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Delta 4-Heavy rocket demo launch timeline
Posted: December 1, 2004

T-0:00:05.5 Engine start
The three Rocketdyne RS-68 main engines begin to ignite as the liquid hydrogen fuel valves are opened, creating a large fireball at the base of the rocket. The engines powers up to full thrust of 102% for a computer-controlled checkout before liftoff.
T-0:00:00.0 Liftoff
The hold-down bolts are released and the inaugural flight of Boeing's Delta 4-Heavy rocket is underway from Cape Canaveral's pad 37B. The three umbilical swing arms extending from the launch pad tower retract from the rocket at T-0 seconds.
T+0:00:50.0 Begin engine throttling
The center Common Booster Core engine throttles down to 58% thrust over the next five seconds. The booster stage conserves fuel while the outer two CBCs remain at full throttle.
T+0:01:20.9 Max-Q
The vehicle experiences the region of maximum dynamic pressure. The rocket hits Mach 1 about three seconds later as the three liquid hydrogen/liquid oxygen engines continue to fire.
T+0:02:33.0 Roll maneuver
The rocket begins a 50-second roll maneuver to a "wings-level" orientation as it heads downrange, arcing over the Atlantic.
T+0:03:54.7 Outer CBC throttling
With engine shutdown coming up for the outer Common Booster Cores, the RS-68 powerplants start throttling down from 102 percent. They will achieve a 58 percent throttle in five seconds.
T+0:04:05.3 Outer CBC shutdown
The engines on the two outer Common Booster Cores complete their firings and shut down.
T+0:04:08.4 Outer CBC jettison
The outer Common Booster Cores separate from the center stage to fall into the Atlantic Ocean.
T+0:04:09.3 Engine throttle up
After operating at minimum throttle for the past three minutes, the center Common Booster Core's RS-68 main engine revs up to 102% power.
T+0:05:17.0 Engine throttle down
The center Common Booster Core throttles its engine down again to 58% to prepare for shutdown.
T+0:05:33.4 Main engine cutoff
The center CBC has consumed all of its fuel and the RS-68 engine cuts off.
T+0:05:41.0 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+0:05:54.4 Second stage ignition
The upper stage begins the first of several firings using its Pratt & Whitney RL10B-2 liquid hydrogen/liquid oxygen engine to reach the desired orbit for the DemoSat spacecraft payload.
T+0:06:04.5 Nose cone jettison
The five-meter diameter payload fairing that protected the DemoSat cargo atop the Delta 4 during the atmospheric ascent is no longer needed, allowing it to be jettisoned in two halves.
T+0:12:47.8 Upper stage shutdown
The RL10 upper stage engine shuts down to complete its first firing of the launch. The rocket and attached satellite reach a parking orbit of 99.94 by 134.8 nautical miles with an inclination of 28.8 degrees.
T+0:15:45.0 Nanosat sep signal
The command is issued to deploy the two university-built Nanosat spacecraft mounted to the side of DemoSat. The tiny nanosats physically separate at T+plus 16:23.0.
T+0:20:29.5 Restart upper stage
The upper stage reignites its RL10 engine to begin the trek from the initial parking orbit around Earth to the targeted geosynchronous orbit.
T+0:28:31.6 Upper stage shutdown
The second burn by the upper stage is completed with the new orbit achieved featuring a high point of 19,651 nautical miles, low point of 148.4 nautical miles and inclination of 27.3 degrees. The rocket begins a multi-hour coast through space to reach apogee where another engine burn will occur to circularize the orbit.
T+5:37:13.0 Restart upper stage
The upper stage restarts its cryogenic engine to finish the task of boosting DemoSat into the intended orbit.
T+5:40:27.3 Upper stage shutdown
The powered phase of the Delta 4-Heavy's demonstration mission concludes. The upper stage begins using thrusters to orient itself to the proper payload deployment attitude.
T+5:49:37.5 Spacecraft separation
The DemoSat satellite simulator is released from the Delta 4-Heavy rocket's upper stage, completing the vehicle's test flight. The targeted orbit is circular at 19,623 nautical miles with an inclination of 10 degrees.

Data source: Boeing.