I've written a draft paper called Progress Towards a Program for Human Expansion which summarizes the work so far in a different kind of "space program", one that actually starts on Earth. The core idea is that we have not actually finished exploring and settling the Earth, because our technology is not good enough. Therefore we start by developing some advanced technologies like self-expanding distributed production, cyclic material flows, generalized resource extraction, along with using existing ones like automation and robotics. This enables expanding to difficult locations like deserts, frozen climates, and the oceans, and later to the somewhat more difficult locations in space.
The improved technologies apply everywhere, including the temperate locations where most people live today. So they can improve the quality of life for the vast majority of people. That justifies developing the technologies for their own sake, even if you never used them in space. But being able to extract useful products from raw rock, building a comfortable place to live in hostile conditions, and near 100% recycling of materials are also the things you need to really live in space.
These ideas grew out of the space systems engineering wikibook I have been writing. At first, I was just including tutorial examples for the different propulsion and space construction methods being explained. I gradually realized you could put the examples together to make a potentially better total program than what NASA, for example, is following now. I still plan on finishing the textbook, because a modern one covering the subjects is needed. But as the ideas for this new approach to space evolve, I want to start sharing them with you.