Ten Years Ago Today: Remembering the Delta IV Heavy and the Rocket That Defined an Era

Ten years ago today, a United Launch Alliance Delta IV Heavy rocket lifted off from Space Launch Complex 37B at Cape Canaveral carrying the NROL-37 mission for the National Reconnaissance Office. It was one of 16 missions the Delta IV Heavy would fly over its lifetime, and for those of us who were there to photograph it, one of the most visually extraordinary rockets ever to leave Florida's Space Coast.

The Delta IV Heavy is gone now. Its final flight came in April 2024, closing the book on a rocket program that traced its roots back 60 years to the earliest days of the American space program. Standing at the pad, the Heavy was unmistakable: three Common Booster Cores strapped together, each burning liquid hydrogen, producing a fireball at ignition that briefly engulfed the lower third of the vehicle before the rocket climbed free. It was, as more than one engineer called it, the most metal thing in the launch business.

The Delta IV Heavy first flew in 2002. Over the course of its operational life it launched some of the most significant payloads in American national security and science history. It carried NASA's Orion spacecraft on its first flight test in December 2014, an unmanned shakedown mission called EFT-1 that put the capsule through the high-speed re-entry conditions it would need to survive on the way back from deep space. It sent the Parker Solar Probe on its way to the Sun in 2018. And it launched mission after classified mission for the National Reconnaissance Office, the agency responsible for America's spy satellite constellation.

All but four of its 16 missions were for the NRO. Most launched from SLC-37B here at Cape Canaveral. A handful flew from Vandenberg in California. Every one of them was a spectacle.

What replaced it is a different kind of rocket, and its path to operational status was harder than ULA anticipated. Vulcan Centaur, designed to replace both the Atlas V and the Delta IV Heavy, flew its second certification mission in October 2024, but a solid rocket booster nozzle fell off mid-flight, delaying Space Force certification by months. Vulcan finally received full certification for National Security Space Launch missions in March 2025. Then, at the end of that year, longtime ULA CEO Tory Bruno departed the company, leaving a leadership void at a critical moment in Vulcan's development. 2025 fell short of ULA's launch projections by most measures.

But Vulcan is flying. It uses Blue Origin BE-4 engines burning liquid natural gas, comes in configurations ranging from no solid rocket boosters to six, and is certified to fly the most demanding national security payloads. It is the primary launch vehicle for Amazon's Project Kuiper broadband constellation, with the first Kuiper launch on Vulcan scheduled for September from SLC-41 at Cape Canaveral. ULA says 2026 and 2027 will be pivotal years for establishing Vulcan's place in a launch market now crowded by Falcon 9, Falcon Heavy, and New Glenn.

Whether Vulcan fills the void left by the Delta IV Heavy depends on what you valued about the older rocket. As a capable heavy lift vehicle, Vulcan makes a credible case for itself. As a spectacle, nothing quite replaced what happened at SLC-37B when those three cores lit up.

We were there for NROL-37 ten years ago today. The photos are in the gallery below.

Photography by Michael Seeley, We Report Space