Moon colony first. Kalpana 1 and O’Neill Cylinders second. Mars afterthought.
My plan would be:
Constructing the Sea Dragon. Originally designed in 1962, the Sea Dragon is a massive rocket capable of lifting 500 tons of materiel into low earth orbit and somewhat less to the moon. Its design and components are of utmost simplicity, making it extremely reliable as well as the safest possible rocket. Construction within five to ten years.
A lunar colony of 500 with the establishment of an industry capable of constructing a space habitat. Within ten to twenty years to be fully operational.
A Kalpana style habitat housing several thousand inhabitants. Within twenty to thirty years.
Construction of an O’Neill Cylinder, housing several hundred thousand inhabitants. Within thirty to fifty years.
An ‘Orion’ style nuclear pulse rocket to explore our solar system. Within ten to fifteen years.
https://www.youtube.com/watch?v=DSK_mymJvkM&feature=youtu.be Total cost for all projects: $20 billion a year times 50 years - One trillion dollars; the cost of the Iraq war or one thirtieth of the yearly cost of the United States defense budget.
There would be no emphasis whatsoever in colonizing Mars or any of the other planets. It’s simply not cost effective compared to free-floating space habitats. What’s more, O’Neill cylinders can replicate a terrestrial habitat, and provide a full earth-like gravity.
Sea Dragon rocket in comparison with other rockets.
Kalpana 1. Courtesy of Bryan Versteeg.
O’Neill Cylinder.
Orion nuclear pulse rocket.