WASHINGTON — The third in a series of highly secure U.S. military communications satellites is on track to launch Sept. 18 aboard a United Launch Alliance Atlas 5 rocket from Cape Canaveral Air Force Station, Fla.

A two-hour launch window opens at 3:04 a.m. EDT.

The first satellite in the constellation, AEHF-1, was launched in August 2010 but took more than a year to reach its operational orbit due to a propulsion glitch. AEHF-2 joined AEHF-1 in orbit in May 2012. Air Force Col. Rod Miller, chief of the protected milsatcom division at Space and Missiles System Center in Los Angeles, said in a prelaunch conference call with reporters Sept. 10 there have been no issues with the satellites since entering service. 

The satellites are designed to provide assured and highly secure communications links under all conditions, including a nuclear war.  One AEHF satellite is designed to provide more capacity than the entire legacy Milstar constellation.

Lockheed Martin Space Systems of Sunnyvale, Calif. is expected to build a total of six satellites under a contract worth an estimated $9 billion or more, including associated ground systems.

Northrop Grumman Aerospace Systems of Redondo Beach, Calif., provides the satellites’ communications payloads.

The fourth AEHF satellite is expected to launch in 2016 or 2017, Miller said.

Meanwhile, Lockheed Martin announced Sept. 12 the Netherlands became the second international partner to use the AEHF system in July by exchanging voice and data with United States and Canada.

Canada successfully tested the system in May. 

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...