The launch of US Air Force’s (USAF) Advanced Extremely High-Frequency- 6 (AEHF-6) communication satellite has been delayed due to technical issues.

United Launch Alliance (ULA) said that its Atlas V rocket was supposed to carry the satellite into space on 19 March. The mission ‘is now scheduled for no earlier than 21 March’.

According to ULA, an off-nominal valve reading was observed during launch vehicle processing.

In an update, the company said: “Additional time is needed for the team to replace and retest the valve.”

The Atlas V rocket will take off from Cape Canaveral Air Force Station Space Launch Complex-41, Florida, US.

The launch will be done on behalf of the US Space Force Space and Missile Systems Center.

This step will mark the launch of the final AEHF secure military communication satellite into an optimised geosynchronous transfer orbit.

The AEHF satellite system has been manufactured by Lockheed Martin Space Systems and is operated by the US Air Force (USAF).

The system comprises a series of six military communication satellites, which will replace the currently in-orbit Milstar system.

The Atlas V 551 rocket is being assembled at Cape Canaveral’s Vertical Integration Facility (VIF).

The newly developed final AEHF satellite of the mission includes a 3D printed remote interface unit.

The fifth AEHF system was launched last year on 8 August from Cape Canaveral Air Force Station on board ULA’s Atlas V rocket.