Process for the control of a space craft performing a precession movement and apparatus for the realization thereof

A process for position control of a spacecraft undergoing a predetermined precession movement about its longitudinal axis in preparation for release of at least one payload therefrom, said craft having displacement means capable of imparting driving thrust and torque to said craft, said process comprising the steps of:

• a. predetermining and recording successive desired positions to be occupied by said craft at corresponding successive time intervals, driving torques impartable by said displacement means, and at least one minimum impulsion bit, said desired positions being determined relative to an inertial reference frame;
• and
• b. for each said successive time interval and corresponding desired position performing the following steps:
• i. determining said craft's actual angular velocity and actual position relative to said reference frame;
• ii. deriving from said craft's actual angular velocity and actual position a desired transverse velocity to be imparted to said craft to permit said craft to move into desired position;
• iii. determining from among said recorded driving torques one driving torque to be imparted to said craft and determining a driving time which permit said craft to achieve said transverse velocity;
• iv. actuating, for said driving time, said displacement means such that said displacement means imparts said one driving torque to said craft;
• and
• v. repeating steps i-iv until said craft moves into desired position.