Atlas V scrubs opening NROL-101 launch attempt

United Launch Alliance’s Atlas V rocket was to carry a National Reconnaissance Office satellite to orbit Wednesday in a launch which also marks a major milestone for the next-generation Vulcan rocket as Atlas V debuts the new GEM-63 solid rocket boosters from Northrop Grumman — the start of a switch away from the Aerojet Rocketdyne boosters. Liftoff was set from Florida’s Cape Canaveral Air Force Station and SLC-41 at 17:54 Eastern Standard Time (22:54 UTC) on Wednesday, 4 November; however, a liquid oxygen tank farm valve at the pad caused an unplanned hold and subsequent scrub to the mission. More

(Source: NASASpaceFlight.com - Nov 5)