STS073-101-018 (20 October-5 November 1995) --- Payload specialist Fred W. Leslie maneuvers his body to a position conducive to research at the Crystal Growth Furnace (CGF) aboard the science module in the cargo bay of the Earth-orbiting Space Shuttle Columbia. Crystallization has been discovered to be more effectively studied in the weightless environment of space than on Earth, because the gravity-induced phenomena that obscure or change the process or change the process are greatly reduced or eliminated. Leslie was joined by a second guest researcher and five NASA astronauts for 16 full days of in-space research in support of the United States Microgravity Laboratory (USML-2) mission.