Video: Liftoff of Atlas 5 on NROL-55

Northrop Grumman’s launch team aborted an Antares rocket launch from Virginia’s Eastern Shore minutes before liftoff Sunday evening. The rocket is set to loft a Cygnus cargo freighter toward the International Space Station with nearly four tons of supplies and experiments.

In a significant milestone preparing for liftoff of the world’s most powerful rocket, SpaceX test-fired 31 of the booster’s 33 methane-fueled engines Thursday in South Texas as the company eyes a launch attempt as soon as March.

A SpaceX Falcon 9 rocket lifted off from Vandenberg Air Force Base in California at 10:34 a.m. PST (1:34 p.m. EST; 1834 GMT) Monday. The launch, under contract to Spaceflight, carried into orbit 64 small satellites from 17 countries, the largest multi-payload rideshare mission ever flown on a U.S. rocket. The Falcon 9’s first stage booster previously flew on two missions from Florida, and landed again on a drone ship in the Pacific Ocean after Monday’s launch.