LOS ANGELES - After successfully delivering a U.S.-European ocean-monitoring satellite into orbit, a SpaceX rocket made a hard landing on a floating barge in the roiling Pacific, breaking a support leg and toppling over.

SpaceX announcers said the first stage of the Falcon 9 was not upright after reaching the 300-by-170 foot landing pad in choppy seas about 200 miles west of San Diego on Sunday.

The rocket launched as planned at 10:42 a.m. from Vandenberg Air Force Base, northwest of Los Angeles, streaking through a cloud-filled sky before eventually sending its second stage and a Jason-3 satellite into orbit.

The failed landing was a setback for the Hawthorne, California, company's plan to reduce launch costs by reusing rockets rather than having them fall into the ocean. Meteorologists predicted swells of 10- to 13-feet where the barge waited for the landing attempt.

SpaceX founder Elon Musk said on Twitter that the rocket's speed at touchdown was OK, "but a leg lockout didn't latch, so it tipped over after landing."

Two previous attempts to land a rocket on a barge in the Atlantic failed, but last month SpaceX succeeded in returning a rocket to a vertical landing at Cape Canaveral, Florida, after putting a cluster of satellites into orbit.