Atlas V on pad for Saturday launch of military satellite

An Atlas V rocket is poised for a 7:07 a.m. Saturday launch of a next-generation military communications satellite from Cape Canaveral Air Force Station.

The 19-story bronze and white United Launch Alliance rocket, bolstered by three strap-on solid rocket motors, rolled from its roughly 300-foot tall Vertical Integration Facility hangar at 6:53 a.m. today and settled on the Launch Complex 41 pad about 30 minutes later.

The mission plans to launch the first Advanced Extremely High Frequency spacecraft, which is designed to handle the most critical military communications even during a nuclear war.

The Lockheed Martin Corp.-built AEHF-1 spacecraft, weighing about 13,500 pounds on the pad, is the first in a nearly $6.5 billion program that will at first augment and then replace the Air Force's aging Milstar constellation of five satellites.

The weather forecast during Saturday's nearly two-hour launch window is very good, with an 80-percent chance of acceptable conditions for launch. There's a chance of isolated showers.

If the launch scrubs because of weather or a minor technical issue, the next attempt would be at 6:59 a.m. Monday, when the forecast is slightly worse.

We'll have live coverage of the countdown here in the Flame Trench starting around 5 a.m. Saturday, including a ULA Webcast scheduled to begin 20 minutes prior to liftoff. Check out more detail on the mission in ULA's Mission Overview.

We'll also be sending text message updates on the status of the launch in the early morning hours -- sign up for them here.

IMAGE: A United Launch Alliance Atlas V rocket with the Air Force’s Advanced Extremely High Frequency-1 (AEHF-1) satellite rolls out to its Space Launch Complex-41 launch pad arriving at 7:25 a.m. EDT today. The launch of the AEHF-1 mission is set for Saturday with a launch window of 7:07-9:06 a.m. EDT. The AEHF constellation of satellites will provide 10 times greater capacity and channel data rates six times higher than that of the existing Milstar II communications satellites. Photos by Pat Corkery, United Launch Alliance.