WASHINGTON - Orbital Sciences Corp. on Wednesday launches the test flight of an unmanned rocket to the International Space Station, as NASA forges ahead with its plan to privatize US space missions.

The Cygnus capsule, hitched to Orbital Science’s Antares rocket, is set to blast off at 10:50 am (1450 GMT) from NASA’s Wallops Flight Facility, for a Sunday rendezvous with the ISS.

Orbital Sciences is one of just two private US companies enlisted by NASA to carry payloads to the orbiting space station. The other is California-based Space Exploration Technologies, or SpaceX.

Wednesday’s demonstration flight — the first to the ISS by the Virginia-based Orbital Sciences — is meant to show that Cygnus can successfully deliver cargo to the space station.

If the test is successful, it could lead to regularly scheduled missions within months.

NASA is eager to give private industry the job of carrying cargo and crews, in hopes of cutting costs, now that its space shuttle fleet has been retired.

“This is so critical for NASA to continue to resupply the ISS,” said Alan Lindenmoyer, director of the US space agency’s commercial crew and cargo program.

Lindenmoyer said that outsourcing the flights “allows NASA to focus on the more challenging efforts of continuing human exploration deeper into space.”