After long delays, ULA’s most powerful missile is preparing to launch a secret spy satellite

After several weeks of delay due to equipment malfunctions and poor weather, the United Launch Alliance is set to launch its most powerful missile from Cape Canaveral, Florida, by launching a secret spy satellite for the National Reconnaissance Office. The mission is finally ready to fly a full month after the first missile launch attempt, which was aborted just three seconds before takeoff.

The missile launched on the ULA mission is the Delta IV Heavy, a gigantic vehicle consisting of three missile cores linked together to provide additional thrust. It is one of the most powerful missiles in the world, although it falls short of the power packed into the Falcon Heavy. ULA does not fly Delta IV Heavy often, as it is an expensive vehicle, but the company does use the missile for large and heavy satellites heading into ultra-high orbits.

The payload of the missile is the NROL-44, and like all NRO missions, its purpose is hidden in secrecy. The office simply notes that “NROL-44 supports the NRO’s overall national security mission to provide intelligence data to top US policymakers, the intelligence community and the Department of Defense.” ULA has already launched 29 missions for the NRO, many of which have required Delta IV Heavy.

ULA was ready to launch NROL-44 in the early hours of the morning of August 29. The ULA is only seconds back before takeoff, with the Delta IV Heavy’s main engines igniting briefly. However, the engines quickly stopped and the missile remained stationary on the launch pad. The ULA later learned that a piece of ground equipment had failed, resulting in a miscarriage. It took the company a few weeks to replace defective equipment.

Other issues with equipment on the launchpad delayed the launch time again, but ULA is hoping to launch this week. Unfortunately the weather was not good, with bad conditions delaying attempts on Mondays and Tuesdays. But finally, there’s a 70 percent chance the weather will team up for the launch tonight – so maybe today is the day.

Delta IV Heavy is scheduled to take off Tuesday at 11:54 PM EST from the ULA launch site at Cape Canaveral Air Force Station. The ULA launch blog will begin at 3:15 PM ET, and webcast will begin at 11:34 PM ET, for anyone still awake and hoping to have a launch in the middle of the night.

Update September 30th, 3:00 pm ET: This post has been updated from an old post, after several launch delays.