4 ms·

I think you underestimate how much a reactor and associated radiators turbines and heat exchangers will weigh

MR4D 4y ago
Sub reactors weigh around 100 tons. Not sure how relevant that is, but certainly liftable. EDIT: Meant to add - much less than the ISS, and I presume multiple launches would be needed. Possible, yes; but practical? not sure.
- hd95489 4y ago
  Sub reactors can dump excess heat into the water. Radiating heat off in space is presumably much more difficult and inefficient . Also not clear if the working fluid is included in that 100t number. It has to be fully closed system in space. Solar has additional advantages in cost, redundancy and simplicity of maintenance. That should but be discounted either
- panick21_ 4y ago
  NASA already has the Kilopower reactor. Starting with that and then building larger version of it is probably what you want to do. They already have a team that is working on that stuff, all they need is more funding and an actual mission.
dotnet00 4y ago
I think you might be overestimating how much they'd weigh. It isn't like they need a MW or even GW scale reactor up there right away, and kW reactors like NASA's Kilopower are expected to be ~1.5t, easily allowing several dozen (so, ~600kW worth) to be carried on one Starship. That said, while nuclear power would be pretty useful in permanently shadowed craters and during lunar nights, Kilopower is probably still not mature enough and the public too scared of the nuclear boogeyman for them to power a moon base this decade.
- panick21_ 4y ago
  A larger version of Kilopower is probably what you want. And that probably enough for now. But I also think a machine that mass produces enough solar panels and batteries on the moon wouldn't be that light. Kilopower is pretty mature, all it needs it to be actually tested in space. > public too scared of the nuclear boogeyman We can not be hostage to a uninformed public opinion. NASA can go ahead with these things just fine. The public doesn't know the difference between a nuclear battery that are often used and a small reactor. The public doesn't start a revolution everytime nuclear is mentioned. NASA and DoD are literally going to test a nuclear thermal rocket, if they can do that, a tiny nuclear reactor shouldn't be an issue.
  - dotnet00 4y ago
    I agree that we should not be held hostage to uninformed public opinion, but I feel that we effectively are being held hostage by it. As you mention, the public can't even tell the difference between an RTG and a reactor and while that doesn't stop flagship missions like Perseverance, it does limit how innovative NASA can be with the use of nuclear technology in space. NASA and the DoD do have the plan to test a nuclear thermal rocket, but it's in such an early stage that much of the public isn't even aware of it. I'm certain there will be much more backlash from the uninformed masses as the program approaches the point of testing in space, and I'm not at all confident that it won't be cancelled as a result. Hell, with how low the standards are with Congresspeople, I wouldn't be surprised if the program is shut down by them for similar reasons, without much public involvement.

MR4D 4y ago

Sub reactors weigh around 100 tons. Not sure how relevant that is, but certainly liftable. EDIT: Meant to add - much less than the ISS, and I presume multiple launches would be needed. Possible, yes; but practical? not sure.

hd95489 4y ago
Sub reactors can dump excess heat into the water. Radiating heat off in space is presumably much more difficult and inefficient . Also not clear if the working fluid is included in that 100t number. It has to be fully closed system in space. Solar has additional advantages in cost, redundancy and simplicity of maintenance. That should but be discounted either
panick21_ 4y ago
NASA already has the Kilopower reactor. Starting with that and then building larger version of it is probably what you want to do. They already have a team that is working on that stuff, all they need is more funding and an actual mission.

dotnet00 4y ago

I think you might be overestimating how much they'd weigh. It isn't like they need a MW or even GW scale reactor up there right away, and kW reactors like NASA's Kilopower are expected to be ~1.5t, easily allowing several dozen (so, ~600kW worth) to be carried on one Starship. That said, while nuclear power would be pretty useful in permanently shadowed craters and during lunar nights, Kilopower is probably still not mature enough and the public too scared of the nuclear boogeyman for them to power a moon base this decade.

panick21_ 4y ago
A larger version of Kilopower is probably what you want. And that probably enough for now. But I also think a machine that mass produces enough solar panels and batteries on the moon wouldn't be that light. Kilopower is pretty mature, all it needs it to be actually tested in space. > public too scared of the nuclear boogeyman We can not be hostage to a uninformed public opinion. NASA can go ahead with these things just fine. The public doesn't know the difference between a nuclear battery that are often used and a small reactor. The public doesn't start a revolution everytime nuclear is mentioned. NASA and DoD are literally going to test a nuclear thermal rocket, if they can do that, a tiny nuclear reactor shouldn't be an issue.
- dotnet00 4y ago
  I agree that we should not be held hostage to uninformed public opinion, but I feel that we effectively are being held hostage by it. As you mention, the public can't even tell the difference between an RTG and a reactor and while that doesn't stop flagship missions like Perseverance, it does limit how innovative NASA can be with the use of nuclear technology in space. NASA and the DoD do have the plan to test a nuclear thermal rocket, but it's in such an early stage that much of the public isn't even aware of it. I'm certain there will be much more backlash from the uninformed masses as the program approaches the point of testing in space, and I'm not at all confident that it won't be cancelled as a result. Hell, with how low the standards are with Congresspeople, I wouldn't be surprised if the program is shut down by them for similar reasons, without much public involvement.