The development of an ultra-lightweight solar panel using space solar sheets is currently being carried out. This panel is utilizing space solar sheets consisting of InGaP/GaAs dual-junction high-efficiency thin-film solar cells. The panel employs a simple frame-type structure. A breadboard model was manufactured. The dimensions of the 1.0-cm-thick unit panel were about 55 cm ?? 70 cm. Each panel weighs approximately 0.68 kg. In addition to three basic panels, two lateral panels were recently developed and added to the basic panel. This breadboard model achieved high specific power of about 91 W/kg. Moreover, five panels were stacked, resulting in a total thickness of 6 cm. Acoustic and sine vibration tests were performed on the model. The results demonstrated the high durability of the ultra-lightweight solar panel in an acoustic and vibration environment.