Down and Out on Mars and Venus

[Aaaaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaatopia]

can we make the middle of mars spin to create a magnetic field?

[Grenartia]

Nuclear reactors are a serious problem on Mars: how do you cool them?

You could probably use some sort of geothermal cooling. Or a heat exchanger to the Martian atmosphere. Mars is already cold. Also use a reactor with a negative void coefficient. Which self regulates heat.
Reactors do not have to be cooled by external water body.
We managed to put one on a aircraft for example.

Beat me to the punch. PBRs, specifically, can use gaseous CO2 for coolant.

[Risottia]

Nuclear reactors are a serious problem on Mars: how do you cool them?

You could probably use some sort of geothermal cooling. Or a heat exchanger to the Martian atmosphere. Mars is already cold. Also use a reactor with a negative void coefficient. Which self regulates heat.
Reactors do not have to be cooled by external water body.
We managed to put one on a aircraft for example.

The heat capacity per volune of the martian atmosphere is way lower than the terrestrial one.
And you'd have to carry refined nuclear fuel from Earth. I would guess using locally-produced PV panels would be easier , although slower.

[Grenartia]

You could probably use some sort of geothermal cooling. Or a heat exchanger to the Martian atmosphere. Mars is already cold. Also use a reactor with a negative void coefficient. Which self regulates heat.
Reactors do not have to be cooled by external water body.
We managed to put one on a aircraft for example.

The heat capacity per volune of the martian atmosphere is way lower than the terrestrial one.
And you'd have to carry refined nuclear fuel from Earth. I would guess using locally-produced PV panels would be easier , although slower.

Wind power + PV would be good for setting up the infrastructure to mine and refine nuclear fuel in situ.

[Novus America]

You could probably use some sort of geothermal cooling. Or a heat exchanger to the Martian atmosphere. Mars is already cold. Also use a reactor with a negative void coefficient. Which self regulates heat.
Reactors do not have to be cooled by external water body.
We managed to put one on a aircraft for example.

The heat capacity per volune of the martian atmosphere is way lower than the terrestrial one.
And you'd have to carry refined nuclear fuel from Earth. I would guess using locally-produced PV panels would be easier , although slower.

An atmospheric heat exchanger would have to be proportionally larger perhaps, although radiant heat exchange can be used as well. But with geothermal it is less an issue, simply run the hot coolant under the cold ground.

And a negative void coefficient reactor self regulates heat anyways.

PV panels require far more space and materials per the amount of energy produced. Sure you would have to bring in some of the nuclear materials but nuclear requires a very small amount of fuel compared to the power produced.

[Novus America]

The heat capacity per volune of the martian atmosphere is way lower than the terrestrial one.
And you'd have to carry refined nuclear fuel from Earth. I would guess using locally-produced PV panels would be easier , although slower.

Wind power + PV would be good for setting up the infrastructure to mine and refine nuclear fuel in situ.

I think the atmospheric pressure of Mars is too low for wind power to work until we increase the atmospheric pressure. But PV should work.

[Stellar Colonies]

can we make the middle of mars spin to create a magnetic field?

It's easier to build a superconductive ring and operate that than it is to dig down to, melt, and spin up the core of Mars. You'd have to inject tons more energy than the first option just to keep generating a field long enough to be worth it.

[Neanderthaland]

can we make the middle of mars spin to create a magnetic field?

Technically, but it would require...

[Grenartia]

can we make the middle of mars spin to create a magnetic field?

It's easier to build a superconductive ring and operate that than it is to dig down to, melt, and spin up the core of Mars. You'd have to inject tons more energy than the first option just to keep generating a field long enough to be worth it.

Yeah. Its difficult to comprehend the amount of energy it would take to actually do that, and furthermore, its even more difficult to comprehend a scenario where we, as a species, not only use that amount of energy in total, but produce so much energy that we could afford to waste that kind of energy on remelting and spinning the core of a planet.

