Abstract: A motorized window shade assembly for controlling an amount of light through a porthole. A spring roller is positioned by a first side of the porthole and has a torsion spring for imparting a rotating force to the spring roller. A shade is supported by the spring roller and has a first end fixed to the spring roller and a second end extendable over the porthole. A shade actuator is connected to the shade, the shade actuator having one or more of a pulley and cable for moving the second end of the shade across the porthole. A motor assembly is positioned proximate a second side of the porthole, the motor assembly having a motor which receives operating power from a power source. The motor is releasably coupled to the shade actuator for selectively supplying motor-controlled operation to the shade actuator.