The first protein crystallization experiment in M G was launched in Apr i l , 1981 and used Germany's Technologische Experimente unter Schwerelosigkeit ( T E X U S 3) sounding rocket. The protein /3-galactosidase (molecular weight 465 kDa) was chosen as the sample with a liquid-liquid diffusion growth method. A sliding device brought the protein, buffer and salt solution into contact when M G was reached. The sounding rocket gave 6 min of M G time with a cine camera and schlieren optics used to monitor the experiment, a single growth cell. In M G a strictly laminar diffusion process was observed in contrast to the turbulent convection seen on the ground. Several single crystals, ~100 urn in length, were formed in the flight which were of inferior but of comparable visual quality to those grown on the ground over several days (Littke and John 1984). A second experiment using the same protocol but with solutions cooled to —8 °C (kept liquid with glycerol antifreeze) again showed laminar diffusion.