Manual attitude control of the lunar module

During critical phases of the Apollo mission, spacecraft attitude is manually controlled by the astronaut-pilot. In such instances, the pilot's ability to perceive the state of his vehicle and to apply alternatives to the nominal control is an asset. The primary guidance, navigation, and control system uses digital control which is executed on a time-shared basis within the Lunar Guidance Computer. Control laws have scheduled gains, are nonlinear, and follow conditional paths within the computer. Manual attitude control using a rate command/attitude hold mode employs parallel logical paths for fast, precise rate response and for attitude hold about uncommanded axes. Improved handling qualities afford reduced control jet usage and miss distance during the landing.