Euclid cleanliness and contamination control

Abstract Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate nature dark energy, matter and gravity by observing geometry Universe formation structures over cosmological timescales. It will operate at L2 it about 36% sky on 6 year mission, all with high image quality stability. To allow such scientific achievements, an integrated cleanliness contamination control (CCC) have been put in place covering phases development until end operations. This document describes design challenges, engineering AIT solutions used monitor entire life time from organic particulate sources as well in-orbit water ice contamination.