Supported by ESA and Airbus Defence and Space, the Institute of Fluid Mechanics of Toulouse (IMFT) led by Prof Catherine Colin designed a small compact loop for the study of flow boiling in weightlessness, fitting a circuit with a pump, a flow meter, preheaters, a condenser and associated tubing within the strictly limited volume available. To validate the design, a test version has been flown in ESA and CNES parabolic flight campaigns - the former producing bubbly flows in Moon, Mars and terrestrial gravities as well as in microgravity. The experimental device proved fully operational, opening the way to follow-up investigations in-orbit.