The Falcon 9 rocket carrying a 5,721 kilogram, Boeing-built satellite lifted off at sunset from Cape Canaveral Air Force Station on Friday evening, 6:35 p.m. local time (23:35 UTC). It successfully carried a broadcasting satellite for Luxembourg-based company SES up into space.

Head of the private California-based SpaceX company, Elon Musk, reported the target altitude of 40,600 kilometers (25,227 miles) was achieved. "Thanks @SES_Satellites for riding on Falcon 9! Looking forward to future missions," he tweeted.

But the Falcon 9 rocket crashed when it tried to come back to earth heading for a platform about 645 kilometers from the coast of Florida. The aim was to land the discarded, first-stage booster on to a barge in the Atlantic. Just 10 minutes into the flight, the television camera on the platform cut out. Half an hour later, the company indicated the test was unsuccessful.

"Rocket landed hard on the droneship [platform]. Didn't expect this one to work," Musk wrote on Twitter. "But next flight has a good chance." Usually, rocket boosters just fall into the sea. Musk wants to retrieve and reuse boosters to save time and money.

The launch had been delayed four times since February 24.

Hopes for a successful landing of the rocket back on to the sea platform had been played down by SpaceX because of the speed at which it was traveling: "Given this mission's unique ... profile, a successful landing is not expected," SpaceX said in a statement before the launch.

The company, headed by Internet entrepreneur Musk, is trying to perfect its technique of recycling rocket parts in order to make spaceflight cheaper and more sustainable.

Last December SpaceX managed to land a rocket upright on solid ground, but several attempts at ocean touchdowns have failed.

More than 12 SpaceX flights are expected this year.

jm/bw (AP, Reuters, AFP)