How Soon Should We Set Off For Mars?

Jeff Bezos is into heraldry. His Blue Origin factory in Kent, Washington, is littered with it—the company’s feather icon, symbolizing “the perfection of flight”; the slow-but-steady tortoise; the Latin motto “Gradatim Ferociter,” “step by step, ferociously.” His methodical approach notwithstanding, Amazon’s CEO set a couple of deadlines for his spaceflight spinoff this month, both in 2020. That is when Bezos expects to begin flying the …