Snapshots from Atlas 5 launch

United Launch Alliance early Thursday delayed the launch of a triple-core Delta 4-Heavy rocket — the largest launcher in the company’s fleet — until Saturday to allow engineers more time to resolve an issue with a ground pneumatics control system.

United Launch Alliance ground crews are putting the final touches on a Delta 4 rocket scheduled for blastoff Friday evening from Cape Canaveral with a U.S. Air Force communications satellite.

With the Atlas 5 rocket that will boost it into space now assembled and waiting, a $408 million NASA communications satellite is in final preparations for its science data relay mission.