Low-Intensity Low-Temperature (LILT) Power prediction of JUICE solar array

The JUICE spacecraft will operate in an unprecedented environment of low solar intensity, low temperature and very high radiation fluence. Common approaches for power analyses would introduce a large uncertainty in the power prediction and assuming worst-case degradation and loss factors would result in a non-compliance on power. This paper reports the techniques used to accurately predict the solar array power during various phases of the mission. The power cases include a hot-case prediction at Closest Sun Approach (0.64 AU) and Low-Intensity, Low-Temperature (LILT) predictions at Jupiter Orbit Insertion (5.42 AU) and End-of-Life (EOL) (5.03 AU). The begin-of-life cell data were based on LILT performance measurements on ca. 40 cells. The mission particle dose is expressed in terms of Displacement Damage Dose (DDD) for the 3G28 solar cell. Solar cell degradation data measured under LILT conditions are compared with AMO degradation data. Due to the significant spread in LILT radiation test data, a Monte-Carlo analysis was performed to estimate a current mismatch factor at EOL.