STS-115 MS MacLean holds Yeast GAP in the FWD MDDK of the Space Shuttle Atlantis during Joint Operations

S115-E-07274 (9-21 Sept. 2006) --- Astronaut Heidemarie M. Stefanyshyn-Piper, STS-115 mission specialist, works with the Yeast-Group Activation Packs (Yeast-GAP) on the middeck of Space Shuttle Atlantis. Yeast-GAP experiment studies the effects of genetic changes of yeast cells exposed to the space environment. The results will help scientists to understand how cells respond to radiation and microgravity.