Who, or what, is the regulatory body that will eventually authorise Sir RB to launch SS2 with fare-paying passengers, and what certification criteria will apply? If a conventional aircraft like the A380 requires 2,500 hours of flight testing before being certified, surely a spaceplane with so many novel and advanced features will require a vastly more complicated test regime before being certified for passenger flight. If so we are unlikely to see this venture coming to fruition for another 50 years or so at the present rate of testing.