Propulsion provider Aerojet of Sacramento, Calif., test fired an AJ-26 engine May 3 for Orbital Sciences Corp.’s Antares rocket at NASA’s Stennis Space Center in Mississippi.

The full-duration burn was monitored by NASA, Orbital Sciences and Aerojet personnel, Aerojet said in a press release.

Following review of the test data, the engine — the eighth to be tested at Stennis — will be shipped to NASA’s Wallops Flight Facility in Virginia for integration with Orbital’s Antares rocket.

A test firing of Antares’ AJ-26-powered first stage on the launch pad is scheduled for early July. Assuming all goes well, Antares would make its inaugural flight in August. A second flight, currently expected to occur in October or November, would carry Orbital’s unmanned Cygnus cargo tug on a demonstration mission to the international space station.

The AJ-26 is a liquid oxygen- and kerosene-fueled engine based on the NK-3 engine originally designed and built for Russia’s N1 lunar launch vehicle. Aerojet purchased roughly 40 NK-33 engines from Russia in the mid-1990s and, under contract to Orbital, has modified the engines for the Antares rocket.

A total of eight AJ-26 engines have now been tested for Orbital at Stennis.