|The twin solid rocket boosters are ignited and space shuttle Atlantis launches from pad 39A at Kennedy Space Center, Florida.
|Start roll maneuver
|Atlantis beings a roll program to achieve a northeasterly track from KSC, heading toward a 51.6 degree inclination to the equator.
|The shuttle completes the programmed roll maneuver and is now positioned heads down, wings level.
|Start throttle down
|The three liquid-fueled main engines are throttled down to 72 percent rated thrust to ease the vehicle's flight through the dense lower atmosphere.
|Atlantis' main engines begin throttling back up. The engines's thrust level will be taken to 104.5 percent.
|Having consumed all their propellant, the solid rocket boosters are jettisoned from the attachment points on the external fuel tank. The boosters parachute into the Atlantic Ocean for recovery and reuse.
|Start OMS assist
|The twin Orbital Maneuvering System engines on the tail of Atlantis are ignited to begin a 59-second firing to assist the shuttle into space.
|Atlantis can no longer make an emergency Return-to-Launch-Site abort landing at Kennedy Space Center. A problem after this point in flight requiring an abort would lead to a Trans-Atlantic Abort Landing, an Abort-Once-Around or Abort-to-Orbit.
|Rolls to heads up
|A programmed maneuver rolls Atlantis to a heads up position, placing the shuttle atop the external tank. This is done to improve communications between the shuttle and orbiting NASA satellites.
|Atlantis' three main engines are shut down. The external fuel tank is jettisoned moments later. An upcoming firing of the OMS engines will circularize the orbit.