In a 26 March update, ESA announced that after the very first two mirrors were warmed by just 34 degrees, Euclid’s sight was restored, with the telescope’s optics achieving a 15% gain in sensitivity. The process only took a few minutes, with the mirror being warmed from -147 to -113 degrees. The procedure was so successful that it has given operators the confidence to repeat it every couple of months, if necessary, without much impact on Euclid’s six-year survey.

“We expect ice to cloud the VIS instrument’s vision again in the future,” explained Reiko Nakajima, Euclid VIS instrument scientist. “But it will be simple to repeat this selective decontamination procedure every six to twelve months and with very little cost to science observations or the rest of the mission.”