[Updated at 2:30 p.m.] Space Shuttle Atlantis is now successfully in orbit, NASA said.
[Updated at 2:29 p.m.] Space Shuttle Atlantis' main engine cutoff is confirmed, NASA said, and the external fuel tank has separated.
[Updated at 2:28 p.m.] Atlantis is in "excellent shape heading into orbit," NASA said.
[Updated at 2:25 p.m.] NASA said all systems are operating normally on Space Shuttle Atlantis.
[Updated at 2:22 p.m.] Solid rocket booster separation has been confirmed, NASA said.
[Posted at 2:20 p.m.] The Space Shuttle Atlantis has cleared the tower from Kennedy Space Center in Florida.
The crew of six astronauts will deliver an integrated cargo carrier and a Russian-built mini research module to the International Space Station.
There are three remaining shuttle missions - including Friday's scheduled launch - before the program ends.