The Challenger anniversary served as the point of departure for my article about the safety factor for future private-sector orbital spaceships. Space.com's Mike Wall looks at the future safety factor with a slightly different spin. We're talking about orbital spaceflight safety rather than suborbital here, but in the past, SpaceShipTwo designer Burt Rutan has said he wants to make suborbital spaceflight "hundreds of times safer" than the space shuttle. Is that safe enough for you?