Zubrin's Guide to Colonizing Mars | MARS
Humans to Mars does not require building some gigantic nuclear powered interplanetary spaceship. We can do it with the kinds of technology we either have today or know how to build today.
We need to have a heavy lift booster. We take two such boosters for each mission. The first one shoots off to Mars an Earth return vehicle, so now we have a fully fueled Earth return vehicle sitting waiting for us on the Martian surface.
We launch two more boosters off the camp; one shoots out another one of these Earth return vehicle fuel factory combinations. The other shoots out a habitat with a crew of four astronauts in it, perhaps six.
We send the crew out to Mars on a six-month orbit, check out the weather, and then go and land at landing site number one where a fully fueled Earth return vehicle is waiting for us. The crew would be on Mars for a year and a half.
At the end of the year and a half, they get in the Earth return vehicle, they take off, and they fly back home to Earth. They leave behind on Mars their habitat, the nuclear reactor, their various ground vehicles, and other equipment.
Okay, after a number of these things are done, we have a string of bases. After a little while sending people to stay, we can build in our time the first human settlement on a new world.
There's nothing in this that is fundamentally beyond our technology. All it takes is some focus and a little bit of moxy. We can do this.