T-00:00	Liftoff
The Delta 2 rocket's main engine and twin vernier steering thrusters are started moments before launch. The six ground-start strap-on solid rocket motors are ignited at T-0 to begin the mission.
T+01:03.1	Ground SRM Burnout
The six ground-start Alliant TechSystems-built solid rocket motors consume all their propellant and burn out.
T+01:05.5	Air-Lit SRM Ignition
The three remaining solid rocket motors strapped to the Delta 2 rocket's first stage are ignited.
T+01:06.0	Jettison Ground SRMs
The six spent ground-started solid rocket boosters are jettisoned in sets of three to fall into the Atlantic Ocean.
T+02:11.5	Jettison Air-Lit SRMs
Having burned out, the three spent air-started solid rocket boosters are jettisoned toward the Atlantic Ocean.
T+04:23.3	Main Engine Cutoff
After consuming its RP-1 fuel and liquid oxygen, the Pratt & Whitney Rocketdyne RS-27A first stage main engine is shut down. The vernier thrusters cut off moments later.
T+04:31.3	Stage Separation
The Delta rocket's first stage is separated now, having completed its job. The spent stage will fall into the Atlantic Ocean.
T+04:36.8	Second Stage Ignition
With the stage jettisoned, the rocket's second stage takes over. The Aerojet AJ118-K liquid-fueled engine ignites for the first of two firings needed to place the upper stage and STEREO payload into the proper orbit.
T+04:41.0	Jettison Payload Fairing
The 10-foot diameter payload fairing that protected the STEREO spacecraft atop the Delta 2 during the atmospheric ascent is jettisoned is two halves.
T+10:07.1	Second Stage Cutoff 1
The second stage engine shuts down to complete its first firing of the launch. The rocket and attached STEREO spacecraft are now in a coast period before the second stage reignites. The orbit achieved should be circular at 91.9 nautical miles and inclined 28.5 degrees.
T+15:37.0	Second Stage Restart
Delta's second stage engine reignites for a firing to raise the orbit further.
T+17:44.4	Second Stage Cutoff 2
The second stage shuts down. The orbit achieved should be 1,717.7 nautical miles at apogee, 98.8 nautical miles at perigee and inclined 28.5 degrees. Over the next minute, tiny thrusters on the side of the rocket will be fired to spin up the vehicle in preparation for stage separation.
T+17:57.7	Stage Separation
The liquid-fueled second stage is jettisoned from the rest of the Delta 2 rocket.
T+18:34.9	Third Stage Ignition
The Thiokol Star 48B solid-fueled third stage is ignited to propel the STEREO satellites into the intended transfer orbit around Earth.
T+20:03.8	Third Stage Burnout
Having used up all its solid-propellant, the third stage burns out to completed the powered phase of the Delta rocket's launch sequence for STEREO.
T+25:00.7	Payload Deployment
NASA's twin Solar Terrestrial Relations Observatory (STEREO) spacecraft are released from the Boeing Delta 2 rocket. The two satellites will separate apart from each other a few minutes later.

Data source: Boeing.