Gallery: Antares rocket explodes

Technicians working at launch pad 0A at NASA’s Wallops Flight Facility in Virginia completed the final loading of cargo into Northrop Grumman’s Cygnus supply ship late Tuesday, and the Antares rocket was raised vertical again in preparation for Wednesday’s countdown.

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).

NASA has ordered four additional launches to deliver cargo to the International Space Station in 2017 — three from SpaceX and one from Orbital ATK — to cover the research lab’s logistics needs until a new set of resupply contracts take effect.