45th and final Delta IV Weather permitting, the Delta IV Heavy will light up its three hydrogen-fueled RS-68 engines at 1:40 pm EDT (17:40 UTC) Thursday, the opening of a four-hour launch window.

Fiery scenes from a Sept. 24, 2022, liftoff of a Delta IV Heavy rocket. Video by United Launch Alliance The Delta IV Heavy burns ultracold liquid hydrogen, which is a high-performance fuel.

United Launch Alliance teams have set a new target date for the final launch of their Delta IV heavy rocket after a previous attempt was scrubbed late in the countdown last week.

A United Launch Alliance (ULA) Delta IV Heavy rocket is raised vertically at the Space Launch Complex-37 pad in preparation to launch the NROL-70 mission for the National Reconnaissance Office.

Delta IV Heavy, take a bow. From 2004 to 2024, it's been an amazing run. The final launch for United Launch Alliance's powerful rocket is one you won't want to miss. When it launches. At 2:47 p.m ...

The Delta IV Heavy is carrying a classified payload for the National Reconnaissance Office, likely a spy satellite, as part of the NROL-70 mission. In its press materials, ULA described the Delta ...

The Delta IV family of medium-to-heavy launch vehicles made its debut in 2002, and became the closing chapter of the Delta legacy that came to fruition more than 60 years ago.

The Delta IV Heavy is always a spectacular launch thanks to 2.2 million pounds of thrust and an interesting quirk at launch that makes it look like the rocket is on fire. “To me, it is kind of sad.