On Earth, the force of gravity collapses crystals as they form. As a consequence, scientists cannot pinpoint exactly which part of a drug works and which part causes negative side effects. On our mission, we were conducting an experiment with the anticancer drug alpha-interferon, already used successfully worldwide to treat cancer, but with some bad side effects. On our flight, we grew alpha-interferon crystals to help scientists in their effort to eliminate those side effects and improve the drug. Another research project we supported on our mission also depended on a zero gravity environment.
Gypsy moths are very destructive pests, especially to hardwood forests in the eastern United States.
To produce them on the ground has not been very successful. But if you take gypsy moths eggs into space and then bring them back to Earth, at some point they become sterile. We took 5,000 gypsy moth eggs with us. When they hatched after our return, scientists began studying the moths to understand the exact physiological process that produces sterility. The USDA will try to emulate that process on the ground.