CAPE CANAVERAL, Florida – Space Exploration Technologies fired up the engines of its debut Falcon 9 rocket on Tuesday, a key milestone in its quest to fly cargo -- and eventually astronauts -- to the International Space Station.

The engine firing occurred at the privately owned company's Cape Canaveral, Florida, launch site, where the Falcon 9 rocket is being prepared for a company-sponsored demonstration flight this spring.

Results of the engine test, which had been expected to last about 3.5 seconds, were not immediately available. Flames and small puffs of smoke could be seen around the base of the rocket via a NASA video camera.

The rocket is perched on a refurbished oceanside launch pad at Cape Canaveral Air Force Station, just south of the space shuttle launch pads at the Kennedy Space Center.

Space Exploration Technologies, a California-based company known as SpaceX, is owned and operated by Internet entrepreneur Elon Musk. It is building launch vehicles and spacecraft to take over the job of delivering cargo to the space station, which has up to now been government-run.

It holds NASA contracts for 15 Falcon 9 flights -- three test flights and 12 cargo resupply missions to the space station -- worth about $1.9 billion.

Options for additional flights would boost the cargo-delivery contract to more than $3 billion.

President Barack Obama, who plans to hold a summit on space in Florida next month, wants to add $6 billion to NASA's budget over the next five years to spur development of space taxis that can transport astronauts to and from the space station.

With the retirement of the space shuttle fleet later this year, NASA already has turned over station crew transportation to Russia, which charges the United States about $51 million per seat for rides on its Soyuz rockets.