Video: Liftoff of Delta 4 with WGS 7

SpaceX’s next Falcon Heavy mission, set for April 18 from NASA’s Kennedy Space Center in Florida, will launch a powerhouse bus-sized broadband satellite for Viasat into a high-altitude circular geostationary orbit, a demanding flight profile that will require disposal of all three of the rocket’s reusable boosters.

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.

Riding the rails to the launch pad Wednesday morning, the Atlas 5 rocket was rolled out to Cape Canaveral’s Complex 41 for liftoff Thursday night to deploy four NASA satellites that will probe Earth’s magnetosphere for a high-priority research project.