| T-0:00:05.0 |
Engine start |
 |
The 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-0:00:00.0 |
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 Cape Canaveral's pad 37B. The pad's three swing arms retract at T-0 seconds. |
|
| T+0:01:00.7 |
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 Atlantic along a 45-degree flight azimuth. |
|
| T+0:01:40.0 |
Jettison solid motors |
 |
Having used up all their solid-propellant and experienced burnout six seconds ago, the two strap-on boosters are jettisoned from the Delta's first stage. The spent casings fall into the ocean. |
|
| T+0:04:07.2 |
Main engine cutoff |
 |
The hydrogen-fueled RS-68 rocket engine completes its firing and shuts down to finish the first stage burn. |
|
| T+0:04:14.5 |
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+0:04:29.0 |
Second stage ignition |
 |
The upper stage begins its job to place the GPS 2F-6 satellite into space with the first of two firings by the RL10B-2 liquid hydrogen/liquid oxygen engine. |
|
| T+0:04:39.5 |
Jettison payload fairing |
 |
The four-meter diameter composite payload fairing that protected the GPS 2F-6 cargo atop the Delta 4 during the atmospheric ascent is no longer needed, allowing it to be jettisoned in two halves. |
|
| T+0:15:31.5 |
Upper stage shutdown |
 |
The RL10 upper stage engine shuts down to complete its first firing of the launch. The rocket and attached satellite reach an intermediate transfer orbit where it coasts for the next three hours. |
|
| T+3:03:25.0 |
Restart upper stage |
 |
The upper stage reaches the proper point in space and reignites the the RL10 engine to circularize the orbit. |
|
| T+3:05:08.2 |
Upper stage shutdown |
 |
The powered phase of the Delta 4's mission to reach the GPS constellation concludes. The targeted circular orbit is 11,047 nautical miles with an inclination of 55 degrees. |
|
| T+3:15:49.5 |
Separate spacecraft |
 |
The GPS 2F-6 satellite is released into space from the Delta 4 rocket to upgrade the orbiting navigation network. |
