The fundamentals of this are costly. It's way way cheaper to maintain a Stirling cycle generator or aim some PV cells. Seems like someone(s) in JAXA have a pet project they intend to complete regardless of viability.
That's Japan's 1960s bullet time train back to the future audacity. Cost is the excuse economists give to explain they are incapable of getting started because they are ignorant and over rule engineers.
