The Nulltimate project:: building and testing, at low temperature, Achromatic Phase Shifters to prepare the Darwin mission

In the context of the Darwin mission, aiming to detect terrestrial extrasolar planets, European Space Administration (ESA) has an R&D program trying to solve the crucial problems, like flotilla spacecraft control, optical spatial filtering, etc... One of the key optical devices of this mission will be Achromatic Phase Shifter (APS) able to accurately provide a 180degrees phase shift in the IR 6 - 18 microns range. The histitut d!Astrophysique Spatiale (IAS) is leading, in the frame of an ESA granted contract, an European consortium of 9 universities and companies, named Nulltimate, aiming to develop and test three different APS. IAS itself is in charge of the cryogenic test bench facility which is presented here.