BREVARD COUNTY, Fla. — Update: With only seven seconds to go, the launch of the Delta IV Heavy rocket carrying the NROL-44 mission for the National Reconnaissance Office (NRO) was scrubbed Wednesday night.

The launch had previously been scrubbed for Tuesday.

Read our previous story:

Update: The Delta IV Heavy rocket carrying the NROL-44 mission for the National Reconnaissance Office (NRO) has been scrubbed due to weather, ULA announced Tuesday a few hours ahead of the launch.

The launch has been rescheduled for 11:54 p.m. Wednesday

Read our earlier story below:

The Delta IV Heavy rocket carrying the NROL-44 mission for the National Reconnaissance Office (NRO) is set to launch from Cape Canaveral at 11:58 p.m. from Space Launch Complex 37.

It’s an instantaneous launch window, meaning that if it doesn’t launch exactly at that time, the post will have to be rescheduled for a later date.

This mission’s launch has been postponed several times since its original launch schedule in late August. One of the times the engines ignited, and the 235-foot-tall rocket’s launch was aborted quickly after.

PHOTOS: Rocket launches from Central Florida

This mission was scrubbed during the weekend and most recently on Tuesday, September 28, due to weather. These delays have had a cascading effect on the other launches that were supposed to happen from our backyard this week.

“Well, if it’s an NRO mission, they don’t get any more important for our national security purposes,” said Dale Ketchum of Space Florida. “They are very likely the most expensive payloads we put up there. But they can also count the hairs on the people we want to keep an eye on.”

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This is a classified payload of the National Reconnaissance Office, which oversees U.S. spy satellite operations. All we know is that the payload might likely be a U.S. spy satellite.

Since this is a top priority launch, the Heavy rocket needs to take off before any other launches take off this week.

For Wednesday’s night, the mission has a 40% chance of a “go”, mainly due to weather.

There is a cold front pushing through tonight which is bringing a higher than normal chance for showers and isolated storms overnight.

This will be 141st mission for the United Launch Alliance and the 29th mission for the NRO. This will also make the 12th Delta IV Heavy launch and 8th Heavy for the NRO.

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Delta Rockets have been launched since 1960 and this would make the 385th launch since then.

You can watch the rocket launch live on WFTV.com and the WFTV news app.

The science behind the sonic booms Lots of research going on at the Cape and more frequent launches will make these sounds more common.

Follow our Severe Weather team on Twitter for live updates:

• Chief meteorologist Tom Terry
• Brian Shields
• Irene Sans
• Kassandra Crimi
• George Waldenberger
• Rusty McCranie

Cox Media Group