More and more I come to the realization that space travel will never be cheap, easy, and routine as long as rockets are our only way to orbit. We are like 1930's aeronautical engineers trying to develop global air travel using piston engined prop planes. Back then they had to resort to all kinds of dodges like seaplanes, plans for mid ocean refueling stations, super jumbo planes that were so slow they would take several days to cross the atlantic, even small airliners that launched from the backs of larger planes. And no mater how hard the tried all but the shortest trips were so expensive that only the wealthy could travel by air.<br /><br />Then came jet engines. They were more reliable, more powerful, faster, and lasted longer than piston engines. Even better they burned cheap kerosene rather than expensive aviation grade gasoline. Global air travel was now practical. We need the equivalent of a jet engine for space travel. I don't know what it is--beamed power, orbital elevator, airship-to-orbit, scram jets, some form of nuclear engine that will leave the ground facilities habitable--but it probably won't be rockets.