Microconcentrator Solar Panel Architectures Achieving High Specific Power for Deep Space Missions

Microconcentrator photovoltaics (microCPV) are emerging as a promising solution for powering spacecraft in deep space, where conventional solar arrays are challenged by extremely low-intensity, low-temperature conditions. This work presents the design, development, and characterization of two optical architectures aiming at maximizing specific power (W/kg) beyond Mars orbit: (i) a Fresnel microlens array fabricated with silicone-on-glass (SoG) technology, and (ii) a catadioptric concentrator combining refraction and total internal reflection. Triple-junction (3J) and four-junction (4J) microcells were experimentally tested at cryogenic temperatures down to –175°C and irradiance levels representative of Jupiter and Saturn orbits, confirming that voltage recovery at low temperature partially compensates photocurrent losses, thereby validating the use of sub-mm cells under LILT conditions. Ray-tracing simulations show that the Fresnel architecture achieves higher optical efficiency and lower mass, while the catadioptric system provides greater angular tolerance and alignment robustness. The first Fresnel prototypes were successfully manufactured and characterized, showing optical efficiencies of 83%–85% with excellent uniformity across the lens array. A mini-module assembly composed of 72 4-junction microsolar cells showed an electrical efficiency of 25%. These results demonstrate the feasibility of microCPV modules as a high-specific-power alternative to conventional coverglass interconnected cell (CIC) arrays in deep space missions.