Atlantis poised on launch pad for Friday afternoon liftoff

Atlantis is poised for a 2:20 p.m. Friday launch after Kennedy Space Center crews unveiled the shuttle on its launch pad early this evening.

The rotating gantry that had closed around Atlantis on April 22 was swung open 120 degrees into its launch position, an operation that took roughly 30 minutes and was completed just after 6 p.m.

The pad's Rotating Service Structure, or RSS, measures 130 feet high, 102 feet long and 50 feet wide. From the base of the pad 59 feet high, it extends up to 189 feet.

Two eight-wheel trucks on rails move the structure, crossing a permanent bridge over the flame trench.

The RSS has five access platform levels and a room used to transfer payloads into the orbiter payload bay.

The next major step in the countdown will be to clear the pad on non-essential personnel just before midnight, to begin preparations for fueling that is scheduled to start at 4:55 a.m. Friday.

Atlantis and six astronauts plan to fly a 12-day International Space Station assembly mission. The mission is the last scheduled for Atlantis, which will serve as a rescue shuttle for a later flight.

Join us for live coverage of the countdown Friday starting with tanking. You can sign up for text messages (starting early in the morning) here.

At 12:30 p.m., FLORIDA TODAY's KSC Bureau Chief Todd Halvorson and WTSP Tampa's Grayson Kamm will bring you countdown updates and a behind-the-scenes look at the mission.

Special guests include Eve Stavros, the Boeing payload manager responsible for preparing the shuttle's cargo for flight; former NASA astronaut Michael Bloomfield of ATK, who flew twice aboard Atlantis; and NASA astronauts Jim Dutton and Rick Mastracchio, who flew on Discovery on the mission that landed on April 20.