Gallery: Antares rocket explodes

A commercial Cygnus supply ship left the International Space Station on Monday after delivering more than 5,000 pounds of cargo and experiments, ready to start a week of standalone operations to include a groundbreaking microgravity fire experiment and deployment of four commercial weather-monitoring CubeSats in orbit.

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 sixth commercial cargo delivery by Orbital ATK’s Cygnus spacecraft, and the first using an Antares rocket since a launch failure in 2014, will carry more than 5,000 pounds of equipment to the International Space Station.