A SpaceX Falcon 9 rocket lifts off from Cape Canaveral, Fla., early Jan. 10, carrying a Dragon cargo spacecraft to the ISS. Credit: NASA

Updated at 2:00 p.m. EST.

WASHINGTON — A SpaceX Falcon 9 rocket successfully launched a Dragon cargo spacecraft to the International Space Station early Jan. 10, but an effort to land the rocket’s first stage on a ship in the Atlantic Ocean was only partially successful.

The Falcon 9 rocket launched from Cape Canaveral, Florida, at 4:47 a.m. EST and placed the Dragon spacecraft into low Earth orbit ten minutes later. The Dragon berthed with the ISS early Jan. 12.

SpaceX halted a previous launch attempt on Jan. 6 less than 90 seconds before liftoff because of a problem with an actuator on the thrust vector control system in the rocket’s upper stage. That actuator was subsequently replaced. A problem with a static fire test of the rocket’s nine first stage engines postponed an earlier attempt in December.

Dragon is carrying almost 2,400 kilograms of cargo for the ISS. That cargo ranges from food for the station’s crew to an earth sciences experiment that will be mounted outside the station to several CubeSats that will later be deployed from the ISS.

NASA officials said prior to the Jan. 6 launch attempt that they were relying on SpaceX more than ever to support the ISS while Orbital Sciences Corp. recovers from the loss of a Cygnus cargo spacecraft in an Oct. 28 Antares launch failure. The next Cygnus mission, launched on a United Launch Alliance Atlas 5, is not planned until the fourth quarter of 2015.

SpaceX also used the launch for another test of its efforts to make the Falcon 9’s first stage reusable. The company planned, after the first stage separated, to land it on an “autonomous spaceport drone ship” in the Atlantic Ocean several hundred kilometers downrange from the launch site.

That test, though, was only partially successful, according to initial reports. “Rocket made it to drone spaceport ship, but landed hard,” SpaceX chief executive Elon Musk tweeted. “Close, but no cigar this time.”

Musk added that the ship itself was in good condition, but that some support equipment on it will need to be replaced. Video of the landing attempt was not available because of darkness and foggy conditions, he said.

In a series of tweets later Jan. 10, Musk said it appeared that “grid fins” mounted on the stage ran out of hydraulic fluid before landing. The stage uses those fins, along with gimbaling of the engines, to steer towards landing.

Musk said that an upcoming launch will have 50 percent more hydraulic fluid, “so [it] should have plenty of margin for landing attempt next month.” SpaceX spokesman John Taylor said Jan. 15 that SpaceX would make a landing attempt on its next Falcon 9 launch, of the Deep Space Climate Observatory spacecraft, which is currently scheduled for launch from Cape Canaveral on Jan. 29.

Dragon is scheduled to depart from the station on Feb. 10 and return to Earth with more than 1,650 kilograms of experiments and other station cargo.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...