"I’ve been busy," Doob said. "But Tav ought to know that we have simulated and war-gamed the Mars option to within an inch of its life, and it’s just not a good idea." He could see Julia formulating an objection that he didn’t have the patience to listen to. "Anyone who is seriously advocating we go to Mars is—" He didn’t want to say what he was thinking, which was smoking crack, and so he settled for "—not taking some of the practical realities into account. One solar flare at the wrong time could kill everyone."