A steel hemisphere was at the core of the Geophysical Fluid Flow Cell (GFFC) that flew on two Spacelab missions. It was capped by a sapphire dome. Silicone oil between the two played the part of a steller atmosphere. An electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. GFFC flew on Spacelab-3 in 1985 and U.S. Microgravity Laboratory-2 in 1995. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center. (Credit: NASA/Marshall Space Flight Center)