Turbulent premixed combustion, while of increased practical importance, is still not fully understood. A serious barrier to further progress in this area lies in the fact that at the high Reynolds numbers encountered in most turbulent reacting flows the Kolmogorov scale is too small to resolve experimentally. When tests at lower Reynolds number are run, the effects of buoyancy become important. In the present study the effect of buoyancy is removed from a turbulent Couette flow by testing it under conditions of microgravity. In the work reported here the velocity field of the cold flow under normal gravity forces was fully characterized. The feasibility of using acetone planar laser induced fluorescence to measure turbulent passive scalar diffusion was confirmed. It was determined that the full range of turbulence scales could be observed experimentally for Reynolds numbers of interest in subsequent combustion studies. © 1997 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.