Combining robotics with a five-hour 32-minute spacewalk, the Endeavour astronauts accomplished the primary goal of their space station assembly mission Saturday, successfully attaching a sophisticated experiment platform to the Japanese Kibo laboratory module. In the first of five planned spacewalks, astronauts Dave Wolf and Tim Kopra prepped the Japanese Exposed Facility, or JEF, for removal from the shuttle's cargo bay and then went on to other tasks, including the successful deployment of a jammed external storage system.

Koichi Wakata and Douglas Hurley, meanwhile, operating the space station's robot arm, pulled the JEF platform out of the shuttle's payload bay and handed it off to Julie Payette, operating Endeavour's robot arm. After repositioning the station crane, Wakata re-grappled the JEF and moved it into position for attachment to the Kibo module.