The cryogenic pump (or cryopump) of the vacuum chamber reproduces the orbiting satellite environement. Therefore, it enables performance and life testing of the engines developed by ONERA, as similar as possible to the real conditions of use. The cryogenic catchers allow the vacuum to be maintained despite the expulsion of particles, generated by the plasma propulsion of the engine. Indeed, the cold trap captures and freezes the Xenon molecules as they are released, guaranteeing optimal conditions throughout the weeks of testing. To achieve this, anticipation, rigorous design and a focusing on details are the keys to success.