The date for the latest and final advanced EHF (AEHF-6) satellite to launch from Cape Canaveral Air Force Station, Florida, has been pushed back nearly one week, launch provider United Launch Alliance said.

The current launch date is March 19 at 3:22 p.m., the company has shared. AEHF-6 will be launched on an Atlas V rocket, marking the 83rd Atlas V mission and the 11th with the space vehicle’s 551 configuration.

AEHF-6 was delivered to the 45th Space Wing at the Cape on Jan. 11 via an Air Force C-5M Super Galaxy transport aircraft (Defense Daily, Jan. 13). Its launch will be the first for a Defense Department payload under the newly established U.S. Space Force, officials said at the time.

The latest satellite will complete the AEHF constellation, which was built to augment the U.S. military’s Milstar systems, which have been operational since the early 2000s. Lockheed Martin [LMT] is the prime contractor for Advanced EHF. ULA is a joint launch venture between Lockheed Martin and Boeing [BA].

Meanwhile, Lockheed Martin announced Wednesday that AEHF-5 has completed on-orbit testing and the Space Force’s Space and Missile Systems Center (SMC) has transferred satellite control authority to the Space Operations Command (SpOC) at Schriever Air Force Base, Colorado. The fifth AEHF satellite was launched Aug. 9, 2019 on an Atlas V space vehicle.

“This was very much a team effort from our industry partners and dedicated Government professionals, with their focus on mission success this major milestone was accomplished,” said Col. John Dukes, senior materiel leader, Space Production Corps’ Geosynchronous Orbit Division, in the Wednesday release. “AEHF satellites play a critical role for the warfighter and the defense of our nation. Space is fundamental to our way of life, our economy relies on space and this reliance will continue to grow.”