M c =kB.({dot over (b)} m -{dot over (b)} i)=kB.({dot over (b)} m?????I ???{dot over (b)} m) where B is a standardized scalar representing the earth's magnetic field mean value, {dot over (b)}m, is of the unit vector aligned with {dot over (B)}m with the same direction {dot over (b)}i is the unit vector aligned with {dot over (B)}i with the same direction and ??i is the desired angular velocity ve