The Delta 4 rocket that will launch the U.S. military’s highest capacity communications satellite ever built was rolled to the pad this week.

Four astronauts flying on SpaceX’s Crew Dragon “Resilience” spacecraft reached the International Space Station late Monday, one day after launching from the Kennedy Space Center in Florida. The capsule autonomously docked with the space station at 11:01 p.m. EST Monday (0401 GMT Tuesday).

The 75th Atlas 5 rocket rolled to its launch pad at Cape Canaveral on Wednesday, a day before it was scheduled to lift off with a U.S. Air Force satellite to provide warnings of missile launches that might threaten U.S. territories and allies.