While the circumnavigation of the solar system seems farfetched, it may not be once the problem of effective anti-gravitational control is solved.
Donald A. WollheimI think that space flight is a condition of Nature that comes into effect when an intelligent species reaches the saturation point of its planetary habitat combined with a certain level of technological ability... I think it is a built-in gene-directed drive for the spreading of the species and its continuation.
Donald A. Wollheim