WASHINGTON — A May 31 static fire test of the new first stage of Orbital ATK’s Antares launch vehicle should clear the way for that rocket to return to flight in early July.

An Antares first stage, held down on the pad at the Mid-Atlantic Regional Spaceport on Wallops Island, Virginia, fired for 30 seconds at 5:30 p.m. Eastern May 31. The test was designed to verify the performance of the rocket’s RD-181 engines and associated systems, as well as the pad itself.

In a statement, Orbital ATK said that engineers would spend the next several days reviewing the data from the test before declaring the test a success. However, company officials indicated that the test did go as expected.

“Early indications show the upgraded propulsion system, core stage and launch complex all worked together as planned,” said Mike Pinkston, the general manager and vice president of the Antares program at Orbital ATK, in a statement, adding that it “appears to be a successful test.”

Should that ongoing analysis confirm that the test was a success, which may take up to two weeks, Orbital ATK expects to move ahead with plans for the launch of a Cygnus cargo mission to the International Space Station on an Antares. That mission, designated OA-5, would likely launch in early July, although no official launch date has been announced.

The launch will be the first for the upgraded version of the Antares, and the first since an October 2014 failure. That accident was linked to the vehicle’s original AJ26 engines, refurbished Soviet-era NK-33 engines supplied by Aerojet Rocketdyne. Orbital announced shortly after the accident it would discontinue use of the AJ26 engines, selecting RD-181 engines provided by Russian company NPO Energomash.

Orbital ATK noted that each newly-manufactured RD-181 goes through extensive acceptance testing. In addition, one engine went through seven test firings, accumulating 1,650 seconds of run time before being inspected. “The successful stage test, along with the extensive testing of each new RD-181, gives us further confidence in the first stage propulsion and in moving forward to launch,” Pinkston said in the statement.

The first stage tested on the pad will not be flown on the July flight, but will instead be inspected and reconditioned for another Cygnus launch to the ISS, designated OA-7, scheduled for the fall. Orbital ATK said the Antares that will launch the OA-5 mission in July is in the final stages of integration and testing at Wallops.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...