Watch the Falcon 9 launch from pad 39A

Orbital ATK and SpaceX won Pentagon contracts worth a combined value of up to $241 million Wednesday in public-private partnerships crafted to hasten the U.S. military’s move away from Russian-supplied propulsion to deliver national security satellites to orbit.

This will be the 50th Dragon vehicle to visit the International Space Station, including the Dragon 1 vehicles that were berthed to the orbiting lab. Docking with the Harmony module is anticipated Monday, Aug. 25, at 7:30 a.m. EDT (1130 UTC).

Northrop Grumman called off the launch of an Antares rocket and a Cygnus space station cargo freighter Thursday night on Virginia’s Eastern Shore, the third aborted countdown in less than 24 hours for three different U.S. rockets.