Remarks concerning the validity of the measured diffusion coefficients in liquid metal systems on the Russian MIR space station

Acta Astronautica, Vol. 48 (2001), contains in pp. 59–70 an article discussing the benefits of conducting liquid metal diffusion experiments in space using the Canadian Microgravity Vibration Isolation Mount (MIM) [B.V. Tryggvason, R.F. Redden, R.A. Herring, W.M.B. Duval, R.W. Smith, K.S. Rezkallah, S.Varma, The vibration environment on the International Space Station: its significance to fluid-based experiments, Acta Astronautica 48 (2001) 59–70]. Two main problems have been identified with this published article: (1) On the basis of experimental results, the authors claim that the diffusion coefficients of gold in lead measured on the ground are much higher than those obtained under microgravity conditions. Close examination of the problems encountered during processing of the capillary diffusion couples on the MIR space station reveals that this claim cannot be justified. (2) The authors further conclude that there is a linear relationship between diffusion coefficient ( D ) and temperature ( T ) when g -jitter is suppressed. This conclusion is questionable because the methodology used to determine the processing time and temperatures on the MIR space station does not seem to be scientific.