First results of Euclid de-icing campaign
During ESA Euclid’s first months in space, some water molecules absorbed from the air, during assembly on Earth, were being gradually released by parts of the spacecraft. Cold surfaces like the mirrors in Euclid’s instruments tend to attract these molecules, where they formed a very thin layer of ice – the width of a DNA-strand. This thin layer was starting to hinder the satellite’s vision. That is why operation teams on the ground started a de-icing campaign. They sent commands to the satellite to heat the instrument mirrors individually and remove the layer of ice.
This graph shows the impact of one of the first operations. It shows the percentage of light collected by Euclid’s VIS instrument during the heating of a mirror. After about 90 minutes, the sublimation temperature of ice was reached – the temperature at which ice can transform directly into water vapour in the vacuum of space. From this temperature onwards, the release of ice proceeded swiftly, and the layer was essentially removed after another 19 minutes, when the mirror reached a temperature of –117 °C.
With Euclid's vision cleared at the very first stage of the procedure, scientists and engineers could tell where precisely the ice had formed, and where it is likely to form again. But it will be simple to repeat this targeted procedure every six to twelve months.
Its vision fully restored, the satellite can continue its mission to investigate the dark Universe.
