Top-Secret Mission To Launch Tuesday Night

A giant Delta IV Heavy rocket is scheduled to blast off next Tuesday night with a top-secret payload, and the Air Force today released a five-hour launch window that narrows in on the time the behemoth booster will be taking off.

Now nestled within its mobile service tower at Launch Complex 37 at Cape Canaveral Air Force Station, the rocket will be thundering aloft between 7 p.m. and midnight Tuesday. All indications now are that the T-zero time will be not too long after the opening of that window -- possibly around 7:45 p.m. The Air Force and the National Reconnaissance Office are expected to release the scheduled launch time on Monday.

The Delta IV Heavy will carry a classified payload into orbit for the NRO, the super-secret organization that owns and operates the nation's constellation of spy satellites.

Those include photo and radar reconnaissance satellites, electronic eavesdropping spacecraft, ocean surveillance satellites as well as orbiters that relay imagery and data back to Earth.

You can watch the launch live here in The Flame Trench. We'll be broadcasting live coverage from United Launch Alliance, a joint partnership of Lockheed Martin and Boeing that was formed to launch U.S. government satellites, including pyaloads for the NRO, the Department of Defense, NASA and the National Oceanic and Atmospheric Administration (NOAA).

The launch coverage will begin about 25 minutes before liftoff and continue through the time the rocket's payload fairing is jettisoned. The NRO will not release any information on the status of the mission after that time, and there will be no pre-launch or post-launch news conferences.

The U.S. Air Force 45th Space Wing is warning mariners to stay out of a Launch Hazard Area off the coast of Cape Canaveral between 5:45 p.m. Tuesday and 12:45 a.m. Wednesday.

You can check out a map of the danger zone here: Delta IV Launch Hazard Area.

Officials with the Air Force's Eastern Range will clear the area prior to launch to make certain mariners are not exposed to falling debris in the event of an explosive failure early in flight.

People entering the danger zone during between 5:45 p.m. Tuesday and 12:45 a.m. Wednesday can be fined up to $250,000 and jailed for up to six years.

ABOUT THE IMAGE: Click to enlarge the Air Force image of the inaugural Delta IV Heavy launch in December 2004. You can also click the enlarged image to get an even bigger view. The first launch was a flight demonstration that failed to place its dummy payload in the intended orbit. The launch Tuesday will be only the third for the Delta IV Heavy. A Defense Support Program missile-warning satellite was successfully deployed on the second flight in November 2007.