4 ms·

Submarines run on nuclear. Wouldn't nuclear be the natural choice on mars?

by acchow 2y ago

ceejayoz 2y ago
Those are big, and heavy. https://www.oregon.gov/energy/safety-resiliency/Pages/Naval-Nuclear-Transport.aspx https://www.oregon.gov/energy/safety-resiliency/Pages/Naval-... > The submarine reactor compartments that have been taken to Hanford are about 33 feet high and 40 feet in length. They weigh between 1,130 and 1,680 tons. Eventually, the Navy may deactivate its Ohio class submarines in the same manner. Those compartments would be much larger and heavier. Submarines don't have to get them into orbit.
- JumpCrisscross 2y ago
  In case you're serious, nobody is suggesting launching a water-cooled reactor to Mars. Between the idiot ends of the power-source spectrum bounded by, on one end, a U.S. Navy PWR and, on the other end, Martian Aramco, we have the reasonable options of solar power, batteries, RTGs and fission-powered Stirling engines [1][2]. [1] https://www.nasa.gov/directorates/stmd/tech-demo-missions-program/kilopower-hmqzw/ https://www.nasa.gov/directorates/stmd/tech-demo-missions-pr... [2] https://www.nasa.gov/tdm/fission-surface-power/ https://www.nasa.gov/tdm/fission-surface-power/
  - ceejayoz 2y ago
    I think solar's the far more likely option, yes. Cheap, light, low-maintenance. Maybe fuel cells for night. RTGs aren't gonna power a good-sized base; they're a few hundred watts at best. edit: I very much hope Kilopower pans out.
  - jujube3 2y ago
    What is wrong with launching a water-cooled reactor to Mars? Or more likely launching the materials needed to build it. The active components of a reactor are quite tiny -- most of the bulk is in the shielding, which won't be necessary on an already radioactive planet like Mars.
    - ceejayoz 2y ago
      Mars isn’t radioactive. A reactor would still need shielding.
      - greenbit 2y ago
        Only if you intend to stand near it while it's running. Not trying to be glib, just pointing out that at least initially, there might not be any humans near. Admittedly, radiation might be a bother for high density electronics (CPUs, RAM, etc), but maybe it'd be cheaper to shield the bot-brains. Bots could rely on the power for a few years and when the humans get there, if nothing else you could drop all the rods in and let the rad flux die down. I know, I wouldn't want that in my back yard either, but Mars is exactly nobody's back yard at present. Bootstrapping a (necessarily!) technological civilisation on another planet is not an un-risky business.
        ceejayoz 2y ago
        Barring significant progress in robotics we'll still need humans to maintain the thing.
        JumpCrisscross 2y ago
        > we'll still need humans to maintain the thing Sure, but you're not going to need major shielding for the first few hundred reactors on the planet. Putting the stuff that requires maintenance away from the reactor will be enough for a few decades. (Put simply, the aspiring interplanetary powers who insist on heavily shielding their reactors aren't going to be releavant on the ground. You can launch a second reactor for the cost of one's shielding.)
      - jujube3 2y ago
        Dirt works fine for shielding, when you live on a planet whose soil is already toxic to life. And yes Mars is radioactive, because it has no magnetosphere. Especially when there is a solar flare.
Manabu-eo 2y ago
Submarines are encircled by water, that is very good at absorbing heat. Nuclear power stations are also invariably close to a large source of water. There is no such thing on Mars, and that significantly increases the mass and size of your radiators, making it uncompetitive with solar for example, unless the waste heat is needed for something else.

Submarines run on nuclear. Wouldn't nuclear be the natural choice on mars?

by acchow 2y ago

Submarines run on nuclear. Wouldn't nuclear be the natural choice on mars?

Those are big, and heavy. https://www.oregon.gov/energy/safety-resiliency/Pages/Naval-Nuclear-Transport.aspx https://www.oregon.gov/energy/safety-resiliency/Pages/Naval-... > The submarine reactor compartments that have been taken to Hanford are about 33 feet high and 40 feet in length. They weigh between 1,130 and 1,680 tons. Eventually, the Navy may deactivate its Ohio class submarines in the same manner. Those compartments would be much larger and heavier. Submarines don't have to get them into orbit.

JumpCrisscross 2y ago
In case you're serious, nobody is suggesting launching a water-cooled reactor to Mars. Between the idiot ends of the power-source spectrum bounded by, on one end, a U.S. Navy PWR and, on the other end, Martian Aramco, we have the reasonable options of solar power, batteries, RTGs and fission-powered Stirling engines [1][2]. [1] https://www.nasa.gov/directorates/stmd/tech-demo-missions-program/kilopower-hmqzw/ https://www.nasa.gov/directorates/stmd/tech-demo-missions-pr... [2] https://www.nasa.gov/tdm/fission-surface-power/ https://www.nasa.gov/tdm/fission-surface-power/
- ceejayoz 2y ago
  I think solar's the far more likely option, yes. Cheap, light, low-maintenance. Maybe fuel cells for night. RTGs aren't gonna power a good-sized base; they're a few hundred watts at best. edit: I very much hope Kilopower pans out.
- jujube3 2y ago
  What is wrong with launching a water-cooled reactor to Mars? Or more likely launching the materials needed to build it. The active components of a reactor are quite tiny -- most of the bulk is in the shielding, which won't be necessary on an already radioactive planet like Mars.
  - ceejayoz 2y ago
    Mars isn’t radioactive. A reactor would still need shielding.
    - greenbit 2y ago
      Only if you intend to stand near it while it's running. Not trying to be glib, just pointing out that at least initially, there might not be any humans near. Admittedly, radiation might be a bother for high density electronics (CPUs, RAM, etc), but maybe it'd be cheaper to shield the bot-brains. Bots could rely on the power for a few years and when the humans get there, if nothing else you could drop all the rods in and let the rad flux die down. I know, I wouldn't want that in my back yard either, but Mars is exactly nobody's back yard at present. Bootstrapping a (necessarily!) technological civilisation on another planet is not an un-risky business.
      - ceejayoz 2y ago
        Barring significant progress in robotics we'll still need humans to maintain the thing.
        JumpCrisscross 2y ago
        > we'll still need humans to maintain the thing Sure, but you're not going to need major shielding for the first few hundred reactors on the planet. Putting the stuff that requires maintenance away from the reactor will be enough for a few decades. (Put simply, the aspiring interplanetary powers who insist on heavily shielding their reactors aren't going to be releavant on the ground. You can launch a second reactor for the cost of one's shielding.)
    - jujube3 2y ago
      Dirt works fine for shielding, when you live on a planet whose soil is already toxic to life. And yes Mars is radioactive, because it has no magnetosphere. Especially when there is a solar flare.

Manabu-eo 2y ago

Submarines are encircled by water, that is very good at absorbing heat. Nuclear power stations are also invariably close to a large source of water. There is no such thing on Mars, and that significantly increases the mass and size of your radiators, making it uncompetitive with solar for example, unless the waste heat is needed for something else.