An apparatus is disclosed for a hybrid electric power system for use in a multi-wheeled hybrid electric vehicle, and particularly for use in hybrid electric vehicles designed for operation in hostile environments where reliability and survivability of the propulsion system of the vehicle are important. The hybrid electric power system advantageously comprises at least one segmented electrical machine having multiple pairs of parallel stator segments with a magnetic rotor segment between each pair, for generating power from a thermodynamic engine, or for providing power to a driven wheel of the hybrid electric vehicle. A hybrid electric power system is also provided which comprises at least one distributed segmented electrical machine which comprises a distributed electrical energy storage system.