[selven]

Launching orion from the ground would be extremely unfeasible. The best space-colonizing strategies all involve setting up a base in Earth orbit, with some space elevators attached, and building ships for colonization from there. It has to be done this way because a Mars mission would spend only half of its fuel getting to Mars - the other half is spent getting out of the gravity well. If we could mine and build in space, we can skip that step (and safely detonate some nukes to launch our spaceships)

[stcredzero]

For purely physical reasons, the Project Orion study disagrees with you. According to their models, a robust surface to orbit launch schedule would result in a couple of extra deaths a year worldwide from cancer. Compared to the extra cancer deaths from burning coal, this is nothing! Compared to worldwide deaths from automobile traffic? Compared against the potential economic benefit?

Unfortunately, it would be politically infeasible.