See Larry Niven's "Ringworld", 1970.

At the time, I remember reading a book by Gerard K. O'Neill, an astrophysicist from Princeton, that went into some detail about the design of a space colonization system in the form a huge rotating cylinder. But because of our political leadership, the US is now unable to do what we could do 50 years ago - put a human in orbit. The Space Shuttle program - a museum piece. NASA's Constellation program canceled in favor of some ill-defined, lightly funded future manned program. In a few short years the US has gone from being the leader in manned space exploration to a distant third behind the Chinese and Russians. Very sad.

I'm reminded of Larry Niven's 'Ringworld' and 'Ringworld Engineers'. I think he pre-dated the NASA summer conference.

...sure look like scaled down version of Larry Niven's Ringworld!

The Exploration of Space. In it he talks about a timeline for colonizing the solar system and the first 100 years are mostly robotic missions. So we seem to be about on track considering he wrote it in 1951.

http://archive.org/details/TheExplorationOfSpace

The US has the capability to put people in orbit utilizing SpaceXs Falcon/Dragon platform, its just not NASA sanctioned to do so yet.

Based on design and performance to date the Falcon launch vehicle is way ahead of anything in its class. It had to shut down an engine mid-flight and recalculate orbital parameters in real-time for a nominal insertion. Consider me impressed!