Colonies Will be Built in Space

...the goal of planet colonization has been challenged by a radically different notion of the Final Frontier Created by Princeton professor of physics Gerard K.O'Neill, this new concept is based on one of those revolutionary propositions that are so simple they seem self-evident. The surface of a planet, O'Neill asserts, is not a very good place to house a post industrial society. Free space itself, he says, ist he natural ecological habitat for a high energy, high-growth technological species.

The best single presentation of O'Neill's Ideas is found in his book The High Frontier (William Morrow, 1976):"On a planetary surface," he argues, "we are the 'gravitationally disadvantaged,' at the bottom of a deep hole in potential energy. To raise ourselves from earth into free space is equivalent in energy to climbing out of a hole 6461 kilometers deep, a distance more than 600 times the height of Mt. Everest. Does it make sense to climb with great energy out of one such hole, drift across a region rich in energy and materials, and then laboriously climb back down into another hole, where both energy and matter are more difficult to get and to "use?" Answering with a resounding no, O'Neill explains how we could build a variety of space habitats, spacetowns, and eventually space cities,starting in the L-5 area (the most stable of the five Legrange points where the earth-moon gravitational fields balance out to zero.) Dr.O'Neill writes in ane asy, nontechnical style and stresses, after demonstrating the engineering soundness of his designs, that the resources and enormous new energy such space habitats would capture would stave off the Doomsday and New Dark Ages predicted by the professional pessimists of the Club of Rome and the pop ecology movement.

It doesn't make sense to fall down into the gravity-hole of a planet to colonize its surface after you have climbed out of the gravity hole of your homeworld.