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:
Space tourism Big Falcon Spaceship (BFS). During the period from 2001 to 2009, the publicized price for flights brokered by Space Adventures to the International Space Station aboard a Russian Soyuz spacecraft was in the range of US$20–40 million. 7 space tourists made 8 space flights during this time. Some space tourists have signed contracts with third parties to conduct certain research activities while in orbit. By 2007, space tourism was thought to be one of the earliest markets that would emerge for commercial spaceflight. Space Adventures is the only company that has sent paying passengers to space. In conjunction with the