There is a central ethical dilemma at the heart of our human expansion into space. It does not concern the issue of state versus the private sector, and it does not concern whether or not we should go.

As a point about realpolitik, we are going. Even if Presidents Trump and Putin, as well as Xi Jinping in China, were to reverse their current positions and instead say ‘no’ to space, their opposition would not stick. The next set of political leaders, or those who came after, would simply reverse it. The political and economic dynamics for expansion are too far advanced to be put into reverse. We may argue about whether or not there is an innate human urge to find new frontiers (I think there is not), but the economics and politics of the thing are enough to ensure that this is going to happen.

Rather, the ethical dilemma concerns a conflict between two kinds of justice. On the one hand, justice across the current generation of humans. This points towards a need to broaden inclusion, and to increase the number of players in the space sector. On the other hand, there is the issue of justice between generations. This points towards the importance of sustainability, and the importance of avoiding too rapid an expansion of our overall human activities in space.