关于这张图
S127-E-007079 (29 July 2009) --- Astronaut Christopher Cassidy is pictured on the flight deck of the Space Shuttle Endeavour during the July 20 spacewalk of astronauts Dave Wolf and Tom Marshburn. Cassidy, Wolf and Marshburn, all three mission specialists, are part of a 13-member station population for now -- an aggregation made up of seven shuttle astronauts and six Expedition 20 crew members.
