 At T+49 seconds into launch, the pulse beacon on the Atlas guidance system ceased operating, which prevented the transmission of any steering or cutoff discreets for the remainder of the launch.Backup commands from the missile programmer were used to perform booster jettison and Agena separation, but without the guidance program, it was impossible to perform the necessary fine tuning maneuvers to put the Atlas on the correct flight path.SECO occurred due to propellant depletion rather than a programmed cutoff command, causing the Agena and probe to be accelerated higher and faster than planned.