WASHINGTON — SpaceX on Monday successfully test-fired its Falcon 9 rocket in a dress rehearsal for the May 7 launch of its Dragon spacecraft on a cargo-bearing mission to the International Space Station.

The test, known as a static fire of the rocket's nine main engines, lasted just two seconds, but allowed engineers to "run through all countdown processes as though it were launch day," SpaceX said on its website.

The test-fire took place at Cape Canaveral Air Force Station in Florida, after a brief delay due to a problem with one of the flight computers, which had set an improper limit for the rocket firing.

The glitch was fixed within about an hour and the countdown resumed.

"Success -- two second burn!" SpaceX tweeted after the test-fire sent billowing white smoke into the air around the gleaming white rocket.

"Engineers will now review data as we continue to prepare for the upcoming mission."

SpaceX aims to be the first private company to send its own spacecraft to the orbiting research lab, a capacity that only Russia, Japan and Europe can currently handle since the US shuttle program ended last year.

The Dragon spacecraft has also been built to carry humans to space, and the company, owned by Internet entrepreneur and PayPal co-founder Elon Musk, hopes that a successful cargo trip to the ISS will soon lead to a manned mission.

"Woohoo, rocket hold down firing completed and all looks good!!" Musk tweeted after the test.

On May 7, the gumdrop-shaped Dragon capsule will carry 1,149 pounds (521 kilograms) of cargo for the space lab and will also aim to return a 1,455-pound load to Earth, NASA has said.

The launch is scheduled for 9:38 am (1338 GMT).

SpaceX made history with its Dragon launch in December 2010, becoming the first commercial outfit to send a spacecraft into orbit and back.

SpaceX and several other companies are competing to be the first to operate a private capsule that could tote astronauts and cargo to the ISS.

Russia's Soyuz capsule is currently the world's sole means of transporting both astronauts and cargo to the orbiting space station.

Other companies in the private space race include aerospace giant Boeing, the Nevada-based Sierra Nevada Corporation and Washington state-based BlueOrigin LLC.

NASA has channeled $270 million to firms hoping to join the new commercial space race and hopes to foster a billion-dollar industry over the next decade.