Photos: Mobile gantry retracted at Delta 4 launch pad

These photos show the 330-foot-tall mobile service tower moving into position for liftoff of a Delta 4 rocket from Cape Canaveral’s Complex 37B launch pad Friday.

The 218-foot-tall (66-meter) rocket is set for liftoff during a launch window opening at 6:56 p.m. EDT (2256 GMT) and extending to 9:05 p.m. EDT (0105 GMT). The mission’s payload is the U.S. Air Force’s tenth Wideband Global SATCOM spacecraft, valued at roughly $400 million, to extend the reach of the military’s highest-capacity satellite communications network.

The Delta 4 rocket will be powered off the launch pad with an Aerojet Rocketdyne RS-68A main engine and four solid rocket boosters built by Northrop Grumman Innovation Systems. The hydrogen-fueled core stage and solid-fueled strap-on motors will combine to generate 1.8 million pounds of thrust at liftoff.

See our Mission Status Center for live updates on the countdown and flight.

Credit: United Launch Alliance
Credit: United Launch Alliance
Credit: Alex Polimeni/Spaceflight Now
Credit: United Launch Alliance
Credit: United Launch Alliance
Credit: Walter Scriptunas II / Spaceflight Now
Credit: United Launch Alliance
Credit: United Launch Alliance
Credit: United Launch Alliance
Credit: Alex Polimeni/Spaceflight Now
Credit: Walter Scriptunas II / Spaceflight Now
Credit: Alex Polimeni/Spaceflight Now
Credit: Alex Polimeni/Spaceflight Now
Credit: Alex Polimeni/Spaceflight Now

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