They are both extremely difficult to accomplish with current technology. The issue with Mars is that it has no magnetosphere [1], and as such, all habitats will have to be underground and/or shielded with very thick layers of lead, dirt and water.
Man made colonies will have the same problem, in addition to requiring space manufacturing and assembly at a level that is currently impossible.
If SpaceX brings the cost of space flight down to its basic energy costs, we will have solved one problem. The other problem is the power generation required to conduct space manufacturing at a large scale. Solar, although consistent, is low in power density and thus requires large amounts of surface area that is very difficult to maintain in space.
Until we crack compact, high yield fusion, I doubt we will make much progress in realizing our space-faring dreams. This was also the opinion of the late Robert Bussard, inventor of the Bussard ramjet and the polywell fusor.
1. http://www.space.com/24731-mars-radiation-curiosity-rover.ht...
Man made colonies will have the same problem, in addition to requiring space manufacturing and assembly at a level that is currently impossible.
If SpaceX brings the cost of space flight down to its basic energy costs, we will have solved one problem. The other problem is the power generation required to conduct space manufacturing at a large scale. Solar, although consistent, is low in power density and thus requires large amounts of surface area that is very difficult to maintain in space.
Until we crack compact, high yield fusion, I doubt we will make much progress in realizing our space-faring dreams. This was also the opinion of the late Robert Bussard, inventor of the Bussard ramjet and the polywell fusor.
1. http://www.space.com/24731-mars-radiation-curiosity-rover.ht...