 The RETRO, FIDO, and GUIDO controllers monitored spacecraft trajectory and handled course changes.The second row also consisted of several controllers, the ENVIRONMENTAL, PROCEDURES, FLIGHT, SYSTEMS, and NETWORK.The ENVIRONMENTAL controller, later called EECOM, oversaw the consumption of spacecraft oxygen and monitored pressurization, while the SYSTEMS controller, later called EGIL, monitored all other spacecraft systems, including electrical consumption.