After almost nine days of cooperative work onboard the International Space Station and Space Shuttle Discovery, the STS-121 and Expedition 13 crews bid farewell to each other prior to the undocking of the two spacecraft. Pictured are astronauts Piers J. Sellers, STS-121 mission specialist; European Space Agency (ESA) astronaut Thomas Reiter, Expedition 13 flight engineer; Stephanie D. Wilson, STS-121 mission specialist; and cosmonaut Pavel V. Vinogradov, Expedition 13 commander representing Russia's Federal Space Agency. Undocking of the two spacecraft occurred at 5:08 a.m. (CDT) on July 15, 2006.