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 and flew on STS-118 as a mission specialist. A second journalist-in-space program, in which NASA green-lighted Miles O'Brien to fly on the space shuttle, was scheduled to be announced in 2003. That program was canceled in the wake of the Columbia disaster on STS-107 and subsequent emphasis on finishing the International Space Station before retiring the space shuttle. Initially, senior figures at NASA strongly opposed space tourism on principle; from the beginning of the ISS expeditions, NASA stated it wasn't interested in accommodating paying guests. The Subcommittee on Space and Aeronautics Committee On Science of the House of Representatives held