Euclid cleanliness and contamination control

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