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 in June 2001 revealed the shifting attitude of NASA towards paying space tourists wanting to travel to the ISS in its statement on the hearing's purpose: "Review the issues and opportunities for flying nonprofessional astronauts in space, the appropriate government role for supporting the nascent space tourism industry, use of the Shuttle and Space Station for Tourism, safety and training criteria for space tourists, and the potential commercial market for space tourism." The subcommittee report was interested in evaluating Dennis Tito's extensive training and his experience in space as a nonprofessional astronaut. With the realities of the post-Perestroika economy in