Video: Soyuz launcher ready for rollout

Check out photos taken by two astronauts who ventured outside the International Space Station on Saturday, running more than 300 feet of wiring that will eventually be connected to new docking ports to receive commercial spaceships built by Boeing and SpaceX.

Riding a specialized railroad car before dawn Friday, a Soyuz rocket rolled out of a cavernous assembly building and arrived at its launch pad at the Baikonur Cosmodrome in Kazakhstan for liftoff Sunday with American, Russian and Italian crew members heading for the International Space Station.

Concern about a possible ammonia coolant leak Wednesday prompted astronauts on the International Space Station to evacuate the U.S. segment of the complex and shelter in the Russian portion of the outpost while flight controllers scrambled to untangle initially confusing telemetry.