Experiment. Astronaut Albert Sacco Jr. inspecting a zeolite crystal in a cylindrical autoclave on the mid-deck of the Space Shuttle Columbia during Mission STS-73. This crystal growth experiment was one of the few on this mission that was conducted both in the main part of the shuttle and in the United States Microgravity Laboratory (USML-2). Most of the experiments conducted by the seven-strong crew were done solely in the USML-2 carried in the shuttle's cargo bay. Research was done on fluid physics, materials science, biotechnology, combustion science and commercial space processing techniques. Mission STS-73 lasted from 20 October to 5 November 1995.