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The Mission

Rocket: Delta 4-Heavy
Payload: DSP 23
Date: Nov. 10, 2007
Window: 8:39-10:41 p.m. EST (0139-0341 GMT)
Site: SLC-37B, Cape Canaveral, Florida
Satellite feed: Galaxy 26, Transponder 5, C-band, 93° West

Mission Status Center

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Video archive

Delta 4-Heavy launch

The first operational Delta 4-Heavy rocket launches the final Defense Support Program missile warning satellite for the Air Force.


Day 15 highlights

Video highlights from Discovery's final full day in space for STS-120.


Day 14 highlights

Flight Day 14 was undocking day as Discovery depated the station to begin the journey toward home.


Day 13 highlights

The shuttle Discovery astronauts say goodbye to their space station crewmates on Flight Day 13 of the STS-120 mission.


Day 12 highlights

Spacewalking astronauts come to the rescue and repair the station's damaged solar array. Highlights are packed in the Flight Day 12 movie.


Day 11 highlights

Preparing tools, maneuvering the space station robot arm and unberthing the shuttle boom for spacewalk are highlighted in the Flight Day 11 movie.


STS-120 SRB cameras

Spectacular footage from six cameras mounted on shuttle Discovery's solid rocket boosters.

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Day 10 highlights

The astronauts getting equipment ready for the solar array repair spacewalk was the focus of activities on Flight Day 10.


STS-120 day 9 highlights

This Halloween edition of the flight day highlights is complete with Clay Anderson's costume.


STS-120 day 8 highlights

Moving the Port 6 truss to its permanent spot on the station and the ripped solar blanket are shown in the Flight Day 8 movie.


STS-120 day 7 highlights

Juggling of the Port 6 solar array truss between the station and shuttle robotic arms highlighted work on Flight Day 7.


STS-120 day 6 highlights

Spacewalk to detach Port 6 truss and discovery of debris in a solar array rotary joint are highlighted in the Flight Day 6 movie.


STS-120 day 5 highlights

Highlights from Flight Day 5 see the astronauts enter into the newly-installed Harmony module.


STS-120 day 4 highlights

The Flight Day 4 highlights movie shows Harmony's attachment to the station and the Discovery mission's first spacewalk.


STS-120 day 3 highlights

This movie shows the highlights from Flight Day 3 as Discovery docked to the space station.


STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 launch videos

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STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


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More video

Delta 4-Heavy rocket fires away from Cape Canaveral

Posted: November 11, 2007

It is America's largest unmanned space booster. Its level of complexity causes engineers to liken it to launching three rockets at one time. And its fiery blastoffs create a dazzling yet heart-in-your-throat sight. Now, the mammoth Delta 4-Heavy has entered operational service with Saturday night's successful ascent carrying a critical surveillance satellite.

Credit: Ben Cooper/Spaceflight Now
Towering more than 230 feet tall and packing nearly two million pounds of thrust from its three hydrogen-fueled main engines, this rocket is built to loft big payloads. And the roomy nose cone offers spacious accommodations for exceptionally large spacecraft.

The Delta 4-Heavy's characteristics make it well suited for launching a Defense Support Program (DSP) missile warning satellite into geosynchronous orbit 22,300 miles above the planet.

But in its lone previous flight three years ago, the Heavy encountered an unexpected problem within its fuel lines, causing the engines to snuff out a few seconds early and leaving the rocket well short of the intended orbit. That December 2004 launch was only a test, an Air Force-financed demonstration flight designed to uncover the unknown flaws in the system before expensive and vital national security payloads were entrusted to the big booster.

"It's always better to find a problem than to have a latent and yet-to-be-discovered (problem). That's part of why we considered the Heavy demo such a success. It was a very subtle problem, but we found it and we fixed it," said Col. Jim Planeaux, the Delta group commander at the Space and Missile Systems Center.

The test rocket was outfitted with vast amounts of data-collecting sensors to understand all aspects of the ascent, leading to some other changes before the first operational launch.

Credit: Ben Cooper/Spaceflight Now
"We took a lot of readings on accelerations, vibrations, acoustics in the various compartments of the vehicle. In a few cases (we) determined that they were higher than we expected and we either modified the hardware slightly or moved some of the components to a more benign environment. We finished all of those (modifications) late last year, and we're very comfortable with the vehicle we've got."

Rocket-maker United Launch Alliance and the Air Force, both confident that the Heavy was ready for a real mission, fired off the rocket from Cape Canaveral in Florida at 8:50 p.m. EST (0150 GMT) Saturday evening.

Hidden inside the long metallic nose cone rode the Defense Support Program 23 spacecraft, the last in a series of eye-in-the-sky satellites designed to spot enemy missile launches and nuclear explosions.

