Space expansionism, science fiction, and space developments are intimately linked. SF from Verne, Wells, and others inspires space expansionists, and SF is shaped by space discoveries. SF makes space expansionism seem plausible but is often unbound by scientific possibility. An assessment of building block, life-engineering, and transformative technologies reveals that large-scale space activities are becoming more feasible, but creating enclosed ecologies, geo-engineering and terraforming remain doubtful. Anticipating the consequences of new technologies (technology assessment) remains difficult. Technology governance is plagued by recalcitrant syndromes. Theorists of catastrophic and existential risk view space colonization as necessary to escape a long list of possible major calamities (including hostile artificial superintelligence and misused genetic engineering for improved humans, called transhumanism). Human survival increasingly depends on competent futurism and social capacities to steer technology with reversals, regulations, and relinquishments, but these are difficult to establish and maintain. Can vital arrangements of restraint survive large-scale space expansion?
