It seem very doubtful that we’ll have practical fusion power any time soon or necessarily ever. [...] This also means that the internal structure will undergo constant low-level neutron bombardment which seriously reduces the lifespan of basic parts such as the electromagnets used.
Automatically self-repairing nanotech construction? (To suggest a point where a straightforward way of dealing with this becomes economically viable.)
You would need not only self-repairing nanotech but such technology that could withstand both large amounts of radiation as well as strong magnetic fields. Of the currently proposed major methods of nanotech I’m not aware of any that has anything resembling a chance to meet those criteria (with the disclaimer that I’m not a chemist.) If we had nanotech that was that robust it would bump up so many different technologies that fusion would look pretty unnecessary. For example the main barrier to space elevators is efficient reliable synthesis of long chains of carbon nanotubes that could be placed in a functional composite (see this NASA Institute for Advanced Concepts Report for a discussion of these and related issues). We’d almost certainly have that technology well before anything like self-repairing nanotech that stayed functional in high radiation environments. And if you have functional space elevators then you get cheap solar power because it becomes very easy to launch solar power satellites.
I’m not talking about plausible now, but plausible some day, as a reply to your “It seem very doubtful … any time soon or necessarily ever”. The sections being repaired could be offline. “Self-repair” doesn’t assume repair within volume of an existing/operating structure, it could be all cleared out and rebuilt anew, for example. That it’s done more or less automatically is the economic requirement. Any other methods of relatively cheap and fast production, assembly and recycling will work too.
Ah ok. That’s a lot more plausible. There’s still the issue that once you have cheap solar the resources it takes to make fusion power will simply cost so much more as to likely not be worth it. But if it could be substantially more efficient than straight fission then maybe it would get used for stuff not directly on Earth if/when we have large installations that aren’t the inner solar system.
Estimating feasibility using exploratory engineering is much simpler than estimating what will actually happen. I’m only arguing that this technology will almost certainly be feasible on human level in not absurdly distant future, not that it’ll ever be actually used.
Automatically self-repairing nanotech construction? (To suggest a point where a straightforward way of dealing with this becomes economically viable.)
You would need not only self-repairing nanotech but such technology that could withstand both large amounts of radiation as well as strong magnetic fields. Of the currently proposed major methods of nanotech I’m not aware of any that has anything resembling a chance to meet those criteria (with the disclaimer that I’m not a chemist.) If we had nanotech that was that robust it would bump up so many different technologies that fusion would look pretty unnecessary. For example the main barrier to space elevators is efficient reliable synthesis of long chains of carbon nanotubes that could be placed in a functional composite (see this NASA Institute for Advanced Concepts Report for a discussion of these and related issues). We’d almost certainly have that technology well before anything like self-repairing nanotech that stayed functional in high radiation environments. And if you have functional space elevators then you get cheap solar power because it becomes very easy to launch solar power satellites.
I’m not talking about plausible now, but plausible some day, as a reply to your “It seem very doubtful … any time soon or necessarily ever”. The sections being repaired could be offline. “Self-repair” doesn’t assume repair within volume of an existing/operating structure, it could be all cleared out and rebuilt anew, for example. That it’s done more or less automatically is the economic requirement. Any other methods of relatively cheap and fast production, assembly and recycling will work too.
Ah ok. That’s a lot more plausible. There’s still the issue that once you have cheap solar the resources it takes to make fusion power will simply cost so much more as to likely not be worth it. But if it could be substantially more efficient than straight fission then maybe it would get used for stuff not directly on Earth if/when we have large installations that aren’t the inner solar system.
Estimating feasibility using exploratory engineering is much simpler than estimating what will actually happen. I’m only arguing that this technology will almost certainly be feasible on human level in not absurdly distant future, not that it’ll ever be actually used.
In that case, there’s no substantial disagreement.