Space Shuttle Discovery on Wednesday will move from the Orbiter Processing Facility to the Vehicle Assembly Building, NASA announced.

Discovery will lift off no sooner than Dec. 7, when a launch is set for 9:38 p.m., the first liftoff in darkness in years.

The shuttle then will head for the International Space Station (ISS), where its crew will add to construction of the artificial moon, and also will begin rewiring the ISS to make use of the increased solar-display electrical generating capacity installed by crew members on the last shuttle mission.

That was when Space Shuttle Atlantis hauled the giant P3/P4 truss into orbit and attached it to the ISS.

In preparing for the next mission, with Discovery, the giant orbiter vehicle this week will be moved from the processing facility at Kennedy Space Center, Fla., to the assembly building, a 1 mph journey that will begin at 6 a.m. ET.

Once there, the external fuel tank and twin solid rocket boosters will be attached to the orbiter.

After entering orbit, the crew of Discovery will execute an 11-day mission to the ISS. That STS-116 Discovery crew of seven astronauts will deliver a third truss segment, a SPACEHAB module and other key components during the shuttle’s 20th mission to the space station.