ULA’s most powerful rocket is about to launch a secret spy satellite for the U.S. NRO.

United Launch Alliance (ULA) plans to launch its most powerful rocket at Cape Canaveral, Florida, due to equipment failure and bad weather,media reported. It is reported that after the first launch of the rocket a full month later, the mission is finally ready to fly. The first launch failed three seconds before launch.

ULA's most powerful rocket is about to launch a secret spy satellite for the U.S. NRO.

The rocket in charge of the ULA mission is Delta IV Heavy, a huge launch vehicle that provides extra thrust from the core of three bundled rockets. Although it is less powerful than SpaceX’s Falcon Heavy rocket, it is still one of the most powerful rockets in the world. ULA doesn’t often launch Delta IV Heavy because it’s an expensive vehicle, but the company uses it to launch large, heavy satellites into ultra-high orbit.

It is understood that the rocket’s payload this time is NROL-44, as with all NRO missions, its purpose is to keep secret. The office said only that the NRO-44 supports the NRO’s overall national security mission and provides intelligence data to senior U.S. policy makers, intelligence agencies and the Department of Defense. To date, ULA has performed 29 missions for NRO, many of which have been performed with Delta IV Heavy.

The Delta IV Heavy rocket is scheduled to launch tuesday at 11:54 p.m. EST from the ULA launch site at Cape Canaveral Air Force Station. ULA’s launch blog will begin at 3:15 p.m. EST and the webcast will begin at 11:34 p.m.

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