Containerless Processing in Space—Thermophysical Property Measurements Using Electromagnetic Levitation

Electromagnetic levitation is a novel tool for measuring thermophysical proper- ties of high-temperature metallic melts. Contamination by a crucible is avoided, and undercooling becomes possible. By exploiting the microgravity environment of an orbiting spacecraft, the positioning fields can be further reduced and undesired side effects of these fields can be minimized. After two successful Spacelab flights of the electromagnetic levitation facility TEMPUS, an advanced electromagnetic levitation facility is presently being studied for accommodation on the IInternational Space Station, ISS. Due to the permanent nature of the ISS, an operational concept must be defined which allows the exchange of consumables without exchanging the entire facilty. This is accomplished by a modular design, which is preseInted. For all experiments, like measurement of specific heat, of surface tension and viscosity, of thermal expansion, and of elec- trical conductivity, noncontact diagnostic tools must be either improved or developed. Such tools are, for example, pyrometry, videography (high-speed and high-resolution), and inductive measurements. This paper summarizes the scien- tific results obtained so far and deduces some lessons learned that will be incor- porated into the new design and will lead to both new results and a higher precision of the data.