Four Te-doped InSb crystals were directionally solidified under microgravity conditions at the International Space Station (ISS). Three Te-doped InSb crystals were grown at R = 5 mm/h. One crystal was grown at R = 3.33 mm/h. The distribution of Te was measured using secondary ion mass spectroscopy (SIMS). The initial transients in Te concentration were found to be consistent, yielding a diffusivity of Te in InSb melts of D = 1 x 10(-5) cm(2)/s. One experiment revealed a diffusion controlled final transient. In all experiments, the charge was pressurized by a piston and spring device, to prevent de-wetting. (C) 2007 Elsevier B.V. All rights reserved.