The bubble, drop, and particle unit (BDPU)

The Bubble, Drop, and Particle Unit (BDPU) is an instrument conceived to study the dynamics of transparent fluid mixtures in Spacelab’s microgravity environment. The scientific objectives of BDPU in its present configuration will essentially be the investigation of (1) bubbles, drops, and particles in liquids with nonuniform temperature and concentration fields, (2) formation and dynam-ics of the solidification fronts, and (3) interaction between intrusions and solidification fronts. The heart of the facility is the exchangeable test container which can, within some limits, be adapted to the investigator’s requirements. The diagnostics of the fluid under investigation are essentially opti-cal: direct view, slice view, Schlieren, interferometry, and thermography. Several devices are used for fluid management and production of bubbles and drops in liquid matrices. BDPU is a candidate for the IML-2 mission.