[Neanderthaland]

It's easier to build a superconductive ring and operate that than it is to dig down to, melt, and spin up the core of Mars. You'd have to inject tons more energy than the first option just to keep generating a field long enough to be worth it.

Yeah. Its difficult to comprehend the amount of energy it would take to actually do that, and furthermore, its even more difficult to comprehend a scenario where we, as a species, not only use that amount of energy in total, but produce so much energy that we could afford to waste that kind of energy on remelting and spinning the core of a planet.

I also have a sneaking suspicion that remelting and spinning the core of a planet might inadvertently render the surface - you know - molten.

[Galloism]

Yeah. Its difficult to comprehend the amount of energy it would take to actually do that, and furthermore, its even more difficult to comprehend a scenario where we, as a species, not only use that amount of energy in total, but produce so much energy that we could afford to waste that kind of energy on remelting and spinning the core of a planet.

I also have a sneaking suspicion that remelting and spinning the core of a planet might inadvertently render the surface - you know - molten.

From the standpoint of terraforming, that would be quite literally terraforming. Just might take longer than we prefer.

[Grenartia]

Yeah. Its difficult to comprehend the amount of energy it would take to actually do that, and furthermore, its even more difficult to comprehend a scenario where we, as a species, not only use that amount of energy in total, but produce so much energy that we could afford to waste that kind of energy on remelting and spinning the core of a planet.

I also have a sneaking suspicion that remelting and spinning the core of a planet might inadvertently render the surface - you know - molten.

I mean, if you go about it wrong, it absolutely can, but the fact that Earth has a molten and spinning core and a solid surface (ignoring the oceans, ofc) would seem to indicate its possible. Maybe a MegaChernobyl could remelt the core without sterilizing the surface.

[Neanderthaland]

I also have a sneaking suspicion that remelting and spinning the core of a planet might inadvertently render the surface - you know - molten.

From the standpoint of terraforming, that would be quite literally terraforming. Just might take longer than we prefer.

On the plus side: we'd probably get to see Olympus Mons go off. So there's that.

[Neanderthaland]

I also have a sneaking suspicion that remelting and spinning the core of a planet might inadvertently render the surface - you know - molten.

I mean, if you go about it wrong, it absolutely can, but the fact that Earth has a molten and spinning core and a solid surface (ignoring the oceans, ofc) would seem to indicate its possible. Maybe a MegaChernobyl could remelt the core without sterilizing the surface.

The problem is that the amount of energy required is many orders of magnitude larger than humanity can currently produce. Even if we used up all of the fissile material on Earth, it wouldn't even come close to being enough.

But say, for instance, that you have this much energy. Your problem now is that you need to get all that energy 2,100 miles under ground. And the second law of thermodynamics prevents us from concentrating energy without spending more energy. There are some ways to get around this, but the short of it is: your waste energy is probably going to be... what's a good word? "Catastrophic?" Something like that.

[Grenartia]

I mean, if you go about it wrong, it absolutely can, but the fact that Earth has a molten and spinning core and a solid surface (ignoring the oceans, ofc) would seem to indicate its possible. Maybe a MegaChernobyl could remelt the core without sterilizing the surface.

The problem is that the amount of energy required is many orders of magnitude larger than humanity can currently produce. Even if we used up all of the fissile material on Earth, it wouldn't even come close to being enough.

But say, for instance, that you have this much energy. Your problem now is that you need to get all that energy 2,100 miles under ground. And the second law of thermodynamics prevents us from concentrating energy without spending more energy. There are some ways to get around this, but the short of it is: your waste energy is probably going to be... what's a good word? "Catastrophic?" Something like that.

Yee.

[Novus America]

I mean, if you go about it wrong, it absolutely can, but the fact that Earth has a molten and spinning core and a solid surface (ignoring the oceans, ofc) would seem to indicate its possible. Maybe a MegaChernobyl could remelt the core without sterilizing the surface.

