Gathering Ice on Mars for Paraterraforming

[GTOM]

Paraterraforming requires lots of water and CO2, much of them freezen in the polar caps.
What could be the plausible ways to collect them? In low gravity and thin air, could ship sized land vehicles or maybe entire cities move? Or should they build lots of villages powered by a central nuclear power plant, and connect them with maglev trains?

 

[.Scott]

It would be a mining operation.
To reduce transportation costs, I would think that you would want to find a place where solar energy and accessible ice were not too far from each other.

Regarding Martian nuclear power - in the long run, I suspect it's inevitable. But consider this:
Our first Martian voyages have been and will continue to be powered by devices that we carry to Mars. In the midterm, we can expect that there will be a transition to mix of made-on-Earth/made-on-Mars so that interplanetary transport costs can be brought to a minimum.

So how much MWe worth of Nuclear Power plant could we ship?
You might look at the BWRX-300 currently in development. It would produce 300MWe (Megawatts electric), but note that it is still a building - and a big heavy building at that. The reactor vessel alone is comparable in size to any of SpaceX's Star ship stages and is much heavier. It's not clear whether that reactor can be parsed up and reassembled on Mars. Much of what's in the reactor building would also be made-on-Earth, but the building would absolutely need to be made-on-Mars.

There are smaller nuclear modules, such as this one, and Navy reactors such as the A1B. They are probably more transportable than the BWRX-300 (I can't find their masses). If the modules are less than about 120 tonnes, the SpaceX Starship system could get them to the Martian surface.

Nuclear power will be competing with solar power. When looking at solar panel ratings, "AM0" refers to solar conditions in Earth orbit - outside of our atmosphere. Mars average distance from the Sun is 50% greater than Earth's (almost exactly), so applying the inverse square law, Martian solar power will be about 44% of AM0 conditions. That said, look at this SprectroLab solar cell data sheet. Per this datasheet, their AM0 "bare cell" power is 1.353 Kw/M², so under Martian mid-day conditions, it should produce about 595w/M².
The weight of these cells is specified as: "84 mg/cm² (Bare) @ 140 μm (5.5 mil) Ge wafer thickness".
Assuming we build the conductors and solar support structures from Martian resources, this gives us 840g/M² and a power to transport weight ratio of 0.71w/g. If we still wanted 300MWe, it would have a mass of about 423Mg or 423 metric tonnes. This would be about 4 ship-fulls using the SpaceX Starship system with Earth orbit refueling. You wouldn't be getting the 24-hour availability of power that nuclear provides, but this is doable and the mining can be done in daylight.

 

[GTOM]

It would be a mining operation.
To reduce transportation costs, I would think that you would want to find a place where solar energy and accessible ice were not too far from each other.

Regarding Martian nuclear power - in the long run, I suspect it's inevitable. But consider this:
Our first Martian voyages have been and will continue to be powered by devices that we carry to Mars. In the midterm, we can expect that there will be a transition to mix of made-on-Earth/made-on-Mars so that interplanetary transport costs can be brought to a minimum.

So how much MWe worth of Nuclear Power plant could we ship?
You might look at the BWRX-300 currently in development. It would produce 300MWe (Megawatts electric), but note that it is still a building - and a big heavy building at that. The reactor vessel alone is comparable in size to any of SpaceX's Star ship stages and is much heavier. It's not clear whether that reactor can be parsed up and reassembled on Mars. Much of what's in the reactor building would also be made-on-Earth, but the building would absolutely need to be made-on-Mars.

Nuclear power will be competing with solar power. When looking at solar panel ratings, "AM0" refers to solar conditions in Earth orbit - outside of our atmosphere. Mars average distance from the Sun is 50% greater than Earth's (almost exactly), so applying the inverse square law, Martian solar power will be about 44% of AM0 conditions. That said, look at this SprectroLab solar cell data sheet. Per this datasheet, their AM0 "bare cell" power is 1.353 Kw/M², so under Martian mid-day conditions, it should produce about 595w/M².
The weight of these cells is specified as: "84 mg/cm² (Bare) @ 140 μm (5.5 mil) Ge wafer thickness".
Assuming we build the conductors and solar support structures from Martian resources, this gives us 840g/M² and a power to transport weight ratio of 0.71w/g. If we still wanted 300MWe, it would have a mass of about 423Mg or 423 metric tonnes. This would be about 4 ship-fulls using the SpaceX Starship system with Earth orbit refueling. You wouldn't be getting the 24-hour availability of power that nuclear provides, but this is doable and the mining can be done in daylight.

Dust is also a problem. It is sticky.

 

[mfb]

Per this datasheet, their AM0 "bare cell" power is 1.353 Kw/M², so under Martian mid-day conditions, it should produce about 595w/M².

That's the total incoming radiation. Solar cells can't reach 100% efficiency.

Mars has only ~0.4 g but it doesn't have highways. Moving things around there is harder than on Earth.

Generally it's unclear why you would want to spread out, apart from essential activities for mining and research that cannot be done remotely.

 

[DaveC426913]

I would think that you would want to find a place where solar energy and accessible ice were not too far from each other.

Sunlight at high (+ or -) latitudes on Earth is reduced because of the amount of atmo the sun has to pass through obliquely. Sans atmo, the solar influx at the poles should the same as at the equator (per unit area, normal to the sun's rays).

Mars has an atmo of only 1/50th of Earth's. Presumably, there's little to be gained by setting up anywhere other than at the poles, where the resources are. Mars has an inclination of about 25 degrees, so you'd not want to be too close to the poles, or youd be in darkness much of the time.(Of course, Mars' spectacular dust storms negate the advantage gained by a thin atmo.)

 

[Rive]

So how much MWe worth of Nuclear Power plant could we ship?

I have a distant feeling that 'mining' and rather: processing that water would require quite the amount of heat too. So maybe it's not just about raw MWe.

Also, I suspect that looking for examples above hundred MW // amongst carriers may be misleading.
Submarines, maybe?

 

[.Scott]

I have a distant feeling that 'mining' and rather: processing that water would require quite the amount of heat too. So maybe it's not just about raw MWe.

Also, I suspect that looking for examples above hundred MW // amongst carriers may be misleading.
Submarines, maybe?

Yes submarines and Aircraft carriers - which I mentioned.
But these structures are so large that they don't usually come with a "total mass" specification - in the same way that a home doesn't have a mas specification.
Also, I wanted to split the mass in terms of the relatively low-tech part that could be made on Mars and the part that would require Earth manufacturing.

I don't think that Martian nuclear is out of the question. But I suspect there will be lots of Ice mining before it happens.

 

[DaveC426913]

Does an aircraft carrier have sufficient mass to noticeably deflect a plumb bob?