In space vehicles, the typical configurations for the Solar Array Power Regulators in charge of managing power transfer from the solar array to the power bus are quite different from the corresponding devices in use for terrestrial applications. A thorough analysis is reported for the most popular approaches, namely Sequential Switching Shunt Regulation and parallel-input Pulse Width Modulated converters with Maximum Power Point Tracking. Their performance is compared with reference to a typical mission in low Earth orbit, highlighting the respective strengths and weaknesses. A novel solar array managing technique, the Sequential Maximum Power Tracking, is also introduced in the trade-off and was demonstrated able to boost energy harvesting, especially in the presence of mismatching in the solar array. It also can achieve top levels of reliability using a rather simple control hardware. Its operation was verified both by a Matlab–Simulink model and by an experimental breadboard.

Small satellites are known to provide low-cost access to space, enabling fast and cheap validation of new technologies for space missions. ASTROBIO is a 3U CubeSat (size 100xl00x300 mm3), that was injected into an orbit crossing several times a day the cloud of radiation known as the Van Allen Belts. As a result, the solar panels are exposed to an enhanced dose rate and undergo in a few days the same degradation that would be observed after several years of space flight in Low Earth Orbit. We used this unique opportunity to validate the new End-Of-Life optimized Triple Junction solar cells (CTJ-EOL) produced in Italy by CESI. The spacecraft solar panel comprises two types of solar cells produced by the same manufacturer: the well-established CTJ-30 and the new CTJ-EOL. Their performance was separately monitored and the related telemetries were downloaded for off-line elaboration. This manuscript reports and analyses the telemetries received by our Ground Station and by the networked stations distributed all over the globe. Data analysis clearly and unequivocally demonstrated the superior ruggedness of the End-Of-Life optimized devices: in the first week, the CTJ-30 performance dropped like it would be expected along a 10-years+ mission in the most-commonly-used orbits, whereas degradation of the CTJ-EOL was barely detectable. The results also show that in-orbit testing can provide unique information about the operation of solar cells in the intended operational environment as well as an easy verification of the device's functionality, useful to complement standard characterization procedures for radiation hardness involving costly and time-consuming laboratory tests under particle beams.