>>512137659
>they can't make fusion work on Earth
Invalid assessment. Dirtside fusion is supposed to be a big water boiler. In space you simply blast plasma out your tailpipe. Much easier.
>cancer
If my theories prove correct then metastatic cancer will be easily neutralized in the future. Localized tumors are a surgical issue, rest would be perhaps worries about premature aging effects due to DNA damage (could also be managable).
>you will need to mine a lot of resources from the mining belt
Ram accelerators. Ram accelerators. Ram accelerators.