Is anyone ready to see a heavy-lift rocket fly? Especially one that creates a giant fireball seconds before launch?
United Launch Alliance’s largest booster, the Delta IV Heavy, has not been launched since January 2019. Now the big rocket — the world’s second most powerful launch vehicle after SpaceX’s Falcon Heavy — is back on track to lift a classified payload for the National Exploration Agency.
The launch of this “NROL-44” mission is scheduled for Thursday at 2:12 a.m. EDT (06:12 UTC) from Space Launch Complex-37 at Cape Canaveral Air Force Station. The weather forecast for the launch is favorable, with only a minor concern about a chance of violating the cumulus cloud rules. Forecasters predict an 80 percent chance of good weather at the launch opportunity.
The mission was originally supposed to take place a day earlier, but United Launch Alliance postponed it for a day, with just a simple statement that it had been moved “due to customer request”.
Consisting of three common booster cores, the Delta IV Heavy can lift nearly 29 tons to low Earth orbit. It has flown 11 times since its largely successful debut in December 2004. It’s expensive, costing several hundred million dollars per launch, but before the Falcon Heavy, it was the only rocket capable of delivering heavy payloads to the military’s toughest jobs. In addition to the military manifesto, the rocket has also launched two missions for NASA, a demonstration flight of the Orion space capsule in 2014 and the Parker Solar Probe in 2018.
After this launch, the rocket will be able to fly again as early as October with a new classified mission. Including Thursday morning’s launch attempt, there are only five missions left before the Delta IV Heavy rocket retires. United Launch Alliance plans to replace it with the more cost-competitive Vulcan rocket, which will debut in late 2021 or early 2022.
The company’s webcast of the launch, embedded below, begins Thursday at 1:52 a.m. EDT (05:52 UTC).
List image by Trevor Mahlmann