International Space Station (ISS)

Hovering in space some 240 miles above the blue and white Earth, STS-110 astronaut M.E. Morin participates in his first ever and second of four scheduled space walks for the STS-110 mission. He is seen toting one of the S0 (S-Zero) keel pins which were removed from their functional position on the truss and attached on the truss' exterior for long term stowage. The 43-foot-long, 27,000 pound S0 truss was the first of 9 segments that will make up the International Space Station's external framework that will eventually stretch 356 feet (109 meters), or approximately the length of a football field. This central truss segment also includes a flatcar called the Mobile Transporter and rails that will become the first "space railroad," which will allow the Station's robotic arm to travel up and down the finished truss for future assembly and maintenance. The completed truss structure will hold solar arrays and radiators to provide power and cooling for additional international research laboratories from Japan and Europe that will be attached to the Station. The mission completed the installations and preparations of the S0 truss and the Mobile Transporter within four space walks. STS-110