The problem is that the amount of energy required is many orders of magnitude larger than humanity can currently produce. Even if we used up all of the fissile material on Earth, it wouldn't even come close to being enough.

But say, for instance, that you have this much energy. Your problem now is that you need to get all that energy 2,100 miles under ground. And the second law of thermodynamics prevents us from concentrating energy without spending more energy. There are some ways to get around this, but the short of it is: your waste energy is probably going to be... what's a good word? "Catastrophic?" Something like that.

Maybe take a few thousand years of nuclear waste, pack it on city seized asteroids and smash them into Mars but that probably would be umm a tad disruptive...

[Grenartia]

The problem is that the amount of energy required is many orders of magnitude larger than humanity can currently produce. Even if we used up all of the fissile material on Earth, it wouldn't even come close to being enough.

But say, for instance, that you have this much energy. Your problem now is that you need to get all that energy 2,100 miles under ground. And the second law of thermodynamics prevents us from concentrating energy without spending more energy. There are some ways to get around this, but the short of it is: your waste energy is probably going to be... what's a good word? "Catastrophic?" Something like that.

Maybe take a few thousand years of nuclear waste, pack it on city seized asteroids and smash them into Mars but that probably would be umm a tad disruptive...

1. The waste would have to be reprocessed into enriched fuel.
2. Simply dropping it on Mars would not be sufficient to get the fissionables to the core.
3. Thousands of years is pretty long, even by terraforming standards.
4. It would certainly be disruptive towards any life we've sent there to create a biosphere.
5. The radiation dose any organism receives from the fallout would likely dwarf the radiation dose received from the Sun and cosmic rays, thus defeating the entire point of the endeavor in the first place.

[Novus America]

Maybe take a few thousand years of nuclear waste, pack it on city seized asteroids and smash them into Mars but that probably would be umm a tad disruptive...

1. The waste would have to be reprocessed into enriched fuel.
2. Simply dropping it on Mars would not be sufficient to get the fissionables to the core.
3. Thousands of years is pretty long, even by terraforming standards.
4. It would certainly be disruptive towards any life we've sent there to create a biosphere.
5. The radiation dose any organism receives from the fallout would likely dwarf the radiation dose received from the Sun and cosmic rays, thus defeating the entire point of the endeavor in the first place.

Well if you got a big enough asteroid going fast enough it could smash through the crust and probably liquify part of the planet but... yeah it is a grossly impractical idea.

[Laurel]

We could build a massive magnetic field in front of Mars (i.e. closer to the Sun) and leave Mars in the magnetotail, allowing Mars to have less radiation and solar wind stripping than even Earth.

How could this be accomplished, and how expensive might it be?

[Grenartia]

1. The waste would have to be reprocessed into enriched fuel.
2. Simply dropping it on Mars would not be sufficient to get the fissionables to the core.
3. Thousands of years is pretty long, even by terraforming standards.
4. It would certainly be disruptive towards any life we've sent there to create a biosphere.
5. The radiation dose any organism receives from the fallout would likely dwarf the radiation dose received from the Sun and cosmic rays, thus defeating the entire point of the endeavor in the first place.

Well if you got a big enough asteroid going fast enough it could smash through the crust and probably liquify part of the planet but... yeah it is a grossly impractical idea.

The goal isn't just re-melting the core. The goal is doing so without re-melting the surface.

[Novus America]

Well if you got a big enough asteroid going fast enough it could smash through the crust and probably liquify part of the planet but... yeah it is a grossly impractical idea.

The goal isn't just re-melting the core. The goal is doing so without re-melting the surface.

Well that is the point. The two are pretty contradictory ideas.

[Neanderthaland]

We could build a massive magnetic field in front of Mars (i.e. closer to the Sun) and leave Mars in the magnetotail, allowing Mars to have less radiation and solar wind stripping than even Earth.

How could this be accomplished, and how expensive might it be?

It's really difficult to guess at the expense, because it would require technology that doesn't currently exist.