Watch The World's Largest Rocket Launch A Top Secret Spy Satellite

We don't know the type or purpose of the new spy satellite being launched by the US National Reconnaissance Office. What we do know is that its launch, aboard the world's largest rocket, is happening today, weather permitting — and it's definitely going to look spectacular. An earlier Delta IV Heavy launch by the NRO, delivering... something? (Image: ULA)

As is appropriate for a super-secret-spy mission, details of the mission are very shadowy. The NRO has described satellite NROL-37 simply as a "national security payload" designed by the NRO, the United Launch Alliance (who builds the Delta IV series), and the Air Force.

NROL-37 Mission Patch (Image: NRO)

They also released this mission patch, which they explained cryptically as a "mission Patch [that] depicts a knight standing in front of the US flag in a defensive posture. The eagle on the chest represents freedom."

Although details on what it will carry are sparse, details on the rocket itself are much clearer. Currently, ULA's Delta IV Heavy rocket is the world's most powerful rocket. When SpaceX's Falcon Heavy rocket gets off the ground this year, though, it will scoop that title away from the Delta IV.

The Delta IV Heavy will be blasting off from Florida's Cape Canaveral Air Force Station. It was scheduled to lift off at precisely 3:59am AEST (weather permitting), but the weather is looking a little dicey, as you can see in this shot below from this morning. With just five minutes to spare, launch control pushed the schedule back to 4:55am AEST, on account of the weather. Another pushback put the launch window to 5:05am AEST, but they missed that one too. There are some fears of a lightning storm in the area. They're hoping it clears up soon and trying and figure out if it can still make it up today.

Update 7:24am AEST: The launch has been rescheduled to 7:58am AEST. Live commentary will resume at 7:48am AEST.

Update 8:05am AEST: With 50 seconds to spare, the launch was called off and re-scheduled, due to weather conditions. It’s set to go back up at 3:51am on Sunday.

You can watch the whole thing right here.

Image: ULA