They've been exploring smaller designs with better efficiency. Not just because of the shortage, but also because evergy gram counts in a spacecraft... Well ma

They've been exploring smaller designs with better efficiency. Not just because of the shortage, but also because evergy gram counts in a spacecraft... Well maybe every kilogram, but you got my point. Any savings in mass count, and if you get to cut 1% from the spacecrafts final mass, it can mean a lot in terms of speed and timings for the mission. Wikipedia link: https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator#Efficiency https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge... The thermophotovoltaic cells look lik a very interesting approach, don't know why they haven't been used yet. With them, Cassini could've used 2 RTGs instead of 3, resulting in a mass saving of 57.5 kg (2% lower dry mass from one less RTG) and some extra power. I do take into account that this technology ws probably not developed enough when Cassini launched.