The first of three Inmarsat-5 Global Xpress (GX) satellites being built by Boeing has completed a key system life test, paving the way for it to launch later this year.

The satellite performed as expected during the spacecraft thermal vacuum test, which simulated the cold, airless vacuum of space.

"We remain focused on continuing to complete crucial milestones to successfully deliver this series of satellites," said Craig Cooning, vice president and general manager of Boeing Space and Intelligence Systems.

"The Inmarsat-5 series is built on our 702HP model of satellites, which is flight-proven with over 20 spacecraft in orbit."

When operational, the Inmarsat-5 satellites will support Inmarsat's Global Xpress network, the world's first high speed, mobile broadband service, providing vital data connectivity for government and commercial users on land, at sea and in the air.

The two remaining satellites, which will complete Global Xpress' global coverage, are currently in production at Boeing's Satellite Development Center.