CAPE CANAVERAL -- 

United Launch Alliance has postponed the launch of an Atlas V rocket from the Space Coast.

After the rocket was rolled the launch pad, an issue with an environmental control system duct that failed near its connection to the Mobile Launch Platform was identified.

The vehicle will be rolled back to the Vertical Integration Facility so the duct can be replaced.

The launch is now set for Wednesday, June 20 from Launch Complex 41 at Cape Canaveral Air Force Station.

The rocket will carry a classified payload into orbit on behalf of the U.S. National Reconnaissance Office