Delta IV Heavy's US Spy Satellite Launch

Space.com

United Launch Alliances Delta Heavy IV rocket launch from Space Launch Complex-37 at Cape Canaveral Space Force Station in Florida for the final time. The rocket carries the  NROL-70 mission for the National Reconnaissance Office.   Credit: ULA

Transcript

00:00 [ Music ]

00:03 To mitigate the fireball created

00:05 by the hydrogen-burning Delta IV Heavy rocket,

00:08 the staggered engine start sequence begins with ignition

00:11 of the launch table HBOs,

00:12 burning off the excess hydrogen injected into the flame duct.

00:18 Next, the starboard Delta IV roving lights,

00:20 igniting its RS-68A engine.

00:23 Then the center and port RS-68A engines ignite

00:27 and generate more than 2.1 million pounds of total thrust

00:31 to lift the 1.6 million pound triple core rocket off the pad.

00:35 Shortly after liftoff, Delta begins a pitch

00:42 over to attain the proper flight path while minimizing the

00:45 pressure the vehicle experiences during flight.

00:47 Delta then reaches Mach 1, the speed of sound,

00:52 followed by the rocket reaching maximum dynamic pressure

00:55 as it travels through Earth's atmosphere.

00:57 With propellant depleted in the port and starboard boosters,

01:04 the engines shut down and the boosters jettison

01:07 to shed their weight.

01:08 The remaining booster engine then throttles to full power

01:11 to maximize performance against gravity losses.

01:14 Once propellant levels deplete in the center booster,

01:18 the engine shuts down and the booster is jettisoned

01:21 from the second stage.

01:22 The vehicle now weighs approximately 6%

01:25 of what it did at liftoff.

01:26 Following jettison of the center booster,

01:32 the Delta Cryogenic Second Stage,

01:35 or DCSS, main engine ignites.

01:38 During ascent, NROL-70 is protected inside a 5-meter

01:42 diameter metallic payload fairing.

01:44 After traveling through the densest part

01:47 of Earth's atmosphere, the payload fairing is jettisoned.

01:49 The Delta IV Cryogenic Second Stage carries the last payload

01:56 to launch on a Delta IV rocket to its final orbital destination,

01:59 where it will begin its national security mission.

02:02 [ Sound Effects ]

02:06 [ Silence ]

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