Astronauts on the International Space Station may have to wait for some supplies because a resupply cargo ship encountered an unexpected snag.

Northrop Grumman's NG-18 Cygnus cargo spacecraft is loaded with four tonnes of supplies, including food, research equipment, and other hardware.

Its launch from Virginia on Monday morning went as smoothly

After disengaging from the rocket it was riding on, its journey to the ISS hit an unexpected snag.

One of the spacecraft's two solar arrays, in particular, failed to unfurl and deploy.

"Northrop Grumman is gathering data on the second array deployment and is working closely with NASA."

Northrop Grumman remains confident that the Cygnus spacecraft can complete its journey with the remaining power — and even stay on schedule.

"Northrop Grumman has informed NASA that Cygnus has enough power to dock with the International Space Station on Wednesday, November 9."