I’m not sure about the goal of Mars settlement. There are a lot of things about it that sound nice, but there’s something a bit unthoughtful in many of the arguments in favor of it. I’ve heard a lot of claims that people should settle Mars as a backup in case global warming ruins the earth. Okay, maybe, but wouldn’t it be better to spend that $20 billion on investing in clean power and perhaps inventing technology that can reverse global warming or at least mitigate its potential impacts? Mars colonization isn’t much of a deal if everyone on earth — or at least a big chunk of the population — dies and only the people on Mars live because earthlings were too stupid both to take care of the planet we had and to try to repair the damage we had caused.