SpaceX achieved another space industry first yesterday when it launched a Falcon 9 rocket that has flown before, a key step in billionaire entrepreneur Elon Musk's quest to cut the cost of space flight.

The rocket blasted off at around 6.30pm EDT (10.30pm GMT) from the Kennedy Space Center in Florida to deliver a communications satellite into orbit for Luxembourg-based satellite operator SES SA .

Musk's SpaceX, formally known as Space Exploration Technologies Corp, made history in December 2015 when it landed an orbital rocket for the first time, a feat it since has repeated seven times.

By reusing rockets, SpaceX aims to cut its costs by about 30 per cent, the company has said. It lists the cost of a Falcon 9 ride at $62 million but has not yet announced a price for flying on a used rocket.

Proving the concept works is crucial to SpaceX, which is moving on from an accident in September that damaged another Florida site.

SpaceX also is working on a passenger spaceship, with two unidentified tourists signed up for a future trip around the moon. The company's long-term goal under founder Musk is to fly people to and from Mars.

For its 33rd mission, SpaceX is reusing a Falcon 9 booster that originally flew in April 2016.

After sending the SES-10 satellite on its way to orbit, the rocket's first-stage turned around and landed itself on an ocean platform. SpaceX could fly the booster a third time, said company spokesman John Taylor.

The rocket's second-stage, which is not recovered, continued firing to carry SES-10 into an initial egg-shaped orbit high above Earth. It will provide TV and other communications services to Latin America.