NASA Flow Director Stephanie Stilson talk during the countdown for space shuttle Discovery to launch on mission STS-120.

In the firing room of the Launch Control Center at NASA's Kennedy Space Center, NASA Flow Director Stephanie Stilson (left) and Shuttle Launch Director Mike Leinbach (center) talk during the countdown for space shuttle Discovery to launch on mission STS-120. At right is Assistant Launch Director Doug Lyons. Liftoff was on time at 11:38:19 a.m. EDT. Discovery carries the Italian-built U.S. Node 2, called Harmony. During the 14-day STS-120 mission, the crew will install Harmony and move the P6 solar arrays to their permanent position and deploy them. Discovery is expected to complete its mission and return home at 4:47 a.m. EST on Nov. 6. Photo credit: NASA/Kim Shiflett