An experiment in floating-zone processing of indium was performed on Space Transportation System (STS) Flight 41-D on September 4, 1984. An indium crystal 1 cm in diameter and 7 cm long was grown. The polycrystal-line indium used as the feedstock had been doped with approximately 100 ppm thallium to investigate the distribution coefficient of thallium in indium; the result was K =CS/CL< 0.03. Indium was chosen for study because its low melting point and the low vapor pressure of the melt at that temperature would simplify the apparatus and reduce the electrical energy and cooling requirements. Another advantage is that the properties of liquid indium probably preclude time-dependent thermocapillary flows. The experiment also served as the first flight test of the Fluids Experiment Apparatus (FEA), a new multiple-purpose apparatus we have developed for low-cost, entry-level materials processing, physics and chemistry experiments in Earth-orbit. The experiment confirmed the flight-worthiness of the FEA and the suitability of indium for exploratory floating-zone experiments in Earth-orbit.