A growing world population, currently over seven billion, has limited options for the future because of the thermodynamic limits to growth within the biosphere. The post-growth economy described in Chap. 4 is likely to be appropriate for a stationary society without significant economic growth of the kind seen to date. Alternatively, or complementarily, pioneers might venture industrial expansion into space. The plans for supplying the earth with energy by satellite solar power plants in geostationary orbit, which were discussed internationally and interdisciplinarily in the 1970s and 1980s, are available for the start of this. People from habitats orbiting the Lagrange point L5 at the same distance from the Earth and the Moon could build the power plants with material from the Moon and energy from the Sun. As an economic instrument for shifting from the present economic growth, which cannot be sustained on Earth, to a stationary development path or a development path leading into space, the shifting the burden of taxes and levies from the expensive, weak labor to the (currently still) cheap, powerful production factor energy is proposed. The obvious risks of a departure into space have to be weighed against the restrictions of social mobility and individual freedom, which may well become necessary again in a stationary society according to the experiences of the past millennia—unless politics, economy and individual behaviour orient themselves more strictly than ever before to the ethical recommendations of the great wisdom teachings and world religions.