[thechao]

Fusion will be necessary if we plan to colonize the solar system beyond Mars, and not at Jupiter. It's cold, dark, and scary, out there.

[tsimionescu]

We won't, not with anything resembling current technology. So, if we were to imagine a colonized solar system, there is a good chance it's not fusion that gets us there, but some currently unknown technology.

[AtlasBarfed]

Jeez, they invented the core tech in the 60s. An orion pulse nuclear ship can get a small city to Jupiter in a month.

You don't need a wonder technology to cart around the solar system, well, unless you are talking ECONOMICAL technology.

I'm not sure how expensive H-bombs are to make at scale.

[tsimionescu]

I'm not talking just about transportation, I'm also talking about the technology required to make an actually self-sustaining human colony anywhere outside the Earth. That is the part that only exists in principle - when you go to the details, we don't actually have any idea how we could build even a Mars colony that is truly self-sustaining, never mind one on a more inhospitable world.

Note that when I say self-sustaining, I don't just mean power, food, air, and water. I mean everything that a high-tech colony actually needs - plastics, machined parts, microprocessors, software, and so on.

[pfdietz]

Power can be beamed out to interstellar distances, so fusion isn't necessary.

For that matter, if a space colony is equipped with a mirror for concentrating the sunlight needed to illuminate the inside as if it were Earth, and we place the limiting distance as that at which the mass of the mirror is equal to the mass of the space colony, the distance is about 1 light year.