Stratospheric Flight of a Balloon-Borne Solar Cell Testing Facility

Characterizing solar cells in real AM0 environment is cost-effective with respect to ground measurements. For this reason, we designed a balloon-borne test facility to perform I/V curve characterization of solar cells in the stratospheric environment. This paper outlines the design of the facility and the results of a successful first flight that carried three different cells to an altitude of 35 km. The data collected show that peak power is achieved inside the tropopause, where the extreme cold conditions are favorable, rather than at higher altitudes, where - in spite of the higher irradiance - the cells tend to overheat.