A case in point is the company's announcement that it has decided which fuel will be used in the first passenger-carrying flights of the suborbital spacecraft. The solid fuel grains that will fuel the world’s largest operational hybrid rocket will be a thermoset plastic similar to nylon.
When SpaceShipTwo launches after being dropped by the WhiteKnightTwo carrier aircraft, it will be powered into orbit by a hybrid rocket motor developed by Sierra Nevada Corporation that uses solid rocket fuel and nitrous oxide as an oxidizer. The gas oxidizer means that, unlike conventional solid rocket motors, it can be shut down at will.
Its predecessor, SpaceShipOne, used hydroxyl-terminated polybutadiene (HTPB), which is a classic fuel for solid rocket motors. But after reviewing data collected from static test firings, Virgin Galactic has decided on an alternative fuel for the remainder of the test flights of SpaceShipTwo and for the first commercial flights.