Live in Orbit: Cargo carrier bolted to station

Astronauts have driven 16 bolts into place to tightly fasten a cargo carrier to an International Space Station docking port just before 6 p.m. EDT.

The relocation of the Italian-built Leonardo module from shuttle Discovery's payload bay to the station sets the stage for days of work to unload nearly eight tons of critical supplies.

The cylindrical module weighed nearly 28,000 pounds on the ground.

It's delivery to the station is the main purpose of Discovery's 13-day mission, in addition to swapping a station crew member - Nicole Stott for Tim Kopra - and replacing an ammonia tank upcoming during spacewalks.

Work to transfer a smaller amount of cargo from the shuttle's mid-deck has already begun, but it the gear inside Leonardo are the big-ticket items.

They include two stations for conducting research on materials and fluids and a freezer for storing experiment samples, equipment that will help transition the station to more productive use as a science facility.

Other equipment sounds more mundane - a bedroom and a treadmill named after comedian Stephen Colbert - but is important to the long-term health of six station residents.

Crew members on the outpost exercise more than two hours a day to minimize bone and muscle density.

Hatches between Leonardo and its docking port won't open until early Tuesday, after leak checks and pressurization of the vestibule separating the hatches.