STS073-353-010 (20 October - 5 November 1995) --- Payload specialist Albert Sacco Jr. checks out the Zeolite Crystal Growth (ZCG) on the middeck of the Earth-orbiting Space Shuttle Columbia. ZCG evaluated Zeolite crystallization and growth in the microgravity environment aboard Columbia in order to achieve high yields of large, nearly perfect crystals in space. Zeolites are complex arrangements of silica and alumina that occur naturally as well as synthetically.