STS070-329-022 (13-22 JULY 1995)--- Astronaut Donald A. Thomas, mission specialist, prepares to activate the Microcapsules in Space (MIS-B) experiment on the space shuttle Discovery?s middeck. MIS-B is an Army project to improve the understanding of microencapsulated drug technology and demonstrate the feasibility of producing pharmaceutical microcapsules in the weightlessness of space. This is the second flight of the experiment, which originally flew on STS-53 in 1992. Microcapsules are tiny spheres about 50 to 100 micrometers in diameter (about the thickness of a strand of human hair). They are used to develop high-performance chemical products and innovative pharmaceuticals such as time-release prescriptions. The drug used in the MIS experiments was ampicillin.