STS073-131-014 (20 October-5 November 1995) --- Astronaut Kent V. Rominger, STS-73 pilot, uses a camcorder to record progress in the Hand-Held Diffusion Test Cell (HHDTC) experiment. This test dealt with crystal growth by liquid-to-liquid diffusion. Four HHDTC units containing four test cells each produced protein crystals by diffusing one liquid to another. Rominger joined four other NASA astronauts and two guest researchers for 16 days of in-space United States Microgravity Laboratory 2 (USML-2) research aboard the Space Shuttle Columbia.