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Re-Entry Mode
In this automatic command mode, spacecraft angular rates about the pitch and yaw axes are dampened to within +/-4 degrees/second and to within +/-2 degrees/second about the roll axis (Figure Below). Roll attitude is controlled to within +/-2 degrees of the attitude commanded by the digital computer input to ACE. The computer roll input to ACE consists of either a bank angle attitude command or a fixed roll rate command depending upon the relationship between the predicted touchdown point and the desired touchdown point. Roll to yaw crosscoupling is provided to minimize the spacecraft lift vector.