Space architecture of space and a space transportation infrastructure can be accelerated. Virgin Galactic has indicated plans for an orbital craft, SpaceShipThree. The demand for space tourism is one without bound. It is not difficult to imagine lunar parks or cruises by Venus. Another impetus to become a spacefaring species is planetary defense. The classic space mission is the Earth-colliding asteroid interception mission. Using nuclear detonations to split or deflect the asteroid is risky at best. Such a tactic could actually make the problem worse by increasing the amount of asteroid fragments that do end up hitting the Earth. Robert Zubrin writes:
Tourism on the Moon Tourism on the Moon Lunar tourism may be possible in the future if trips to the Moon are made available to a private audience. Some space tourism startup companies are planning to offer tourism on or around the Moon, and estimate this to be possible sometime between 2023 and 2043. Tourist flights would be of three types: flyby in a circumlunar trajectory, lunar orbit, and lunar landing. Some of the space tourism start-up companies have declared their cost for each tourist for a tour to the Moon. Two natural attractions would be available by circumlunar flight or lunar orbit, without