A Double Ellipsoid Mirrof Furnace for Zone Crystallization Experiments in Spacelab. The lines k in K were twin lamellae.
G are the remnants of gas bubbles in the solution zone.
These bubbles, due to the buoyancy, floated at the upper interface in the ground sample, whereas in the microgravity sample they were in the whole zone. The facility was turned off by the controlling computer because of insufficient flow of coolant. The abrupt turn-off of the facility also upset the cooling program. Instead of controlled temperature reduction from 1070 to 870 K within 32 min, the sample was practically quenched. This experiment was marginally successful because of the unplanned furnace shutdown.