Spaceflight Insider

Next launch of Delta IV Heavy delayed

United Launch Alliance Delta IV Heavy Cape Canaveral Air Force Station Space Launch Complex 37 EFT-1 photo credit Mike Howard SpaceFlight Insider

File Photo Credit: Mike Howard / SpaceFlight Insider

CAPE CANAVERAL, Fla. — The flight of United Launch Alliance‘s next Delta IV Heavy rocket, with a payload for the National Reconnaissance Office (NRO), has been delayed, according to a May 27 statement on the company’s website.

Originally scheduled to take to the skies on June 4, ULA delayed the launched per the request of the customer. No other reason was specified, but the spacecraft and booster are reported to be secure on the pad.

When it does launch, it will loft the NROL-37 mission—a classified spy satellite—for the NRO from Space Launch Complex 37 (SLC-37) located at Cape Canaveral Air Force Station in Florida.

When it does launch, it will be the 32nd Delta IV mission since the launch vehicle first started flying in 2002. Additionally, it will be the 10th NRO mission to be launched atop a Delta IV and the ninth in the Heavy configuration—the first launch of which occurred on Dec. 21, 2004.

The last time a Delta IV Heavy launched was in December 2014 when Exploration Flight Test-1 (EFT-1) sent the first spacecraft designed for humans, Orion, beyond low-Earth orbit (LEO) on a test mission.

This booster is currently the world’s highest capacity rocket currently in operation. It can launch up to 63,470 pounds (28,790 kilograms) to LEO and 31,350 pounds (14,220 kilograms) to geostationary transfer orbit (GTO).

It has three Common Booster Cores (CBC) that are 17 feet (5.1 meters) in diameter and 134 feet (40.8 meters) tall. All together with the second stage and payload fairing, the rocket stands 236 feet (72 meters) above the pad.

The three CBCs each sport an RS-68A engine with a sea level thrust of 702,000 pounds (3,100 kilonewtons). The second stage has an RL10-B-2 engine with a thrust of 24,750 pounds (110 kilonewtons).

After NROL-37, the next launch of the Delta IV Heavy isn’t expected to occur until July 2018 when it launches Solar Probe Plus on a mission to study the Sun’s outer corona.


Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.

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