam? Citation needed.

Ahh, keep talking long enough and it's obvious you don't know what your talking about. We can easily do 20g on earth: https://en.wikipedia.org/wiki/High-G_training 1g is much easier in mars gravity as you can simply tilt the chamber at an angle while spinning it. Training centrifuges generally have the chamber on a hinge so you automatically get the correct angle. Now, sure you lose some energy to friction. But, not…

A small centrifuge is not a viable place to have an entire colony to live in. Sure, you can stick someone in a high-g centrifuge by himself for a little while, but I'm talking about a habitat that people live indefinitely. Equating the two clearly shows you don't know what you're talking about.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#160

Post by Retric »

gorkonsine wrote: post #159
Retric wrote: post #157

Earlier quoted context omitted.

Ahh, keep talking long enough and it's obvious you don't know what your talking about. We can easily do 20g on earth: https://en.wikipedia.org/wiki/High-G_training 1g is much easier in mars gravity as you can simply tilt the chamber at an angle while spinning it. Training centrifuges generally have the chamber on a hinge so you automatically get the correct angle. Now, sure you lose some energy to friction. But, not…

A small centrifuge is not a viable place to have an entire colony to live in. Sure, you can stick someone in a high-g centrifuge by himself for a little while, but I'm talking about a habitat that people live indefinitely. Equating the two clearly shows you don't know what you're talking about.

> having a major engineering challenge due to the existing gravity?

Rotating a habitat is a hard problem in space or on a planet. But, Mars's is gravity would make the problem easier not harder. The atmosphere might be a problem, scale might be a problem etc etc, but gravity is not. Further, there may be little need for 24/7 1g, perhaps a tiny room to work out in is enough, perhaps you should sleep in 1g or perhaps 1/3 is enough for sleep etc.

But, again gravity is not the problem. And yes such a massive fundamental failure in understanding is a clear sign of incompetence.

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