Overcoming public disengagement with space as a frontier of exploration and as a potential realm of habitation is the predominant obstacle to the creation and maintenance of a broad, comprehensive, multilateral crewed space exploration and colonization initiative.
A serious campaign should be mounted to help rebuild and sustain a domestic and multinational constituency interested and invested in space as a living destination and as a source of economic and scientific activity. Documentary films, high profile airings of space related events, educational opportunities, direct involvement learning, legislative and policy making efforts, government initiatives, private sector support, and other cross-platform outreach programs are absolutely essential to successfully reinvigorate the public imagination around the world and to achieve a multi-planet human civilization.
People must rediscover space as a possible arena of habitation or exchange and they must be convinced that human beings can and should be living beyond this planet. Without broad support by a global public, any attempt to articulate such an ambitious space exploration and settlement program is likely to fail or fall far short of stated goals.
Disappearance of space colonization from the popular imagination can be traced to a variety of historical and latent reasons, from the perceived regularization of moon landings in the 1970s to the Challenger and Columbia shuttle accidents, but regardless of causal importance, the aggregate effect has been to erase affirmatively imagining living beyond the earth from public discourse. The possibility of colonizing our solar system has been discredited, creating a broadly shared perception overshadowing any attempt to either argue, plan, or actively pursue human settlement of space and, in fact, preordains these efforts to failure.
If popular discourse can be reframed, if colonization of other planets or planetary bodies can be reclaimed from its associations with impossibility, then the most significant obstacle to this goal can be overcome.