They say Approximately 10 kg of MLI covers Euclid's two science instruments, but this material can absorb 1% of its own weight in water so at most 100 grams of

They say Approximately 10 kg of MLI covers Euclid's two science instruments, but this material can absorb 1% of its own weight in water so at most 100 grams of water. Assuming they were careful, maybe a tenth of that remains, so around 10 grams of water, a small fraction of which sublimates and eventually meets a mirror and deposits there. They say it's "several layers of molecules". I suppose they could have used another type of insulation, but since they also have very precise temperature requirements, maybe it was a trade off they had to make.