WASHINGTON — It took two tries, but Space Exploration Technologies Corp. (SpaceX) successfully test-fired all nine engines comprising the first stage of its Falcon 9 rocket April 30 in preparation for a scheduled May 7 demonstration flight in which the vehicle will launch the company’s Dragon cargo capsule toward the international space station.

“Engineers will now review data as we continue preparations for the upcoming launch,” SpaceX spokeswoman Kirstin Grantham said in a statement emailed to the press after the test was completed.

The 2-second hot-fire test took place on SpaceX’s launch pad at Cape Canaveral Air Force Station in Florida. The liquid-fueled engines ignited at 4:15 p.m., about an hour later than scheduled.

The countdown for the first attempt was halted around 3 p.m. when the “flight computer aborted [the] rocket hold down firing,” Elon Musk, SpaceX’s founder and chief executive, said via Twitter.

SpaceX of Hawthorne, Calif., holds a $1.6 billion contract to fly supplies to the international space station. Before it can begin those deliveries, the company must complete a final demonstration flight in which Dragon is scheduled to approach and then berth with the station before returning to Earth.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.