T-0:00:05.5	Engine start
The Rocketdyne RS-68 main engine begins to ignite as the liquid hydrogen fuel valve is opened, creating a large fireball at the base of the rocket. The engine powers up to full throttle for a computer-controlled checkout before liftoff.
T-00:00.0	Liftoff
The rocket's two strap-on solid rocket motors are lit, the four hold-down bolts are released and the Delta 4 lifts off from Vandenberg SLC-6 pad. The pad's two swing arms retract at T-0 seconds.
T+00:58.3	Max-Q
The vehicle experiences the region of maximum dynamic pressure. Both solid motors and the RS-68 liquid hydrogen/liquid oxygen engine continue to fire as the vehicle heads downrange, arcing over the Pacific along a 154-degree flight azimuth.
T+01:35.0	Solid motor burnout
Having used up all their solid-propellant, the two strap-on boosters experience burnout. However, they remain attached to the first stage for the next 20 seconds while the vehicle flies clear of the San Miguel and Santa Rosa islands.
T+01:55.0	Jettison solid motors
The two Alliant-built strap-on boosters are jettisoned from the Delta's first stage. The spent casings fall into the ocean.
T+03:54.9	Begin engine throttling
With engine cutoff nearing, the RS-68 powerplant starts throttling down from 102 percent. It will achieve a 57 percent throttle in five seconds.
T+04:05.9	Main engine cutoff
The hydrogen-fueled RS-68 rocket engine completes its firing and shuts down to complete the first stage burn.
T+04:11.9	Stage separation
The Common Booster Core first stage and the attached interstage are separated in one piece from the Delta 4's upper stage. The upper stage engine's extendible nozzle drops into position as the first stage separates.
T+04:26.4	Second stage ignition
The upper stage begins its job to place the classified NRO payload into space with the first of two firings. The stage features a Pratt & Whitney RL10B-2 liquid hydrogen/liquid oxygen engine.
T+04:36.5	Jettison nose cone
The four-meter diameter composite payload fairing that protected the classified spacecraft atop the Delta 4 during the atmospheric ascent is no longer needed, allowing it to be jettisoned in two halves.
T+14:21.7	Upper stage shutdown
The RL10 upper stage engine shuts down to complete its first firing of the launch. The rocket and attached spacecraft reach an ellipitcal parking orbit of 104 by 1,196 nautical miles with an inclination of 62.5 degrees.
T+40:12.0	Restart upper stage
The upper stage will coast to the parking orbit's high point where the RL10 engine reignites to raise the altitude for deployment of the payload.
T+43:34.2	Upper stage shutdown
The powered phase of the Delta 4's mission to loft classified payload concludes. The targeted orbit is 601 by 20,308 nautical miles with an inclination of 62.4 degrees.
T+50:04.5	Begin spin-up
The next step in preparing for deployment of the payload is gently spinning up the stage like a top to 5 rpm.
T+54:14.5	Spacecraft separation
The classified spacecraft for the U.S. National Reconnaissance Office is released from the Delta 4 rocket, completing the first West Coast Evolved Expendable Launch Vehicle mission.

Data source: Boeing