A Delta IV rocket launch of a top-secret satellite from Vandenberg Air Force Base has been delayed until January.
United Launch Alliance officials said Wednesday that the the Dec. 13 launch of the Delta IV Medium rocket has been postponed to allow more time to conduct tests.
Liftoff now is planned for no earlier than Jan. 10 from Space Launch Complex-6 on South Base.
The extra time will allow the team to conduct additional validation on software and systems associated with the new avionics gear, ULA said.
“Common Avionics is a newly designed suite of avionics, flight software and ground systems that will fly on both Atlas V and Delta IV,” ULA officials said in a written statement.
“This upgraded command and control system was designed to reduce cost and improve reliability.”
The upcoming mission, dubbed NROL-47, will be the first flight of the Common Avionics system on Delta IV.
The vehicle and spacecraft remain stable, ULA officials added.
The rocket is set to carry clandestine cargo for the National Reconnaissance Office.The launch period will not be released until the departure date nears.
A delay for Delta means a Falcon rocket planned for December may be the only launch of the month from Vandenberg, and the last of the year.
That mission involves lifting another 10 Iridium Next communication satellites to space and marks the fourth set to fly in 2017.
Liftoff is planned for 5:32 p.m. Dec. 22 from Space Launch Complex-4.
In all, SpaceX has been hired to conduct eight missions to deliver 75 Iridium Next satellites, with the launches planned every two months.
A total of 81 satellites are scheduled to roll off the Arizona assembly line, with 66 serving as the operational satellites to replace the existing Iridium network, officials said.
The remainder will serve as spares, some positioned in space and others waiting on the ground to be called into service.
The replacements for the first-generation Iridium satellites that mostly launched from Vandenberg will continue to allow satellite phone and other communications around the globe.