DSP satellites have been flying since November 1970, rocketing into orbit aboard various versions of now-retired Titan rockets and the space shuttle. This final one -- DSP 23 -- has been waiting more than two years for the new Heavy to hoist it into space.

The Delta 4-Heavy is created by taking three Common Booster Cores -- the liquid hydrogen-fueled motor that forms a Delta 4-Medium's first stage -- and strapping them together to form a three-wide rocket, and then adding the powerful upper stage.

Each 15-story booster core features a Pratt & Whitney Rocketdyne RS-68 main engine that generates 650,000 pounds of thrust while burning supercold liquid hydrogen and liquid oxygen propellants. The cryogenic upper stage has the Pratt & Whitney Rocketdyne RL10B-2 powerplant.

Credit: Ben Cooper/Spaceflight Now
As the countdown entered the final seconds, liquid hydrogen rushed through the three RS-68 engines and then the powerplants roared to ignition. A massive cloud of fire raced up the rocket, creating a visually awesome but terrifying display. A dozen explosive bolts holding the vehicle to pad 37B detonated as clocks struck zero to free the Heavy to begin climbing as three launch pad swing arms pulled back.

Data from the test flight showed the ignition fireball created hot temperatures around the nose cone, leading to another change for the DSP satellite launch.

"We've done a lot of thinking about it since (the test). It does get pretty hot up around even the payload vents. So to mitigate that, we've added some modifications to this particular payload fairing to essentially keep the plume out as the vehicle rises and still allow the payload compartment to vent properly," Planeaux said.

"When you've got a payload that's very sensitive to contamination, we had to go through some fairly elaborate measures to ensure we were well protected there."

The three identical main engines, the world's largest hydrogen-fueled rocket engine and each capable of generating 17 million horsepower, propelled the vehicle into a clear night sky with three distinct red-hot plumes trailing more than 200 feet long.

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About 50 seconds into flight, the center Common Booster Core's engine was throttled back to its minimum power level of 57 percent thrust to conserve fuel that became important later. The starboard and port boosters continued firing at full throttle -- 102 percent thrust -- through the launch's first four minutes before emptying their liquid hydrogen and liquid oxygen propellant tanks and shutting down the RS-68 engines. The boosters peeled away and plummeted into the Atlantic Ocean.

Once the outer boosters were shed, the center stage finally throttled back up to 102 percent for more than a minute of propulsion, consuming that fuel supply saved during the period of reduced thrust. The stage was jettisoned about five minutes, 40 seconds after liftoff, leaving the rocket's upper stage and payload to continue the journey to orbit.

About 13 minutes into flight, the upper stage completed its first burn to achieve an initial parking orbit above Earth and entered an hour-long coast mode until it reached the extreme western Pacific Ocean northeast of Australia. That is where the RL10 engine was re-ignited to reach a geosynchronous transfer orbit stretching 22,000 miles at its high point.

The stage then coasted in this orbit, eventually reaching the apogee where the RL10 engine was fired for a third time starting at T+plus 6 hours, 10 minutes. The three-minute burn circularized the orbit over the equator off the western coast of South America.

At 3:09 a.m. EST, the 5,179-pound DSP satellite was released from the Delta 4-Heavy rocket to complete the launch.

"Last night's successful countdown and flight culminate a tremendous amount of hard work by the entire Air Force launch team and our industry partners. Congratulations to all who made this challenging and spectacular launch of the DSP 23 satellite a reality," Planeaux said.

Credit: Chris Miller/Spaceflight Now
"As the first operational launch of a Delta 4 Heavy Lift Vehicle, it marks a major milestone accomplishment for the EELV program and for assured access to space."

Bringing the Heavy version of the Air Force's Evolved Expendable Launch Vehicle family into operational service, the military has now successfully replaced the retired Titan rocket fleet for deploying large satellite payloads.

"This success highlights the continued maturization of our EELV program," said Brig. Gen. Susan Helms, 45th Space Wing commander at Cape Canaveral.

Another Heavy is next up on the Delta 4's launch schedule. An April liftoff is planned from Cape Canaveral to deliver a classified spy satellite into orbit for the U.S. National Reconnaissance Office.

Officials plan a five-month gap between Saturday's flight and the subsequent launch while engineers complete a thorough review of data.

"That has a five-month standoff to digest all of the analysis and redo all of the loads for the payload. But we look forward to not taking any more time than that to launch NROL-26," said Mark Wilkins, United Launch Alliance vice president for Delta Programs.

Another secret NRO launch using a Heavy from the Cape is planned in 2009, followed no sooner than 2010 the first Heavy flight from California's Vandenberg Air Force Base with another NRO payload. Outfitting of that West Coast pad to install equipment for the larger rocket has begun.

For more on Defense Support Program 23 satellite launched Saturday night, see our separate story here.

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