Qualification Test Results of IMM Triple-Junction Solar Cells, Space Solar Sheets, and Lightweight&Compact Solar Paddle

Development of a high specific power, low stowage volume and lightweight solar paddle utilizing high-efficiency, thin-film, InGaP/GaAs/InGaAs inverted metamorphic triple-junction solar cell has been completed. The cell exhibits the efficiency of as high as 32% with sufficient radiation resistance. Owing to the high efficiency of the cell, the paddle achieved the specific power of greater than 150 W/kg. Qualification and reliability tests for the cell and paddle were carried out. The results confirmed that both the cell and paddle have enough capability to use them in space. Space demonstration of the paddle is now in preparation.