Gallery: Antares rocket explodes

The first pair of RD-181 rocket engines set to launch on Orbital ATK’s redesigned Antares rocket are in the final stages of acceptance testing in Russia ahead of their export to the United States in early July, officials said.

The mission, dubbed NG-20, marks the first of three planned flights of Cygnus aboard a Falcon 9 rocket. Liftoff occurred at 12:07 p.m. EST (1707 UTC).

Watch the post-launch news conference from the Kennedy Space Center following the successful launch of an Atlas 5 rocket on December 6, carrying the Orbital ATK Cygnus cargo ship bound for the International Space Station.