RetiredF4
From an AWST article posted earlier (Sept 7, 2009)
For maneuvring outside the atmosphere, SS2 is fitted with a cold-gas reaction control system, with nozzles in the nose for pitch and yaw, and in te wing tips for roll thrust.
The SS2 reaction control system is remotely similar to the Space Shuttle Orbiter RCS. For the SSO re-entry was considered to start down from 400kft and a concept of "blended control" was applied, handing over roll control first to aileraons, then pitch control to the body flap, and rudder coming in last reaching the transsonic regime. This staged transition from RCS to aerodynamic control is said to have been the main requirement driving to Fly by Wire.
(see e.g.
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The SS2 has to make the transition both ways and a learning curve has to be made again. One of the many challenges in the development program.