I am trying to figure out what course humanity will take to the stars. I imagine it to be of mostly utilitarian approach, which is easier to predict than superficial stuff like sending probes to this or that planet. For example to build a self-sufficient space colony at L4 point of the earth-moon system it would have to be big enough to grow food. And if it had to support, say, 10,000 people we're looking at something akin to Starship Generations. This would mass hundreds of millions (more likely several billion) metric tonnes. It makes no sense to launch this much material from the earth, so the moon is the next choice. So we need a Lunar Mining Machine to refine raw lunar regolith into aluminum, titanium, etc. and then another facility to manufacture finished components. Then we need a lunar launch facility to heft those billions of metric tonnes up to the L4 Lagrange Point. What is the shuttle payload capacity anyway? 40 tonnes? How many shuttles have been launched in the last 20 years? One hundred?

In order to complete construction in 50 years we would need 100,000-times the launch capacity that we have on earth, up-and-running on the moon!!!

Seriously, it'll take 1000's of years. Empires rise and fall in this time period. Civilization itself arose in this time period. This is an evolutionary timespan. The human species will probably not even look the same, or act the same, when we finally build our first self-sufficient space colony.

Comments?