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 long term. It has been suggested that travel is necessary in order to maintain relationships, as social life is increasingly networked and conducted at a distance. For many people vacations and travel are increasingly being viewed as a necessity rather than a luxury, and this is reflected in tourist numbers recovering some 6.6% globally over 2009, with growth up to 8% in emerging economies. Tourism Tourism is travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours. Tourism may be international, or within the