One of the most powerful rockets in service is scheduled to carry a classified spy satellite for the U.S. Department of Defense aloft from Florida before dawn Thursday.
United Launch Alliance plans to send the satellite into space at 2:12 a.m. EDT aboard the company's Delta IV Heavy, a triple-engine launcher that creates a collective 2.2 million pounds of thrust.
That compares to SpaceX's Falcon Heavy, the most powerful of today's rockets, with 3.4 million pounds of thrust at liftoff.
The ULA mission is to lift off from Cape Canaveral Air Force Station's Complex 37B. A 20 percent chance of stormy weather that could delay the launch exists, according to a U.S. Space Force forecast. In case of delay, the launch could come early Friday or Saturday.
"This is a large, heavy satellite, and the rocket will be fully loaded with fuel," said Tony Taliancich, ULA's director and general manager of launch operations. "That means the rocket will rise off the pad slowly. It looks quite majestic."
The mission, dubbed NROL-44, will be the 12th launch of a Delta IV Heavy, first used in 2004, Taliancich said. He said the nose cone, or fairing, is the largest available today. The upper stage produces 24,750 pounds of thrust.
"This is a three-burn mission to get to this orbit," Talianich said, noting that the upper stage engine will fire twice.
The National Reconnaissance Office, the agency that oversees the launch, is part of the Defense Department. According to its mission statement, it is responsible for developing, launching and operating America's reconnaissance satellites, along with data-processing facilities.
That data is used by the National Security Agency and National Geospatial-Intelligence Agency to produce photos, maps, reports and other tools for the president, Congress, national policymakers, warfighters and others.
The Delta IV Heavy, named so as the fourth version of the Delta rocket, was developed to launch for the reconnaissance office, U.S. Space Force and NASA. It also launched NASA's Orion capsule in a 2014 test flight and sent the Parker Solar Probe into the sun's outer atmosphere.
ULA plans only three more Delta IV Heavy launches from Florida — including this week's launch — and two more from Vandenberg Air Force Base in California. After that, the company plans to use its Vulcan rocket, which is under development.
