Efforts to troubleshoot and resolve an issue with the top-secret national security satellite to be carried aloft by a Delta 4-Heavy rocket has slipped the launch into the New Year.

File photo. Credit: Boeing/Carleton Bailie

The United Launch Alliance booster sits atop Cape Canaveral's pad 37B in preparation for the NROL-26 mission, which will deploy the clandestine payload into orbit for the U.S. National Reconnaissance Office.

No public information is available about the satellite or the problem delaying the launch.

Once targeted for flight in May, the highly complex launch involving the mammoth booster and a cargo undoubtedly sophisticated has been pushed back several times. This most recent snag caused officials to scrap a December 16 launch date.

It was decided this week that the launch would be rescheduled to January, thereby giving engineers sufficient time to analyze the trouble and develop a solution. In addition, the new plan will avoid ground crews working through a launch campaign over the holidays.

A new formal launch date has not been established, though officials are hoping for a mid-January opportunity.

This Delta 4-Heavy rocket was rolled out to the launch pad at the end of March. Several pages of photography from earlier in the year are available:

• Panoramas inside the hangar
• Vehicle before rollout
• The trip to pad 37B
• Rocket goes vertical

The Delta 4-Heavy is created by taking three Common Booster Cores -- the liquid hydrogen-fueled motor that forms a Delta 4-Medium's first stage -- and strapping them together to form a triple-body rocket, and then adding an upper stage.

It will be the third launch of the Heavy. A test flight was conducted in December 2004, followed by the first operational launch last November that delivered a missile-warning satellite into orbit for the U.S. military.