Billionaire Elon Musk's company SpaceX launches 64 satellites at once

SpaceX has launched its Falcon 9 rocket, sending an unusual payload into space -- 64 satellites at the same time, a US record.

And the company headed by US tech billionaire Elon Musk marked another milestone on Monday in its bid to make rockets more re-usable, like airplanes: the blast-off used a recycled booster for the third time.

California-based SpaceX has landed more than 30 of these boosters back on Earth, and has begun re-using them on subsequent missions.

In the past, companies have typically allowed rocket parts costing many millions of dollars to fall like junk into the ocean.

Monday's landing of the first stage was flawless, like many before it.

Several minutes after liftoff, the tall, white portion of the rocket -- known formally as the first stage -- separated from the second stage.

The booster then fired its engines and made a controlled, upright landing on a platform in the Pacific Ocean, video from SpaceX's live webcast showed.

Meanwhile, the second stage pressed deeper into space, carrying 15 micro-satellites and 49 CubeSats belonging to 34 different clients including public, private and university sources from 17 different countries including South Korea, France and Kazakhstan.

The launch was chartered by a company called Spaceflight, which specialises in space "rideshares," or putting multiple satellites on the same rocket.

Microsatellites weigh a few dozen pounds (kilograms) and CubeSats are even smaller.

The satellites will be placed into orbit over the next several hours.

Not all the clients have scientific missions.

The Nevada Museum of Art sent up a sculpture called "Orbital Reflector" by artist Trevor Paglen.