1st Ld: SpaceX launches cargo mission, attempting to land rocket on boat

SpaceX, a private U.S. firm, on Tuesday afternoon launched its sixth cargo mission to the International Space Station and made a second attempt to land the spent first stage of its Falcon 9 rocket on a ship in the Atlantic Ocean.

The California-based company's Dragon cargo ship, filled with more than 4,300 pounds (1,950 kg) of supplies and payloads, lifted off at 4:10 p.m. EDT (2010 GMT) aboard the Falcon 9 rocket from Cape Canaveral Air Force Station in the state of Florida.

But the world may be more interested in the so-called precision- landing of the Falcon 9's first stage, which will be conducted after its separation from the second stage as part of a reusable- rocket test. Endite