Accomplishing a crucial test before its scheduled launch next week, SpaceX's Falcon 9 rocket fired nine main engines for three-and-a-half seconds Saturday morning, briefly ramping up to nearly a million pounds of thrust while the booster was firmly held to the ground.

The Falcon 9 rocket's main engines fire at 10:50 a.m. EST Saturday. Credit: SpaceX

The successful test firing occurred at 10:50 a.m. EST (1550 GMT) at Complex 40 in Cape Canaveral, Fla.

SpaceX issued a two-sentence statement on the company's website and Twitter account.

"Full duration static fire! We'll continue to review data but today's static fire appears to be a success," the company said.

No other details were available Saturday night.

The Falcon 9 rocket's nine Merlin first stage engines were expected to ignite for 3.5 seconds, reaching full power for at least 2 seconds before shutting down in a simulated abort.

Four swing arms at the base of the 154-foot-tall rocket held the vehicle on the launch pad as steam and exhaust streamed out of a flame trench on the east side of the complex. The event was webcast on SpaceX's website, and the company released the preliminary result of the test less than a half-hour later.

The test came at the end of several hours of countdown preparations, including filling of the rocket's two stages with a full load of propellant.

SpaceX aborted two engine firing attempts, first due to a high engine chamber pressure reading Friday, then because of a low gas generator pressure Saturday morning. Both issues were in Engine No. 6.

The plans to launch the Falcon 9 rocket as soon as Tuesday. Backup launch opportunities are available Wednesday and Thursday.

The launch window each day opens at 9 a.m. EST and closes at 12:22 p.m. EST (1400-1722 GMT).

The mission is SpaceX's first test flight under NASA's Commercial Orbital Transportation Services program, which aims to develop private spacecraft to deliver cargo to the International Space Station after the retirement of the space shuttle.

NASA has agreements with SpaceX and Orbital Sciences Corp. to design and test new launch vehicles and robotic cargo freighters.

Tuesday's launch will place the Dragon spacecraft in a 186-mile-high orbit, where it will demonstrate propulsion, navigation, computer and communications systems for about three-and-a-half hours, according to SpaceX.

The unmanned capsule will plunge back to Earth, deploy parachutes and splash down in the Pacific Ocean off the coast of California. SpaceX is deploying a recovery team to the landing zone to retrieve the spacecraft.

After at least one more test flight, the Dragon spacecraft will fly 12 operational cargo resupply missions to the space station beginning as soon as late 2011. SpaceX holds a $1.6 billion contract with NASA for the flights, but the deal could be worth up to $3.1 billion if all options are exercised.

The Dragon spacecraft is also a candidate for NASA's commercial crew program to carry astronauts to and from the station beginning in three to five years.