Delta 4 Heavy Readies for Launch Tonight

The weather forecast is excellent for today's planned 7:45 p.m. launch of a Delta 4 Heavy rocket carrying a secret national security satellite.

Meteorologists for the Air Force's 45th Space Wing predict only a 5 percent chance that ground level winds could interfere with the launch. Read the forecast here.

Today at Cape Canaveral Air Force Station's Launch Complex 37, United Launch Alliance workers began rolling back the rocket's 330-foot mobile service tower at 10 a.m.

The Flame Trench will continue to update launch preparations and webcast ULA's live mission broadcast starting around 7:20 p.m.

The broadcast will end less than 10 minutes into flight when the payload's protective shroud breaks away, with no comment on whether the classified spacecraft separates successfully and reaches its intended orbit.

Spaceflightnow.com will report that the satellite, named Advanced Mentor, will be used for electronic eavesdropping.

The mission for the National Reconnaissance Office - the agency that operates the nation's fleet of spy satellites and dubs itself "the nation's eyes and ears in space - will be the third-ever flight by a Delta 4 Heavy, the most powerful American unmanned launch vehicle.

The rocket's first stage consists of three common booster cores strapped together, together generating about 2 million pounds of thrust.

The Delta 4 Heavy's inaugural flight in 2004 was a demonstration that delivered a dummy payload short of its intended orbit. The first and only operational flight to date, in November 2007, was a success.

Check out this Delta 4 product card to learn more about the rockets.

"It's all come togehter with the space systems, the launch vehicle and the ground systems," said Rick Navarro, a senior ULA launch manager, as the service tower rolled back. "From all these perspectives, we're go. Basically what's left to do is clear the area and start the countdown."

IMAGE NOTE: Click on the image to enlarge it. A United Launch Alliance Delta 4 Heavy rests on its launch pad at Cape Canaveral Air Force Station's Launch Complex 37 this morning, after a 330-foot tall mobile service tower was rolled back from the rocket. Photo credit: Mike Brown, Florida Today.