First Flights of a New Test Facility for Solar Cell Characterization in the Stratosphere

ECAPS (Experimental Characterization of Advanced Photovoltaics in the Stratosphere) is a new solar cell test facility developed to allow accurate characterization of photovoltaics in the near-space environment. The system is design to fly on both large zero-pressure balloons and on small sounding (weather) balloons, providing a low cost, quick access alternative route to the stratospheric AM0 environment. In 2022, ECAPS flew on a sounding balloon flight from central Italy and on the SOLAR mission by CNES (HEMERA programme) from Timmins, Canada, successfully testing several last generation and experimental solar cells and demonstrating the viability of the system for cell characterization and calibration. Further flights are scheduled for 2023 from both locations. In this paper, the key concepts of the facility design and a summary of the flight results are reported.