After some technical issues pushing the launch time from 2:04am to 3:28am, United Launch Alliance's Delta IV Heavy rocket called an abort at T-3 minutes just as the engines were getting ready to ignite. The launch vehicle has since been saved at the pad and has all propellants drained out of the tanks. United Launch Alliance teams will be reviewing all of the data from last nights launch attempt and have a minimum recycle time of 7 days to get the rocket ready to liftoff. An issue with a ground system caused the onboard systems to call off the launch to protect the vehicle, pad, and most importantly, the customers payload.
The payload on this mission is a satellite for the National Reconnaissance Office and its purpose and appearance is unknown.