NASA’s human spaceflight program has been gradually losing ground since the Challenger disaster 25 years ago. Retirement of the Space Shuttle fleet and cancellation of the Bush Administration’s Constellation program signal an uncertain future for one of the most important scientific initiatives in human history. Although Congress and the Obama Administration have cobbled together a framework for proceeding with future missions, human spaceflight today lacks a core mission or rationale that can sustain political support during a period of severe fiscal stress.
Mars is the sole destination for the human spaceflight program that can generate sufficient scientific benefits to justify the scale of expenditures required. It is also the only destination likely to sustain political support across multiple presidential administrations. Mars is the most Earth-like place in the known universe beyond our own planet, and it is the one location that could conceivably support a self-sustaining human colony. It has water, seasons, atmosphere and other features that may hold important lessons for the future of the Earth, but unlocking those lessons would require a sustained human presence on the Red Planet’s surface.