A more useful and efficient primary aim is space research with unmanned systems. While it's undoubtably cool to send people to space and keep permanent human settlement as on the ISS, and this may become more important in the future, we get far more bang for our buck when science projects are conducted by rovers and probes as we've done with all the planets. Human settlement is more for glory than for science, and it should be a secondary goal. Private companies are already exploring human possibilities in space, which is great.