Well, what makes you think a lava tube is safer? :P I think they'd have to be conditioned and sealed and that might be just as problematic. But what I said bef

Well, what makes you think a lava tube is safer? :P I think they'd have to be conditioned and sealed and that might be just as problematic. But what I said before applies here, too. With enough focus and budget we can advance in pretty much any technology we want. The question is, the ones that can make it happen (investors, governments), do they really want to do it? Does it pay for them?