Astronauts Mark Polansky and Christopher Cassidy

Astronauts Mark Polansky (left), STS-127 commander; and Christopher Cassidy, mission specialist, close the hatch on the middeck of Space Shuttle Endeavour prior to undocking from the International Space Station to conclude 11 days of cooperative work onboard the shuttle and the station. Undocking of the two spacecraft occurred at 1:26 p.m. (EDT) on July 28, 2009. (Credit: NASA)