While NASA is planning to send the first human explorers to Mars sometime in the 2030s, several non-governmental organizations, including at least one private company (SpaceX), are looking at more aggressive timelines starting in the 2020s. They’re also setting a higher bar: rather than sending astronauts for a limited-duration mission, the goal is establishing a permanent human settlement.

My interest is in identifying new technologies that could be disruptive, and sending large numbers of people to Mars definitely qualifies. I decided to take the idea of sending people to Mars seriously and filled in the details of how one could do it.

Emerging Futures' first study, Energy and Resource Impacts of an Earth-Mars Human Transport System, describes the model I used to simulate the spacecraft and associated infrastructure needed to send one million people to Mars over the next century. In addition to estimating the mass, volume and numbers of spacecraft required, I calculated the energy and resource needs of such a system, in order to ensure that it would not put undue strain on resources both on and off of the Earth.

What I found was both reassuring and concerning. On the one hand, the mass and energy requirements overall are actually quite modest compared with what is consumed today globally. I found that building the fleet of spacecraft would require about 17 million tons of material, equivalent to 10 years of U.S. aluminum production, but spaced over about 100 years. The required propellant, or rocket fuel, needed to power these spacecraft would amount to approximately 100 times this mass.